“What’s new with GPS?” people often ask me when I tell them my job. Recently, I have been responding by telling them about the other three GNSS constellations now fully available. However, as reflected every month in these pages, that is but one of many developments that combine to make satellite navigation ever more accurate, reliable and ubiquitous.
While the GPS program is old by the standards of the digital age, it has never been static. In the 1970s, when GPS was developed, the expected accuracy for civilians was tens of meters, though pioneering commercial users began right away to chip away at the system’s limitations by developing differential GPS (DGPS), carrier-phase positioning, and other techniques. By the end of the next decade, better signal processing and the implementation of DGPS had brought civilian accuracy to about one meter. In the 1990s, phase-ambiguity resolution made real-time centimeter accuracy standard for surveyors.
As the adoption of cell phones exploded, it became imperative to locate them to preserve the 911 system. Initially, this was done using the time-of-arrival of signals to handsets from towers, because it was assumed that GPS receivers could not be made sufficiently small, cheap, fast, power-efficient and accurate to work in cell phones. The implementation of assisted GPS, now standard in all smartphones, largely solved those problems.
Precision for civil GPS users increased by an order of magnitude in May 2000, when President Clinton ordered the removal of Selective Availability, and substantially once enough satellites began to broadcast the L2 civil (L2C) code, enabling ionospheric corrections. Later, the modernized signals in the L5 band enabled sub-meter accuracy without augmentations and very long-range operations with augmentations. There are now more than 80 signals in that band, on GPS, Galileo and BeiDou satellites. On the military side, the effort to deploy M-code signals, cards and receivers continues.
Over the years, in addition to modernized satellites and signals, improvements have included the development of PPP, RTK and hybrid techniques; the proliferation of local, regional and global correction services; improved jamming and spoofing detection; and the increasing integration of GNSS receivers with other RF receivers as well as with inertial, optical, radar, lidar and other sensors.
Future improvements may include:
signal authentication
commercial systems in low Earth orbit that would have a signal strength on the surface three orders of magnitude greater than current GNSS, greatly boosting indoor reception and protection from jamming
inertially aided extended coherent integration, a.k.a. “supercorrelation,” which makes moving GNSS receivers more sensitive to signals they receive directly than to reflected ones
3D-mapping-aided GNSS, which enhances the positioning algorithms by identifying non-line-of-sight signals; this is being pioneered by Google in nearly 4,000 cities, relying on its 3D city models and machine learning.
The moment I send this month’s issue to the printer, I will think of more past and future improvements. As soon as you receive it, many of you will think of yet more. What’s new with GPS? A lot.
A roundup of recent products in the GNSS and inertial positioning industry from the August 2021 issue of GPS World magazine.
OEM
GNSS board
Photo: Javad GNSS
With GLONASS dynamic calibration
The TRE-3S GNSS board measures 100 x 80 mm, weighs 87 g and tracks 874 channels with all-in-view satellite tracking. It includes numerous features to protect against interference and improve signal output: spectrum data output, spoofing detection, advanced multipath reduction, in-band interference rejection, GLONASS 0.2-mm dynamic calibration, heading determination, attitude determination and fast acquisition channels. The TRE-3S receives GPS L1/L2/L2C/L5; Galileo E1/E5A/E5B/AltBoc/E6; GLONASS L1/L2/L3; BeiDou B1/B1C/B2/B3; QZSS L1/L2/L5/L6 (L61/L62); and SBAS L1/L5. It has a 20-Hz update and real-time kinematic (RTK) rate for real-time positioning and raw data (code and carrier). Optional features include tracking QZSS L6 (LEX) and IRNSS L5/S-band, and a data update rate and RTK rate of 100 Hz.
For high-precision applications with L-band corrections
Photo: Maxtena
The M9HCT-A-SMA is a patented helix antenna for GNSS plus L-band corrections services, suitable for high-precision and autonomous multi-frequency applications. It provides simultaneous GNSS reception in a rugged, compact form factor. The M9HCT-A-SMA is suitable for high-precision applications such as the UAV market, where high performance and low weight are driving features in antenna selection. The active helix design features Maxtena’s patented compact and lightweight Helicore technology, which provides excellent pattern control, polarization purity and high efficiency in a compact form factor.
New eXtended Filtering (XF) is now employed in the TW3900 series of Accuntena precision antennas. The XF feature mitigates interference from all near-band signals and ensures the antenna provides the purest possible GNSS signals. The custom XF filtering has been tested to mitigate new (in Europe and Japan) and existing LTE signals, enabling the XF antennas to produce clean and pure GNSS radio frequency data. The XF models are TW3972XF, TW3972EXF, TW3972LGXF, TW3967XF and TW3967LGXF. All are triple-band antennas that support GPS/QZSS (L1/L2/L5), GLONASS (G1/G2/G3), Galileo (E1/E5ab), BeiDou (B1/B2/B2a), NavIC L5 and L-band correction services.
The iGS320 cycling computer builds on the u-blox M10 positioning platform, leveraging the M10’s ultra-low power consumption, compact size, and ability to track all four GNSS to offer endurance athletes a superior user experience. Adopting the M10 in its iGS320 cycling computer brought iGPSPORT an 80 percent increase in the power autonomy to deliver 72 hours of continuous tracking, up from 40 hours in their previous device. Concurrent reception of up to four GNSS constellations increases coverage and accuracy in otherwise challenging signal environments.
