GPS World

Author: Tony Murfin

  • Drone developments: Avionics, fuel cells and swarms

    The first year I was at the Association for Unmanned Vehicle Systems International (AUVSI) convention in 2012 (well before it became Xponential) in Las Vegas, Nevada, I spent a lot of time looking for any exhibitors who were thinking of business in commercial unmanned aerial systems (UAS).

    At that time, the U.S. military had not yet suffered the major budget cuts that were to shortly impact extensive military development and use of UAS. So, asking around UAS developers at the AUVSI conference as to when they might think of applying their systems to commercial applications, and the potential changes that integration in the U.S. National Airspace System (NAS) might require … Well, there wasn’t much interest.

    I often heard the response that the Federal Aviation Administration (FAA) was so far away from allowing commercial UAS operations in the U.S. that it just wasn’t worth even considering what would be required.

    In the years that followed, it has been somewhat refreshing to see the tone and shape of the annual AUVSI convention shift towards the commercial world. And with U.S. Federal Aviation Administration (FAA) regulations now in place for sUAS, and with continuing growth in commercial and developmental operations, it’s clear that a good part of the industry is looking toward the civilian market. Not to say that military UAS development is lagging far behind, but it now seems that we have the prospect of a somewhat more balanced civilian/military marketplace for UAS.

    Now, we not only have regularized commercial operations under FAA regulations, we are also hearing more often that Beyond Visual Line of Sight (BVLOS) UAS applications are being developed and modes of operation are being established.

    ADS-B (automatic dependent surveillance – broadcast) now appears to be one of one of the prevalent systems that BVLOS applications depend on, since the FAA is implementing ADS-B throughout the U.S., and it’s recognized as a likely component of increased-range UAS operations.

    Avionics for Drones

    uAvionix in California focuses on equipment aircraft, offering transponders and sensors for integration into UAS and for manned aricraft. Their latest ADS-B offering is a small, lightweight, low-power transponder for unmanned aircraft. Power consumption is low enough to be powered by battery pack for 2 hours, yet is powerful enough to provide visibility to other aircraft and UAVs up to 200 miles away, and uAvionix recently achieved U.S. Federal Communications Commission (FCC) approval for this unit. The ping200S is designed to meet the requirements of TSO-C199 as a Class A Traffic Awareness Beacon System (TABS).

    When integrated with a suitable ADS-B GNSS receiver, such as the uAvionix pingNAV GNSS sensor, a UAS would become compatible with the ADS-B system — a significant step towards BVLOS operations. An ADS-B-equipped aircraft can detect and locate other aircraft and warn them of its precise position. The FAA has mandated that all aircraft operating in the NAS be ADS-B equipped by 2020.

    PingNav is a small, light and low-cost ADS-B OUT compliant navigation source that supports GPS/QZSS, GLONASS, Galileo and Satellite Based Augmentation Systems (SBAS) and has a battery backup for quicker position initialization. The unit also has dual static ports for pressure altimeter readings and includes integrated security and integrity technologies, including Receiver Autonomous Integrity Monitoring (RAIM).

    U.S. Department of Transportation Report

    Meanwhile, the U.S. Department of Transportation (DoT) recently issued its final “Beyond Traffic 2045” report. The report discusses anticipated air, rail and road transportation challenges in the coming years.

    UAS issues mentioned included drone delivery, noting that Google, Amazon and DHL have been evaluating use of unmanned aircraft for several years. Remotely piloted drone deliveries may shortly provide high value and/or urgent cargo to hard-to-reach locations; delivery of medical supplies in remote areas following a natural disaster has already been demonstrated.

    Nevertheless, deliveries by drone in highly populated areas will require higher levels of security and safety and will have to overcome privacy risks, so it will likely take longer to verify these capabilities.

    Anti-Drone Systems Forecast

    Forecasts for growth of the drone market are already reaching heady proportions — one forecast expects sales to reach US$127 billion by 2020! But now the global anti-drone market is being forecast to reach US$1.14 billion by 2022. Maybe having lots of anti-drone systems preventing drone operations could slow down the growth of drone business itself?

    Drones in the wrong hands are seen as a possible threat to our security systems, so detection and disabling drones is now becoming a requirement to support those security systems. Growth of the anti-drone market is being driven by more frequent security breaches by unidentified drones and by the use of drones for terrorist activities.

    Fuel-Cell Power Drone

    EnergyOr Technologies in Montreal, Canada, has been successful in developing and fielding compact fuel-cell products targeted at the growing drone market. Its EPOD fuel cell is the source of power for its H2QUAD 1000 drone, selected by French Air Force’s Centre d’ Expertise Aérienne Militaire (CEAM) for development testing under a Joint Development Agreement (JDA). The JDA is aimed at advanced development of long-endurance UAVs powered by EnergyOr’s fuel-cell system technology.

    But what do you do when your fuel-cell-powered drone runs out of juice? For battery-powered drones, it’s easy to take them home and plug them in to recharge them, but their useful range and endurance is somewhat limited. So EnergyOr came up with a recharging system for its fuel cells — just hook up your tired drone to a portable hydrogen recharging set-up and you’re good to go again.

    EnergyOr’s H2QUAD 1000 is a fuel cell powered
 quadrotor UAV capable of carrying a 1 kg payload 
for more than two hours, which is around four times longer
 than battery-powered UAVs. The turn-key solution includes a Ground Control Station (GCS), gimbaled 4K camera, portable hydrogen filling station and data acquisition/diagnostic system, as well as onsite operator training and engineering support.

    Military Swarms?

    Lastly, it appears that the U.S. military is taking on the challenge of using swarms of low-cost semi-autonomous UAVs for reconnaissance. During a full-scale test in October 2016, a swarm of 103 UAVs were deployed from three F/A‐18 Super Hornets over China Lake, California.

    The “Perdix” (Greek mythology character who was turned into a partridge) swarm UAV was originally developed by MIT. It has two sets of wings with a 3D printed plastic body, a small rear-mounted propeller, is battery powered and carries a small camera. Perdix software has been refined considerably and is now sixth generation and has external update capability.

    More than 670 have been flown, and the Department of Defense plans soon to produce them in batches of 1,000 — which might be a good thing, since they only have an endurance of around 20 minutes. Deploying drones from a fast jet can be a problem, but Perdix is now able to withstand the buffeting and turbulence from release speeds of Mach 0.6 and temperatures of -10° C.

    After release, the swarm drones communicate with each other and perform formation flying exercises similar to a surveillance mission. But the swarm doesn’t precisely know how it will undertake a given task before it’s released — so each drone communicates and works with other drones, without a specific leader, and can readily adapt to drones joining or leaving the team.

    To sum up, BVLOS advances using commercially available ADS-D avionics for drones, DoT planning for anticipated integration into U.S. national airspace (albeit warning that it may take more than anticipated for Amazon and others to eventually make deliveries using UAVs), growth in anti-drone systems keeping in step with the explosion in the market for drones, hydrogen fuel-cell powered drones, and military drone-swarms for surveillance. There is a lot going on in the developing UAV/UAS market sector.

    Tony Murfin
    GNSS Aerospace

  • When inertial can help with GNSS solutions

    When inertial can help with GNSS solutions

    A number of organizations are focusing on how inertial can help GNSS receivers to provide more stable, reliable position outputs when signals are hard to receive. Papers presented in September at the ION GNSS+ 2016 conference in Portland, Oregon, demonstrate that there is indeed a lot of focused effort in this area.

    The conference showcased several integrated inertial GNSS solutions from a range of companies. For example, NovAtel is developing a novel way to make better use of lower precision MEMS inertial for certain land applications. Qualcomm is moving forward with a low-cost visual inertial to advance autonomous vehicle developments. And researchers in Germany from a university spin-off company are studying a multi-sensor solution.

    Inertial integration aiding

    Many people have heard about the NovAtel SPAN inertial/GNSS system. SPAN inertial-integration-aiding software has now been available integrated on NovAtel GNSS engines for a number of years. Combined with various external inertial packages providing real-time inertial aiding data, this system enables positioning outputs over a wider range of more difficult signal environments where GNSS alone might be too stressed to perform well.

    According to the website, NovAtel currently offers SPAN with MEMS inertial products including various models from Honeywell, Litef, Analog Devices and Sensonor, along with a number of fiber-optic and high-precision tactical grade inertial measurement units (IMUs).

    Recent SPAN development efforts have been focused on improving the performance of combined GNSS/SPAN/MEMS IMUs. The premise of the work is that in land-vehicle applications, a “land profile” can be applied that constrains velocity based on a range of acceptable vehicle dynamics. This includes applying limits to the cross track and vertical velocities of the vehicle.

    In testing this land model, with equipment mounted in the NovAtel test van, three types on IMU were run through three different test scenarios. The IMUs were:

    • Epson G320 — Low power, small size MEMS IMU
    • Litef μIMU-IC — Larger tactical-grade performance IMU still based on MEMS sensors
    • Litef ISA-100C — Near-navigation-grade IMU using fiber optic gyros (FOG).

    The three test scenarios involved environments with clear sky, partially obstructed sky view (downtown urban canyon) and a parking garage with no view of the sky and no satellite signal reception.

    The Epson MEMS IMU appeared to be at a disadvantage from the beginning, given the higher performance units to which it was being compared. But NovAtel’s objective was to demonstrate that even this lower end device, when combined with GNSS, SPAN and the land profile, enables pretty good positioning results.

    The tests indicated that positioning with integrated higher performance units did not benefit to the same extent as when coupled with the low-end MEMS units in land-profile mode. Acceptable positioning was indeed possible with the Epson MEMS and when the constraints of land profile were able to limit position excursions when GNSS was lost, as in the parkade tests at Calgary airport shown in the figure above.

    Ryan Dixon and Michael Bobye from NovAtel Inc. wrote this ION GNSS+ paper, “Performance Differentiation in a Tightly Coupled GNSS/INS Solution.” Ryan Dixon is the chief engineer of the NovAtel Synchronized Position Attitude Navigation (SPAN) GNSS/INS products, and Mike Bobye is a principal geomatics engineer at NovAtel Inc.

    Visual inertial odometry

    Qualcomm also presented some interesting results for the integration of visual inertial odometry (VIO) with GNSS. VIO measurements are constructed from a stream of camera frames combined with inertial measurements and can provide high-accuracy relative positioning. In experiments in a not-too-severe urban-canyon environment, this approach has been seen to reduce 95 percent horizontal error by two-thirds compared to GPS alone.

    For applications such as autonomous vehicles and advanced driver assistance systems (ADAS), 50-meter errors, which can be typical for stand-alone GPS in urban canyons, just won’t cut the mustard. So Qualcomm has been looking for another source of aiding that would help reduce errors significantly.

    The test set-up used a Sony Xperia Z3 phone as the source for the camera data and separate VIO processing, along with a single-frequency CSR SiRFstarIV GPS module on a custom hardware board for raw pseudorange and Doppler range-rate measurements. A high-precision NovAtel OEM6 GNSS/IMU SPAN-CPT module was used as ground-truth for position measurements.

    Two scenarios were used to evaluate the proposed approach. The first scenario is an 870-meter drive in downtown Somerville, New Jersey, with a duration of 261 epochs. This represents a mild urban-canyon environment with loss of signal errors of a few tens of meters.

    (Left) Part of the trajectory for the drive testing; (right) walk through building with no GPS coverage.
    (Left) Part of the trajectory for the drive testing; (right) walkthrough building with no GPS coverage.

    Results from the drive testing include several large GPS errors that the GPS+VIO solution is able to significantly reduce, while the walkthrough building tests appear to demonstrate a continuous GPS+VIO position solution.

