A report filed with NASA’s Aviation Safety Reporting System and published in June outlines how a passenger aircraft flew off course during a period of GPS jamming and nearly crashed into a mountain. Fortunately, an alert radar controller intervened, and the accident was averted.
Friedman Memorial Airport serves the ski resort town of Sun Valley, Idaho. Mountain peaks in the area are in excess of 12,000 feet. Airport arrival and departure procedures are carefully structured to ensure aircraft maintain safe distances from terrain.
According to the report, when “Aircraft X” arrived there was “…an abundance of smoke in the area” of the safe arrival route. Also “During this time there was widespread GPS jamming… Almost every aircraft was reporting…GPS outages.” Two previous flights had advised that their GPS signals were interrupted, but came back on line in time to make a safe approach to landing.
Aircraft X also reported problems with GPS, and then advised air traffic control that GPS had come back on line and was working well. The controller then cleared the aircraft for a GPS-based approach, including descending to 9,000 feet. Communications with and control of the aircraft was switched from Salt Lake Center (250+ miles away) to the tower at the local airport.
Shortly thereafter, the controller in Salt Lake City noticed Aircraft X straying off course. Also, it was at 10,700 feet altitude and nearing a 10,900 feet mountain. He quickly contacted the local control tower and the aircraft was directed back onto a safe flight path.
The report concludes that “Had [the Radar Controller] not noticed, that flight crew and the passengers would be dead, I have no doubt.”
Dana A. Goward is president of the Resilient Navigation and Timing Foundation.
Quectel Wireless Solutions has launched a compact dual-band GNSS module, the LC79D, that supports the L1 and L5 bands from navigation satellites to improve positioning accuracy.
Featuring concurrent multi-constellation GNSS receivers on dual GNSS bands, LC79D uses L1 and L5 bands for GPS, Galileo and QZSS satellites, L1 band for GLONASS and BeiDou satellites, and L5 band for IRNSS satellites.
Compared to GNSS modules that use the L1 band only, LC79D can generally increase the number of visible satellites, significantly improve positioning drifting when driving in rough urban canyons and enhance positioning accuracy.
Embedded with a low-noise amplifier (LNA) and multi-tone active interference, the module provides higher sensitivity and reliable anti-jamming capability, ensuring exceptional acquisition and tracking performance even in weak signal areas. Multiple communication interfaces including UART and SPI simplify customer designs and accelerate time-to-market for customers’ products at reduced costs.
With dimensions of 10.1 × 9.7 ×2.4 millimeters, the tiny LC79D meets the requirements of size-sensitive applications. Compact design, low power consumption and high performance make it suitable for vehicle, people and asset tracking as well as sharing economy applications.
“The launch of LC79D shows Quectel’s global leading position to provide positioning modules for applications requiring higher accuracy and reliability, especially in rough environments with weak signals,” said Wang Min, automotive and GNSS product director at Quectel. “LC79D gives customers high-level integration and flexibility to realize precise positioning in real time.”
The LC79D module was showcased at MWC Shanghai 2019 during June 26-28.
GNSS chip manufacturers and positioning systems developers are working on bespoke devices for autonomous driving. This month, we look at a development with embedded functional safety.
By Fabio Pisoni, Domenico Di Grazia, Giuseppe Avellone, Luis Serrano, Brett Kruger, Laura Norman and Natasha Wong Ken
INNOVATION INSIGHTS by Richard Langley
I DRIVE A 10-YEAR OLD KIA SPORTAGE. It is still quite roadworthy despite having to contend with New Brunswick winters. However, it lacks some of the safety features that are present in newer cars. There is no back-up camera, no forward-collision warning, no automatic emergency braking, and no blind-spot warning, for example. These are just some of the safety systems that come as standard or optional on most new cars these days. Still, the driver is responsible for the safety and operation of the car at all times. True, help might be provided for parallel parking and cruise control, but that’s about it for automated operation with most vehicles.
But things are changing and changing fast. Real automation is coming to automobiles. Already partial automation is available in some high-end vehicles that can take over steering, braking and acceleration in certain circumstances. The driver is still responsible for other aspects of the vehicle’s operation including paying attention to road conditions. Soon, we will have conditional automation where the car can drive itself but the driver must stay alert and be prepared to take over immediately at any time. Next will come high automation where a computer fully drives the car at certain times on certain routes such as a highway. Multiple systems, including back-up systems, will maintain a required safety level and the car will determine if it is safe to operate autonomously. If not, it could pull over to the side of the road and shut down. And finally, we may have full automation of cars. They will be able to drive on any road under virtually any conditions and won’t need any controls such as steering wheels or accelerator or brake pedals.
Augmented GNSS guidance will play a major role in the automation of vehicles. As with any navigation or guidance system, there are four important requirements: accuracy, availability, continuity and integrity. Perhaps the most obvious requirement, accuracy describes how well a measured value agrees with a reference value, typically the true value. How well a system accounts for various errors or biases determines the accuracy of corrected measurements and, ultimately, the accuracy of a derived position. A navigation system’s availability refers to its ability to provide the required function and performance within the specified coverage area at the start of an intended operation. In many cases, system availability implies signal availability. Environmental factors such as signal attenuation or blockage or the presence of interfering signals might affect availability. Ideally, any navigation system should be continuously available to users. But, because of scheduled maintenance or unpredictable outages, a particular system may be unavailable at a certain time. Continuity, accordingly, is the ability of a navigation system to function without interruption during an intended period of operation.
While accuracy, availability and continuity of a guidance system are all important, it is the integrity or trustworthiness of the system that is paramount. It is why the automotive industry has already developed integrity standards for the automation of vehicles. And it is why GNSS chip manufacturers and positioning systems developers are working on bespoke devices for autonomous driving, whatever the level of automation. In the Innovation column this time around, we’ll learn about one such development — one with embedded functional safety.
Autonomous driving applications are raising the requirements for onboard GNSS receivers to new highs. Position accuracy, protection levels, high availability, robustness of operation and integrity are the priorities shaping a new class of automotive components and architectures. Autonomous driving deals with life-critical issues: the expectation of reliability and safety for this new generation of receivers, as well as for other sensors and systems, is very high.
