FocalPoint has added new functionality to its Supercorrelation technology, S-GNSS, to simplify the integration process for chipset companies.
The company has introduced an API interface between a GNSS chipset and an application or operating system that runs on its own navigation engine, easing deployment of Supercorrelation.
Based on the existing Android open-source interfaces, the S-GNSS API will allow a normal GNSS chipset to run S-GNSS in a separate external host processor. With this additional software added to the GNSS chipset, the overall system can get the performance improvements necessary to upgrade the GNSS receiver to a S-GNSS receiver and offer enhanced positional capabilities.
The S-GNSS API outputs the multipath-free line-of-sight correlation peak for each satellite and the corresponding corrected frequency, codephase and status flags. Optional outputs can be enabled with turn-on keys, spoofer detection and localization, and instantaneous magnetic-free heading estimation.
Supercorrelation has recently been awarded the National Technology award for Security Innovation of the Year and is recognized by the UK Royal Institute of Navigation and the Institute of Navigation. This development is the latest technical upgrade for the S-GNSS product portfolio.
The U.S. Department of Transportation (DOT) has unveiled its Complementary Positioning Navigation and Timing (CPNT) Action Plan, which contains steps the department is taking to drive CPNT adoption across the United States transportation system and within other critical infrastructure areas. This plan was mentioned by Robert Hampshire — Deputy Assistant Secretary for Research and Technology and Chief Science Officer, U.S. DOT — during his keynote address at the annual Civil GPS Service Interface Committee (CGSIC) meeting on September 12, at ION GNSS+, which GPS World’s Editor-in-Chief, Matteo Luccio, is attending.
In 2020, the U.S. DOT Volpe National Transportation Systems Center conducted field demonstrations of various PNT technologies that could offer complementary service if GPS is disrupted. The department was able to gather information on PNT technologies at a high technology readiness level that can work in the absence of GPS.
The U.S. DOT have selected 11 candidate technologies to demonstrate positioning or timing functions:
Two vendors demonstrated low-Earth orbit satellite PNT technologies — one L-band and one S-band;
two vendors demonstrated fiber-optic timing systems, both based on the White Rabbit Precision Time Protocol;
one vendor demonstrated localized database map matching database, inertial measurement unit, and ultra-wideband technologies; and,
six vendors demonstrated terrestrial radio frequency PNT technologies across low frequency, medium frequency, ultra-high frequency, and Wi-Fi/802.11 spectrum bands.
Five of the selected technologies were demonstrated at Joint Base Cape Cod in Massachusetts, and six were demonstrated at NASA Langley Research Center in Virginia. The demonstrations were scenario-based implementations modeled on critical infrastructure use cases under different operating conditions.
Two central recommendations from the demonstration were made: the U.S. DOT should develop system requirements for PNT functions that support safety-critical services; and the U.S. DOT should develop standards, test procedures, and monitoring capabilities to ensure that PNT services, and the equipage that utilize them, meet the necessary levels of safety and resilience identified in recommendation one.
The U.S. DOT has also released a request for information (RFI) as one of the steps in driving adoption of complementary PNT services to augment GPS. The department is planning a resiliency test, evaluation, and performance monitoring strategy for PNT-dependent transportation systems.
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An exclusive interview with Julian Thomas, managing director, Racelogic. For more exclusive interviews from this cover story, click here.
In which markets and/or applications do you specialize?
We originally designed our LabSat simulator for ourselves, because we supply GPS equipment to the automotive market. Then, we decided to sell it into that market, which is our primary market, for other people to use. That’s where we started, but it has moved on since then. We supply many of the automotive companies who use it for testing their in-car GPS-based navigation systems.
However, we’ve moved on to our second biggest market, which is the companies that make deployment systems for internet satellites, which use it for end-of-life testing. Several of our customers use it. That’s because we do space simulations, so we can simulate the orbits of satellites. That’s very useful when they’re developing their satellites.
We supply many of the major GPS board manufacturers — such as NovAtel, Garmin, and Trimble — when they’re developing their boards and testing their devices. We supply many of the phone companies — such as Apple and Samsung — and many of the GPS chip manufacturers — such as Qualcomm, Broadcom, and Unicom. More or less any company that’s into GNSS.
How has the need for simulation changed in the past five years, with the completion of the BeiDou and Galileo GNSS constellations, the rise in jamming and spoofing threats, the sharp increase in corrections services, and the advent of new LEO-based PNT services?
It all started off very simple, with just GPS, which was one signal and one frequency. We got that up and working very well and it helped us a lot. Then we got into this market. In the last few years, we’ve had to suddenly invent 15 new signals. We do two systems, really: one is a record-and-replay system. You put a box in a car, on a bike, in a backpack, or on a rocket, and you record the raw GPS signals; then you can replay those on the bench. That requires greater bandwidth, greater bit depth, smaller size, battery power, all of that.
