Global Aerospace has made available a standard operating procedure (SOP) manual for small unmanned aircraft system (UAS) operations through its partnership with the Unmanned Safety Institute (USI). Global Aerospace will be exhibiting at booth 745 at the AUVSI’s Unmanned Systems 2015, held May 4-7 in Atlanta.
The “Visual Line of Sight SOP” outlines general operating procedures for UAS and will be made available to qualified Global Aerospace customers. USI is a subsidiary company of Global’s SM4 program partner, Waypoint Global Strategies.
Through the SM4 program, Waypoint and USI provide Global’s UAS customers with discounted consulting and data analytics services and access to flight training.
“Standard procedures are the foundation of safe operations,” said Alex Mirot, president of USI. “We are excited about offering this SOP manual to Global Aerospace customers as a way to promote safety and reduce errors.”
USI offers its clients customized workshops, assistance in drafting and adopting policy and procedures, risk assessment and management, safety assurance, and safety promotion.
Chris Proudlove, senior vice president and team leader, complex risks at Global Aerospace said, “Global Aerospace continues to develop products and tools for the rapidly growing sector of UAS. This comprehensive manual will provide an excellent resource for operators of small UAS.”
April marks the 20th anniversary of GPS FOC. U.S. Air Force Space Command declared Full Operational Capability (FOC) for the GPS constellation April 27, 1995, signifying the system met all requirements with 24 operational Block II/IIA satellites in their assigned orbital slots and providing both the military Precise Positioning Service (PPS) performance standard and the civil Standard Positioning Service (SPS) performance standard.
FOC was formally announced on July 17, 1995.
GPS IIF-9 Launch on March 25
As this magazine went to press on March 19, the U.S. Air Force’s ninth GPS Block IIF satellite (GPS IIF-9) was being readied for a March 25 launch [since successfully launched]. The satellite was encapsulated in the Delta IV rocket’s 4-meter-diameter nose cone at a processing facility, and moved to the launch pad at Space Launch Complex 37 for mating to its booster inside the mobile service tower.
Launch is scheduled for March 25 at 2:36 p.m. U.S. Eastern time from Space Launch Complex 37 at Cape Canaveral Air Force Station, Fla. GPS IIF-9 marks the 29th Delta IV launch and the 57th operational GPS satellite to launch on a ULA or heritage launch vehicle.
CNAV Performance Compares Favorably to Legacy Signals
A March 5 announcement concerning the new L2C and L5 GPS civil signals states: “CNAV Message Types 10, 11, 30 and 33 are currently transmitted on seven GPS IIR-M (L2C) and eight GPS IIF satellites (L2C and L5). A Modernized Navigation (MODNAV) Tool integrated with the GPS ground control software (Architecture Evolution Plan or AEP) is generating the CNAV data messages. Daily CNAV uploads began December 31, 2014, and the U.S. Air Force reports that signal performance of CNAV matches or slightly outperforms Legacy performance: average user range error (RMS URE) from 25 February – 3 March 2015 was 0.50 m for Legacy and 0.57 m for Modernized; best week for Modernized signals since the broadcast initiated April 2014 was 0.42 m for 6 – 13 January 2015.
“Users are reminded that these CNAV signals are ‘pre-operational’ and should be used with discretion until they become fully operational; the L5 message is currently set unhealthy,” concluded Rick Hamilton, CGSIC Executive Secretariat, USCG Navigation Center, in a status email to the Civil Global Positioning System Service Interface Committee (CGSIC).
Galileo Six, Seven, Eight: Lay Them Straight
The original (in red) and corrected (in blue) orbits of the fifth and sixth Galileo satellites, along with that of the first four satellites (green).
On March 17, some stations participating in the International GNSS Service Multi-GNSS Experiment acquired E1 and E5a signals from Galileo 6 (FOC-FM2, GSAT0202). The satellite is using pseudorandom noise code E14.
This development follows the successful repositioning of the sixth Galileo satellite into a corrected orbit, which will now allow detailed testing to assess the performance of its navigation payload. A 20-meter-diameter antenna at the European Space Agency’s (ESA’s) Redu center in Belgium will study the strength and shape of the navigation signals at high resolution.
Launched with the fifth Galileo last August, its initial elongated orbit saw it traveling as high as 25,900 kilometers above Earth and down to a low point of 13,713 kilometers — confusing the Earth sensor used to point its navigation antennas at the ground.
A recovery plan was devised between ESA’s Galileo team, flight dynamics specialists at ESA’s ESOC operations centre and France’s CNES space agency, as well as satellite operator SpaceOpal and manufacturer OHB. This involved gradually raising the lowest point of the satellites’ orbits more than 3,500 km while also making them more circular.
The fifth Galileo entered its corrected orbit at the end of November 2014. Both its navigation and search-and-rescue payloads were switched on the following month to begin testing. Now the sixth satellite has reached the same orbit.
This latest salvage operation began in mid-January and concluded six weeks later, with 14 maneuvers performed in total. Its corrected position is effectively a mirror image of the fifth satellite’s, placing the pair on opposite sides of the planet. The exposure of the two to the harmful Van Allen Belt radiation has been greatly reduced, helping to ensure future reliability.
The corrected orbit means they will overfly the same location on the ground every 20 days. This compares with a standard Galileo repeat pattern of every 10 days, helping to synchronize their ground tracks with the rest of the constellation.
“I am very proud of what our teams at ESA and industry have achieved,” said Marco Falcone, head of the Galileo system office. “Our intention was to recover this mission from the very early days after the wrong orbit injection. This is what we are made for at ESA.”