    “Robust Positioning from Visual-Inertial and GPS Measurements” was written by Urs Niesen, Venkatesan N. Ekambaram, Jubin Jose, Lionel Garin, and Xinzhou Wu, all of Qualcomm Research.

    Multiple sensors

    Finally, researchers at the Technical University of Munich (TUM) in Germany have focused on bringing outputs from as many sensors as economically feasible into an integrated GNSS solution. A precise model for multipath is included that applies amplitude, code delay, phase shift and Doppler shift for each reflected signal. The magnetometer measurements provide rough attitude information, which enables robust GNSS attitude ambiguity fixing.

    This research has led to the release of an integrated product by a European Space Agency (ESA) incubator company, Advanced Navigation Solutions (ANavS).

    The ANavS module integrates a multi-constellation u-blox GNSS receiver with a Sensonor 3D accelerometer/gyroscope/magnetometer, a Bosch barometer/thermometer and a built-in dual-band Taoglas GPS/GLONASS antenna. Real-time kinematic (RTK) positioning was tested by TUM students using the measurements from the multi-sensor module and a virtual reference station (VRS). A second multi-sensor module placed on the rear of the vehicle enabled attitude determination.

    “Reliable RTK Positioning with Tight Coupling of 6 Low-Cost Sensors” was authored by Patrick Henkel, Technische Universität München, and Houcem Hentati, Advanced Navigation Solutions, Munich, Germany.

    All of these options are providing GNSS with the support it needs in tight signal situations.

  • UAV Update: Fuel cells, Droneboxes and hostile drones

    We might have thought of fuel cells in the past coming from historical problems way back on Apollo 13, or more recently in connection with advanced hybrid cars. But now it seems they are one source of long endurance flight for UAVs. Not really a surprise when there are claims of energy levels of 1000 watt/hour per kilogram versus 150 Wh/kg for lithium batteries.

    H3 Dynamics in Singapore has released its Hywings UAV, for which it claims up to 10 hours endurance, provided by the on-board fuel cell. The UAV can carry a high-definition camera, a FLIR thermal camera with data storage and a multispectral imaging camera used for the inspection of agricultural fields.

    Dronebox and quadrotor UAV
    Dronebox and quadrotor UAV

    Dronebox is another H3 innovation designed to enable regular, repeatable, autonomous inspection and remote sensing missions from a field-located drone system.

    Dronebox and quadrotor UAV

    Droneboxes enable autonomous takeoff and landing of a quadrotor UAV from a remote base. When the UAV automatically lands on the base, rapid contact charging is initiated to “refuel” for the next mission. Power is derived from built in solar-collection panels and from conventional “mains” power.

    Drone missions may be scheduled on a regular basis for routine flights to monitor facilities, or be dispatched automatically by an alarm. Data collected by the UAV is downloaded and may be processed and delivered to a client over a cloud service.

    Mindful that not all drone operators are of the friendly kind, more UAV detection, location and disabling systems are being developed and fielded. Elbit Systems in Israel has just unveiled what it calls “a unique solution for protection of closed air spaces, national infrastructures and other critical areas against hostile drones.”

    ReDrone is designed to detect, track and take-out different types of drones using a wide range of RF transmissions. The system can distinguish between a drone’s signals and its operator’s control signals, as well as determining the direction of both the drone and the operator. The system operates over 360 degrees, providing real-time situational awareness of multiple, simultaneous drones within the protection area.

    After detecting a target, the ReDrone system disrupts the radio and video communication between the UAV and the operator, and jams or spoofs the GPS data, sending the hostile UAV off track and preventing an attack.

    Meanwhile, General Atomics — the manufacturers of the venerable Predator military UAV — may be seeking to enhance its civilian image by offering one of its company owned aircraft for humanitarian relief efforts. The Angel One is based on the jet-powered Predator-C Avenger UAV, which is apparently able to carry significant internal cargo. Up to 8,500 pounds of Humanitarian Daily Ration packets (HDRs) for 3,400 people can be delivered by Angel One to ensure that urgently needed food and medical supplies quickly reach victims of war or natural disasters around the world.

    Angel One can fly up to three missions of three hours each day — so, for a mission to deliver aid to a place like Syria, the base of operations would need to be overseas. An internal cargo bay door release mechanism enables two separate drops of aid per mission. The drop area is then evenly distributed with aid packages, ensuring greater delivery success for people in need on the ground over traditional pallet drops, which can be damaged or lost entirely.

    And good news for family visitors to Orlando and California entertainment parks: Disney has obtained a waiver from the Federal Aviation Administration (FAA) to allow them to fly drones over their theme parks.

    Disney World and Disneyland have no-fly zones, which were put in place in 2003 before war with Iraq. Disney cited those zones in its waiver request, saying their UAVs “will not interrupt national airspace activity.” Disney asked for the FAA OK last year to fly drones at their parks for entertainment displays, including fireworks displays — the waiver now allows Disney Flixel drones to fly at night. In granting the request, the FAA told Disney that it had established adequate mitigation for risk — probably including flying mostly over water at a maximum height of 150 feet while remaining at least 100 feet away from any visitors.

    Finally, AeroVironment in California, who may be better known for its military UAS offerings, has decided to make a run at the commercial market. AeroVironment makes the Raven hand-launched system, which is the most widely used unmanned aircraft system in the world today. They also have a suite of different UAS for various types of applications.

    Photo: The AeroVironment Quantix

    The AeroVironment Quantix is a vertical takeoff and landing quadrotor drone that transitions to horizontal flight after take-off, providing the benefits of fixed-wing aircraft range, reliability and efficiency. Controlled via software on an Android tablet device using one-touch planning and launch, collected data after flight may subsequently be processed within the AeroVironment Decision Support System (AV DSS). This cloud-based data analytics platform incorporates a high level of automation backed by extensive research, using key algorithms to deliver processed results.

    Available by spring 2017, this UAS system is aimed at allowing users to improve operational efficiencies, minimize risk and increase profitability.

    AeroVironment’s commercial Quantix UAV airborne.
    AeroVironment’s commercial Quantix UAV airborne.

    To plan a mission, the operator traces a finger on a map on the tablet to establish an area of interest. The system then guides the operator through an automated pre-flight check of the vehicle and flight plan. Selecting “fly,” Quantix performs a detailed built-in test procedure, optimizes its flight path for maximum coverage, launches, and lands vertically when its mission is complete. On-board color and multispectral sensors gather data over hundreds of acres. The system also includes “land now” and “return home” safety-control features.

    AeroVironment’s DSS then processes stored flight data to produce high-resolution datasets and analysis of agriculture fields and vineyards, bridges, railroad tracks, pipelines, roads and many other valuable assets — cloud-based storage enables archiving of large amounts of image data for historical trend analysis.

    In summary, we have fuel cells on UAVs that make for extended flight time, and remote “drone depots” for automated, recurring inspection systems, another drone detection and disabling system, a Predator available to dispense humanitarian aid, Disney ready to run Flixel light displays at its theme parks, and another UAS defense contractor turning to the commercial market with a complete UAS monitoring, inspection and data processing solution.

    Just a small sample of what’s showing up in the unmanned aircraft system market segment.

  • Why tether drones? Plus: Trimble divestiture, Intel expansion, ISIS

    Why tether drones? Plus: Trimble divestiture, Intel expansion, ISIS

    I’ve always thought that tethered drones would have a major disadvantage over regular flying vehicles, in that their range is really limited and therefore their applications would be few and far between. However, a recent release by Drone Aviation got me thinking otherwise.

    The company is taking the route many tech companies have followed to protect their technology and enhance their market position, by patenting unique technical elements — in this case, the Electric Tethered Aerial Platform (ETAP) technologies of their drone tether system.

    So why the change of heart about tethered drones? The drone industry is becoming increasingly specialized in its offerings, so why not drones and aerostats with the advantage of no detectable uplink or downlink transmissions, which can also stay aloft for 8+ hours? You might even load the base into a truck and move the area of operations around. Maybe more use to the military for somewhat covert reconnaissance missions, but Drone Aviation indicates that applications such as newsgathering, law enforcement, infrastructure and pipeline inspections, and event management would also benefit from longer endurance drone operations.

    Anyway, someone thinks this is a good idea, because Drone Aviation was just awarded a $400,000 contract by a “U.S. Department of Defense (DoD) customer” for WAAT electric tethered drones, plus complete in-field support packages and operator flight training.

    drone_inspectionAnd don’t forget those ads currently running on TV with dual operators inspecting oil refinery stacks using a free-flying six-rotor drone — maybe BP would also feel somewhat safer avoiding potential refinery-stack collision damage if the video inspection drone were to be tethered?

     

    Trimble and 3D Robotics Divest

    One of the hot-news items of the month has to be that Trimble has divested its UAS mapping business that it bought from Gatewing in Belgium in 2012. Having worked in this sector for the last four years, Trimble decided to concentrate on core software technology for UAS that integrates positioning, remote sensing and photogrammetry.

    Delair-Tech in Toulouse, France, has acquired the Trimble UAS business for undisclosed terms. Delair is already a supplier of long-range, fixed-wing UAS solutions for industrial inspection and asset management applications, and intends to grow the acquired business by joining the Trimble UAS business to its existing portfolio of airborne mapping solutions.

    Trimble has not entirely disconnected from its UAS business — rather, it has also formed a strategic alliance with Delair-Tech as a preferred provider of fixed-wing UAS solutions, with Trimble providing software, data processing and deliverables to UAS operators across multiple vertical markets. To ensure full segment coverage, Trimble has also joined up at the same time with Microdrones in Siegen, Germany, an existing provider of multi-rotor UAS solutions, under another preferred-supplier strategic alliance. Both Delair-Tech and Microdrones will support Trimble distributors to provide UAS mapping solutions for Trimble’s customers around the world.

    It’s easy to guess that Trimble may have found that directly competing in this emerging airborne mapping market to be harder than it looked, with many existing capable UAS operators and a market that is perhaps developing more slowly than expected. So stepping back to focus on its core competences and selling what it does best should cost less and allow it to address all airborne operators, rather than competing with all of them. Not a pattern that Trimble may have followed closely in the past as it entered more and more market segments, but one that might let it more easily pick winners in the UAS segment.

    And for 3D Robotics in Berkeley, California — the company that was seen as the U.S. supplier of drones at one time with its Solo and 3DR drones systems — it, too, is out of the UAV platform manufacturing and supply business. In just 12 months, the company has gone from the height of being an industry-leading drone startup to dumping its drone products. As a consequence, 3D Robotics has laid off more than 150 people and spent a good part of its initial funding.

    Poor sales at the beginning of the year and highly competitive drone products, mostly from DJI, have forced a move away from consumer drones. Initial production problems may have also doomed the launch of its commercial drone products.

    3D Robotics CEO Chris Anderson flying solo.
    3D Robotics CEO Chris Anderson flying solo.

    Although 3D Robotics might be up against the ropes, it is retrenching and, like Trimble, is focusing on the development of software and service applications. CEO Chris Anderson has declined to discuss his company’s financial situation, but has said that 3D Robotics is now solely focused on enterprise software.

    ISIS Flies Explosive Drones

    An unwelcome use of UAVs has now unfortunately emerged in Iraq. Kurdish forces fighting ISIS in northern Iraq last week shot down a small drone. They believed it was just one of many commercially available drones, such as the DJI Phantom, which have been seen flying reconnaissance missions, so they picked it up to transport it back to their outpost to examine it.

    Unfortunately, the drone had been rigged with on-board explosives disguised as a battery, and the device exploded, killing two. Of three known such drone attacks in Iraq, only this one has apparently caused casualties. There was only a small amount of explosives, but it was enough to kill. There may be several known existing systems that can be used to defeat such attack drones, but the equipment needed has not yet reached this war zone.