The other is pure signal simulation. We simulate the signals coming from the satellites from pure principles. So, we’ve had to dive into how those signals are structured, reproduce them mathematically, and then incorporate that in into our software. That’s been 15 times the original work we thought it would be, but as we add each signal it tends to get a bit simpler until they add new ways to encode signals, and then it gets complex again. We’ve had to increase our bandwidth, increase our bit depth for the recording to cover all of these new signals.
Because our systems record and replay, they’re used a lot to record real-world jamming. In many scenarios, our customers will take one of our boxes into the field and record either deliberate jamming or jamming that’s been carried out by a third party. Then they can replay that in the comfort of their lab.
With regards to spoofing, we’ve just improved our signal simulation. So, we can completely synchronize it with real time. We can do seamless takeover of a GNSS signal in real time. We can reproduce the current ephemeris and almanac. If we transmit a sufficiently powerful signal, we can completely take over that device. Then we can insert a new trajectory into it. That’s a very recent update we’ve done.
If the complexity and amount of your work has gone up so much in the last few years but you cannot increase your prices at the same rate, what does that do to your business model?
It’s the same people that produce the signals in the first place, so they still have a job. However, as we add more signals and capabilities, we tend to get more customers as well.
Oh, so, you’re expanding your market!
Right, right.
Regarding some of the new PNT services being developed, how do you simulate them realistically without the benefit of recordings of live sky signals?
It is all pure signals simulation. You go through the ICD line-by-line and work out the new schemes. Here’s an interesting anecdote. Our developer who does a lot of the signal development is Polish and is also fluent in Russian. When we were developing the GLONASS signals, he was working from the English version of the GLONASS ICD. He said that it didn’t make any sense. So, he looked at the Russian version and discovered that the English one had a typo. When he used the Russian version, everything worked perfectly. He told this to his contacts at GLONASS and they thanked him and updated the English translation of their document. So, you are very, very much reliant on every single word in that ICD.
Are there typically differences between the published ICD and the actual signal?
No, no. Apart from the Russian one, which had a typo, they’re very good. For example, we’ve recently implemented the latest GPS L1C signal. My developer spent six months recreating it and getting all the maths right and the only way you could test it was to connect it to a receiver and hit “go.” It just worked the first time. He almost fell off his chair. The ICD in that case was very, very accurate.
Hope that Xona’s ICD is just as good.
Yeah.
Are accuracy requirements for simulation increasing, to enable emerging applications?
Yes, absolutely. No one can have too much accuracy. Everyone’s chasing the goal of getting smaller, faster, and more accurate systems. They want greater precision and better accuracy from their simulators, as well as a faster response. We do real-time simulators and they want a smaller and smaller delay from when you input the trajectory to when you get the output. Luckily for us, Moore’s law is still in effect, so, as the complexity of the signals and the accuracy requirements increase, computers can churn through more data. Luckily, we’re able to keep up on the hardware side as well, because much of our processing is done using software. Some companies do it in hardware and some companies do it in software. We concentrate on the software side of things.
Here’s another interesting anecdote from my Polish guy. He noticed that the latest Intel chips contain an instruction that multiplies and divides at the same time but that it wasn’t available in Windows. So, he put in a request with Microsoft for that operational code and they incorporated it into the very latest version of dotnet, which has improved our simulation time by 7%. I see little improvements like that all the time.
Are all your simulators for use in the lab or are some for use in the field? If the latter, for what applications and how do they differ from the ones in the lab? (Well, for starters, I assume that they are smaller, lighter, and less power-hungry…)
All our systems are designed to be used inside and outside the lab. They can all be carried in a backpack, on a push bike, in a car. We do that deliberately, because we come from the automotive side of things, so we have to keep everything very small and compact.
Besides automotive, what are some field uses?
Some of our customers have put them in rockets, recording the signal as it goes up, or in boats. We have people walking around with an antenna on their wrist connected to one of our systems, so that they can simulate smartwatches. There are many portable applications. We have a very small battery-powered version, which makes it very independent.
Are there any recent success stories that you are at liberty to discuss?
Our most exciting one is a seamless transition for simulation that we developed to replace or augment GPS in tunnels. We’ve been talking to many cities around the world that are building new tunnels. Because modern cars automatically call emergency services when they crash or deploy their airbags, they need to know where they are, of course. Cities need to take this into account when they are building new tunnels, which can pass over each other or match the routes of surface streets. Therefore, accurate 3D positioning in the tunnels has become essential. It requires installing repeaters every 30 meters along each tunnel and software that runs on a server and seamlessly updates your position every 30 meters. As you enter a tunnel, your phone or car navigation system instantly switches to this system. It’s been received very well because it’s mainly software and the hardware is pretty simple. We’ve brought the cost down to a fifth of the cost of standard GPS simulators for tunnels. So, we’re talking to several cities about some very long tunnels, which is very exciting.