The decision whether to use the two satellites for navigation and search-and-rescue purposes will be ultimately made by the European Commission, as the system owner, based on the in-orbit test results and the system’s ability to provide navigation data from the improved orbits.
March 27 Launch Date for Galileo Seven, Eight
The seventh and eighth Galileo satellites, set for launch together on March 27, were placed onto the Fregat upper stage of their Soyuz ST-B launcher in mid-March. [The satellites have been successfully launched.]
The Fregat stage will hold the satellites in place during their four-hour flight into orbit 22,300 kilometers above the Earth. Then, at the correct altitude, the two satellites are sprung away in opposing directions.
The Fregat upper stage was blamed for theAugust mis-delivery of Galileo satellites five and six. The root cause of the anomaly producing the wrong orbits was a shortcoming in the system thermal analysis performed during stage design, according to findings by an independent inquiry board.
The anomaly occurred during the flight of the launcher’s fourth stage, Fregat. It occurred about 35 minutes after liftoff, and was due to a temporary interruption of the joint hydrazine propellant supply to the Fregat thrusters. The interruption in the flow was caused by freezing of the hydrazine, resulting from the proximity of hydrazine and cold helium feed lines, these lines being connected by the same support structure, which acted as a thermal bridge. Ambiguities in the design documents allowed the installation of this type of thermal bridge between the two lines.
IRNSS Launch Scheduled for March 29
The launch of the fourth satellite for the Indian Regional Navigation Satellite System, previously scheduled for March 9, was postponed until March 29 at 13:00 UTC, due to the replacement of a faulty telemetry transmitter on the satellite. [The satellite has been successfully launched.]
IRNSS-1D will be fourth in the seven-spacecraft IRNSS constellation.
BeiDou, Too, in Late March
There are indications that the first satellite in the BeiDou Phase 3 expansion may be launched by the end of March [since successfully launched]. Apparently, a BeiDou satellite has been shipped to the Xichang launch site, and tracking ships have left port for the open ocean. Also, a philatelic first day cover for the launch (a common Chinese practice) has been issued with a March 2015 inscription. This is likely a launch of a medium Earth orbit (MEO)satellite.
Where It All Began for Galileo and EGNOS
The European Space Agency issued a press information notice on June 11, 1995 — in the same timeframe as the GPS FOC announcement noted on the previous page — titled “Europe’s Contribution to a Navigation Satellite System.”
“The European Commission, the European Space Agency (ESA), and the civil aviation organisation EUROCONTROL have agreed to cooperate on a joint programme).The European Satellite Navigation (ESN) Action Programme, elements of which are GNSS-1 [First Generation Global Navigation Satellite System] and GNSS-2, is planned to run for five years (from mid-1995 to mid-2000) with a budget of the order of 150 million euros.
“National aviation authorities and the parties involved in the action programme see Europe’s commitment to satellite navigation as being of strategic significance for the future.
“The main objective of the programme is to develop technologies that will ensure that data from the two existing Global Navigation Satellite Systems — the United States’ GPS and Russia’s GLONASS — which are both under military control, will also be available for civil use on a reliable basis and will provide the requisite precision.In parallel, studies will be conducted in order to make preparations for a second generation satellite-navigation and positioning system (GNSS-2), to be deployed as from 2005.
“In the first phase (GNSS-1), ESA’s contribution to the joint action programme will be EGNOS [European Geostationary Navigation Overlay Service].Satellites stationed in geostationary orbit at an altitude of about 36,000 km will relay to aircraft, shipping or road vehicles information that will enable the recipients to determine their actual positions with greater precision than is possible by using GPS/GLONASS data alone.Civil users of those systems receive artificially degraded data deviating by about 100 metres.EGNOS, will enable in particular, to increase the number of satellites that can be seen by a given user within the geostationary broadcast area.
“Around the period 2005–2008, after completing a trial period, the new system is due to be used as sole means.”
Galileo, Previously GNSS-2
“It is planned to develop GNSS-2 in the period between 2005 and 2020, building on experience acquired under GNSS-1.From the technical viewpoint, the second generation will be a considerable improvement on the first in terms of reliability, precision and availability.
“However, if Europe were to confine itself to developing the relevant technologies, its industry would have only a very slim chance of being involved in the construction of the satellites for the system or in the control and user segments for a second-generation civil system (GNSS-2). Given that U.S. and Russian firms are the current leaders in this area, it is necessary for strategic reasons for Europe to carry out a comprehensive development and demonstration programme as it must be able to prove it has the requisite capabilities before GNSS-2 becomes operational, which, in the experts’ opinion, will be from 2005.
“The time schedule foreseen for the different steps can be summarised as follows:
GNSS-1 mission analysis and definition studies: mid-1995 to mid-1996
European GNSS-1 pre-operational mission (task 1): to end 1997. Development of the geostationary network, following the Inmarsat III launch and first ranging demonstration phase
GNSS-1 (task 2): 1996 to end 1998. In parallel to the development of the network, the Ground Integrity Channel will be set up, followed by a second demonstration phase
GNSS-1 (task 3): 1997 to early 2000. Wide Area Differential service for precision approaches to be set up and tested
Introduction of GNSS-1 as sole means: 2000/2003.”
GPS World is indebted to Richard Langley’s CANSPACE archive of historical documents for this note of interest.
Mason, Bruce & Girard Inc. (MB&G), a natural resource consulting firm, has released version 2.0 of its mobile mapping application, MobileMap.
MB&G MobileMap provides GIS capabilities to field staff. It focuses on supporting large datasets and integrating information from diverse sources. The app provides data visualization, analysis and editing while operating in disconnected environments.