    Intel Extends Its Presence

    On a much happier note, while Trimble and 3D Robotics are getting out of UAVs, Intel is extending its UAS market presence with the launch of an improved Falcon 8+ system, now marketed for the first time under the Intel name.

    Intel Falcon 8+ octocopter drone.
    Intel Falcon 8+ octocopter drone.

    The UAV has full electronic system redundancy with redundant batteries, redundant communication between critical flight components and redundant aerial sensing. A triple-redundant autopilot uses three redundant inertial measurement units (IMUs) that compensate for environmental issues like strong electromagnetic fields or winds, and the vehicle also carries high-precision GPS.

    The Intel Falcon 8+ is aimed at industrial inspection, surveying and mapping, and is geared toward professionals and expert use. The system is capable of detailed images with millimeter accuracy and can provide structural analysis that helps users detect and therefore prevent more damage to infrastructure. Structural inspections can be run time and time again to monitor for wear and tear, as this UAV has repeatable waypoint navigation capability.

    Mock Medical Delivery

    Exploring another opportunity where the use of drones may improve life for the rest of us, UPS and CyPhy Works recently demonstrated the delivery of medical supplies to an island off Marblehead, Massachusetts.

    ups_medical_delivery_uavDuring the mock delivery, the Persistent Aerial Reconnaissance and Communications (PARC) UAS flew from Beverly, Massachusetts, to Children’s Island, about three miles off the coast, delivering an asthma inhaler to a child. UPS is investigating the use of drones for the delivery of humanitarian aid around the world, and at home is also testing drones to verify their warehouse stock.

    And finally, Heliceo in Nantes, France, has come up with the DroneBox, which contains most of the electronics you might need for a drone of your own making, or you could also buy one of Heliceo’s several complete drone models and systems built around the DroneBox.

    Heliceo’s patented solutions are available to suit both plane and multi-rotor drones. The unit contains GNSS RTK receivers, an autopilot, telemetry, data storage, communication, a flight controller and avionics. The DroneBox RTK is a “technology concentrator,” and with its 24-million-pixel camera is capable of detecting a coin from around 500 feet. Heliceo claims that its integrated solution can contribute up to 70 percent of the value of the entire drone.

    The box is equipped with two GNSS receivers (one for navigation and one for Trimble RTK measurements), and the camera is optimized by a calibration process that corrects optical lens aberrations. Each acquired image is recorded with its latitude, longitude and altitude, which allows the subsequent creation of georeferenced 2D scaled maps or 3D digital terrain models.

    So several steps forward for various UAV/UAS initiatives, some things from which we can still learn, and maybe a couple of steps back for a fledgling industry facing inevitable consolidation. But at this stage, it’s good to see there is still enough investment and enthusiasm to take on a wide range of opportunities. Some will fail, some will succeed, and the winners will hopefully find ways to further improve our way of life and hopefully make money in the process. And for goodness sake, let’s get some new or existing anti-drone solutions out there soon for U.S. troops and their allies.

    Tony Murfin
    GNSS Aerospace

  • What does ION GNSS+ reveal about the GNSS industry?

    What does ION GNSS+ reveal about the GNSS industry?

    Back again in Portland, Oregon, the 2016 Institute of Navigation’s ION GNSS+ conference was a great opportunity for the GNSS community to catch up on what’s been cooking in the industry, and of course who’s been doing what in the research community.

    The attendees eagerly took to a wide range of technical paper presentation sessions, and from time to time came to take a look at what industry had to offer on the exhibit floor. Lots of engaging research reports, from work undertaken over the last year by academia, again drew a significant number of attendees from around the world.

    On the other hand, industry continued the trend to go to trade shows in application sectors and pull back somewhat from ION GNSS+ as a place to look for product sales. So the number of companies on the ION show floor remained around the same or maybe a little less than in the previous few years. Nevertheless, the quality of the companies exhibiting remained high and there were some interesting newcomers.

    A number of major GNSS receiver manufactures have pulled back from ION, so there were only two established U.S. companies and two new U.S. entrants at the show. On the other hand, GNSS simulation companies were at ION in force — eight all told, or twice as many as the receiver manufacturers present who have been their historic customers. But the trend in GNSS simulation now appears to be to move down stream towards the needs of integrators and systems outfits — in segments such as automotive, UAV and agriculture — with lower cost, very capable simulators.

    Receiver makers roll out new tech

    As a consequence, the NovAtel and Septentrio booths got a lot of attendee traffic, while BDStar (Unicore receivers and Harxon antennas) and ComNav also had a number of visitors to their booths. As usual, NavTech, who represent almost all the manufacturers, also had a busy exhibit.

    OEM7600 dual-frequency receiver.
    OEM7600 dual-frequency receiver.

    NovAtel chose to launch its OEM-7 series of GNSS receivers and a newly designed VEXXIS high-precision antenna at ION GNSS+, which is a somewhat refreshing return to the ION GNSS+ launch platform we used to see in the past. A new highly integrated ASIC at the heart of this receiver now provides, amongst other features, 555 channels, L-band support, inertial SPAN capability and an intriguing “Interference Toolbox”. The toolbox enables integrators to localize interference effects over a wide band — especially helpful for densely packed electronics, which you might expect in a UAV, for instance.

    Interference Toolbox Screenshot.
    Interference Toolbox Screenshot.

    Septentrio didn’t have a whole lot of new product announcements, but as usual the company has been working hard at improving existing capabilities on its receivers. The AsteRx4 receiver that uses a new ASIC has been available for a while, but it too boasts 544 channels — perhaps too many to actually be used in practice — robust heading, centimeter-level RTK and decimeter-level PPP (with TerraStar and Veripos corrections) with dual L-band channels, and an improved suite of advanced interference mitigation (AIM+) capabilities. This helps detection and removal of the effects of “chirp jamming” from low-power “cigarette-lighter” jammers — using signal analysis and adjustment of adaptive notch filters.

    Septentrio did announce a new PolaRx5TR packaged time-and-frequency transfer receiver and a contract with the Jet Propulsion Laboratory (JPL) for reference stations and timing. A report by UNAVCO also found its way into my inbox, which related comparative testing of the PolaRx5 and other manufacturers’ receivers in connection with a UNAVCO RFP – Septentrio did O.K. and was selected as a preferred vendor, which no doubt influenced the JPL award and added to an already good first half year for the company.

    The Septentrio PolaRX5TR.
    The Septentrio PolaRX5TR.

    BDStar had a range of GPS, GLONASS, Beidou receivers from its subsidiary Unicorecomm, along with an impressive selection of antennas from Harxon, another of its Chinese subsidiaries. Both product lines have done very well in the Chinese market, and BDStar would like to sell more in North America.

    ComNav also displayed a similar range of GNSS receivers and antennas, with new versions of both since last year, and a strong desire to break through into the US market.

    Simulators a big presence

    Simulator companies at ION included the more established Spirent, Spectracom, CAST, IFEN and Rohde & Schwarz — we could even now consider RaceLogic/LabSat as a record-and-playback fixture in the market. But in the wings and making lots of waves at the show were Syntony from France and Skydel from Montreal, Canada.

    Spirent brought its usual large-scale GNSS simulators to ION, but also featured an interference detection and software analysis suite, a 16-bit high-fidelity record/playback unit, along with a new multi-frequency simulator aimed at downstream integrators. The GSS200D Detector finds interference effects and is able to relate them to the threats in the environment around a receiver. The object is to help debug an installation by finding internal interferers. The analysis tools can also help differentiate between regular equipment interference and potential external jammers.

    Spirent's new GSS200D detector.
    Spirent’s new GSS200D detector.

    Spirent also displayed a record/playback unit that has 16-bit playback capability, enabling a user to record and review a particular interference event, and then feed their new commercial simulator in order to replicate the interference. So a passing isolated jamming event can be analyzed in detail. Multiple reruns are possible to confirm the effect on the target system, and following equipment modifications, prove that the problem has indeed been neutralized.

    Spirent analysis tools.
    Spirent analysis tools.

    RaceLogic introduced its new wideband LabSat 3 record/playback system for GPS L1, GLONASS L1, Galileo E1, BeiDou B1, QZSS and SBAS. Recording live signals for any or all of these signals then allows later playback of a canned sample for equipment debugging on the bench. The LabSat product line has been around for some time, and this addition increases the debug capability for downstream users at an affordable price in a very portable format. When used with the RaceLogic SatGen software system, the user has access to a powerful toolset for testing new GNSS devices.

    labsat-real-time-w
    LabSat 3 and SatGen test set-up.

    Spectrcom displayed its multi-frequency, multi-constellation simulator and also featured a GNSS vulnerability test system for interference detection and system debugging. The company’s approach requires two simulators, both synchronized by an atomic clock, allowing a PC-based Test Scenario Control to generate reproducible interference effects for debugging.

    CAST Navigation is already moving downstream quite quickly with its CAST-SGX handheld GNSS simulator. With a touchscreen display, this simplified L1 GPS simulator (with P-code option) is ideal for test-bench debugging.

    Rohde & Schwarz had its usual array of high-end test equipment, with a test set-up aimed at demonstrating testing of a Wi-Fi indoor location application on a smartphone.

    rohdeschwarz-test-slide

    IFEN showed up with a completely re-engineered simulator with huge frequency/channel capacity. The Titan GNSS Simulator houses up to 8 RFSIM modules, each of which carries 32 configurable satellite signals. A fully configured Titan chassis can therefore provide 256 channels of GPS L1/L2/L5, GLONASS G1/G2/G3, Galileo E1/E5/E6, Beidou B1/B2/B3, IRNSS L5 and S-band, QZSS L1/L2/L5/LEX and all current L1/L5 SBAS signals. Titan also has up to four independent RF outputs.

    IFEN Titan GNSS Simulator.
    IFEN Titan GNSS Simulator.

    Skydel is one of the newcomers in GNSS simulation, but has made significant inroads first appearing last year at ION. Skydel now boasts a full-up, reconfigurable GPS, GLONASS, Galileo, Beidou “software” simulator which the company claims to sell at a 1/3 the price of a conventional hardware simulator. And during the year, Skydel teamed up with Talen-X in Ohio, who have embedded Skydel software-defined in a U.S.-sourced GPS/GLONASS/Galileo/Beidou simulator that can include GPS P/Y and M-code.

    Broadsim from Talen-X powered by Skydel.
    Broadsim from Talen-X powered by Skydel.

    Syntony rises high by going under (the ground)

    The noise in simulation at ION was, however, created by Syntony from Toulouse in France. Syntony recently won a 15-simulator order from OneWeb — the outfit that plans to launch a 640 internet connectivity satellite constellation through 2020. With funding secured from Virgin Group and Qualcomm in 2015, initial satellite build is underway at Airbus Defence and Space, launch services are contracted with Arianespace to provide 21 multi-sat launches on Soyuz beginning in 2017 with optional launch service with Virgin Galactic. So Syntony is likely going to be able to build, deliver and be paid for its 15 simulators, which will be used for testing GPS capability that is integrated into each comms satellite.

    Syntony 128-channel GNSS Simulator "Constellator."
    Syntony 128-channel GNSS Simulator “Constellator.”

    Syntony’s simulator is also software-defined and is reconfigurable. The software-defined heart of this system comes from a Syntony GPS/Galileo receiver, and a version of this receiver has now been sold for use in the Airbus Adeline re-usable space module. This receiver is a “multi-antenna receiver” in order to avoid signal or tracking loss while switching between antennas during the Safran launcher rotation. The catch here is that Syntony must develop this receiver to Airbus critical airborne software=qualification standards — no mean feat! Syntony is also providing a version of its Constellator simulator for testing this multi-antenna input receiver.

    An ECHO record/playback system is also available, which includes high-fidelity 16-bit RF outputs.