A roundup of recent products in the GNSS and inertial positioning industry from the August 2023 issue of GPS World magazine.
SURVEYING & MAPPING
Laser Scanner With several integration options
The VQ-840-G is a fully integrated compact airborne laser scanner designed for combined topographic and bathymetric airborne and UAV-based surveying. The system is offered with an optionally integrated and factory-calibrated inertial measurement unit/GNSS system and can be complemented with an optional camera or IR rangefinder. It also has an optional integrated inertial navigation system. The scanner carries out laser range measurements for high resolution surveying of underwater topography with a narrow, visible green laser beam, emitted from a pulsed laser source. The VQ-840-G has high spatial resolution due to a measurement rate of 200 kHz and high scanning speed of up to 100 scans/second. Riegl, riegl.com
Laser Scanning System A versatile reality capture solution suitable for surveying, construction and engineering users
The X9 is designed to enhance performance in more environments while leveraging Trimble’s X-Drive technology for automatic instrument calibration, survey-grade self-leveling and laser pointer for georeferencing. The X9 expands on Trimble’s X7, delivering longer range, higher accuracy, shorter scan times and sensitivity, improving scan results. Advanced processing and a high-performance laser increase the sensitivity of all scans, enabling the X9 to capture difficult dark or reflective surfaces. A new center unit design also improves signal transmission for better scan quality. The X9 provides accurate and dependable data, enabling confident decision making both in the field and in the office through in-field registration with Trimble Perspective and FieldLink software by minimizing the need for target deployment. The auto-calibration eliminates the need for annual calibration. In addition, the X9 includes survey-grade self-leveling with the industry’s widest compensation range for fast, easy setup. The X9 data can be delivered directly from the Perspective or FieldLink software to Trimble’s office software — including the Realworks 3D scanning software — business center office software, SketchUp and Tekla, or exported to industry-standard formats to produce application-specific deliverables. Trimble, trimble.com
Survey Cameras For photogrammetric applications and to complement lidar survey data
The C5 and C30 orthographic and oblique cameras are designed for aerial surveys. The systems provide high-quality imaging solutions for photogrammetric applications and to complement lidar survey data. The C5 camera is an efficient and lightweight system for aerial surveys, weighing 290 g for increased flight endurance. Its compact size of 75 mm x 63.5 mm x 102.5 mm allows easy integration into UAVs. The C30 camera’s weight is 600 g with a size of 110mm x 108 mm x 85 mm. The C30 is also designed for aerial surveying. The C5 and C30 cameras’ universal installation design makes them compatible with a wide range of fixed-wing and rotor UAV platforms. Both cameras are supported by the CHCNAV’s BB4 Mini and P330 Pro UAVs as well as the DJI’s M300 RTK. The C5 and C30 cameras give maximum flexibility for photogrammetric applications. They can be used independently on real-time kinematic-enabled UAVs to capture high-resolution imagery or installed directly on the CHCNAV’s lidar series to colorize point cloud data. This feature allows seamless imagery and lidar data integration for a more complete view of the surveyed area. CHC Navigation, chcnav.com
GNSS Palm RTK For surveying and mapping, GIS and more
The T20 is light, weighing 0.68 kg, and has low power consumption with 12 hours of battery life. It integrates functions such as a GNSS module, datalink module, 4G, 5.0 dual-mode Bluetooth, data memory system and more. Powered by the SinoGNSS K8 high precision module, the T20 has 1,590 channels and can track all running and planned constellations including GPS, BDS, GLONASS, Galileo, QZSS and satellite-based augmentation systems. Additionally, the anti-interference algorithm enables the T20 to maintain accurate positioning and perform well in complex environments, providing surveyors with high-quality measurements. The T20 is equipped with a third-generation inertial measurement unit from ComNav, which can be tilted and measured at an angle up to 60°. The T20 is also equipped with a U50 datalink module, which enables it to switch between base and rover. The T20 is compatible with mainstream real-time kinematic receivers on the market. ComNav Technology, comnavtech.com
Hybrid Imaging and Lidar Sensor Designed for airborne mapping