MobileMap supports an unlimited number of base maps and feature types, and allows users to quickly switch between data by turning layers on and off. Version 2.0 of MobileMap provides flexibility in how data is organized on a device, and by supporting Esri’s shapefile format, users can define the map symbology of shapefiles.
By targeting the Android platform, MobileMap takes advantage of a large range of device options as well as capabilities unique to Android such as support for MicroSD cards, which greatly enhance storage capacity while dramatically reducing data transfer speeds for large datasets.
A major component of this release is improved data sync capabilities. MobileMap leverages enterprise GIS technology from Esri by enabling seamless sync with ArcGIS Server and ArcGIS Online feature services. Users will always have data that is backed up and up-to-date. By establishing a Wi-Fi connection, data can be synced to a secured service. In order to provide greater control over this process, MobileMap allows users to separate sync into separate upload and download tasks.
According to MB&G, MobileMap 2.0 provides improved measurement and navigation capabilities; users can now measure both distance and area of features and can choose the appropriate map units for each parameter.
MobileMap 2.0 displays the distance and direction to any selected feature, allowing field staff to navigate to management areas, survey plots or specific assets. Another new capability is the ability to perform offline search of features. While other mapping tools use internet connections to search for relevant data, MobileMap supports the ability to search offline data to identify where particular attributes or conditions exist in the landscape. When features are discovered, they are highlighted and the map zooms to their extent. These capabilities provide field staff with a valuable tool for discovering data and locating areas of interest.
MobileMap’s data capture also has been improved. Previous versions supported GPS tracking of a travel path and the ability to define new features using GPS coordinates, or by tapping to create points or vertices in lines and polygons. Users now can collect lines and polygons by tracing the desired shape in a single motion.
Data entry has been improved by supporting additional business rules, such as range domains and required fields. Data managers can carefully specify data integrity rules using Esri data models, and MobileMap will respect and enforce those rules in the field. This functionality helps to ensure that MobileMap users will collect high quality data thereby minimizing the need for data editing back in the office.
Winners in the 30 categories will be announced in October.
The 2015 European Satellite Navigation Competition (ESNC), an international innovation competition that recognizes the best ideas in satellite navigation, will run from April 1 to June 30. Winners will be announced in October.
There are more than 20 regions participating, and the ESNC will award prizes worth a total of €1 million in 30 categories.
“Satellite navigation is an essential element of modern mobility and a key technology in particular, in the age of a data-driven economy. This is exactly where the European Satellite Navigation Competition comes in. It provides a public platform to the creative community in order to help promising ideas turn into solutions that are commercially mature and generate added value for society,” said Alexander Dobrindt, Germany’s Federal Minister of Transport and Digital Infrastructure (BMVI).
A jury of international research and industry experts will select the year’s overall champion among the winners of the categories, which comes with an additional €20,000 and access to a six-month incubation program in the champion’s preferred region.
International kick-off for the 2015 ESNC is scheduled for April 21 in London.
“As the Galileo satellite constellation continues to expand, efforts to promote corresponding applications will become increasingly important. This is where the ESNC is already playing a key role,” said Matthias Petschke, the European Commission’s director of satellite navigation programs. “As such, the Commission is definitely looking forward to seeing the creative and innovative GNSS-based applications submitted this year.”
This year’s special topic prizes are being sponsored by the European GNSS Agency (GSA), the European Space Agency (ESA), the German Aerospace Center (DLR) and the Ministry of Transport and Digital Infrastructure (BMVI) in cooperation with the German Federal Ministry for Economic Affairs and Energy (BMWi). Entrants may submit prototypes to the GNSS Living Lab Challenge, while the University Challenge specifically addresses students and research assistants.
“Those who enter the ESNC benefit in particular from our global network, which provides them with tailored support in developing their business concepts and bringing them to market,” said Thorsten Rudolph, managing director of Anwendungszentrum GmbH Oberpfaffenhofen.
All of the information on this year’s prizes, partners, and terms of participation is available at the ESNC website.
McMurdo Group, maker of end-to-end search and rescue solutions, has received formal certification from the U.S. Federal Aviation Administration (FAA) and European Aviation Safety Agency (EASA) for its Kannad Integra ARINC 429 Navigation Interface.
Based on the ARINC 429 GPS communications standard for most commercial aircraft, the interface, when used with the Kannad Integra Emergency Locator Transmitter (ELT), provides dual GPS redundancy that can result in aircraft being found much faster compared to standard ELTs in event of an emergency. The solution has already been selected by aircraft manufacturers including Pilatus, Embraer and Airbus Helicopters.
Traditional ELTs rely on an aircraft’s external antenna and GPS equipment, which is subject to failure in the event of an emergency. The Kannad Integra ELT, however, can operate independently of the aircraft to provide key positioning data through its built-in internal antenna and embedded GPS receiver. The Integra ARINC 429 navigation interface stores the latest known position of the aircraft based on the aircraft navigation system data. This data is then used by the built-in Integra GPS for better location accuracy and a higher chance of rescue.
The Kannad Integra ELT and Integra ARINC 429 Navigation Interface are suitable for commercial aircraft, helicopters, business jets and airlines. Once activated, the Integra ELT transmits a distress signal to alert international rescue services to the emergency location via the global Cospas-Sarsat Search and Rescue satellite system, which has helped to save more than 37,000 lives since 1982.
“McMurdo’s Kannad products have been chosen by the world’s leading aircraft manufacturers and airlines for their quality, reliability and innovation,” said Christian Belleux, head of McMurdo’s Kannad Aviation Business Unit. “This new ARINC 429 interface is yet another example of how we are helping to shape the present and the future of aviation safety.”