    Finally, Syntony was able to capture a proof-of-concept location infrastructure project for Stockholm, Sweden’s, underground metro. The metro stations are pretty deep underground, as they have been dug under the sea in and around Stockholm, and no one had been able to come up with a system that would enable emergency 911 calls with associated essential localized position information to be carried from within the stations. Syntony was able to provide a GPS-like signal infrastructure at the stations which is compatible with GPS-enabled smartphones. It worked well, and Syntony verified that there was no radiation of the signal outside any of the entrances to the test station — so no GPS interference. It actually worked so well that Syntony got the contract to equip all 50 metro stations in Stockholm, and the Syntony is now working to spread its system around the metros of all major cities, worldwide.

    Defining the Galileo PRS signal…

    Then I came across Fraunhofer towards the end of the show, and their posters about a Galileo PRS (Public Regulated Service) receiver. Now, we know that there has been significant discussion between the different security services of countries across the European Union, and its taken a lot of time to get to a definition of the PRS signal and who has access. So it wasn’t surprising that there was no hardware on the Fraunhofer booth; what’s surprising is that there was any mention of such a receiver being available and telling attendees at a conference in the U.S. that it’s available.

    I talked to a couple of people at their booth, and indeed there is such a receiver, but they really couldn’t tell me anything about it because telling is strictly verboten! Another strange anomaly of the Galileo program — the participants seem to want to let the U.S. know that they have the capability for a special access service, and a receiver is available to work with it, but they can’t tell us anything about it. I guess the idea may be to rattle the cage of the U.S. P-code/M-code guys, and let them know Galileo has caught up at last… But Fraunhofer has an idea of how to make things available to, well, err …. to somebody. They have a concept to have cellphone users who want PRS to connect with their cloud receiver, and they will decode and provide PRS position back over the internet. That solves the whole security thing…. OK, that should do it.

    Where inertial stands

    I also made the rounds of the inertial and inertial/GPS guys at the show, and there were quite a few. From Northrop Grumman and Systron Donner and their mil-spec high-end FOG and RLG and Quartz MEMS tube-shaped inertial units — could they be for shells or missiles? — to Silicon Sensing’s MEMS accels and gyros and their move out of automotive and towards high-precision performance, to Sensonor’s high-performance commercial MEMS/GNSS units, there were actually only a few of the inertial-aiding outfits present. Yet everything we hear is that for anything that moves, we really should use integrated inertial/GNSS, and UAVs especially want lots of that! So this part of the business looks to be quite healthy too…

    Now another ION GNSS+ conference has come and gone — and I was reminded that maybe I’ve actually been to 95 percent of the ION September conferences over the last 30 years. And as I write, the last of the late Friday paper sessions are crawling to a close.

    ION still remains a good place to come and learn, a place to meet industry colleagues and a place to see a little of what industry is up to. Definitely worth the trip, and don’t forget your business cards next year.

    Tony Murfin
    GNSS Aerospace

  • Unmanned update: Government and industry join to resolve issues

    Unmanned update: Government and industry join to resolve issues

    The White House has joined in to support continued growth of the emerging unmanned aerial vehicle (UAV) industry. Unmanned aircraft systems (UAS) technologies are powering a revolution in unmanned flight.

    Already used by government, by research organizations, and by industry for more efficient and safe applications, drones are now becoming a developing part of the United States economy. A new initiative by the Office of Science and Technology Policy (OSTP) brought together 150 UAS community leaders for a recent workshop at the White House. The event was held to find out more about the UAS industry, where it’s headed, and to seek ideas for how government might contribute.

    Given that the current administration has only limited time remaining, the group proposed some significant issues that could be launched, or at least where there should be focus. The only short-term goal that could be achieved by the end of the year is the release by the Federal Aviation Administration (FAA) of a Notice of Proposed Rulemaking for UAV operations over people.

    One principle objective should be for the Federal Communications Commission (FCC) to develop rules in concert with industry for licensing allocated frequency spectrum. While the FAA has yet to develop rules for higher altitude, larger-UAV operations, the UAS industry requires spectrum for command and control of aircraft at high altitudes and for beyond visual line of sight operations. The FAA and FCC regulations should be developed in parallel.

    The group felt another problem that should be tackled is UAS Traffic Management (UTM). While NASA has been investigating prototype UTM options and various industry leaders have been advocating a number of different approaches, the group seemed to indicate that unless government took some form of leadership role, a number of different, incompatible solutions might be developed.

    Finally, there was discussion about how a number of states are implementing local UAS regulations, while the FAA believes it has responsibility for all U.S. airspace. However, large numbers of small UAS (sUAS) are expected to operate at lower altitudes, so local authorities believe they should assert more control, even though they were comfortable in the past ceding control of manned aviation to the FAA. However, nationwide, uniform safety regulations appear to be just as critical for UAS as for manned aircraft, which seems to imply that the FAA should lead the effort.

    So, some good issues were identified that need serious work to enable UAS operations, but it’s always a problem when someone else gets stuck with the responsibility to find solutions — which will be the case when the administration changes. Hopefully the new guys will also believe how beneficial UAS will be for the economy and will chase down and help overcome these barriers.

    Package Delivery

    Meanwhile, on the package delivery front, Google’s Project Wing has been approved by FAA to begin testing, albeit within the confines of Northern Plains UAS test site in North Dakota. The heavier Google delivery drones will be tested from the ground up to 29,000 feet with external loads, and efforts will be made to fly them beyond line of sight without chase aircraft. Google will also prototype a low-altitude airspace management system for the tests that uses inexpensive comms and data technologies.

    While authorization in the U.S. was still pending, Google went looking for somewhere to test its prototype drone delivery system, and in August 2014 undertook testing in Queensland, Australia. At that time Google was using a vertical take-off UAV system — they delivered portable radios and water bottles to farmers.

    Google tests delivery drones in Australia.
    Google tests delivery drones in Australia.

    Word is that Google is now looking at fixed-wing UAVs and cargo slung from them — maybe for transporting heavier packages.

    Google’s new delivery drone?
    Google’s new delivery drone?

    And further North in Ontario, Canada, Drone Delivery Canada (DDC) is moving forward with the development and implementation of a commercial drone delivery platform for retailers, service organizations and government agencies. In remote parts of Canada, access to some communities can be difficult to impossible for conventional means. DDC expects to add additional sites later this year for beyond visual line of sight (BVLOS) testing, working with the Canadian government towards obtaining its operator status. DDC also just announced an agreement with a Canadian retailer to test and integrate its drone system with the retailer’s existing depot-to-depot delivery logistics.

    DDC prototype drone delivery system.
    DDC prototype drone delivery system.

    And not to be left out of this picture, 7-Eleven has been working with drone manufacturer Flirtey to test autonomous delivery of convenience store items. Dispatched from a Nevada 7 Eleven store, two deliveries were completed to a local customer’s house using precision GPS, where the Flirtey drone hovered and gently lowered each package of goodies.

     

    Flirtey drone delivers 7-Eleven goodies.
    Flirtey drone delivers 7-Eleven goodies.

    So, while the White House now seems to be actively engaged in supporting the introduction of UAS into commercial operations in the U.S., we still have many significant obstacles to overcome — not least are access to control frequencies, the development and introduction of drone traffic-control systems, and the coordination of federal and state rule-making. But this apparently has not deterred several organizations, including Google, DDC, Flirtey/7-Eleven, Amazon, Walmart and others, to trial drone package delivery. U.S. states have also recognized the promise of everything connected with UAVs and their operations, and are collaborating with the FAA to establish large swaths of the airspace for UAV testing.

    What with the White House and states already on the UAV bandwagon, surely it won’t be long before we crack the nut and get significant commercial operations approved and underway.

    Tony Murfin
    GNSS Aerospace

  • Navigation progress for indoors and UAVs

    Navigation progress for indoors and UAVs

    I didn’t get to this year’s IEEE/ION PLANS meeting in Savannah, Georgia, in April, but I did find a few papers that interested me. You might have read past articles of mine that looked at the challenges of indoor navigation. And, of course, unmanned vehicles technology also is one of my favorites.

    So, I was pleased to find papers that addressed a few key issues for me:

    • An approach that employs cooperative smartphones to achieve about 3 meters indoor location.
    • Another look at the problems in using smartphone embedded GNSS for RTK positioning.
    • Relative positioning between UAVs using GNSS, radio and inertial, and also adding image processing in a GNSS denied environment.
    • Analysis of encounter-alerting issues for UAV detect and avoid systems.

    Indoor navigation

    Indoor navigation is an area which is seeing quite intense research, and several companies have now put initial products on the market. The general approach has been to use sensors within smartphones combined with radio-frequency (RF) signals which seem to be readily available in stores and malls which indoor location is finding commercial applications.

    If a position can be generated by an internal GNSS receiver within the phone in an outdoor setting prior to entering a building, the trick is to carry that position forward as GNSS signals disappear when the user moves away from the entry area. Inertial sensors in the phone are usually not accurate enough to do this job on their own, so ranging using RF from Bluetooth and Wi-Fi transmitters/beacons may be integrated to provide a position solution. Magnetic sensors in the phone have also been used to detect fixed metal structures within a building and use this data to aid location determination.

    The problem is that you need an up-to-date database of where the Wi-Fi and Bluetooth are located, and it has been taking a lot of work to map or “fingerprint” the interiors of buildings — and guess what, these “beacons” often are moved after a mall or store is mapped, so RF ranging can become quite inaccurate.

    So, fearless investigators from the University of Buckingham and University of Northampton in the U.K. have come up with the concept of using ranging between cooperative smartphones to aid each other and achieve location accuracies of 5-10 meters.

    While outdoors with good GNSS position, the inertial sensors in each phone are calibrated, each phone gets position using its internal GPS and a network is formed between the phones using their relative positions. Then when a phone goes inside the building, step counting is used to maintain relative positioning in the network. This can result in around 3 meters positioning for the interior phone.

    Well, yes, not everyone has two other buddies waiting around so one guy can go in and find the classic comic store, but for applications such as firefighters, urgent/health care, and security/police, this approach might work well.

    Cooperative smartphone location overview.
    Cooperative smartphone location overview. (From “UNILS: Unconstrained Indoors Localization Scheme based on cooperative smartphones networking with onboard inertial, Bluetooth and GNSS devices,” H.S. Maghdid, A. Al-Sherbaz, N. Aljawad and I.A. Lami.)

    Another paper looked hard at the options there might be to resolve problems with GPS performance which has previously precluded running RTK on smartphones. If we could achieve centimeter positioning on a mass-market basis, many current applications which are inhibited by cost, could become possible and revolutionize even the way we live. People have already used external solutions to solve some of the problems, but leading researchers at Texas U, with Broadcom and Radiosense support, may have come up with a self-contained solution.

    It is known that there are issues with the capability of the GNSS chip and oscillator components in smartphones — the observables they produce are not currently of sufficient quality to sustain RTK performance. So these researchers worked with Broadcom, who supplied them with an Android smartphone, which provided access to raw code and carrier-phase outputs and was also able to process these measurements internally.

    A smartphone’s Android software stack with the GNSS components and data flow highlighted.
    A smartphone’s Android software stack with the GNSS components and data flow highlighted. (From “On the Feasibility of cm-Accurate Positioning via a Smartphone’s Antenna and GNSS Chip,” T.E. Humphreys, M. Murrian, F. van Diggelen, S. Podshivalov, K.M. Pesyna, Jr.)

    Carrier phase measurements in smartphones suffer from five anomalies not found in survey-grade GNSS receivers — but four of these can be fixed in post-processing. The remaining phase measurement error increases with time and precludes RTK centimeter-level positioning — it could be the result of round-off error due to processing limitations. Otherwise it seems possible that carrier-phase differential GNSS positioning might be achievable.