The CountryMapper is designed for large-area imaging and lidar mapping. Combining a large-format photogrammetric camera with a high-performance lidar unit into a single system, the CountryMapper collects foundational geospatial data simultaneously to support a wide variety of user applications. The CountryMapper combines imaging and lidar sensor modules into a highly efficient hybrid airborne system. The sensor features CMOS-based Leica MFC150 camera modules that leverage true mechanical forward-motion-compensation to deliver high image quality. The sensor’s new Hyperion3 lidar unit features 60° field of view, improving the performance and flexibility of the system compared to previous lidar modules, while reduced laser divergence provides greater planimetric accuracy and better foliage penetration. The CountryMapper fully integrates with Leica HxMap multi-sensor end-to-end processing workflow, enabling distributed processing of images and point clouds to optimize productivity for very large data sets. The CountryMapper supports applications such as orthophoto generation, terrain mapping, hydrography, forestry monitoring and infrastructure management. Users of previous-generation sensors can leverage their initial investment and upgrade their systems to the CountryMapper configuration. Leica Geosystems, leica-geosystems.com
MOBILE
GNSS Network Rover Complete with an integrated MEMS IMU
The Triumph-3NR (T3-NR) is a small, lightweight GNSS network rover with more than 25 hours of run time on a single charge. The T3-NR easily connects to real-time networks for corrections to get GNSS real-time kinematic with inertial measurement unit tilt compensation. The network rover has 874 channels and can track all constellations. It features an internal GNSS antenna, Wi-Fi, Bluetooth, and is USB compatible. The T3-NR is suitable for demanding industrial applications. JAVAD, javad.com
Antennas Suitable for lawn mowers and other mobile applications
The HX-CSX014A is a high gain, low profile and compact antenna with a new structure that simplifies integration into lawn mowers and minimizes the overall machine dimension. It features small size, high sensitivity and low power consumption. The HX-CSX231A, is a ready-to-use GNSS antenna with a highly reliable structure that makes it small and lightweight. It exhibits 4.5 dBi high gain performance with ultra-low signal loss. It also delivers wide beam width that covers wide frequencies with high marginal gain, a perfect option in complex environments. Additionally, the HX-CSX231A’s advanced LNA features improved signal filtering, out-of-band rejection, restrained unwanted electromagnetic interferences and a strong multi-path reduction capacity. Harxon, en.harxon.com
DEFENSE
PNT Device Enables dismounted maneuver operations even where GPS is compromised or denied
The TRX DAPS II provides assured positioning, navigation, and timing (PNT) to dismounted users by disseminating assured position and time to dependent devices in GPS-challenged environments. TRX DAPS II fuses inputs from M-code GPS, inertial sensors, and complementary PNT sources. It is a small, lightweight PNT device that supports both standalone operation and integration with the Nett Warrior ensemble. It also can distribute PNT information to a customized tactical watch. The TRX DAPS II solution employs a modular architecture and adheres to Army PNT interface standards, facilitating the addition of new PNT sensors as threats evolve. This device will be in production for the Army later this year. TRX Systems, trxsystems.com
TIMING
Image: Microchip Technology
Atomic Clock Maintains system synchronization when GNSS signals are denied
The 5071B cesium atomic clock can perform autonomous time keeping for months in the event of GNSS denials. This device is the next-generation commercial cesium clock to the 5071A. The 5071B is available in a three-unit height, 19-in rackmount enclosure, providing a compact product to work in environments where it can be easily transported and secured versus a larger alternative designed specifically for laboratory environments. The 5071B has upgraded electronic components to address possible obsolescence or non-RoHS circuitry. The clock provides 100 ns holdover for more than two months, maintaining system synchronization when GNSS signals, such as GPS, are denied. As a cesium beam tube product with no deterministic long-term frequency drift, the 5071B provides absolute frequency accuracy of 5E-13 or 500 quadrillionths over all specified environmental conditions for the life of the product. For military applications requiring rapid deployments for system radars, 5E-13 stability eliminates the need for the acquisition of external synchronization sources prior to radiating. Microchip Technology, microchip.com
OEM
GNSS Positioning Modules
For multiple applications
automation of moving industrial machinery, and the ZED-F9P-15B provides customers in the mobile robotics market with an L1/L5 option in addition to the L1/L2 bands. These two modules are based on the u-blox F9 high-precision GNSS platform. The NEO-F9P and the ZED-F9P-15B GNSS modules feature concurrent reception of GPS, Galileo, and BeiDou; multi-band L1/L5 real-time kinematic; short convergence times; and reliable performance. The modules deliver centimeter-level accuracy in seconds and come in small, high-precision form factors.