When subjected to very strong interference, a GNSS receiver can be totally blinded and stop working. This is often the scope of intentional jammers. However, in a number of cases the presence of interference is severe enough to significantly decrease receiver performance, but not so much as to make the receiver lose its lock on the satellite signals or blind the acquisition of the satellite signals.
Such intermediate power values turn out to be the most dangerous cases, because sometimes they cannot be detected, but lead to a worsening of the positioning performance. The accuracy of the position solution depends on, among others, the quality of the pseudorange measurements and/or the phase measurements. Thus, when radio-frequency interference (RFI) degrades the pseudorange and phase measurements or induces cycle slips on the phase measurements, the accuracy of the position solution will decrease.
Impact on the Front End
The front-end filters the incoming signal, demodulating it to the chosen intermediate frequency before performing the analog-to-digital conversion (ADC).We must consider the presence in the front end of the adjustable gain control (AGC) between the analog portion of the front end and the ADC. When the GNSS band is interference-free, AGC gain depends almost exclusively on thermal noise, since the received signal power is below that of the thermal noise floor. When in-band interference is present, the AGC will squeeze the incoming signal to match the maximum dynamics of the ADC, causing a reduction of the amplitude of the useful signal, which may be lost. This may typically happen in the presence of some kind of wide-band interference (WBI) spread over a bandwidth larger than the passband of the front-end filter.
With narrow-band (NBI) or continuous-wave interference (CWI), statistics of the digital signal at the ADC output are also affected. In this case the AGC can still compress the input signal to avoid a stronger saturation, but the following receiver stages will have to deal with a GNSS contribution quantized only on lower levels.
In the presence of stronger interference, even the other components of the front end (filters and amplifiers) may be led to work outside of their nominal regions, generating nonlinear effects or clipping phenomena (in which the signal amplitude exceeds the hardware’s capability to treat them). In both cases, spurious harmonics are generated and mixed with the useful signal in the front end itself.
Impact on the Acquisition Stage
If the interference is not driving the AGC/ADC to full saturation, the acquisition module is still able to perform its task, processing the interfered signal to estimate the code phase and the Doppler shift with respect to the local code. The correlation with the local code can be seen as a spreading operation followed by a filter.
Figure 1. GPS L1 C/A acquisition search space in (a) an interference-free environment and in the presence of (b) –140 dBW in-band CWI; (c) –135 DBW in-band CWI; (d) –130 dBW in-band DWI.
Figure 1 showsthe acquisition search space for different levels of theinterfering power of a CWI from –140 to –130 dBW compared to the interference-free case. The search spaces depicted for the four scenarios are achieved using 1 ms of coherent integration time and three non-coherent accumulations, and the peak-to-noise-floor separation defined as
is considered as a figure of merit. The value of αmean decreases as the interfering power increases, thus increasing the probability of a false alarm. With the increasing power of the CWI, a modulation effect in the search space floor in the Doppler domain dimension can be observed. Such an effect is mainly determined by the new harmonics components generated by the multiplication between the locally generated carrier and received CWI. Such an effect also depends on how the interfering signal and the useful GNSS signal are combined at the entrance to the acquisition block, which in turn depends on the random variables φ0 and θint.
In the presence of WBI, a different effect is observed in the acquisition search space. Considering a band-limited Gaussian white noise spread all over the GNSS useful filtered signal components, the effect on the CAF envelop is an increase in the noise floor. This increases the search space noise floor. The presence of additive band-limited noise causes a uniform increase in the noise floor tin the search space that might mask the correct correlation peak and thus fool the acquisition process.
Impact on the Tracking Stage
Interference impact on the tracking stage has a direct consequence on the quality of the measured pseudorange. Harmful interfering signals increase the variance of the time-of-arrival (TOA) estimate by the discriminator and modify the shape of the S-curve of the code discriminator, thus creating in some cases a bias in the measurements.
Figure 2 depicts outputs of the early-prompt-late correlators. In the presence of in-band CWI and of NBI, the interference is injected 9.3 seconds after the beginning of the tracking stage where the receiver is correctly locked on the received signal. A CWI, shifted 200 kHz with respect to the signal intermediate frequency (in correspondence with a C/A code spectrum line), increases the noise at the correlators outputs and leads to harmonic behavior of the early-prompt-late correlator outputs.
Figure 2. GPS L1 C/A code tracing error comparison: coherent and non-coherent early-late processing (CELP and NELP).
NBI increases the variance of the correlators’ outputs; this directly increases the pseudorange error and the noise on the receiver phase measurements. Additive band-limited noise leads to an overall increase in the carrier phase discriminator output variance over the 3σ threshold, which for a PLL two-quadrant arctangent discriminator is 45 degrees. When in presence of strong CWI, a sudden jump of the phase discriminator output is detected as soon as the CWI is injected onto the received signal.
Impact on the Estimated Signal-to-Noise Ratio
Sticking to the definition of C/N0 as the ratio between the received power and the power spectral density due to thermal noise at the input of the receiver, the presence of interference should not change the value, since the thermal noise is not increasing. However, the C/N0 value provided by the receivers is estimated on the basis of the correlator outputs at the tracking stage. For this reason the estimation is affected by the presence of the additional (nonthermal) noise generated by the interference. The variation of the C/N0 can also be used as observable for interference (or other threats) detection.
Chapters: The Interference Threat; Classification of Interfering Sources and Analysis of the Effects on GNSS Receivers; The Spoofing Menace; Analytical Assessment of Interference on GNSS Signals; Interference Detection Strategies; Classical Digital Signal Processing Countermeasures to Interference in GNSS; Interference Mitigation Based on Transformed Domain Techniques; Antispoofing Techniques for GNSS. The book is intended for members of the engineering/scientific community with pre-existing knowledge of satellite navigation principles and GNSS.