    However, the researchers also studied antenna performance and found that its gain pattern was significantly affected by strong local multipath. The impact is that deep, unpredictable fading and large phase error will compromise centimeter-accurate positioning.

    So we’re not quite there yet, but with a new smartphone version showing up almost every other year, it is always possible that researchers and manufacturers will eventually evolve designs in the right direction, and ultimately solve the problem.

    Unmanned aerial vehicles

    Meanwhile, researchers at West Virginia University have been investigating methods to maintain relative positioning between UAVs in flight. With drone “swarms” and cooperative drone missions becoming more common, if a simple method could be derived to maintain relative separation, these applications could become more prevalent, especially in a GPS denied environment.

    So, with only noisy ranging radios between UAVs, and an onboard navigation system solution on each vehicle, the researchers set about developing an algorithm which can maintain relative position. The solution is complicated by the geometry between the UAVs, how often range measurements are made, and the noise in those measurements. To constrain these variables, the study was run assuming the UAVs travel at the same altitude.

    The study concluded that— provided the UAVs travel in the same direction, parallel to each other — that their algorithm could find a solution all the time. The focus of the study appears to be on determining hearing and relative bearing between the vehicles and results were varied depending on the frequency of range measurements, the amount of noise and the geometry. So a few steps forward along the path towards making drones work together in a hostile environment where GPS is jammed. (See “Cooperative Relative Localization for Moving UAVs with Single Link Range Measurements,” J. Strader, Y.Gu, J.N. Gross, M. De Petrillo, J. Hardy.)

    Another study on the same problem of maintaining relative position between drones was also undertaken by West Virginia University, Systems & Technology Research and the Air Force Research Laboratory. However, their solution didn’t only use ranging between vehicles. It took advantage of inertial measurements on each drone, computer vision calculations derived from downwards looking cameras on both UAVs, and finally magnetometer measurements were also added into a Kalman filter solution.

    UAV platform payload diagram and assumptions.
    UAV platform payload diagram and assumptions. (From “Unmanned Aerial Vehicle Relative Navigation in GPS Denied Environments,” J. Hardy, J. Strader, J.N. Gross, Y. Gu, M. Keck, J. Douglas, C.N.Taylor.)

    With several additional sensor measurements, the researchers were able to predict that relative positioning could be maintained in a GPS denied environment. They also considered ranging radio, magnetometer and vision update rates, and the performance/update rate of various quality inertial sensors. The principle objective is to enable accurate target hand-off between drones as one approaches the other. Overall, they found their model could support 10-meter-level position and 0.5 degree accuracy.

    Finally, for safe operation of UAVs in the U.S. National Airspace System (NAS), minimum Detect and Avoid (DAA) standards for small to medium size UAVs are being developed for operations within drone-accessible airspace. DAA has to provide the “see and avoid” for unmanned aircraft systems (UAS) that pilots of manned aircraft use to avoid other aircraft. So surveillance sensor information needs to supply the UAV and the remote Pilot in Command (PIC) operator with the situational awareness needed to remain well clear of other aircraft.

    Part of what DAA should provide are alerts working to universal standards for all UAS.

    HazardZone
    Zones used in alert evaluation. (From “Analysis of Alerting Performance for Detect and Avoid of Unmanned Aircraft Systems,” S. Smearcheck, S. Calhoun, W. Adams, J. Kresge, F. Kunzi.)

    The research presented by CAL Analytics and General Atomics (with technical support and guidance by RTCA committee SC-228 and NASA) outlined the evaluation alerts generated when other aircraft are anticipated to penetrate into a well-clear volume around a UAV.

    Alerts can be “missed,” “late” and “early” — all of which can impair DAA performance and safety and which need to characterized and mitigated. Sensors currently under consideration for use in DAA include Automatic Dependent Surveillance Broadcast (ADS-B), active surveillance transponder and airborne radar — this study looked at ADS-B and radar and the trade-off that they provide related to desirable and undesirable alerts.This analysis will likely feed into the development of UAS DAA alerting standards and requirements.

    Typical DAA tracker approach.
    Typical DAA tracker approach. (From “Analysis of Alerting Performance for Detect and Avoid of Unmanned Aircraft Systems,” S. Smearcheck, S. Calhoun, W. Adams, J. Kresge, F. Kunzi.)

    Radar surveillance errors were found to increase the probability of Missed, Late, Short, Early and Incorrect Alerts, all of which is bad news for radar. ADS-B surveillance errors increased the probability of Short, Early, and Incorrect Alerts. However, ADS-B did not lower performance as much as radar — better news for ADS-B. All levels of surveillance errors were seen to increase the amount of alerting jitter, with radar seeing the most significant undesirable effects.

    Guardian UAS used in DAA tests.
    Guardian UAS used in DAA tests.

    Highly reliable, proven DAA systems are likely an essential part of the safety system for UAS if they are to become a regular part of operations in the NAS. General Atomics has tested a DAA system including GA’s Due Regard Radar (DRR) aboard a U.S. Customs and Border Protection (CBP) Guardian Unmanned Aircraft System (UAS), a maritime variant of the Predator B UAV. The DAA system also includes Honeywell’s Traffic Alert and Collision Avoidance System (TCAS) and Sensor Tracker, specifically designed for DAA.

    Schiebel Camcopter S-100 demonstrating detect and avoid system.
    Schiebel Camcopter S-100 demonstrating detect and avoid system.

    And, also in December of  last year, a Schiebel Camcopter S-100 flew demonstration flights with an NLR-developed AirScout Detect and Avoid System. Two helicopters flew “intruder” profiles against the UAV during the demonstration. The Camcopter S-100 flew several scenarios and “unexpectedly” encountered an intruder aircraft. The system determined in real time the corrective action to maintain separation from the intruder aircraft.

    So, progress on indoor navigation, research towards running RTK on smartphones, relative positioning between UAVs, and advances in Detect and Avoid solutions for UAVs. Something of a mixed bag, but all promise further progress around different solutions for a number of market navigation segments.

  • Retailers, airspace, undetectable drones: UAV developments zoom ahead

    A lot is happening in the world of UAVs.

    Amazon and Walmart are making plans toward faster delivery of goods by drone, while TV dramas bring drones into their stories. And evaluation and test of technologies to protect airports and aircraft from unwanted drone incursions is picking up speed — while sense-and-avoid technology takes big steps forward toward integration of drones in the U.S. National Airspace.

    Amazon and Walmart. Amazon is working hard to enable deliveries using drones — even advocating a “high-speed” transit zone 200-400 feet above ground level. Delivery drones can then zoom between warehouse and customer carrying goods so orders show up super quick, right on your doorstep.

    Proposed Amazon drone-traffic-control system.
    Proposed Amazon drone-traffic-control system.

    Drone-traffic-control would be automated — too many drones over too many cities to use conventional air-traffic control. With a buffer zone of 100ft above drone traffic and regular manned aircraft, and no-fly zones around airports, low speed localized drone-traffic would transit from the high speed area to the delivery point. And recreational model aircraft and other drones would be limited to flying in designated areas, or up to 200ft within drone-traffic-control segments. Amazon seems to indicate that the technology to enable all this is already pretty well there — it’s selling the concept and developing the regulations which will take the most time.

    So not wanting to miss out on automation using drones, Walmart is now talking about using drones in warehouses to monitor stock levels. Inventory control currently uses manual stock-taking which takes up to a month for just one pass through a large facility — while a complete stock count is possible in one day using hi-res drone-camera data.

    Walmart warehouse.
    Walmart warehouse.

    To keep pace with the competition for its on-line business, its essential for Walmart to avoid out-of-stock and overstocked items, and tight, rapid inventory control is the key. So drones in warehouses, and data analytics is where they are headed.

    Walmart is already looking for approval from the U.S. Federal Aviation Administration (FAA) to test home delivery using drones, so it may not be long before their drones get out of the warehouses and start testing how to fulfill online orders, too.

    NCIS New Orleans. I was just thinking about this month’s drone update article while imitating a couch potato watching TV last evening, when NCIS New Orleans airs a show built around drones. A Predator pilot uses his day-time skills frying drone operations to search for a missing person. He buys an “undetectable drone” from a couple of drone geeks and makes aerial maps around his base. There were segments of simulated Predator operations, protests about overseas drone operations, an octocopter on the street in New Orleans and a DJI hobby drone flown on camera by a young boy. Other than a couple of technical errors, the show demonstrated just how much drones are now becoming part of our daily life, and how much the public is hearing about UAV technology.

    And talking about undetectable drones — the FAA is using its Pathfinder Program to investigate a defensive system to protect airports from drone incursions. The FAA will evaluate a UK system known as Anti-UAV Defence System (AUDS) developed by Blighter Surveillance, Chess Dynamics and Enterprise Control Systems— the system is claimed to be able to detect, track, disrupt and defeat drones.

    AUDS system.
    AUDS system.

    National Airspace. Increasingly concerned about reports of UAVs flying too close to an airport or to manned aircraft the FAA and the Department of Homeland Security (DHS) have been searching for a system that can defend against drones.

    The AUDS system uses electronic scanning radar, precision infrared, daylight cameras and specialist video tracking software to detect and track even small drones up to six miles away. An inhibitor then disrupts the drone radio control signals. The whole sequence of detect, track, disrupt, defeat process typically only takes 8-15 seconds. And the system has already undergone over 400 hours of ‘live’ testing against small UAVs.

    In addition, the MITRE Corporation — a technical service organization which supports several U.S. government agencies — is investigating products and technology to detect and stop drones, through a funded competition called “Countering UAS Challenge”. Eligible solutions need to detect small airborne UAS, and discern and interdict those that are perceived as threats, forcing them to be recovered safely with an intact payload. MITRE has now selected eight finalists who will compete in live flight tests in August to determine the winners of a $100,000 prize package.

    So although efforts are underway to protect airports and aircraft from wayward drones, the bad press that drones have been getting recently might not all be appropriate. The FAA recently released drone sighting data for March this year which has now been analyzed in some detail by the Academy of Model Aeronautics (AMA). AMA found that within the 582 drone sightings reported only 3.3% appear to involve near-misses or close calls.

    Drone Sightings. Given that over a million drones were sold during the 2015 Thanksgiving-Christmas holiday season, it does appear that drone “sightings” are on the decline, and related reports to law enforcement also appear to be going down. So its possible that the FAA drone registration program, and the industry-FAA Know Before You Fly have positively improved the operation of drones by the public.

    And while we’re all looking for ways to detect and deter drones from the ground, General Atomics (GA) has announced the successful operational testing of an airborne anti-collision radar system which includes GA’s Due Regard Radar (DRR) and Honeywell’s Traffic Alert and Collision Avoidance System (TCAS) and Sensor Tracker. Tests were carried out aboard a U.S. Customs and Border Protection (CBP) Guardian UAS, a maritime variant of the Predator B.

    GA’s Due Regard Radar (DRR) drone.
    GA’s Due Regard Radar (DRR) drone.

    During encounters with a Cessna fixed wing aircraft and a Blackhawk helicopter, safe separation was ensured between the UAV and the other traffic. Overland testing began at the GA facility near Palmdale, California, and concluded over the eastern Pacific Ocean. The tests confirmed that the pilot of the UAV had as a clear picture of surrounding air traffic as if he was flying in the cockpit of a manned aircraft. The tests also confirmed operational compatibility between the DRR radar and the maritime surface search radar carried by the Guardian UAV.

    This is a significant step forward — albeit on a military drone — towards technologies which will ultimately enable integration of UAVs into the U.S. National Airspace. If we are also getting recreational operators to be more mindful of safely operating their hobby drones, and we can also prevent unwanted encroachment on airports and manned aircraft, then plans for delivery drones might also begin to make some progress.