Its small size, coupled with very low power consumption and ANN-MB1 antenna compatibility, makes the NEO-F9P suitable for a wide range of uses. Offering reliable and efficient positioning, the module supports open as well as standards-based correction services for enhanced performance, such as the u-blox PointPerfect GNSS augmentation service. u-blox, u-blox.com
Image: Septentrio
GNSS Receiver Module
Features built-in AIM+ technology for interference mitigation
The mosaic-X5 is a multi-band, multi-constellation GNSS receiver in a low power surface mount module with a wide array of interfaces. It is designed for mass market applications such as robotics and autonomous systems — capable of tracking all GNSS constellations, supporting current and future signals. The mosaic-X5 has an update rate of 100 Hz, is easy to integrate, and is optimized for automated assembly. The mosaic-x5 is suitable for autonomous vehicles, logistics and port operations, mining and construction, precision agriculture, rail, robotics, surveying and mapping, UAVs and more. Septentrio, spetentrio.com
Xona Space Systems has partnered with the Air Force Research Laboratory (AFRL) and the U.S. Space Force under a $1.2 million Direct to Phase II SBIR (Small Business Innovation Research) contract to work toward a secure low Earth orbit (LEO) positioning, navigation and timing (PNT) constellation leveraging Xona’s PULSAR service.
The contract was awarded through an AFWERX SBIR Open Topic, after Xona demonstrated its LEO PNT technology using the “Huginn” demo satellite in late 2022.
Xona is developing PULSAR – a high-performance PNT service enabled by a commercial constellation of dedicated LEO satellites.
The PULSAR service aims to advance PNT security, resilience and accuracy capabilities by augmenting existing GNSS while also operating as an independent PNT constellation.
“Our partnership with the AFRL Space Vehicles directorate and USSF’s Space Warfighting Analysis Center will give Xona the expertise necessary to seamlessly integrate PULSAR into the U.S. national security space architecture,” said Brian Manning, CEO, Xona Space Systems. “Early assessment of unique DOD PNT requirements will set us up for a successful transition to operational service.”
Colonel Jeremy Raley, commander of the Phillips Research Site and director of the AFRL Space Vehicles Directorate, said the investment will contribute to force design analytics that consider contributing signals from multiple orbit regimes.
“Lessons from this effort will pave the way for future defense programs to successfully utilize commercial space assets for flexible and diverse satnav that is resilient to the adversarial threat,” Raley said.
Preceding the award, Xona became the first company to launch a privately funded PNT mission progressing from concept to on-orbit in less than 12 months. Since then, Xona has partnered with major companies such as Hexagon | NovAtel, Septentrio, Spirent, Safran, and StarNav. In April 2023, the company moved into its new headquarters in Burlingame, California, where the company plans to start the production of PULSAR satellites.
In May the President’s PNT Advisory Board heard a presentation about a National Guard project called NITRO. RNT Foundation President, Dana Goward, recently spoke with the project’s leader, Maj. Gen. Richard R. Neely, Adjutant General, Illinois National Guard, to find out more.
Mr. Goward: Thanks for speaking with us, General. Could you start by telling us what NITRO is and why it’s important?
Maj. Gen. Neely: Of course. NITRO is a project to ensure that the National Guard and our state’s first-responder partners can maintain communications and other critical functions even if we lose GPS timing signals.
NITRO is an acronym for Nationwide Integration of Timing Resiliency for Operations. ]You know how we in the military love our acronyms.
Telecoms and most of the rest of America’s critical infrastructure are dependent on timing from GPS. However, GPS signals are weak, highly vulnerable and under threat.
In addition to bad actors who can and do jam and spoof signals, accidental interference happens all the time. Operations at the Dallas and Denver airports were each interrupted by accident for more than a day last year, for example. A couple of years ago, a passenger airliner almost hit a mountain because of interference with GPS.
Q: It sounds like this is a safety of life issue.
A: It is. Right now, if we lost GPS signals and had to respond to a domestic attack, natural disaster, or other contingency, I am confident there would be additional unnecessary casualties. We are building NITRO so that we can save those lives and keep America safe.
Q: So how does NITRO work?
A: In addition to GPS, it gets multiple sources of space-based and terrestrial time from government and commercial providers. NITRO can use any trusted source. It is not provider- or vendor-specific.
Inputs are combined and compared, matched to the nation’s atomic clocks keeping Coordinated Universal Time, and users are sent the best accurate time multiple ways including over fiber, terrestrial broadcast, and resilient wireless networks.
Another great way in which I think it will be useful: NITRO gives us a common operating picture that can help detect and terminate GPS disruptions and anomalies around the country.
Q: Is the National Guard the only user?
A: Absolutely not! This is a state/federal partnership. The states’ Adjutant Generals are working with their Homeland Security Advisors to make it available to state, local, and tribal first responders. In some instances, also to critical infrastructure.
Even though we are in the early stages of implementation, NITRO is being used by seven states and 256 organizations and it is protecting more than 33 million people, including citizens here in Illinois.
Q: Is NITRO a tasking from the President or Congress? Who told you to do this?
A: NITRO helps execute long standing presidential policy and orders, as well as the recently released National Cybersecurity Implementation Plan. It also meets congressional mandates for backups and alternatives to GPS timing.
However, we created NITRO because we identified a serious threat to the National Guard’s mission execution. It closes 11 operational gaps for us, all without changes to end-user equipment.