FabIo Dovis holds a Ph.D. in elecronics and communications engineering from Politecnico di Torino, Italy, where he is an associate professor.
The GPS World Galileo Product Showcase, from the April 2015 issue, features the latest products from seven top companies.
GPS/GLONASS/Galileo Receiver
Septentrio AsteRx3 Photo: Septentrio
The AsteRx3 is a multi-frequency GPS/GLONASS/Galileo receiver is designed for demanding industrial applications. AsteRx3 features simultaneous high-quality GPS, GLONASS and Galileo tracking and a range of innovative features, such as the patented Galileo AltBOC tracking, the advanced multipath mitigation algorithm APME, LOCK+ tracking for exceptional tracking stability under high vibration conditions, RTK+ for extended RTK baselines and faster initialization, and AIM+, Septentrio’s Advanced Interference Mitigation technology, offering centimeter-level measurement quality for high-precision positioning, even in challenging environments.
The IFEN SX3 multi-GNSS software receiver Photo: IFEN
IFEN’s SX3 multi-GNSS software receiver tracks all known GNSS signals in view, including Galileo signals, in real time on a standard laptop now and in the foreseeable future (up to 1,000 channels in parallel on a core i7). The included RF front end offers four RF frequency paths with 50-MHz bandwidth each, covering the entire GNSS L-band spectrum. The USB 3.0 interface enables high-speed data transfer with up to 8-bit quantization. An optional dual RF input front end can be used for attitude determination, reflectometry and other applications requiring the synchronized input from two antennas. An optional built-in shock and vibration robust OCXO reference oscillator (MIL-STD 202G) is available, which replaces the standard high-quality TCXO normally used.
The SX3 software lets users configure the data processing, including changing loop bandwidths, integration times and the main processing rate, and choosing between different correlation types. The software includes a multi-correlator providing a two-dimensional (code and Doppler) correlation function visualization in real-time. The receiver comes with several powerful processing algorithms like vector tracking, to improve the tracking of weak signals in degraded environments.
The NEO-M8L Automotive Dead Reckoning (ADR) module by u-blox has integrated motion, direction and elevation sensors. The module integrates gyro and accelerometer with u blox’ GNSS platform M8 to achieve high indoor/outdoor positioning performance for road vehicle and high-accuracy navigation applications.
The module is able to track all visible GNSS satellites including GPS, GLONASS, BeiDou, QZSS and all SBAS, with Galileo to be supported in a future firmware version. Concurrent reception of two GNSS systems is supported. The NEO-M8L module can output a position up to 20 times per second.
In addition to accessing the integrated module’s gyro and accelerometer data, accident reconstruction systems can provide the location of an accident to facilitate insurance claims even if a collision occurs in a tunnel or park house. High-end navigation devices are able to guide drivers through tunnels of several kilometers because of the accuracy of u-blox’ ADR system. Stolen vehicles can be located instantly due to continuous monitoring of sensor data and storage of location in non-volatile memory.
The NovAtel FlexPak6D enclosed GNSS receiver is a flexible dual-antenna solution for application developers seeking a high-precision heading-capable positioning engine for space-constrained applications.
Designed for efficient and rapid integration, the compact receiver tracks Galileo as well as GPS, GLONASS and BeiDou. Antenna placement is flexible: the antenna baseline can be set according to space available on a vehicle and heading accuracy required. The modular OEM6 firmware enables users to configure the receiver for unique application needs. Scalable for sub-meter to centimeter-level positioning, the FlexPak6D delivers NovAtel’s ALIGN precision heading and relative heading firmware, as well as its GLIDE firmware for smooth decimeter-level pass-to-pass accuracy and RAIM for increased GNSS pseudorange integrity.
The GNSS simulator in the vector signal generator R&S SMBV100A Photo: R&S
The GNSS simulator in the vector signal generator R&S SMBV100A is designed for development, verification and production of GNSS chipsets, modules and receivers. The simulator supports all possible scenarios, from simple setups with individual, static satellites up to flexible scenarios generated in real time with up to 24 dynamic Galileo, GPS, GLONASS, BeiDou and QZSS satellites. The simulator also supports Assisted GNSS (A-GNSS) test scenarios, including generation of assistance data for Galileo.
The simulator offers real-time simulation of realistic constellations with up to 24 satellites and unlimited simulation time. Flexible scenario generation includes moving scenarios, dynamic power control and atmospheric modeling. Users can configure realistic user environments, including obscuration and multipath, antenna characteristics and vehicle attitude.
The all-in-one TRIUMPH-LS by JAVAD GNSS combines a high-performance 864-channel GNSS receiver, all-frequency GNSS antenna, and a modern featured handheld. The 864 all-in-view channels include Galileo E1/E5A/E5B, GPS L1/L2/L5, GLONASS L1/L2/L3, QZSS L1/L2/L5, BeiDou B1/B2 and SBAS L1/L5.
The TRIUMPH-LS offers GUIDE data collection, Visual Stake-out (VSO), navigation, six parallel RTK engines, more than 3,000 coordinate conversions, advanced CoGo features, and rich attribute tagging on a high-resolution, bright, 800 x 460 bright display. Two 3-megapixel cameras enable recording of images along with GNSS data.
With VSO, the virtual location of a point to be staked can be seen by a “flag” shown on the Triumph-VS camera image. This visual aid helps users navigate quickly to a point and makes stakeout jobs fast and easy. VSO can be used as a convenient way to get close to a target point before switching to the regular stakeout mode to perform precise measurements.