  • AUVSI showcases Xponential growth of UAV market

    AUVSI showcases Xponential growth of UAV market

    AUVSI's newly christened "Xponential" show drew together hundreds of commercial UAV products and services. (Photo: Joelle Harms, GPS World)
    AUVSI’s newly christened “Xponential” show drew together hundreds of commercial UAV products and services. (Photo: Joelle Harms, GPS World)

    The Association for Unmanned Vehicle Systems International (AUVSI) hosted another big UAV show this month. Renamed Xponential, to denote the rapid growth in unmanned systems, the May 2-5 gathering in New Orleans was up to its billing — with 8,000 attendees from 55 countries, and 650 exhibitors.

    The morning plenary sessions notably included a pitch from Amazon for a low-level, high-speed transit zone for delivery drones and associated tight operational controls. FAA Administrator Michael Huerta announced the formation of an industry advisory group to speed up integration of drones into the National Airspace and relaxation of rules to allow students to operate UAS for educational and research purposes.

    However, there was much corridor discussion of the FAA’s intransigence as the introduction of regulations for drones continue to be delayed. The feeling seemed to be that other nations are already adapting quickly to accommodate drone applications in their airspace, while the FAA is felt to be holding back the development of a multi-billion-dollar industry in the U.S.

    The Ernest N. Morial Convention Center is huge, with several large exhibit halls, and the AUVSI show floor used every bit of the space, filling it with booths and exhibits. Almost every company had something to announce about their growing business in unmanned aircraft systems (UAS), or in unmanned ground or water vehicles.

    Global Hawk advancements

    I’ve always been interested in Global Hawk and its ups and downs as it progressed through U.S. and European start-and-stop programs, so I was delighted when I got an invitation to talk with the Northrop-Grumman team at their booth.

    Global Hawk (Photo: USAF)
    Global Hawk (Photo: USAF)

    With a declared operational ceiling of 50,000 feet and various payloads, Global Hawk is an ideal high-altitude reconnaissance platform. While the 2011–12 U.S. budget cuts threw a wrench into their programs with the U.S. military, Global Hawk found other places to demonstrate its capability — like over Japan’s crippled Fukushima Daiichi nuclear plant and with NASA flying into heavy weather.

    X-47B UCAS
    X-47B UCAS

    Things are now much better, with many systems in U.S. inventory, several operational bases around the world and with at least one Global Hawk airborne 24/7. With 34-hour endurance, store and forward capability and a huge 1,200-pound payload option, this UAS program is now really airborne. And anyone into UASs must have seen clips of the X-47B UCAS carrier landings and aerial refueling — hopefully this program will also soon extend past the demonstration phase.

    UAS equipment suppliers

    There were plenty of UAS equipment suppliers at the show. Here’s just a sample:

    • Embention has developed its UAS autopilot (Veronte Autopilot) so that it is certifiable to aviation hardware and software standards, anticipating equipment regulations similar to those for manned aircraft. It is Do178 and Do254 compliant.
    • Epiq Solutions has a large number of wireless solutions from cellular to 6 GHz.
    • VectorNav introduced the MEMS-based Tactical Series, including the VN-110inertial measurement unit and attitude heading reference system (IMU/AHRS), the VN-210 GPS-aided INS (GPS/INS), and the VN-310 dual-antenna GPS/INS.
    • Spectracom brought its new VersaSyn all-in-one time-and-frequency GPS master clock ND network time server to the show, for UAS on-board payload sync solutions. In addition, all the latest in GNSS simulation tools were on display at the Spectracom booth.
    • Freewave displayed a range of wireless solutions, including a long-range 900-MHz control and data link for UAS.
    • The Sensonor iMAR iNAT-M200.
      The Sensonor iMAR iNAT-M200.

      Amimon again presented its “zero-latency” HD video-link system. Its Connex product is apparently becoming the standard for movie-making using drones, as well as for high-definition inspection applications.

    • FLIR announced the Vue Pro R thermal-imaging camera series for commercial drones.
    • Gladiator Technologies (LKD Aerospace) showed its extensive range of gyro, inertial and GPS/INS products.
    • Sensonor announced the integration of its STIM300 IMU within the iMAR iNAT-M200 inertial navigation system and for the iATTHEMO-C high-precision heading, attitude, position and velocity reference product.
    • KVH has partnered with Geodetics to provide high-performance positioning and navigation products for commercial applications requiring high levels of precision for unmanned platforms and ground navigation. The KVH 1750 IMU that Geodetics is integrating provides highly accurate six-degrees-of-freedom angular rate and acceleration data, contributing to a high-performance commercial off-the-shelf (COTS) solution.
    • Geodetics is integrating the KVH 1750 IMU into both a GPS-aided inertial navigation system (Geo-iNAV Advanced) and a high-accuracy relative navigation, positioning and orientation system (Geo-RelNAV). These COTS products are available for commercial applications such as manned and unmanned platforms for land, air and sea — surface or subsea — mobile mapping systems, photogrammetry and terrestrial navigation. Also featured at Exponential was Geodetics’ Geo-MMS Lidar Mobile Mapping System, which can achieve 10-25 centimeter point-cloud georeferencing when using real-time kinematic positioning.

    Videos from the Xponential show floor

    Three major GNSS OEM companies were also at the show:

    • Septentrio is apparently avoiding the need for ground control points for surveying. The ReProcessed Kinematic (RPK) GeoTagZ solution on the AsteRx-m UAS OEM board eliminates the need for a real-time fixed station datalink while still guaranteeing RTK centimeter-level accuracy. This simplifies set-up, reduces the power drain from the on-board radio, and eliminates the loss of data due to unreliable radio links — things that often plague UAV operations. GeoTagZ software uses GNSS data recorded by the receiver and combines it with the base station reference file to calculate centimeter-level RTK positions for georeferencing photographs taken by the UAV.
    • NovAtel came to AUVSI Exponential to meet the company’s many customers in the UAS business — a large number of different UAS applications integrate NovAtel OEM receivers on-board. With a great first quarter in the bag, NovAtel is also building a new, bigger facility not too far from its existing location in Calgary, Alberta, Canada. Its UAS business is holding steady, despite some cutbacks on existing military programs. NovAtel also announced its latest correction-service offering for Terrastar C (4 centimeter) and Terrastar A (40 centimeter).
    • Trimble introduced the MB-Two GNSS module, which delivers highly accurate GNSS-based heading plus pitch or roll in an advanced industry-standard form factor for system integrators. The MB-Two features an enhanced dual-core GNSS engine with 240 channels capable of tracking L1/L2 frequencies from the GPS, GLONASS, Galileo and BeiDou constellations. The GNSS engine supports Trimble RTX correction services, including CenterPoint RTX and RangePoint RTX, delivered worldwide via L-band satellite. The MB-Two is designed for a wide variety of applications such as unmanned vehicles, agriculture, automotive, marine and military systems.

    UAV teams form, expand

    PrecisionHawk announced teaming arrangements at AUVSI Xponential with Harris Corporation, Insitu and DJI. PrecisionHawk is in the business of providing highly accurate geospatial data to its customers for a number of different applications. Its software packages process aerial data into 2D or 3D products, include a library of on-demand analysis tools, and enable sharing and collaborating.

    DJI has teamed up with PrecisionHawk to offer a complete agricultural analytics solution by linking DJI’s commercial-grade drone hardware to PrecisionHawk’s drone software platform, DataMapper.

    The ADS-B tower with the Xtend antenna. (Photo: Harris Corp.)
    The ADS-B tower with the Xtend antenna. (Photo: Harris Corp.)

    At the same time, Harris and PrecisionHawk have expanded their existing relationship to provide the UAS industry with tools that will enhance operational and situational awareness for drone pilots. The two companies are also moving toward the deployment of a UAS airspace management system using technologies like PrecisionHawk’s LATAS platform.

    Harris’ real-time surveillance database of manned and unmanned traffic is being built into the LATAS platform to give drone pilots a clear picture of their surroundings, while Harris is also integrating LATAS into its systems to provide visibility of drones that may be sharing the airspace to customers such as UAS test ranges and airports, and potentially to manned aircraft pilots.

    Announcements from Insitu

    Insitu announced a strategic alliance with PrecisionHawk to offer expanded aerial technology services across commercial and enterprise markets. The two industry leaders will offer small and large-scale services by integrating hardware and software platforms to deliver more comprehensive data capability to customers.

    The companies will also leverage their participation in the FAA’s Pathfinder Program to collaborate on the research and test of new technologies to enable safe drone flight for extended and beyond-visual-line-of-sight (BVLOS) operations.

    Insitu's Flying Launch and Recovery System (FLARES).
    Insitu’s Flying Launch and Recovery System (FLARES).

    Insitu made a number of other announcements at the Xponential show. Its FLARES launch and recovery system is an innovative solution for both launch and capture of the Insitu ScanEagle UAS. The huge quadcopter with a ScanEagle UAV hung underneath climbs to a few hundred feet, begins forward flight and the UAV is released and initiates independent powered flight.

    For recovery, a cable attached to the ground is carried aloft by FLARES and tensioned by the hovering octocopter. ScanEagle then flies into the cable and is captured by a hook on the leading edge, and the UAS is recovered by ground operators. FLARES is designed to overcome use of the bulky ground catapult, which is normally used to launch ScanEagle.

    Insitu also announced the formation of a separate business unit through which it will address the commercial market. The commercial unit will leverage the company’s 20-plus years of experience in unmanned systems to deliver value to the emerging unmanned commercial aerial data-collection market.

    Insitu also recapped earlier activities off Alaska with Conoco-Philips in 2013 researching ice-flow and whale movements, and operations over the Paradise Fire in Washington’s Olympic National Park in September 2015. Flying in Olympic National Park, ScanEagle delivered more than 37 hours of real-time infrared video to fire incident personnel, which enabled them to pinpoint the fire’s perimeter and areas of intense heat. ScanEagle also assisted helicopter assets to evaluate water-drop locations.

    Insitu is heavily involved with the FAA Pathfinder program and has been developing techniques for UAS beyond visual line of sight operations with BNSF Railway for track inspection. In its first day of operations, ScanEagle provided real-time video covering 64 miles of the 132-mile stretch of track that BNSF has designated for the exercise. ScanEagle is capable of flying for up to 24 hours at speeds of up to 80 knots.

    In summary, Xponential 2016 was a huge conference with a large number of exhibitors representing a good cross-section of the UAS industry, including lots of suppliers from the navigation and guidance sector — actually, just too many to mention everyone. The exhibitors included start-up drone manufacturers and veterans alike, all seemingly motivated by the movement toward opening up airspace to commercial operations. This is an exploding industry in the U.S., but its still waiting for rules from the FAA under which to operate on a regular basis, while other countries are already soaking up market share of the emerging commercial drone business.

    Tony Murfin
    GNSS Aerospace

  • Drones: Registration and regulation move forward amid near misses

    As the popularity of drones for personal use continues to increase, most of the people who have bought them are sensible folks who have registered their vehicles with the FAA (in the U.S.) and other authorities elsewhere. They respect the rules that have been laid down for them to operate — fly below 400 feet (recently increased by the FAA from 200 feet), don’t fly over populated areas or people, and especially stay away from airports and the departure and approach paths for regular aircraft.

    So it’s especially troublesome for these law-abiding drone owners when a wildcat operator gets into the approach path at an airport — and it’s really bad if that airport happens to be one of the busiest in the U.S.

    Unfortunately there are several examples. For instance, a Lufthansa A380 pilot recently reported that a drone passed approximately 200 feet above the huge A-380 aircraft he was flying while it was at 5,000 feet altitude on approach into LAX (Los Angeles airport). The FAA immediately got on the phone to the Los Angeles Police Department responsible for air support.