The International Organization for Standardization (known by the language-independent short form ISO) has issued documents codifying functional safety (FuSa) for automotive applications: ISO 26262: part 1 to part 11. ISO 26262 complements the well-known automotive reliability standard published by the Automotive Electronics Council, AEC-Q100. With respect to FuSa, a system can be defined as functionally safe if it always operates correctly and predictably. More importantly, in the event of failures, the system must remain safe for people. Lastly, as security is becoming paramount, a new standard for cybersecurity in automotive applications — ISO/SAE 21434 — is in development by ISO and SAE International (initially called the Society of Automotive Engineers) that will require a GNSS receiver to be robust against jamming, spoofing and meaconing attacks.
The Automotive Safety Integrity Level (ASIL) is a key part of ISO 26262 compliance, and the standard specifically identifies the minimum testing requirements depending on the ASIL of the component. The ASIL of a component or system depends on the ASIL of the target application. The ASIL is determined at the beginning of a development process. It varies from ASIL-A to ASIL-D, where A is for less critical applications and D for the most critical ones such as steering and breaking systems. ASIL-rated lane-level positioning performance can be demonstrated today by combining an ASIL-B software positioning engine and TerraStar-X correction technology from Hexagon Positioning Intelligence with GNSS measurements from an ASIL-B-rated GNSS chipset.
To conjugate performance requirements with the demand of embedded functional safety, STMicroelectronics has developed TeseoAPP (STA9100), a next-generation GNSS component, designed to meet an ASIL-B level of safety. TeseoAPP is a multi-band GNSS measurement engine. It outputs all the observables, navigation and integrity data required by a safety-critical precise positioning algorithm, located on a host processor. TeseoAPP also computes a local L1 code-based standard position, velocity and time (PVT) solution (SPS) for monitoring and integrity purposes. Also part of the baseline features are autonomous satellite acquisition (cold start condition), real-time assistance, data decoding and storage on external non-volatile memory (NVM), accurate timing and pulse-per-second generation under vehicle dynamics.
RECEIVER ARCHITECTURE
The target architecture for a safety-critical platform is sketched in FIGURE 1, where a host microprocessor is in charge of collecting GNSS observables and sensor data from the TeseoAPP. The latter includes on the same chip die a first configurable RF chain for the L1 signal ensemble and the baseband part for processing all the signals in the served bands, while the second chip is an RF front end (code-named STA5635), configurable for receiving the other served bands (such as GPS L2 or L5, Galileo E5a or E5b or E6, and so forth). The two chips are clearly visible in the photograph of a TeseoAPP evaluation module of FIGURE 2.
FIGURE 1. Block diagram of the TeseoAPP platform for safety-critical applications, featuring surface-acoustic-wave (SAW) filters, a temperature-compensated crystal oscillator (TXCO), non-volatile memory (NVM) and both internal and external STA5635 tuners. (See text for other initialisms used.) Diagram: Authors)FIGURE 2 The TeseoAPP Evaluation Module, including the STA9100 (TeseoAPP) and STA5635 (external tuner). Photo: Authors
The selected frequency plan and constellation configuration depend on the specific autonomous driving scenario and the target geographic area. The TeseoAPP supports a mix of frequencies and signals as shown in TABLE 1. The chipset baseband unit can track up to 80 channels. A tracking snapshot from a rooftop antenna (located at the ST office in Naples, Italy) is illustrated in FIGURE 3.
Both the TeseoAPP and the STA5635 have been designed for ASIL-B following the concept of “safety element out of context” (SEooC) described in ISO standard ISO 26262:2012. In this context, assumptions have been made for the application (such as on the mission profile), identifying the related safety goals from which functional and technical safety requirements have been derived.
TABLE 1. The TeseoAPP (STA5635) supported frequency plans and scenarios.FIGURE 3. Screenshot of the L1-L5 TeseoAPP configuration, from the ST Teseo-Suite tool (using the Naples rooftop antenna). Image: Authors
Following the guidelines identified in the ISO 26262 flow for safety-relevant product development, several safety mechanisms have been identified at the hardware, firmware and system/boot level. The microcontroller unit (MCU) supports dual-core operation in a lock-step configuration to verify processor output errors together with a memory built-in self-test (executed at startup) and error correction code on a safety-related embedded random access memory. Other hardware redundancies have been introduced in safety relevant parts such as triple-voted registers for critical configuration parameters. For the real-time operating system (RTOS), an ASIL-D-level product — the highest level — was selected.Functional safety analysis of the GNSS sub-system has produced a dedicated technical safety concept, including aspects such as tuner operation, interference and jamming mitigation, signals and observables quality management (QM), reliable host communication (using generic end-to-end or E2E protocols for data integrity and resilient flow control), and reliable system software. A simplified overview of all these safety mechanisms is outlined in FIGURE 4, where the orange-colored blocks are specific for the GNSS sub-system.
FIGURE 4. Overview of the TeseoAPP safety mechanisms. (See text for acronyms and initialisms used.) Diagram: Authors
Safety Mechanisms. The technical safety concept of the GNSS sub-system is implemented by a security, integrity and safety (SIS) monitoring layer (see FIGURE 5). The SIS collects information and metrics from other receiver blocks embedded in the RF/baseband hardware and from different components of the GNSS firmware stack. The SIS internally computes integrity risk estimates, which are delivered to a central intelligence monitor (CIM) capable of switching the receiver into a safe state, within a fault-tolerant time interval, when the overall receiver integrity appears compromised. In its simplest form, the CIM can be represented by a weighted sum of integrity risk inputs, followed by some activation function. During this process, a first layer of logic (CIM-L1) combines a subset of signal quality metrics to decide a priori which observables shall be passed to the host or discarded (not delivered).
FIGURE 5 Safety information flow through the TeseoAPP security, integrity and safety layer. (IP = intellectual property; other short forms in text.) Diagram: Authors
The collected signal metrics include quality estimators (based on multi-correlation techniques for example) or classic linear combinations of observables (such as dual-frequency carrier-phase differences or code-minus-carrier). Receiver metrics, on the other hand, have a more global scope and include estimators for inter-frequency biases, system-time cross-checks among constellations, and so on. The fault collection and control unit (FCCU) conveys hardware status flags to the SIS. Typically, an FCCU exception indicates some critical hardware failure and takes a priority path when switching the safe state. For example, a fault in the MCU lock-step monitor will trigger an immediate firmware action, mediated by the FCCU.