Q: With what groups are the NITRO team working?
A: All the states are involved through their adjutant generals, homeland security advisors, and emergency managers. The NITRO board I chair is made up of the adjutant generals from six states.
We are also coordinating across the federal government, especially with the Departments of Homeland Security, Transportation, Commerce, and Energy.
As part of this we are partnering with the Department of Transportation to establish a NITRO engineering and operational site at Joint Base Cape Cod. This will allow engineers from different organizations to see more easily what we are doing and contribute their expertise.
Q: NITRO is going to provide timing signals in places and at times when GPS is not available. Won’t the National Guard also need navigation information?
A: Positioning and navigation are very important, but not quite as critical as timing. So, we are addressing that problem first. And since wireless location and navigation are often based on timing signals, NITRO will provide a good foundation for services and systems that can augment GPS-based navigation.
Q: So, how is the project going?
A: From a technical and operational standpoint, it’s going great. We have very high satisfaction ratings from NITRO users, and states are eager to be connected as soon as possible.
The technologies used are all mature, reasonably low cost, and most components are commercially available. So, engineering-wise it is low risk.
And our team is doing a great job helping folks move from full dependency on GPS to resilient positioning, navigation and timing (PNT) operations.
Q: Do you have any concerns going forward to full deployment?
A: The only thing I worry about is continued funding. Over the next five years we need something less than the cost of one GPS satellite. You would think that would be easy to find for an important effort like this, but it is a state/federal partnership, not a Department of Defense project. So, it falls into a kind of bureaucratic and budgetary no man’s land.
Q: What’s the solution for funding?
A: That’s not our call. The folks at the White House are exploring several alternatives, and I know several members of Congress are also concerned. We see a possibility of this fitting nicely with the recent infrastructure funding bill.
Q: It sounds like NITRO is something America really needs. Let’s hope they find a solution to the funding challenge, and quickly, to keep you on track. Thank you very much for your time!
NextNav has successfully tested its positioning and timing solution that combines the company’s assured position, navigation and timing (PNT) TerraPoiNT system with existing LTE and 5G network signals. The test, which took place in San Jose, California, demonstrated how TerraPoiNT signals can be integrated with existing cellular signals to deliver accurate 3D positioning and timing information that is not reliant on GPS and GNSS signals.
Using dedicated terrestrial transmitters and LTE/5G signals, NextNav’s system delivers accurate and reliable 3D positioning and timing information and can augment or complement GPS in places where GPS signals may not be available. Integrating TerraPoiNT with LTE and 5G signals provides a rapid and cost-effective approach to scaling resilient PNT solutions in GPS-denied environments.
“Whether its utilities, banks, data centers, transportation, or emergency services, critical infrastructure today is reliant on GPS for position, navigation and timing services, making it highly vulnerable to GPS as a single point of failure” said Ganesh Pattabiraman, co-founder and CEO of NextNav. “With this integration, we have demonstrated a highly scalable and lower cost alternative — a 3D PNT solution which overcomes the vulnerabilities of GPS with a complementary ground-based resilient PNT layer that extends PNT capabilities in urban and indoor environments.”
L3Harris has completed a fully autonomous launch and recovery of an autonomous underwater vehicle (AUV) from an underway submarine, referred to as Torpedo Tube Launch and Recovery (TTL&R). The launch used Iver4 AUV technology from L3Harris.
The L3Harris team worked closely with the U.S. Navy to demonstrate AUV launch and recovery through a test program aboard submarines and Navy support vessels.
The recovery of AUVs into an underway submarine allows the host platform to remain covert while the AUV performs surveys and missions in areas inaccessible to the host platform. The AUVs return with data that can be used for tactical and navigational planning — delivering manned and unmanned teaming to a fleet.
According to L3Harris, the company welcomes the continued opportunity to support the Navy in the development of manned and unmanned operational concepts. This capability will increase operational effectiveness and allow SSN-class submarines to serve as an AUV mothership.
Q-CTRL, a quantum technologies company, has partnered with Australia’s Department of Defence to develop quantum sensors that will deliver quantum-assured navigation capability for military platforms.
The company’s partnership is a multi-year effort to field-deploy and validate miniaturized systems on defense platforms. It represents one of the first international partnerships between government and the private sector to apply quantum technology in real defense settings.
Quantum-enhanced navigation technology enables accurate vehicle positioning over long periods when GPS is unavailable. In air, space, underground and underwater, quantum navigation enables long-endurance missions that are otherwise impossible and is resilient against jamming or spoofing.
Q-CTRL announced its quantum sensing division in 2022. The company has worked with partners including Advanced Navigation and the Australian Army to demonstrate and deliver its technology for applications that include remote drone detection.