More than 100 channels are dedicated to continuous interference monitoring. The Triumph-LS monitors and reports interference graphically and numerically with patent-pending interference protection. Interference awareness allows safe GNSS operation in a city, airport and military environment.
The unit can serve as base or rover. It has a GSM modem, UHF transmit and receive, and an internal high-performance geodetic antenna.
The TRIUMPH-LS automatically updates all firmware when connected to a Wi-Fi Internet connection.
TeleOrbit’s software-defined radio receiver and GNSS interference monitoring tool receives and processes all available Galileo signals. Signals that are not yet transmitted and interference sources can be simulated and processed within the software tool.
Within a software-defined radio framework, the analog-to-digital converter is moved as close as possible to the antenna to perform most of the signal processing in software. This leads to adaptable solutions with lower hardware costs that can be easily extended to new signals and systems with only a software update.
The GNSS Software Defined Radio Receiver (GSDR2X) developed by TeleOrbit’s sister company TeleConsult Austria can track most readily available signals from Galileo, GPS and SBAS. By utilizing input from TeleOrbit’s GNSS multi-system performance simulation environment (GIPSIE), even signals not yet transmitted by satellites can be tracked and processed by the GSDR2X. Furthermore, input data can be read from various radio frequency front-ends, either directly or from file.
The modular GSDR2X framework enables new capabilities, such as the GNSS Interference Monitoring Tool (GIMT), which enables the GSDR2X to detect and classify interfering and jamming signals (see figure).
Image showing projected Florida flooding, from flood.firetree.net, using Google Earth with NASA data. Image from flood.firetree.net, using Google Earth.
Surveyors, prepare to get your feet wet. Global warming is about to hit you in the job list. By 2050, a majority of U.S. coastal areas are likely to be threatened by 30 or more days of flooding each year. This according to a December report in Earth’s Future, a journal of the American Geophysical Union.
[Parenthetically, the next issue of Survey Scene, in May, will be written by an actual geodesist. Until then, you have to put up with GPS World’s editor in chief — by no means a surveyor. Patience.]
The study used data from National Oceanic and Atmospheric Administration (NOAA) tide gauges to show the annual rate of coastal floods has accelerated in recent years. These are now five to 10 times more likely today than 50 years ago — and getting worse.
Mitigation decisions could range from retreating further inland to coastal fortification or to a combination of “green” infrastructure using both natural resources such as dunes and wetland, along with “gray” man-made infrastructure such as sea walls and redesigned storm water systems. And that’s not even mentioning such basics as redrawing property lines. Any way you look at it, surveyors are going to be involved.
“As communities across the country become increasingly vulnerable to water inundation and flooding, effective risk management is going to become more heavily reliant on environmental data and analysis,” said Holly Bamford, NOAA acting assistant secretary for conservation and management.
The recent U.S. Hydro 2015 conference in National Harbor, Maryland — an area particularly called out for vulnerability to the oncoming floods — naturally found a lot to talk about in this and related areas of interest for surveyors, with session tracks including: Effects of Climate Change on our Oceans and Waterways; Coastal and Ocean Mapping Initiatives; Advances in Unmanned System Technology, and several more.
Some of the papers presented that GPS World found of interest, and hopes to present or encapsulate in some form in the near future, include:
Resolving Systematic GPS Interference from Aeronautical Distance Measuring Equipment during Mission-Critical Shallow Water Multibeam Surveys
GPS Water-Level Buoy for Hydropgraphic Survey Operations
Examining the Uncertainty Associated with the Establishmenbt of an Ellipsoid to Chart Datum Separation Surface Using GNSS Buoys
Comparison of Horizontal and Vertical Resolvable Resolution between Repetitive Multibeam Surveys Using Different Kinematic GNSS Methods.
And those just came from the poster sessions. In the technical sessions, Jack Riley from the NOAA Coast Survey’s Hydrographic Systems and Technology Program presented a GPS Buoy Water Level Uncertainty Case Study.
Data from on High
Since you can’t get at a coastline from all angles — with any degree of stability, that is — data from overhead, sometimes far overhead, proves invaluable. Such as that provided by aerial digital imagery, LiDAR, and increasingly, satellites.
Because digital aerial images are already in electronic form, they can quickly be processed and made available to users. Most of the special cameras in use nowadays provide direct georeferencing capability, which allows camera position and orientation to be determined automatically using GPS and inertial measurement equipment. An entire mini-industry has grown up around integrating aerial data with that taken from ground surveys.
Light detection and ranging (LiDAR), a remote sensing system, became available for commercial topographic mapping in 1993. An airborne laser scanning system paired with a kinematic GPS receiver and an inertial navigation system can calculate and produce a highly accurate spot elevation. It is possible to obtain point densities that would likely take months to collect using traditional ground survey methods. The National Geodetic Survey (NGS) is currently implementing LiDAR into their shoreline mapping production process.
Our Record So Far
Coverage of these salty issues has been sparse in GPS World and associated newsletters, but not entirely absent. In 2006, the May issue featured “GPS Buoys Nautical Measurement.”
In 2008, Richard Langley edited an Innovation column on “Tsunami Detection by GPS,” featuring work for which co-author Attila Komjathy eventually won a GPS World Leadership Award in 2013. And in 2010, Langley brought forth an Innovation column on “Monitoring Water Level with GNSS.”