POSITIONING PERFORMANCE
To demonstrate the performance that can be achieved using the ST TeseoAPP chipset, Hexagon Positioning Intelligence (PI) has combined measurements from the TeseoAPP with an automotive-grade antenna and Terrastar-X correction technology, and processed the data using Hexagon PI’s software positioning engine. Even with a modern receiver supporting dual-frequency, multi-constellation measurements, such as the TeseoAPP, corrections are necessary to deliver decimeter-level performance and safety information required by an autonomous vehicle.
In clear-sky environments, lane-level positioning accuracy is achieved, enabling GNSS as a key input to autonomous systems. FIGURE 6 shows the horizontal error performance of the combined ST+PI solution in the form of an error time series and an error cumulative distribution function (CDF). The error performance expected from today’s single frequency automotive-grade GNSS without corrections and processing is also shown for comparison.
FIGURE 6. Horizontal error time series and cumulative distribution function (CDF) of the TeseoAPP alone and of the TeseoAPP with Hexagon PI software positioning engine (SWPE) in an open-sky environment. (Image: Authors)
For guidance systems in autonomous applications, the GNSS position must be accompanied by safety information and integrity guarantees. The concept of protection levels (PLs) has been introduced to provide this. A horizontal protection level defines a circle or ellipse around the reported GNSS position, which will have some error, within which the actual position is guaranteed to fall. The Hexagon PI software positioning engine is ASIL-B rated, so its position and PL outputs are available for use in safety-related autonomous applications. The autonomous system using the GNSS position is assured that its actual position is within the protection level ellipse. To output ASIL-B-rated positions accompanied by PLs, ASIL-rated GNSS measurement inputs are required.
Using the inputs and techniques described above, the Hexagon PI software positioning engine calculates PLs for every GNSS position output. The Hexagon PI data from Figure 6 is shown again in FIGURE 7 with accompanying PL information. In this case, a PL with integrity risk of 10-7 is shown, meaning that the actual position error is expected to exceed the reported PL at a rate less than 10-7 per hour.
FIGURE 7. Horizontal error and protection level (PL) including cumulative distribution functions (CDFs) of the Hexagon PI software positioning engine (SWPE) in an open-sky environment. (Image: Authors)
The PLs shown in Figure 7 are typically much greater than the position error. This is because the protection level calculation must account for a large number of potential faults that are not generally present. For instance, undetectable GNSS satellite faults can occur at rates greater than 10-7 per hour, and so must be accounted for in the PL.
In non-clear-sky environments, the GNSS position calculation is complicated by frequent loss of “sight” of the GNSS satellites. This is mitigated by having additional constellations and frequencies. However, for added availability of a precise position in challenging environments, it is necessary to incorporate sensor fusion into the position calculation, typically by using a six degree-of-freedom inertial measurement unit (IMU) as input, which includes three accelerometers and three gyroscopes to measure 3D translational and rotational motion. The IMU can maintain position accuracy for short periods when GNSS is unavailable, such as when driving under an overpass on a highway. The IMU provides a relative positioning output, so the absolute error growth is unconstrained in the absence of GNSS inputs. Therefore, it is important to have the GNSS receiver as the primary sensor in the positioning solution to constrain IMU drift and to reacquire GNSS signals rapidly after emerging from a GNSS outage.
Position error results for a typical highway environment are shown in FIGURE 8 after adding input from an automotive-quality IMU to the Hexagon PI software positioning engine. Small spikes in position error are due to short GNSS outages along the test route. However, the error growth due to loss of GNSS is minimal due to the coupling of the IMU data with the GNSS measurements.
FIGURE 8. Horizontal error time series and cumulative distribution function (CDF) of the TeseoAPP alone, and of the TeseoAPP with Hexagon PI software positioning engine (SWPE) in a highway environment. (Image: Authors)
FIGURE 9 shows the Hexagon PI highway data with accompanying PLs. Though the errors are well-constrained through GNSS outages, the PLs typically increase significantly. This is due to the higher noise of low-cost IMUs, and the uncertainty associated with reacquiring GNSS signals. PLs must account for worst-case IMU performance, which can have errors orders of magnitude greater than the nominal performance. During GNSS signal reacquisition, minimizing receiver noise is critical for fast position reconvergence, reinforcing the need for high-quality GNSS in autonomous applications.
FIGURE 9. Horizontal error and protection level (PL) including cumulative distribution functions (CDFs) of the Hexagon PI software positioning engine (SWPE) in a highway environment. (Image: Authors)
CONCLUSION
The TeseoAPP is the first generation of multi-band GNSS chipsets designed by STMicroelectronics to meet the two main requirements of autonomous driving: accuracy and safety-critical operation. The execution of the ISO 26262 standard for TeseoAPP is still a work in progress and encompasses two main aspects: 1) a safety plan implementation, code quality metrics and processes management and 2) the technical safety concept. Both of these aspects presented specific challenges, mainly due to the inherent complexity of the product and the large amount of firmware involved.
To exploit the maximum benefit of the TeseoAPP in safety-critical automotive applications, a high-accuracy ASIL-B-rated position engine is required. Hexagon PI’s software positioning engine is designed to use measurements from an ASIL-rated GNSS receiver, along with GNSS corrections and IMU data, to generate ASIL-rated position outputs, with accompanying integrity guarantees. The Hexagon PI software positioning engine computes protection levels. The calculation and determination of PLs is required to meet the safety and integrity guarantees necessary in autonomous driving for functionally safe operation.The software positioning engine also outputs ASIL-rated velocity, attitude and absolute time data, although we have not discussed these in this article.
The required high performance and safety expectations suggested, since the early stages of the project, a system composition in which the TeseoAPP was configured as an ASIL-B measurement-engine whereas the ASIL-B software positioning engine algorithms (by Hexagon PI) run on a separate ASIL host processor. We believe this synergy of competencies will represent the key for a successful solution to enable safe and reliable positioning in autonomous driving applications.
ACKNOWLEDGMENTS
The TeseoAPP chipset has been developed with the support and in the framework of the European Safety Critical Applications Positioning Engine project, which is funded by the European GNSS Agency under the European Union’s Fundamental Elements research and development program.
FABIO PISONI leads the GNSS System Architecture and Software Team (Automotive and Discrete Group) at STMicroelectonics Italy in Milan, where he has worked since 2009. He has a degree in electronics from Politecnico di Milano and has previous experience as a GNSS and digital signal processing (DSP) engineer.