By using muon-detecting ground stations synchronized with an underground muon-detecting receiver, researchers at the University of Tokyo were able to calculate a receiver’s position in the basement of a six-story building without requiring GPS signals. The muometric positioning system (muPS) team was led by Hiroyuki Tanaka.
As GNSS cannot penetrate rock or water, muon technology could be used in future search and rescue efforts, to monitor undersea volcanoes, and guide autonomous vehicles underground and underwater. Muons are fast, subatomic-sized particles that have been used to wirelessly navigate underground.
MuPS was first created to help detect seafloor changes caused by underwater volcanoes or tectonic movement. It uses four muon-detecting reference stations above ground to provide coordinates for a muon-detecting receiver underground.
Early versions of muPS required the receiver to be connected to a ground station by a wire. However, new research uses high-precision quartz clocks to synchronize the ground stations with the receiver. The four parameters provided by the reference stations plus the synchronized clocks used to measure the muons’ “time-of-flight” enables the receiver’s coordinates to be determined. This system is called the muometric wireless navigation system (MuWNS).
To test the navigation ability of MuWNS, reference detectors were placed on the sixth floor of a building while a researcher took a receiver detector to the basement floor. They slowly walked up and down the corridors of the basement while holding the receiver. Rather than navigating in real time, measurements were taken and used to calculate their route and confirm the path they had taken.
Transportation Secretary Pete Buttigieg made a surprise appearance at the DOT roundtable on complementary PNT. (Screenshot: DOT)
“If this is a problem, the government should act like it.”
Citing more than 10 years of government studies, warnings and promises, representatives from a wide variety of industries criticized the government recently for doing little to address an important national security problem.
At issue was the need for national backup capabilities for GPS and the essential positioning, navigation, and timing (PNT) signals it provides.
GPS signals are weak and easy to block or imitate. At the same time the signals are used by most technologies including networks, telecommunications, electrical grids, broadcast, mobile radios, transportation, and other critical infrastructures.
After Russia threatened to destroy all GPS satellites in 2021 in its run-up to invading Ukraine, a member of the White House National Security Council told a public meeting “GPS is still a single point of failure” for the nation.
The government was criticized for inaction at a “Complementary PNT Roundtable” hosted by the Department of Transportation (DOT) in early August. The department is the federal lead for civil GPS and PNT issues.
Eight attendees interviewed after the event reported a surprising unanimity of comments and concerns expressed by industry reps at the meeting.
Enough with the studies
A repeated theme was that the government has done enough studies to understand the problem and available technologies.
“They have been studying this for over twenty years,” one attendee observed. “The Volpe [Transportation Systems Center] report came out in 2001. And there have been lots of studies since then. All have just been refinements of those original findings.”
Another consistent theme was disdain for the idea that industry and the free market will solve the problem without government leadership and active support.
“GPS is free,” said one attendee from a company that provides PNT services. “We can and do sell to meet niche demands, but it is laughable to suggest we can ever sell enough subscriptions to be enough of a backup for GPS.”
A major telecommunications company rep echoed the sentiment. Wireless telecom is especially reliant on PNT. “We use GPS and would use Loran and low Earth orbit satellites if they were available, but we are not going to build it on our own. There is just no business case.”
“We have a big list of things we could do that would increase our resilience and/or cut costs,” said another telecom provider. “There is no big driver for most, though. No competitive pressure, no government mandates.”
Government must walk the walk
“The government has been telling us for over a decade that this is a problem,” said one attendee. “If that’s true, why aren’t they acting like it? Transportation is critical infrastructure and needs a GPS backup, for example. So why hasn’t DOT done something?” Of all the criticisms expressed, this was predominant, according to interviewees.
A 2021 Executive Order on responsible use of PNT services encouraged critical infrastructure providers to not rely on GPS.
The government needing to be a lead customer was mentioned a number of times at the event. This would help raise awareness, set an example, and signal to users the issue is important enough to act on.
Government action was also seen by users as key to creating confidence that a technology or service will be around for the long haul. This point seemed to resonate with many of the government representatives as well.
“I am not going to go to the time and expense of adopting something unless I know it is going to be around for 20 years or more. The only way I can be assured of that is if one of the biggest users is the government.”
Adversaries not idle
Of particular concern to some was that America’s adversaries have better, more resilient PNT, and are constantly working against us.
They are building PNT “…systems of systems. Space-based, ground-based, and everything in between-based. They are doing it. We need to get out in front and lead,” said one. China has been particularly active building multiple integrated PNT systems.
“Our adversaries are not stupid” and are going to try to stay in the lead. “They will try to interfere with any frequency, system, or combination of systems selected. We must test and build something that is survivable and resilient.”
“If China, Russia, and Iran had the ability to protect themselves from nuclear attack,” said one attendee, “we would be frantically trying to get the same capability. Yet those countries have backup and complementary systems for PNT, and the United States does not. And we’re not doing anything,” said a participant reflecting upon the event.