And way, way back in 2005, we published “Abreast of the Waves: Open-Sea Sensor to Measure Height and Direction.” This was prior to our digital era, so until we can scan a paper copy into here, we’ll simply give the abstract: “Accurate and timely information on open-sea wave conditions can help in preventing large-scale maritime disasters. This article describes a new, low-cost Global Positioning System (GPS)-based sensor that measures wave height with an accuracy of several centimeters and direction with an accuracy of 5 degrees. The receiver is mounted on a buoy, and a high-pass filter is used to extract the movement of the buoy and thus minimize GPS positioning errors. The data provided by the sensor is intended to improve wave prediction models. In addition, since this GPS-based sensor transmits only analyzed ocean wave data, it reduces the volume of data and leads to lower operating and acquisition costs. The article describes the concept of the GPS-based wave sensor, algorithms that are used for filtering and extracting wave data, as well as the results of open-sea trials.”
So there’s more to come. Watch this space. In the meantime, we leave you with Bob Dylan’s prophetic words, circa 1967.
Well, it’s sugar for sugar And salt for salt If you go down in the flood It’s gonna be your own fault.
Avanti Communications has been appointed by the UK Space Agency to deliver a crucial air navigation project in Africa, SBAS-AFRICA. The satellite operator has been awarded the contract under the agency’s International Partnership Space Programme (IPSP), which exists to open up opportunities for the UK space sector to share expertise in real-world satellite technology and services overseas.
Africa has just 3 percent of global air traffic, and yet air accidents in Africa account for roughly 20 percent of the worldwide total. By demonstrating potential improvements in flight safety via SBAS technologies, the project can provide socio-economic benefits to the continent, according to a news release from Avanti.
Based on prior cost-benefit modeling which identified a €1.7 billion potential economic benefit to the African aviation sector from the deployment of SBAS services, SBAS-AFRICA will help accelerate the adoption of GNSS-based flight operations, positively influence the evolution of aviation safety in Africa and encourage development in the wider African economy.
SBAS-AFRICA will deliver a satellite-based augmentation system for GNSS-based operations in the aviation sector, serving significant parts of Africa in partnership with a number of local stakeholders. The project will use a unique asset, Avanti’s ARTEMIS L1 Navigation transponder, to provide a navigation data broadcast service.
“SBAS-AFRICA brings an innovative and pragmatic approach to deploying SBAS services in Africa,” said Matthew O’Connor, Chief Operating Officer at Avanti Communications. “It establishes crucial collaboration between the UK and a number of African countries, including South Africa and Ghana. Participating countries will benefit hugely from expertise gained, placing them at the forefront of navigation services across the continent and, crucially, helping to improve aviation safety for a major generator of economic benefit in Africa.”
He continued, “The Artemis satellite will play an integral role in this project. We expect that such a showcase for its performance, accuracy and quality will provide further evidence of what can be achieved with this technology and lead to significant commercial opportunities.”
“The UK Space Agency is delighted to play a role in fostering new international partnerships that not only enable innovative UK space companies like Avanti to provide more high-tech exports that can boost our space sector but also allow the UK to widely share the considerable social and economic benefits that space technology and infrastructure can provide,” said David Parker, chief executive of the UK Space Agency.
Sessions on indoor navigation and a keynote from Google at February’s International Navigation Conference (INC15), organised by the Royal Institute of Navigation, addressed the revised E911 positioning requirements in the United States, and flowed over into speculation about E112 emergency calling parameters in Europe’s near future.
According to the 2014 U.S. Federal Communications Commission report, 75 percent of 911 calls now come from mobile phones, more than half of those originate indoors, and around 1 percent of emergency calls contain no location information from the caller (due to distress, confusion, language issues, illness, and so on). The report estimates 10,000 deaths per year in the United States might have been avoided if a landline had been used instead, since location information for landlines can be provided confidently.
Discussion in the breaks of INC highlighted a misunderstanding amongst some parties that E911 mandates the use of GPS for position location determination. In fact,E911 does not mandate any specific technology; it specifies performance criteria in terms of accuracy that must be met. The recently revised performance criteria include indoor performance, and some of the technology discussed at the INC is able to meet these requirements without using GNSS at all.
This could be troublesome for Europe, which is looking at the imposition of Galileo as part of an A-GNSS technology push for the E112 application. The real problems, discussed during INC and in European consultation processes with safety of life services such as E112, are:
the accuracy of the position derived by the device and/or network, and
the timeliness of the delivery of that position to the Public Service Answering Point (PSAP).
The E911 directives address these points directly, and the infrastructure in the cellular networks is in place. Does simply implementing a Galileo capability into a European mobile device solve these problems?
In many outdoor cases, implementing Galileo can bring benefits, including signal diversity. And of course the E112 proposal is greater than just “adding Galileo.” It does address the second problem of timeliness of delivery and data transfer, but there are significant infrastructure upgrades required across Europe for the provision of this location data to the PSAPs.
What the E112 processes do not currently do is specify performance criteria for the position location accuracy. This means that the position estimate provided under E112 is likely to be a cell-ID fix, with an accuracy ranging from hundreds of meters to dozens of kilometers.
Galileo on Mobiles. Further discussion during the conference delved into the realms of the specifics of implementing A-GNSS, including Galileo, onto a mobile device. Conversations centered around if any future E911 or E112 positioning capability would be aligned around a single-chip solution as generally currently deployed on a device, or if some of the functions will be moved up the stack into the operating system (OS) of the device, into software.
Most opinions were against this latter concept, and a panel at the ION GNSS+ last year in Florida concluded the same thing. However, questions were asked about some ideas relating to identifying the emergency number at the time of dialing and then starting the position location determination functions in readiness for the need to provide the device location. This addresses the first bullet point earlier, the accuracy of the position derived by the device and/or network. If this is carried out in the OS or software layers, vulnerability of the system will be increased overall as the OS of a mobile device is a target for the cyber criminal community.