DOMENICO DI GRAZIA is a GNSS signal senior staff engineer at STMicroelectronics Italy in Naples, where he has worked since 2003. He has a degree in telecommunication engineering from the University of Naples Federico II, holds patents in the GNSS area, and has previous experience in digital communications.
GIUSEPPE AVELLONE is in the GNSS System Architecture and Software Team (Automotive and Discrete Group) at STMicroelectonics Italy in Catania, where he has worked since 1998. He has a degree in electronics from Università di Palermo and previous experience as a GNSS and DSP engineer.
LUIS SERRANO is a GNSS technical marketing manager with STMicroelectronics based in Munich. He holds a Ph.D. in GNSS from the Department of Geodesy and Geomatics Engineering, University of New Brunswick, Canada. He has been active in the GNSS precise positioning field since 2007, and holds a patent on GNSS.
BRETT KRUGER is a software engineer specializing in GNSS/INS integration in the Safety Critical Systems Group at the Hexagon Positioning Intelligence (PI) NovAtel brandin Calgary, Canada. He holds an M.A.Sc. in electrical engineering from the University of Toronto, Canada.
LAURA NORMAN is a geomatics engineer specializing in GNSS integrity and protection levels in Hexagon PI’s Safety Critical Systems Group. She obtained her M.Sc. from the Department of Geomatics Engineering at the University of Calgary, Canada.
NATASHA WONG KEN is the Safety Critical Systems product manager at Hexagon PI. She has worked at Hexagon PI since 2012 after obtaining a B.Sc. in geomatics engineering from the University of Calgary.
The second next-generation GPS III satellite — nicknamed “Magellan” by the U.S. Air Force — is encapsulated and ready for its planned July 25 launch.
On June 26, Lockheed Martin Space and United Launch Alliance (ULA) technicians completed encapsulating GPS III Space Vehicle 02 (GPS III SV02) in its launch fairings at the company’s Astrotech Space Operations facility, where the satellite has undergone pre-launch processing and fueling since its March 19 arrival in Florida. This final step enclosed GPS III SV02 in a protective, aerodynamic, nose-cone shell.
In the coming days, the enclosed GPS III SV02 satellite will be mounted to a ULA Delta IV rocket for launch. The current window for launch on July 25 opens at 10:55 a.m. ET.
“GPS III SV02 is launching just a brisk seven months after the nation’s first GPS III satellite lifted off back in December. The first satellite’s performance during on-orbit testing has exceeded expectations,” said Johnathon Caldwell, Lockheed Martin’s vice president for Navigation Systems. “We are excited to deploy more GPS III satellites so this new technology and capabilities can be distributed constellation-wide.”
GPS III satellite production and launch cadence is picking up. On May 27, the Air Force declared the next GPS III satellite, GPS III SV03, available for launch, pending an official launch date.
“More GPS III satellites are coming. If you looked at our production line back in Denver today you would see GPS III space vehicles 04, 05 and 06 already fully-assembled and in various stages of testing. And space vehicles 07 and 08 are being built up at the component assembly level now,” Caldwell added. “It is a smooth, efficient, methodical process.”
Lockheed Martin is under contract to develop and build up to 32 GPS III/IIIF satellites for the Air Force. GPS III will deliver three times better accuracy and provide up to eight times improved anti-jamming capabilities. GPS III’s new L1C civil signal will make it the first GPS satellite to be interoperable with other international global navigation satellite systems, like Galileo.
Additional GPS IIIF capabilities will begin being added with the 11th satellite. These will include a fully-digital navigation payload, a Regional Military Protection capability, an accuracy-enhancing laser retroreflector array, and a search-and-rescue payload.
“Seen & Heard” is a monthly feature of GPS World magazine, traveling the world to capture interesting and unusual news stories involving the GPS/GNSS industry.
Galileo guides Madrid metro buses
Galileo and EGNOS are helping EMT Madrid to improve its services, reports the European GNSS Agency. Madrid is one of the first cities using Intelligent Transport Systems (ITS) with enhanced positioning services. Positioning units in 2,050 public buses mean customers know exactly where their ride is, and when it will arrive. Receivers in the buses use signals from EGNOS and Galileo.
Drought fighters
About 3,000 villages in the Karnataka state of India face serious water shortage. More than 2,000 tankers and 1,800 private bore wells have been hired to meet the need. To ensure the water gets to the right place, all tankers supplying water to drought-hit villages and towns are being equipped with GPS to prevent misuse. The trackers will show the movement of the tankers from the water source to the residential areas.
Bangalore water jugs. (Photo: CamBuff/Shutterstock.com)
Getaway car stopped in its tracks
In March, a Florida Highway Patrol trooper darted a GPS tracker onto the back of a fleeing minivan during a 60 mph chase. As the pursuit carried over county lines, a trooper used his StarChase system to tag the minivan. The FHP used the tracking information to roll out a spike mat to stop the suspected felon. Only a few police agencies in the state have the technology, which is still being tested.
Photo: Starchase
Help for refugees
Between 2013 and 2018, almost 70,000 children in Kenya died of diseases that could have been prevented with vaccines. Two Nairobi teenagers, Kunjal Bharatkumar and Supraja Sayee Srinivasan, paired a health website they created with small GPS devices, tested at Dadaab Refugee Complex. A mother gets a GPS bracelet and her baby a GPS necklace. The trackers turn on when it’s time to alert the mother that her child is due for its next vaccine. Then, mom can take her child to get the shots. If they miss their vaccine appointment, the GPS sends a signal to healthcare workers to provide vaccines. The website can create maps of active diseases.
Dadaab Refugee Complex in Kenya. (Photo: iStock.com/sadikgulec)
RNT Foundation Directors and Congressmen. From left: RADM Jeff Hathaway, USCG (ret); Rep. John Garamendi (D-CA); Rep. Peter DeFazio (D-OR); Dana A. Goward, SES, CAPT, USCG (ret); and CAPT Pauline Cook, USCG (ret). (Photo: Resilient PNT Foundation)
“It’s absolutely vital for national security that we get a terrestrial based, hard backup system [for GPS],” said Congressman Peter DeFazio (D-OR), chairman of the House Transportation and Infrastructure Committee.
His remarks came at an event organized by the RNT Foundation to recognize DeFazio and Congressman John Garamendi (D-CA) for their support of the National Timing Resilience and Security Act of 2018. Representative Garamendi is chairman of the House Armed Services Readiness subcommittee.