Hopeful signs
Several attendees said there were signs the event might not have been “just another government meeting.”
As part of his opening remarks, the event host, DOT Deputy Assistant Secretary Dr. Robert Hampshire, mentioned the bipartisan infrastructure law and affirmed that PNT is infrastructure. This led some to believe funding from the infrastructure legislation could be immediately available if the government decided to act.
Others were cheered by DOT Secretary Buttigieg’s cameo appearance and comments at the event. One remarked it was the first time they had heard a DOT Secretary say “PNT” in over 20 years.
Uncertain outcome
Despite the consistent messaging and potentially hopeful signs, some attendees questioned whether anything would change because of the two-and-a-half-hour event.
“There were about 120 people from industry and a wide variety of government agencies, but what was the point?” asked one. “We all told the government the same things we’ve told them before, often in writing.”
Another was concerned that the event didn’t discuss the most important questions.
“We were talking about individual systems and critical infrastructures,” this person said. “This is a strategic national security issue. We need to get the bullseye off GPS and ensure the United States can’t be blackmailed by having GPS held hostage.”
“And what if there is a major coronal mass ejection? China will come out much better than us because they have survivable PNT. The United States will become a second-rate power to China in an instant. We keep talking about the trees and ignoring the forest!”
One attendee whose company has a very active government relations program reported they hoped the event would help sway those in government still opposed to action.
“It is pretty clear to us that almost everyone in the departments who understand the issues is in favor of doing something as soon as possible. The same with Congress. But even though the National Security Council is worried about this, there are some folks in the Office of Management and Budget who have opposed action for over a decade.”
While some came away buoyed by what they saw as an action-oriented tone to the event, others doubted much would change. “It remains to be seen whether criticism from industry and threats from China and Russia are enough to get the government to finally do something.”
Dana A. Goward is President of the Resilient Navigation and Timing Foundation and serves on the President’s National Space-based Positioning, Navigation, and Timing Advisory Board.
Other sources, such as lidar, can be used to aid navigation in the absence of GNSS signals. (Photo: OxTS)
We discussed complementary PNT with Peter Rylands, senior product manager at OxTS.
What are some of the most promising approaches to complementary PNT and how does simulation technology help?
There are two approaches of particular interest. The first is looking at LEO satellite systems that can provide supplementary and potentially more secure methods of navigation, with global coverage from a single system. But these will still suffer from some of the issues GNSS systems experience, namely, what happens when you can’t obtain a signal?
The second is the use of visual aiding through sensor fusion, such as lidar and cameras, that can provide relative positioning (or absolute positioning once you have a space mapped) using SLAM algorithms. While this may increase onboard hardware dependencies, it creates a localized navigation system that can be better protected from malicious actors.
In contrast, closed-loop systems can look to an infrastructure-based system, allowing free movement within the specific area in which the infrastructure is located and a potentially more reliable source of PNT, especially indoors, where GNSS is not available. Ultra-wideband is definitely the up-and-coming technology here, but systems using Wi-Fi, cameras, Bluetooth and others also are being used.
Simulation, as within many domains, allows users to test on a large scale with fewer barriers to entry than real-world testing and an ease in making iterative changes to find an optimal solution. Whether that is to benchmark performance in locations of interest or to change configuration settings to improve visibility or positioning, simulation allows you to do this without the expense of going straight into the environment itself or configuring the actual vehicle under test.
How does OxTS fit in that mix?
OxTS provides customers with the ability to navigate anywhere; whether for reference data in R&D, georeferencing for survey and mapping, or active navigation of autonomous solutions. To do this we provide an IMU-first offering that we then complement with other technologies. Traditionally, this is with GNSS, to form an INS that can provide centimeter-level accuracy. However, we are also aware of the vulnerabilities of GNSS. For us, this is when it becomes an unreliable source of PNT in denied areas, such as indoors, in urban canyons or under tree canopies.
Because of this, we are also investigating and developing complementary solutions that can enhance our offering for users who need confidence in their position even when GNSS is not available. Whether that is through sensor fusion, our Pozyx UWB solution for indoor navigation or other proprietary software and firmware capabilities.
What kinds of complementary PNT are most useful in addressing specifically the challenges posed by jamming and spoofing and how does simulation help?
We need to look at systems that cannot be impacted by, or have mitigations from, the impact of jamming and spoofing. Solutions that are independent of radio communications or satellite use are then valuable in providing this layer of protection. This is where we could look toward OxTS’s use of IMU technology and visual aiding systems. Simulation technologies would then allow you to run hardware-in-the-loop testing, where the primary GNSS solution can have simulated jamming and spoofing to understand the performance of your complementary and protected systems when GNSS cannot be trusted.