A robust software-based solution is, however, being rolled out in the United Kingdom in the form of eSMS, bringing mobile operators, government and handset vendors together to provide location data via SMS to the PSAP. The advantage of this approach is that no new standards or major infrastructure changes are required, and the time to implement is small.
Further discussions established that future chipsets are likely to use whatever GNSS signals are available, regardless of whether they are GPS, Galileo, GLONASS, Beidou and so on. This, coupled with new signal processing techniques (single-frequency observable for example), increasing sensor clustering on devices, and user demand for services, may make the use of a specific GNSS system above others somewhat redundant. Certainly picking up on a point made by Chandu Thota from Google, GNSS is “not relevant” for their indoor positioning solutions, and technologies they are working on, in both hardware and mapping improvements, are looking at meeting indoor accuracy requirements down to a target requirement of 1 meter, without GNSS.
Taking these points into account, questions were asked from the floor of the conference about the legal position of the EC mandating Galileo as a positioning method as well as the willingness of the global mobile chipset and device industry to be told what to do. Perhaps specifying strong performance criteria, as in the United States, is the way forward to “reboot” the European E112 system. No one disputes that a properly functioning E112 is a life saver and a good thing to do; however, the points discussed here detail some of the concerns expressed during and after hours at INC15.
In February 2015, the Royal Institute of Navigation hosted the International Navigation Conference in Manchester, UK. Keynotes at this well-attended conference included Harold Martin, director of the GPS Coordination Office; Gian Gherardo Calini, the head of market development at the European GNSS Agency; Todd Humphreys from the University of Texas; Chandu Thota from Google; and others. The conference covered multiple technology tracks including indoor navigation, autonomy, quantum technology and the resilience of GNSS systems.
Andy Proctor is lead technologist for satellite navigation at InnovateUK, the UK’s innovation agency. He acknowledges Ramsey Faragher, Cambridge University, for help in the preparation of this article.
We have entered a discussion phase at the magazine, a fierce conversation if you will, occasioned on the one hand by the periodic need to freshen our appearance, but also to re-investigate and re-evaluate our whole approach. The way we do things, and the actual things we do. The thoughts and pre-conceptions and mental equipment we carry with us to do our jobs: gathering and presenting the news and the newest in GNSS technology and business.
In the beginning, or before the beginning, really, I asked myself these questions:
What has changed in the last year?
Where are we succeeding?
Where are we failing?
What have we learned in the last six months?
What is required of us now?
Some of the answers to these questions are of course proprietary, but some at least can be shared. So: What has changed in the last year — in the market?
Among new developments, we can count diversification away from the core of GPS/GNSS standalone technology. Never again, really, will satnav positioning suffice to answer the needs of the day. That ship has sailed. That dog has left the porch.
Certainly, though this is nothing new, we also see more international participation in the market, more international involvement on the part of all GNSS companies, no matter where their base, and more international collaboration.
The story of the year, replacing jamming and interference which were the stories of the last few years, is the rise of unmanned autonomous vehicles (UAVs), whether in the air, on land, or sea.
Finally, as a reflection of these trends, some trade shows and conferences are declining, while others grow in importance, attendance, and exhibitors.
In the context of future change, here’s a question I’d like to ask all of our readers. I welcome your answers to any of the questions you see posed here, or any thoughts at all, even if they consist of more questions. Send all and sundry to: editor @ gpsworld.com
But if you wouldn’t mind, please include this one:
Where do you see your efforts and those of your organization focusing primarily over the next five to 10 years?
A. Primarily on GPS.
B. Inclusive also of multiple GNSS: GLONASS, Galileo, BeiDou, various satellite-based augmentation systems.
C. More broadly, on positioning, navigation, and timing (PNT) systems generally and in an integrated fashion, including other sensors.
D. Encompassing all the above and geospatial software such as geographic information systems (GIS) and location-based services (LBS).
Skipping ahead now to some outcomes, under the heading of what is required of us now, we here at the magazine are leaning more every day on these precepts:
Grow digitally and grow internationally. These are the only true paths to growth, at least in business-to-business publishing.
Spectracom’s GSG-6 Series multi-frequency GNSS signal simulator. Photo: Spectracom
Spectracom has added capability to simulate India’s global navigation satellite system, IRNSS, and Japan’s regional satellite system, QZSS, to its GSG-6 Series multi-frequency GNSS signal simulator. The simulator is designed to be field upgradeable to simulate all current and future GNSS constellations so current customers can benefit from these features without the need for a factory return in most cases.
“Spectracom understands the need for system developers and integrators to be compatible with various GNSS systems. Support for multiple constellations is a requirement in many markets and additional satellites add signal diversity for improved reliability,” said Spectracom Global Sales and Marketing Vice President Rohit Braggs. “Our easy-to-use, compact and affordable GNSS simulator can now be configured with IRNSS and QZSS capability in addition to the big four: GPS, GLONASS, BeiDou and Galileo. Our customers can buy what they need now and easily upgrade in the future, often times without a hardware upgrade.”
In anticipation of the deployment of new GNSS systems, Spectracom ensures that every GSG simulator that leaves the factory is tested for compliance with all L-band signal frequency and modulation specifications as defined in their ICDs, the company said.
The Series 6 multi-frequency simulator is fully capable of all four bands of any system: L1 / E1 / B1; L2 / L2C; L5 / E5 / B2; and E6 / B3.
“As we have seen with our recent roll-out of Beidou and Galileo signal compatibility, when the need for new signals arise, we will offer those capabilities with a simple upgrade path,” Braggs said. “This ensures our customer’s investment is always protected.”