Garamendi first introduced legislation in 2016 to address the nation’s need for a GPS backup system. After going through several iterations, it was signed into law in December. The Act requires the Department of Transportation to establish a terrestrial timing system by 2020. Also, that the new system be expandable to one that can be used for location and navigation.
Congress funded a GPS Backup Technology Demonstration through a Department of Defense appropriation in early 2018. The demonstration was intended to be a joint project of the Departments of Defense, Homeland Security and Transportation. A delay in transferring funds from Defense to the other two departments put the demonstration almost a year behind schedule. Now that the project is underway, Transportation Department representatives have said they want to transition directly from the demonstration to deciding upon and implementing the mandated timing system.
At the event, DeFazio remarked that as a boater and hiker he is an avid user of GPS. He mentioned that it is an “ incredible utility, but I also know of its vulnerability. It’s critical to national security and the meaningful movement of everything in the United States of America from airplanes to surface transportation and others … It’s absolutely vital for national security that we get a terrestrial based, hard backup system.” He also noted that Congressman Garamendi has been the driving force for this issue in the House of Representatives.
Speaking about his current role on the Armed Services committee, Garamendi said “The reality is that the military is not prepared for the loss of the GPS signal, and they are just now becoming aware after seven years of beating them over the head saying ‘guys, what are you going to do when you don’t have GPS?’” Garamendi noted that the military would be a big users of the domestic backup system.
He also regretted that after “… years of people saying ‘single point of failure’ for the American economy and system is the loss of GPS” the nation is not farther along to having a backup system.
The RNT Foundation presented the congressmen with plaques showing images of a GPS satellite and a terrestrial transmission tower, and 0ne of America’s “first GPS devices” — a 102-year-old copy of The American Practical Navigator by Nathaniel Bowditch.
To test the accuracy of the competing satnav smartphone apps, the words ESA and Galileo were traced along ESTEC’s football field. The left side uses single-frequency GPS and Galileo signals, the center uses dual-frequency signals from the two constellations while the right is with precise corrections. The word “ESA” is 15 meters high, while “Galileo” is 7 meters high. (Photos: ESA)
News from the European Space Agency
Europe’s students and young researchers were challenged to design a smartphone app to take advantage of Galileo’s dual-frequency signals. The winning entries should soon be available to the public.
Run by ESA in collaboration with the European Global Navigation Satellite Systems Agency — GSA — plus the European Commission with the support of Google, a total of five teams made it to the final, which took place at ESA’s ESTEC technical heart in the Netherlands.
Following on from last year’s inaugural competition — which has already resulted in the winning app becoming publicly available — this year’s event challenged teams to make use of the dual-frequency capability of the latest smartphones running Android 8.0, including and computing dual-frequency positioning solutions from satnav signals to compare them with their single frequency equivalents. The competition slogan was “Galileo give mE5,” referring to Galileo’s dual E1 and E5 frequencies.
“Galileo give mE5”
The objective of the competition was to reach meter accuracy or less worldwide in unobscured sky, while allowing the user to select Galileo-only positioning, GPS-only positioning and the combination of both on a simultaneous basis, with the potential to include other satnav constellations in turn.
The winner was selected based on technical checks and a jury’s vote. Separate awards were also given to the most innovative app and the winner of a public vote.
The multinational O ThiSaVRoS team — named after the Greek word for treasure — developed the “GNSS Android-based Dual Frequency Iono-estimating Precise Point Positioning” or GADIP3 app.
The multinational ‘O ThiSaVRoS’ team – named after the Greek word for treasure – developed the ‘GNSS Android-based Dual Frequency Iono-estimating Precise Point Positioning’ or GADIP 3 app, winning the ESA-EC-GSA Galileo smartphone app competition 2019. (Photo: ESA)
Winners
The app allows users to perform reliable positioning fixes in real time — selecting which constellations to employ and a choice of single or dual frequency signals — while advanced users can modify the way the positioning is performed, and log all available data for follow-up analysis.
“Our mission goal is to provide precise positioning to everyone,” explained team coordinator Lotfi Massarweh. The O ThiSaVRoS team performed analysis on more than 120 hours of data from stationary, pedestrian and mobile testing to come up with a pre-processing approach involving rejection of signals from low elevation and under a specific signal-to-noise ratio.
The five-person team hail from China, Greece, Italy and Spain, studying at Portugal’s Instituto Superior Técnico Lisboa, Delft University of Technology in the Netherlands, Germany’s Leibniz Universität Hannover and the Universities of Bath and Nottingham in the UK. They worked remotely to develop and test the app over the previous six months.
NavGate allows geo-tagging in augmented reality
The NavGate smartphone app allows the sharing of geo-tags in augmented reality via the phone’s camera, as well as on maps. (Image: ESA)
As their app’s name suggests, O ThiSaVRoS hope to achieve precise point positioning in future, made possible by dual-frequency signal availability, to come close to single-metre-scale precision.
Second place went to the ESTEC-based Team GNSS Tonic’s NavGate app — aimed at bringing people together socially to interesting locations. Users can tag sites of interest to be seen by other people, with the resulting geotags viewable for others either on a map or else directly in augmented reality through their phone’s camera. NavGate could potentially be used for everything from sharing dining recommendations to fishing spots, or meeting up with people during an evening out.
The third prize to the Step with GNSS app by the Romania-based Space Walkers Team, designed to gather data on the paths of users walking outdoors. This game based app is backed up by a server application collecting data from the app users and analysing GNSS performance worldwide or regionally.
Single versus dual frequency
The winner of both the public vote and the most innovative app award went to Universitat Autònoma de Barcelona’s Inari Team and their Inari app.
Inari allows users to select various positioning modes or customise their own, selecting which algorithms and which corrections should be employed as well as specifying constellations and signal frequency. The app can also highlight jamming or spoofing that might be influencing the positioning accuracy.
ESA’s technical evaluation team performed tests of the competing apps in the days running up to the final, including tracing out ESA GALILEO as accurately as possible across the establishment’s football field.
The speaker of the jury, Frank van Diggelen from Google, congratulated the teams on their efforts. “Dual frequency on smartphones is a quite new development, and you really are pioneers in this. The manufacturers are still trying to get things right, and you’re helping them do that bit better. Doing anything for the first time is hard but it’s good to be first, so congratulations for that,” he said.