     

    Just last week, an unmanned aerial vehicle (UAV) was reported to have struck a British Airways Airbus as it descended into London’s Heathrow Airport.

    The increase in drones might be compared to an increase in the bird population, and a recent study concluded that the risk to the airspace caused by single, light-weight drones is probably quite low. The figures also seem to say that the probability of bird-strikes is very low — but tell that to Captain Sullenberger who landed a smaller A-320 in the Hudson River when both engines quit after ingesting geese just after take-off.

    It seems that good airmanship and eyesight have so far avoided any drones being sucked into commercial aircraft engines — no thanks to a small number of irresponsible drone flyers who are tempting fate by intruding into “no-go” airspace.

    Let’s get the FAA small UAV regulations published and give everyone clear rules by which even these people are required to fly their drones. So far, individual section 333 waivers have been granted by the FAA to known characters who apparently want to do things properly. Rules also presumably come with penalties, so we might have some deterrence and more control over wildcat operators.

    Along the same lines, the FAA is researching a new approach which could detect drones and find their operators who fly near airports. The FAA has implemented a number of programs and tools to educate drone operators and make them aware of the dangers of encroaching on controlled airport airspace, but even so, such incidents continue to occur.

    CACI International has therefore been awarded a Pathfinder contract by FAA to investigate technology that will allow the FAA to “identify rogue unmanned aircraft systems” near airports. The CACI solution aims to provide a proven way to passively detect, identify and track UAS/drones and locate their ground-based operators. So, hopefully we may soon have regulations along with a detection system for rule breakers, and we’ll then need an approach to administer penalties. Much better! But let’s pray in the meantime that we don’t have any drone/Sullenberger incidents.

    The FAA has recently predicted sales of commercial UAS will increase from 600,000 in 2016 to 2.7 million by 2020, so we better get a handle on this soon. It’s even forecast that there could be a jump to 2.5 million commercial UAS sold in 2017 should the FAA get its small UAV regulations out and implemented this year, as the agency has announced.

    Meanwhile, the FAA has turned to an industry/agency committee to ask if they could relax the FAA’s own rules for very small drones and under certain conditions allow them to fly over people. The committee — known as the Micro Unmanned Aircraft Systems (UAS) Aviation Rulemaking Committee (the “ARC”) — met and quickly published a report that came up with four categories of small UAV, Category 1 being less than 250 grams and requiring virtually no additional regulation. Basically, a 250 gram drone falling on a person is considered unlikely to hurt anyone. The other categories do need more restrictions, and manufacturers will need to do significant testing to qualify their drones to satisfy the new requirements.

    amazon-prime-drone-4
    The latest version of the Amazon delivery drone.

    Amazon is also trying to do its part to warn people that a drone might be close overhead. The company recently filed a patent for propellers on drones that could emit warning noises in certain phases of flight. As Amazon progresses toward its plan to deliver parcels to homes, it’s looking to enhance the safety of its future drone-based delivery system.

    The object of the patent is to have drone propellers alert people on the ground of the drone’s presence, possibly by broadcasting audible phrases such as “watch out.” Maybe a couple of holes in a propeller might even result in a whistling sound that people would begin to associate with an incoming drone?

    DJI

    Meanwhile, DJI in China remains one of the companies enjoying stratospheric growth as a result of this growing demand. DJI only really surfaced as a drone supplier in the last few years after the release of the Phantom quadcopter, but DJI has actually been around for 10 years. The founder studied in Hong Kong and became interested in flight control systems, which DJI went on to develop. The company started with 20 people based in Shenzhen where there is good access to high-tech talent, but they have now exceeded 5,000 employees. With R&D engineering centers in Asia, Europe and the U.S., DJI now claims to have captured 70 percent of the commercial drone market.

    The DJI Phantom 4.
    The DJI Phantom 4.

    DJI’s focus is to provide drones that are easy to fly, with a great user interface, and then hang high-quality cameras and other sensors on these really maneuverable platforms. Their approach seems to be working — sales are currently growing by around 3-5 times a year, and they also claim to have a valuation of at least $10 billion US!

    DJI tells us that its customers have taken 70 million photos, flown 125 million miles, and operated for 3.9 million hours, with applications including agriculture, search and rescue, sports and news broadcasting, real estate, tourism, wildlife monitoring, archaeology, surveying and mapping, education and dozens of others. DJI is also one of the first manufacturers to introduce geofencing using GPS to ensure operation only in areas that are permitted.

    With a product range that not only has drones for commercial and industrial applications, but also includes flight control systems, still and video cameras and stabilized gimbals for airborne and handheld camera applications, DJI is very well placed to maintain its strong market position.

    AUVSI Convention

    Early next month, the Association for Unmanned Vehicle Systems International (AUVSI) holds its major annual convention in New Orleans, and GPS World will have a contingent of inquisitive people scouring the show floor for news items. So we will have lots more drone stories to tell.

    Tony Murfin
    GNSS Aerospace

  • Hot research: Improved car nav downtown, indoor mapping with drones

    Back in September at the Institute of Navigation GNSS+ convention in Tampa, Florida, one of the papers went a long way to explaining why and how more GNSS satellites in more constellations is better. The natural assumption is that because there are more satellites, a multi-constellation receiver can choose which ones have the best signal and which provide the best solution — and it’s not always the same satellites.

    Best geometry together with best signal strength obviously provide the best solution, but this might change in, for instance, a downtown urban setting for a car using a satellite navigation system. While most Western car-nav systems use only GPS, the study by Martin Escher, Mirko Stanisak, and Ulf Bestmann at the Institute of Flight Guidance, Technical University in Braunschweig, Germany, clearly shows that there is an advantage to embedding multi-constellation receivers in these systems.

    Skyplot of GPS, GLONASS, Galileo and BeiDou satellites at Braunschweig.
    Skyplot of GPS, GLONASS, Galileo and BeiDou satellites at Braunschweig.

    The above skyplot shows a perfect reception of all GNSS satellites during a period of 14 hours — 30 usable satellites — obtained with a high-quality antenna without any obstacles. Car driving downtown will almost never encounter such good GNSS reception.

    The Technical University put two different receivers in a car under static, representative, urban conditions, and went about evaluating reception against that predicted by an in-house simulation. The high-precision survey-grade receiver receiver tracked signals from all four constellations, while a lower cost receiver used in some car-nav systems was configured to only track GPS and Beidou. In this scenario, valid signals were obscured by surrounding buildings and the total number of visible satellites was reduced from 23-30 to 11-18.

    The measurements validated the university simulation model and demonstrated how the high-precision receiver was able to remove multipath and other diffracted or reflected signals, while the lower cost receiver collected all available signals and therefore suffered some accuracy degradation.

    Braunschweig urban scenario.
    Braunschweig urban scenario.
    Predicted satellites reception with an elevation of up to 65° often obstructed by buildings.
    Predicted satellites reception with an elevation of up to 65 degrees often obstructed by buildings.

    The area chosen for this demonstration is dominated by narrow roads with multi-story buildings on both sides of the road. To begin, only GPS positioning was used on the test route — representing the current state-of-the-art for most production car-nav systems. For large portions of the test drive, no GPS-only position solution was achieved because of insufficient GPS measurements.

    POEM-Mar16-4-W

    While there was some improvement in tracking using a multi-constellation receiver, when GNSS differential corrections over a mobile telecom link were incorporated, tracking performance was significantly improved. But when inertial and wheel sensors were also added into the solution, almost perfect positioning was achieved over the whole route.

    Multi-constellation with differential corrections and sensor aiding.
    Multi-constellation with differential corrections and sensor aiding.

    Given that commercial GPS/GLONASS corrections are now available almost everywhere over a large portion of the globe and some assisted GNSS services are beginning to add both Galileo and Beidou corrections, it’s possible that downtown loss of signal for car drivers may soon be a thing of the past. And, of course, many car-nav systems currently incorporate wheel sensor inputs for dead-reckoning when GNSS is lost.

    Drone use in difficult locations

    Another interesting ION GNSS 2015 paper from Adam Schultz, Russell Gilabert, and Maarten Uijt de Haag of The Ohio University details the way a couple of students and their professor set out to fly a drone down corridors and within the halls of the Engineering Department. They are hoping to soon get access to the extensive maintenance tunnel system at Ohio University for more autonomous flights using newer, smaller drones.

    The objective is to investigate the requirements and use of drones for missions in remote or difficult locations for applications such as large building maintenance, search and rescue, and indoor mapping.

    But watch out, people in the Engineering building, if you see an unmanned hex-copter heading toward you on your way to class! Sounds like great fun as the UAV research students see the shots of the scattering inhabitants via the onboard Point Grey FireFly MV color camera!

    The UAV/drone is equipped with a navigation and mapping system for both outdoor and indoor environments, using multiple laser scanners, an inertial measurement unit (IMU), barometric height and GNSS, whenever its available.

    The UAV is a 3DRobotics hex-copter with a payload that includes an onboard processor, two short-range and one long-range laser range scanners, autopilot, Xsense MTI IMU, GPS receiver and a standard Wi-Fi link to relay real-time maps, trajectories and video to the remote operator.

    Ohio U Hex-copter with similar payload as flown through indoor environment (speed ~2m/s).
    Ohio U Hex-copter with similar payload as flown through indoor environment (speed ~2m/s).

    Guidance, navigation and control (GNC) of the unmanned hex-copter is accomplished by tactical and strategic modules. In known environments, the strategic GNC keeps track of the planned and actual flight trajectories and provides the next waypoints for the mission.

    In unknown environments, the strategic GNC maintains a rough estimate of trajectory and the current map of the UAV’s location. The UAV can be flown either manually by the student managing the flight controller or, when in autonomous mode, by the internal UAV flight control computer. Laser scanners provide horizontal position estimation and altitude estimation, while also collecting mapping data.

    The mission manager is programmed with a simple rule-based system that uses the system’s 2D and 3D maps to control the route. The drone flies autonomously through the corridors and rooms, while the UAS operator monitors progress on a laptop. The operator can manually take control of the UAV guidance at any time.

    The autopilot provides magnetometer and inertial measurements that are used to loosely maintain heading when moving from outdoors to indoors. When indoors, the lidar, inertial and optical (LION) mission controller continuously outputs position and orientation and generates short 10-30 second trajectories for the flight controller — providing a series of waypoints and required velocities for the UAV to follow.

    Map generated by the UAV mission controller (red) versus truth reference map (blue).
    Map generated by the UAV mission controller (red) versus truth reference map (blue).

    Should this research ultimately lead to a commercial UAV implementation, it sure would help solve the huge problem we have now for generating indoor maps. The current simultaneous localization and mapping (SLAM) method for generating these indoor maps usually means somebody walks throughout a mall or office building carrying one of several indoor location systems or even taking physical measurements. If a very small UAV were to be flown safely throughout such an indoor location, data would be collected quickly, hopefully with a lot less effort than current methods allow. There’s still a lot of research and development required, but this sure does look promising.

    Tony Murfin
    GNSS Aerospace

    References

    “Future Automotive GNSS Positioning in Urban Scenarios,” Martin Escher, Mirko Stanisak, Ulf Bestmann, ION GNSS+ 2015.

    “Indoor Flight Demonstration Results of an Autonomous Multi-copter using Multiple Laser Inertial Navigation,” Adam Schultz, Russell Gilabert, and Maarten Uijt de Haag, ION GNSS+ 2015.

  • UAV news round-up: Rules, birds and malicious drones

    This month’s column recaps UAV news that you may or may not have picked up over the last few weeks. We start with stories related to the rules for operating drones in the U.S., then we’ll look at bird-like drones — used to scare away birds, new commercial UAV applications, and steps being taken to protect us from malicious use of drones and other possible “impacts” of drones.

    Who owns the air?