Galileo smartphone app competition final
The receiver chipsets inside smartphones routinely make use of Galileo in combination with several other satnav constellations — the U.S. GPS, Russian Glonass and Chinese BeiDou. These chipsets function in ‘black box’ style, making the resulting positioning fixes accessible to users, but without giving any option to the user to select which constellation to employ — or information on Galileo’s particular contribution to the phone’s overall positioning performance.
However, in newer Android smartphones it has become possible to access the raw signal measurements used to compute position, opening the door to the development of applications where the user can indeed select which constellations to employ.
The very latest models also allow the use of dual satnav frequencies, giving a major boost to positioning precision. The higher chip rate of the additional frequency allows the chipset to compensate for signal propagation errors from the signals’ journey through the ionosphere — the electrically active outer layer of atmosphere — and reduces false ‘multipath’ detections caused by signals reflecting off buildings.
The GPS Directorate has released updates to the below Interface Control Documents (ICD). ICDs are the formal means of establishing, defining, and controlling interfaces and for documenting detailed interface design definitions for the GPS program.
Updated Documents
IS-GPS-200: Navstar GPS Space Segment/Navigation User Interfaces
IS-GPS-705: Navstar GPS Space Segment/User Segment L5 Interface
IS-GPS-800: Navstar GPS Space Segment/User Segment L1C Interface
ICD-GPS-240: Navstar GPS Control Segment to User Support Community Interface
ICD-GPS-870: Navstar Next Generation GPS Control Segment (OCX) to User Support Community Interface
Download or view the updated ICDs at GPS.gov or NAVCEN.
59th CGSIC Meeting Set for September
The U.S. Department of Transportation (DOT) and the Coast Guard Navigation Center (NAVCEN) have announced plans for the 59th meeting of the Civil GPS Service Interface Committee (CGSIC).
The meeting will take place Sept. 16-17 at the Hyatt Regency Miami in Miami, Florida, in conjunction with the Institute of Navigation’s ION GNSS+ 2019 conference.
CGSIC meetings are free and open to the public. Subcommittees of the CGSIC for Timing, International Information, and Survey, Mapping, and Geosciences will hold meetings Sept. 16, and a summary of these meetings will be presented to the CGSIC plenary session Sept. 17.
The meeting will include important briefings on the status of ongoing GPS programs and a keynote address by Diana Furchtgott-Roth, deputy assistant secretary, Office of the Assistant Secretary for Research and Technology, U.S. Department of Transportation.
The transaction will create a systems provider with advanced technologies to address rapidly growing segments within aerospace and defense, the companies said. Raytheon is a defense contractor, while United Technologies is an aerospace company comprised of Collins Aerospace and Pratt & Whitney.
The combined company, Raytheon Technologies Corporation, will offer a complementary portfolio of platform-agnostic aerospace and defense technologies, expanded technology and R&D capabilities to deliver innovative and cost-effective solutions aligned with customer priorities and the national defense strategies of the U.S. and its allies and friends.
The merger is expected to close in the first half of 2020, following completion by United Technologies of the previously announced separation of its Otis and Carrier businesses, which are not part of the merger. The timing of the separation of Otis and Carrier is not expected to be affected by the proposed merger and remains on track for completion in the first half of 2020. The merger is intended to qualify as a tax-free reorganization for U.S. federal income tax purposes.
The combined company will have approximately $74 billion in pro forma 2019 sales.
Under the terms of the agreement, which was unanimously approved by the boards of directors of both companies, Raytheon shareowners will receive 2.3348 shares in the combined company for each Raytheon share. Upon completion of the merger, United Technologies shareowners will own approximately 57 percent and Raytheon shareowners will own approximately 43 percent of the combined company on a fully diluted basis.
“Today is an exciting and transformational day for our companies, and one that brings with it tremendous opportunity for our future success. Raytheon Technologies will continue a legacy of innovation with an expanded aerospace and defense portfolio supported by the world’s most dedicated workforce,” said Tom Kennedy, Raytheon chairman and CEO. “With our enhanced capabilities, we will deliver value to our customers by anticipating and addressing their most complex challenges, while delivering significant value to shareowners.”
“The combination of United Technologies and Raytheon will define the future of aerospace and defense,” said Greg Hayes, United Technologies chairman and CEO. “Our two companies have iconic brands that share a long history of innovation, customer focus and proven execution. By joining forces, we will have unsurpassed technology and expanded R&D capabilities that will allow us to invest through business cycles and address our customers’ highest priorities. Merging our portfolios will also deliver cost and revenue synergies that will create long-term value for our customers and shareowners.”
Lidar USA is now offering the option of the Drone Rescue Systems parachute system with all of its DJI M600 UAVs.
As UAVs become increasingly common for mapping applications, the likelihood of a crash increases. The number-one concern for any pilot should be the safety of all people in the vicinity. Equipment safety is number two.
Any mapping-equipped drone will have enough weight to potentially harm a person even if falling from a low altitude flight. The Drone Rescue System greatly mitigates this danger and gives pilots the added assurance that, should the system fail, they have gone the extra mile to prevent harm to any bystanders.
Effective as low as 10 meters with a descent of 3 meters per second, the equipment will land without a hard impact yet quickly enough to keep from being dragged far away.
Photo: Lidar USA
Weighing in at 430 grams in a repackable canister 160 x 75 millimeters in size, the DRS-M600 is designed to auto-release using a patented, airplane-friendly ejection mechanism within milliseconds of detecting a system failure. The size and weight are a major bonus when combined with the airplane-friendly feature, especially for field workers, according to the company.
“We performed our own tests of the Drone Rescue system to ensure the system really worked as advertised,” said Daniel Fagerman, CTO of Lidar USA. “We weren’t disappointed. While it’s an expensive test if it fails, the good news is it that the system worked as well as could be expected. The M600 incurred very little damage that was easily repaired. We feel confident this will be more than just an accessory for our clients but rather a necessity.”
Lidar USA is offering the parachute option to any M600 owners. Watch a video of one of the company’s test flights.
With the smartphone revolution, we are increasingly reliant on today’s global technology networks. The importance of protecting data centers and mobile devices with resilient PNT can’t be overstated. But what is the best way to accomplish this?
By Rohit Braggs, Orolia
Connected devices and cloud applications are the primary technology sources for most people today, and an exponentially growing number of those devices are connected to data centers in some way. Across the world, you can drive past countless acres of data centers that are storing, updating and retrieving the world’s data.
GNSS signals localize and timestamp the data collected from connected devices scattered across the world in diverse time zones and locations. They also provide the critical time synchronization that supports high-efficiency data storage, routing and exchanges across multiple data centers in various locations.
It is essential to protect data centers and their GNSS signal connections from system failure, jamming, spoofing, interference and denial of service. As the reliance on GNSS signals and the number of connected devices grow, so too does the threat of GNSS failure. False or unavailable positioning, navigation and timing (PNT) information at any point within this network can compromise security and completely disrupt user service.
This article explores the role of data centers and how their constant connection to devices enables almost every digital technology that we use today. It identifies key reasons why we should protect this interconnected data system from GNSS signal interference and disruption, in addition to providing information on how to ensure continuous signal monitoring and protection with a practical, cost-effective approach.
Data centers and connected devices affect nearly every aspect of our digital lives, from cloud software and applications to mobile phones and laptops. They store our personal documents, photo libraries and other priceless personal data. They also keep track of business documents, software licenses and other essential business information. In critical infrastructure, they support the daily operations of society’s most important services such as public utilities, banking and financial transactions, telecom, security, medical and defense systems, among others.
Data centers use timestamps as a key mechanism to store, organize and retrieve data. In addition to categorizing data by authorized users and other relevant identification information, the timestamp enables data centers to monitor revisions and retrieve the most recent version of the data.
A good example of timestamped data use is in cloud-based applications, accessed simultaneously by hundreds of thousands of users. In such environments, data is dynamic and changing frequently, which can lead to data conflicts. With accurate, reliable timestamps, a cloud-based application can resolve such conflicts to determine the order in which the data was received.
Why do we need to protect data centers and connected devices from GNSS signal interference?
GNSS signals are the quiet facilitators of many of our day-to-day tasks. In discussing why it is important to protect these signals, it is often easier to imagine what would happen without the accurate, reliable PNT information that these signals provide.
We need to understand two key pieces of information to operate systems: location and time. We need to know exactly where data or assets are located, and we need reliable, consistent time references to synchronize the movement of data and assets for system operations.
There are many documented examples of GNSS signal jamming, spoofing and denial of service attacks worldwide, and these are easy to find with a simple internet search. Here are a few examples of what can happen when the signal is compromised at a mobile or fixed location, but not taken offline. The user might still see that the signal is working, with no indication that the two critical pieces of information, location and time, are being disrupted:
Imagine that the timestamp on a security camera system was spoofed to show a different time than the actual time. Incorrect or missing timestamps on video from surveillance systems is the most common reason for video evidence being deemed as inadmissible in a court of law. A bad timestamp corrodes the credibility of the video as irrefutable evidence and makes it easy to dispute.
Imagine that a bad actor spoofed the time used by financial trading systems. Since these critical systems rely on GNSS-based time and synchronization, an attack on their underlying timing infrastructure could significantly impact the market and cause billions of dollars in damage.
What if the GPS guidance system on your phone or vehicle gave you wrong directions? You could get lost in a wilderness or encounter dangerous driving conditions by trusting the route shown on your device.
What if more people started using commercially available jammers? Some truck drivers have already been caught using unauthorized GPS jammers in their vehicles to avoid monitoring by their employers. In many cases, these deevices have affected nearby critical systems such as air traffic control, financial data centers, and other critical operations simply by being driven past with active jammers. The incidence of these disruptions is on the rise.
Imagine a secure facility using an access control system that is set to automatically lock and unlock doors at a specific time. If someone spoofed the time used by that system, they could trick the doors into unlocking and gain entry.
We are also seeing an uptick in unintentional or environmental signal interference, which can occur in high-density development areas where various wireless transmitting systems can interfere with GNSS reception.
Which technology solutions are best suited to protect data centers and GNSS signals?
The first step toward protecting a GNSS-reliant system is to test the system for vulnerabilities. GNSS simulators and testing protocols can simulate a spoofing, jamming or denial of service attack to evaluate how the system responds to each situation. Knowing the system’s unique challenges and weaknesses can help resilient PNT experts design the best solution for that system.
One of the most common configurations for a fixed site location includes a highly reliable network time server to ensure that accurate timestamps are applied to each data point. A time server that can identify erroneous or spoofed GNSS signals is recommended for any critical application. In addition, a time series database could be installed to categorize and organize the time-stamped data, while identifying any irregularities in the data.
Once you have reliable timestamps and time server management systems, you also need to continuously monitor the signal to detect interference and raise an alarm. A GNSS signal monitoring system can let you know the minute your system is under attack. A GNSS threat classification system can identify the type of threat and mitigate it, depending on the nature of the threat, by filtering the signal to neutralize the interference.
The best way to prevent GNSS jamming is to deny interfering signals access to the receiver in the first place. Smart antenna technology focuses antenna beams to track the good signals from the satellites and reject the bad signals from interferers. Less sophisticated solutions such as blocking antennas can be employed to reject terrestrial-based interference, which is where most GNSS interference sources exist, and they provide a good first-level protection.
Continuous PNT access can also be achieved by using an alternative signal that operates separately from GPS/GNSS and is less vulnerable to the signal attacks that plague GNSS signals.
Emerging PNT Technologies
Over the next few years, new applications of mobile PNT data will further emphasize the need to maintain system integrity against threats. Here are a few examples of emerging technologies.
5G is here for mobile Internet and telecom service, yet with the specific need for microsecond-level synchronization, the challenge to protect the fidelity of the time used in these systems will become more important.
With rising awareness of the need to protect GNSS signals against threats, individuals will need to determine how they can protect their own GNSS-reliant systems as they navigate the Internet of Things and GIS enabled e-commerce. Personal PNT protection is an emerging technology area that could help protect people and their mobile devices on an individual basis, to ensure GNSS is there when it matters. Whether you are embarking on a remote hiking or sea expedition, sharing your coordinates with an emergency dispatcher after an accident, or simply trekking your way through a new city late at night, having resilient GNSS signal support is becoming a necessity.
Alternative signals are now available, and these new signal options, such as STL (Satellite Time and Location), could play an important role in providing better privacy and security functionality. This signal diversity will help protect against threats and interference by adding resilience to the device’s ability to receive reliable PNT data.