    A long time back, the U.S. Congress passed laws which gave the government control above 500 feet and limited land rights so that overflying aircraft could not be considered as trespassing over private property. But, it turns out, ownership of the airspace from the ground up to 500 feet may not be that clear.

    The Federal Aviation Administration (FAA) recently reaffirmed that the agency controls all U.S. airspace, even right down to the ground, but it seems that landowners may still have some claim to their own air directly above their property.

    In a precedent-setting case dating back to World War II, the U.S. Supreme Court said that landowners have rights to as much airspace as they can use for the enjoyment and use of their land. So if “enjoyment and use” entails flying a UAV at up to 500 feet above their property or alternatively requires no UAVs flying above their own roof-line, who’s rights prevail?

    Certainly, there seems to be a number of people who are not too fond of UAVs being allowed to fly over their homes at low altitude. Manned aircraft might be a different kettle of fish as they generally fly higher and don’t seem to bug most people as much. And noise abatement regulations attempt to limit the sound of loud aircraft engines on landing and take-off.

    But with this continuing ambiguity, several state and local governments have already begun to take steps to protect airspace over people’s homes.

    There are currently more than 150 active bills in more than 30 states — either carried over from 2015 or introduced this year.

    Indeed, the FAA, in an effort to dissuade such lawmaking activity, recently released a fact sheet on state and local drone regulations: “Navigable airspace free from inconsistent state and local restrictions is essential to the maintenance of a safe-and-sound air transportation system,” said the FAA. The agency urged local and state lawmakers to consult it before making any new regulations. And it would clearly be far better for drone manufacturers and operators if there was only one set of (FAA) regulations across the whole U.S., rather than each user having to navigate a tangled web of potentially conflicting local and state regulations.

    In the meantime, there has been at least one case in which a property owner sought to protect his “home and castle” by unloading a shotgun into a low-overflying drone. The lawsuit was settled to the benefit of the property owner, rather than the drone operator, so property rights did prevail in this case.

    Nearly 300,000 owners have registered their small unmanned aircraft (sUAV) in the first 30 days using the FAA’s online registration system and have received a refund for the $5 application fee. While the refund period has now expired, the agency continues to see a steady stream of daily registrations.

    The FAA’s registration rule, which took effect on December 21, 2015, applies to sUAV that weigh between 0.55 lbs. and 55 lbs. Existing owners of these aircraft must register before Feb. 19, 2016. The current online system only supports use by recreational or hobby operators, while the FAA hopes to provide commercial operators with access by March 21.

    Name, address and email are required ,and a registration number and printable certificate are then provided. The registration number must be marked on the UAV.

    A drone flies in Russia.
    A drone flies in Russia.

    Meanwhile, Russian President Vladimir Putin has signed a law that obliges all private owners of unmanned aircraft weighing more than 250 grams to register them with the Federal Air Transport Agency.

    According to the new act, which comes into force at the end of March 2016, owners and operators of unmanned aircraft systems (UAS) must also appoint a crew and a commander responsible for flight safety. In order to operate, a flight plan must be submitted to the regional air traffic controllers — as required for manned aircraft operations — and the flight plan has to be followed unless an emergency landing is necessary when there is a threat to public safety.

    Is that a bird or a drone?

    But, of course, the more we try to overcome issues related to UAVs, the more complicated it seems to become. A core element of all FAA authorizations to date has been that a drone should never be operated within several miles of an airport to avoid collisions with aircraft. Now, a company has come up with a drone which carries a broadcast sound unit, programmed with a number of hawk, owl and other bird calls — ideal for scaring feeding or roosting birds away from areas we want to clear, such as at airport runways.

    Bird strikes by aircraft in the critical phases of landing or take-off are a major concern for airlines and airports alike. Many methods have been tried to reduce birds flying around at the sound of loud aircraft noise. Birds can get sucked into engines or can damage other critical aircraft structures. Air blasts that sound like shotguns and flying live falcons are only a couple of methods used to clear birds away from airport approaches, departures and runways.

    Bird-repelling drone.
    Bird-repelling drone.

    In the meantime, at least one enterprising associate prof at the University of Illinois has recognized the requirement and is developing a robotic falcon that chases birds away from airfields.

    flyingfalcon
    A flying falcon.

    Soon-Jo Chung and his team have been supported by funding not only by the National Science Foundation’s CAREER Award program to create the flying falcon above, but also by other sources to develop vision-based navigation. An analytical computer simulation has replicated motion control and avoidance so the robotic falcon can intelligently come up with motion planning algorithms.

    And another the twist to this story is that bald eagles and other birds of prey are being trained to hunt and take down drones in the Netherlands. Dutch police have been investigating this natural “anti-drone technology” to combat criminal use of drones, and to counter the prospect of drones being used to deliver bombs or chemical and biological weapons.

    UAV inspection/monitoring to reduce costs and enhance safety

    A DJI UAV was recently used by Lufthansa Aerial Services to inspect rotor blades on wind turbines. Previously, inspection was somewhat dangerous, and required climbing the wind turbine tower. While cost reduction may be the principle motivation, it’s possible that wind turbine inspection and maintenance periods could also be extended.

    And, in partnership with Flot Systems, Xcel Energy has become the first utility company to use drones in beyond-line-of-sight inspection of more than 320,000 miles of electricity and natural gas infrastructure.

    UAV-inspections

    Xcel began using UAVs to visually inspect substations in 2015, and is one of the first operations to receive FAA approval for research to use “beyond visual line of sight” for these inspections.

    Previously, manned helicopters were contracted that would carry an inspector and would fly along transmission lines. But from a safety viewpoint, flying UAVs near high-voltage lines is less risky for workers and pilots. Transmission line inspectors also used to have to walk through difficult terrain which can also be hazardous.

    (Editor’s note: Look for more information on UAV’s used for utility inspections in the March issue of GPS World.)

    Another major area that can benefit from the use of drones is agriculture. Remote crop inspection through live and recorded video helps farmers gather much better information to support improved crop growth.

    A Hermes 450 may be gathering lots of usable growing crop information this summer, provided an ag project in North Dakota is approved. The UAV can carry up to 400 pounds of sensors and cameras, and collects data at around 92 mph for 14 hours at 8,000 feet, covering 50,000 acres per hour.

    Photos and videos of growing corn, sugar beet and other crops have the potential to identify fertility deficiencies, yield estimates, and weed and disease issues. North Dakota State University (NDSU) is collaborating with the Northern Plains UAS Test Site and Elbit Systems of America to conduct the crop project.

    The operation is planned to cover a whole county in North Dakota, mostly outside line-of-site of the operator, so in this case a manned aircraft is needed to observe the UAV — it’s a safety condition of the FAA Section 333 approval. Many producers in North Dakota are already buying, registering and flying their own smaller UAVs.

    And one drone operator is taking a pro-active approach to help the agriculture industry decide if using drones can help them. Working with the American Farm Bureau Federation, on behalf of several major sponsors, Measure  has released what it calls the Drone Flight Calculator.

    The Drone Flight Calculator quantifies the economic benefits of using drone services for crop monitoring — such as soy, corn or grapes. When data such as fertilizer use, farm size, and crop type are entered, the calculator provides economic returns by acre and for each growing season. Farmers can also learn how much they can expect to save on inputs such as fertilizer and irrigation.

    Drone flies into hurricane

    The National Oceanic and Atmospheric Administration (NOAA) has been working with several UAVs to investigate the tracking and modeling of hurricanes. NOAA successfully deployed a Coyote UAV from a P-3 hurricane hunter aircraft into the eye of Hurricane Edouard in the fall of 2014. The Coyote is a small, expendable UAS that can be tube-launched from an aircraft or from the ground.

    The seven-pound unmanned aircraft was deployed from a free-fall chute in the belly of the plane, which then opened its six-foot wingspan to fly through the storm. It can be controlled from miles away, but was piloted by scientists onboard the P-3.

    A successful calibration flight over Avon Park, Florida, was recently completed, where a Coyote was launched from a P-3 hurricane hunter aircraft to prepare for deployment during storm season.

    “This successful flight gives us additional confidence that we will be able to use this unique platform to collect critical continuous observations at altitudes in the storm environment that would otherwise be impossible,” said Joe Cione, a hurricane researcher at NOAA’s Atlantic Oceanographic and Meteorological Laboratory and chief scientist of the Coyote program.

    Read more about the Coyote hurricane program here, and in the February print issue of GPS World.

    Anti-drone system

    With a particularly military look to it, a consortium of British companies has come up with a system to defeat potential attacks using drones. Dubbed the Anti-UAV Defence System (AUDS), it combines electronic scanning air security radar, a stabilized electro-optic director, infrared and daylight cameras, target tracking software, and a directional radio frequency (RF) inhibitor/jammer system.

    Source: Tony Murfin
    Anti-UAV Defence System (AUDS).

    The portable system can spot small, slow-moving drones up to four miles away using radar. A military-grade camera then tracks it before jamming the radio signals that control it, making it impossible to fly. The whole process can take as little as 15 seconds.

    With incidents of drone-related security breaches occurring regularly, there is a need to address heightened UAV concerns within military, government, critical infrastructure and commercial security organizations. While UAVs have many more positive applications, it’s nevertheless anticipated that they could also be used for terrorism, espionage and smuggling — with cameras, weapons, toxic chemicals, explosives and drugs as potential payloads.

    The AUDS technology has apparently been extensively tested in South Korea, at French government trials and in UK government-sponsored counter-UAV trials.

    In fact, this system or one very much like it underwent a successful trial at London’s Remembrance Day parade. The system was installed on the roof of Scotland Yard, close to where the Nov. 11 ceremonies took place. Police in the UK are apparently looking for such a device to block drones flown by terrorists at major public and sports events.

    Along the same lines, Drone Labs has developed a Drone Detector unit that appears to use audio and radio frequency sensors along with GPS to find not only a drone, but also the location of the operator, over at least a range of 1 kilometer.

    Drone Labs plans to add video, thermal and radar detection capabilities. The object is to provide some level of protection from drones used for illegal activities, such as delivering contraband at prisons. Some operations already using the system include movie sets, celebrities and facility management professionals seeking to protect assets and people from intrusive drones, as well as law enforcement. Presumably, criminals might also use such a system to reduce the risk of detection by law enforcement drones.

    Crashing drone nearly hits skier

    And, while it’s good that we put attention on protecting us from potential drone attacks, it’s unfortunate that we recently witnessed live TV coverage of a drone crash that could have had really bad consequences. In December, one of world’s best Alpine skiers was lucky not to be taken out by a crashing drone carrying a TV camera during a slalom run in Italy. Unfortunately, following the incident, the International Ski Federation (IFS) went on to ban camera drones from its World Cup races.

    IFS’s broadcast partner — Infront Sports and Media — has indicated the likelihood that the control link to the UAV may have been lost, possibly due to radio interference. Infront has decided to engage an external independent expert to formally investigate the incident. IFS noted that the drone operator had agreed to maintain a safe 15-meter distance from the ski slope. However, it’s possible this safety margin was not maintained…..err, well, it would seem so! The drone fell directly onto the ski slope!

    So, maybe it was some over-zealous operator error along with a technical failure — this can happen with any technology — but hopefully no active jamming was involved. For one, I was happy that nothing broke on the overhead camera-carrying wire-system following the action on the field at the Super Bowl this weekend! (It wasn’t such an exciting game in the end anyway.…)

    Almost every day, news about UAVs continues to pour in with updates on regulation, legal aspects of drone operations, new ways to reduce costs by applying drones to an existing task, and privacy and security angles on why and when something should or shouldn’t be done with an unmanned air vehicle. It’s interesting to watch how things develop in this new industry — almost like when GPS was brand-new and just getting started…

    Tony Murfin
    GNSS Aerospace