Another exciting technology development is the concept of smart cities, where technology has the opportunity to increase efficiency, reduce waste and provide many conveniences for the public. As we automate more city systems, it is essential to protect these systems from both accidental and malicious GNSS-based interference to ensure that these systems can make decisions based on reliable, precise PNT data.
Intelligent Transportation Systems (ITS) have the capacity to transform how people and freight travel today, saving lives and bringing goods to market more efficiently than ever. The need to know exactly where a driverless vehicle is in relation to other vehicles at any moment in time is just one of the resilient PNT technology requirements that will rely on GNSS signals.
Finally, authenticated time and location information can help increase cybersecurity for many applications, by limiting data access to a very specific window of time and only in a precise location. This is an area of cybersecurity which has the potential to add new layers of authentication to protect users and their data. With connected devices at the forefront of our access to the world, secure and reliable PNT technologies are more critical than ever.
These are just a few examples among many of the new technology innovations that are in the works to provide us with new benefits in leaps and bounds.
Protecting Our Virtual Brain
Data centers are the technology hubs of today, and their constant connection to devices fuels our ability to access critical information instantly. This networked system serves as a virtual brain that holds our personal memories, charts our progress, enables us to share results and helps us deliver new technology advancements faster than we could ever do before.
As we prepare to embrace our new technology, we should first address the PNT technology challenges of today and ensure that our GNSS signals are resilient and reliable. With this strong foundation in place, we can better protect our current systems and keep pace with evolving threats that would otherwise jeopardize the functionality, safety and security of these new capabilities.
Rohit Braggs is the chief operating officer at Orolia. Based in Rochester, New York, he is responsible for the development and execution of the company’s global business strategy and corporate initiatives. He also serves on the board of directors for Satelles Inc., which provides time and location solutions over the Iridium constellation of low-Earth-orbiting satellites.
Architecture of the X-Survey antenna. (Image: Harxon)
Blocking interference
Interference can be blocked at the data-collection stage, using an advanced antenna.
Harxon’s X-Survey is a compact high-precision GNSS antenna. It provides superior navigation and communication performance in surveying applications. A frontal band-pass filter setting effectively rejects out-of-band signals before they enter the low-noise amplifier of the antenna for signal augmentation.
Meanwhile, the filter itself has insertion loss, making a low insertion loss filter a prerequisite for optimal system noise reduction. To avoid this situation, X-Survey employs ceramic filter with low signal loss and in-band flatness to significantly improve system anti-interference capability and ensure reliable signal receiving.
The mosaic module provides AIM+ mitigation technology. (Image: Septentrio)
Septentrio began to tackle the interference problem more than 20 years go, designing and manufacturing high-precision GNSS receiver technology with emphasis on reliability and robustness. The result is Advanced Interference Monitoring and Mitigation (AIM+) technology which secures the company’s GNSS receivers against jamming and spoofing interference. AIM+ has recently been upgraded with an extended anti-spoofing functionality.
Building on its existing spoofing detection, Septentrio has developed a new anti-spoofing algorithm for its commercial receivers. The algorithm leverages Galileo Open Service Navigation Message Authentication (OSNMA) for spoofing resistance. It was developed in the framework of the GSA FANTASTIC project with the goal of improving the security of timing in critical infrastructure.
Mobile devices and cloud applications increasingly rely on GNSS technology used by telecom companies. Having secure and robust GNSS receivers in telecom infrastructure is key to reliable mobile and positioning services.
Alternative signals
Prototype design of the PNT-5500. (Image: Jackson Labs)
A new reference receiver, Jackson Labs’ PNT-5500, includes a custom Satelles/Iridium (STL) and GPS receiver, and an optional Edge Grandmaster/PTP1588 capability.
Using STL signals received directly through a small antenna mounted on the device, the PNT-5500 provides nanosecond timing synchronization in GPS-challenged environments, including deep indoors (no rooftop antenna required). It provides secure timing during GPS jamming and spoofing events. The unit is designed for high-volume, low-cost telecom small-cell synchronization, and is optionally available with holdover oscillators such as DOCXO and CSAC atomic clocks.
While GPS is vulnerable to jamming and spoofing, the PNT-5500 uses the Iridium infrastructure to provide assured timing that is impervious to spoofing and provides 1,000X higher signal strength compared to GPS, producing jamming resilience and deep-indoor reception. The system is designed to be fully interoperable with legacy equipment, for a low-cost, fully-deployed Assured PNT capability alternative to GNSS today.
Assessing vulnerability
Image: Qascom
Qascom offers several robust PNT services and products, including vulnerability assessment, robust navigation and interference localization.
Vulnerability assessment is the key proactive measure, using cutting-edge signal generators to design and test tomorrow’s receivers. For example, Qascom’s QA707 GNSS simulator tests receivers against emerging jamming and spoofing threats, allowing OEMs to discover in advance any potential vulnerability that may affect the availability and the integrity of the signal.
Robust navigation is supported by advanced mitigation algorithms, equipped with pre and post-correlation algorithms, as well as the inclusion of sensor fusion and dead-reckoning features.
Qascom’s attack detection products include external monitoring networks that support GNSS receivers. These networks provide an accurate perception of the operational environment, allowing threat characterization, classification and forecast. For instance, Qascom’s QB100 enables the simultaneous threat detection and localization by means of a monitoring cluster that delivers 24/7 situational awareness to a set of target receivers within the protection area.
Reliable timing
Meinberg provides GNSS timing solutions for nearly every application type. Its reliable systems are based on firmware built from the ground up by an in-house team of expert engineers. All Meinberg firmware is constantly checked and updated to ensure it adapts to evolving industry standards.
The company’s synchronization systems use a built-in Meinberg GPS receiver or combined GPS/GLONASS clock. They also support a broad range of reference time sources, including 1 PPS, 10 MHz, inter-range instrumentation group time codes (both direct current level shift and amplitude modulated), or network time protocol (NTP) servers. This redundancy in synchronization sources means Meinberg’s systems are protected against a loss of signal. Furthermore, to ensure the correctness of the reference time and date, an intuitive Secure Hybrid System (SHS) feature includes an independent secondary clock for enhanced plausibility checks.
For superior holdover performance, the Meinberg XHERB (with one or two Rubidium modules from Stanford Research) can be added to the Meinberg Intelligent Modular Synchronization (IMS) time and frequency systems. If the reference clock loses its sync source, the XHE chassis will provide the sync reference for the IMS chassis based on its holdover performance.