The Beamo 3D mapping platform enables surveyors to scan a project site and immediately collaborate with teams in the field without lengthy delays or cumbersome equipment. The digital twin created in the platform provides a single and secure source of truth for teams without requiring highly technical knowledge. With a 360-degree camera, surveyor teams can create detailed digital environments that remote teams can use to track progress, collaborate with coworkers, and take accurate measurements without having to physically visit the site.
The Triumph-3 receiver tracks efficiently even in difficult conditions. It can track all current signals and is ready for future satellites. The Triumph-3 can operate as a base together with Triumph-LS and Triumph-LS Plus to efficiently accomplish any geodetic job. Its RTK system communicates via integrated UHF, 4G/LTE, Wi-Fi and Bluetooth channels, and eliminates the need to subscribe to a real-time network for corrections. A powerful and reliable receiver for high-precision navigation systems, the Triumph-3 is based on the Javad GNSS 874-channel chip. It is equipped with an internal 4G/LTE/3G card and secure and accessible microSD and microSIM cards. It also supports Javad’s lift-and-tilt technology.
Eos Bridge enables almost any instrument to become iOS Bluetooth compatible. The pocket-sized device connects to instruments via Bluetooth Classic or serial port, and then transmits data to any Apple iOS device, such as iPhone or iPad, Android device or Windows mobile device. Instruments equipped with non-iOS Bluetooth can connect to Apple iOS devices using the Eos Bridge, including laser rangefinders and utility-locating instruments. Instruments whose only connectivity option is a serial port also can connect, such as any instrument or sensor with an RS-232 serial port. The Eos Bridge is lightweight, at approximately 150 grams (about 5.3 ounces). It can be worn clipped to a belt, stored in a pocket, or mounted to an instrument or sensor. The battery lasts 48 to 72 hours.
The OceanReports web tool provides users with specialized “ocean neighborhood analyses,” including maps and graphics, by analyzing more than 100 ocean datasets instantaneously. Reporting data includes information about habitats and species, industries in the area, potential hazards (such as undersea cables or shipwrecks), the economic value of ocean commerce, and other detailed oceanographic information. The web-based interactive tool for ocean mapping and planning, created by the National Oceanic and Atmospheric Administration (NOAA) and the Department of the Interior’s Bureau of Ocean Energy Management, provides professional users and the general public with opportunities to explore the ocean from their own computer.
HxGN Mass Transit is a geospatial transportation infrastructure management system with 3D and AI capabilities for visualizing and analyzing transit and rail assets and operations. Built on Hexagon’s M.App Enterprise, HxGN Mass Transit provides an advanced digital twin of a city’s entire public transportation network — including tracks, stops, switches, construction sites, ticket machines, benches and garbage cans. It integrates asset and spatial data so operators can visualize and analyze an entire network with accurate and up-to-date information.
The GAJT-410MS provides anti-jamming to marine vessels. (Image: NovAtel)
The GAJT-410MS provides NovAtel’s GPS Anti-Jam Technology (GAJT) for the commercial and defense marine markets. The low SWaP variant protects civil and military operations from interference and jamming, with jammer direction-finding capabilities for enhanced situational awareness in the marine environment. The GAJT-410MS provides dynamic protection on both GPS L1 and L2 bands, as well as Galileo E1, QZSS L1 and L2, and SBAS L1 to combat intentional and unintentional interference.
The ACR 2830 GlobalFix V4 EPIRB marine distress beacon has multiple built-in redundancies to increase chances of survival in an emergency situation. The internal GPS receiver pinpoints the user’s location, which is then transmitted on the 406-MHz distress signal. In the absence of GPS-derived coordinates, the signal can be used to triangulate the position. The beacon’s 121.5 MHz homing signal will bring local search-and-rescue forces directly to the position; an LED strobe light allows them to see the position in low light. A Category 1 Emergency Position Indicating Radio Beacon (EPIRB), the GlobalFix V4 is a float-free device that will automatically activate when submerged in water. Two self-tests monitor transmission, power and battery performance as well as GPS acquisition.
A new connected platform for rail passengers with Wi-Fi, information and entertainment content is being installed on OUIGO Spain trains through the OUIFUN portal. Passengers can connect via smartphones, tablets or PCs, access the internet on board to check email or browse the web, and enjoy entertainment content. Passengers also will be able to get travel status information in real time via an interactive map, access tourist guides or consult a menu for on-board catering. The service, provided by Moment, launched on May 10 on OUIGO’s first high-speed line in Spain connecting Madrid to Barcelona, and will gradually be extended to the whole high-speed OUIGO network.
The ANAFI Ai UAV uses 4G as its main data link between the drone and the operator. The 4G link improves data transmission and enables precise control at any distance. For BVLOS flights, it stays connected even behind obstacles. The 4G link between the drone and the user’s phone is encrypted, with a secure element protecting both software integrity and data privacy. A software development kit enables creation of custom code for flights and gives access to all sensors, including obstacle-avoidance sensors, occupancy grid and internet access.
An introductory model in Sony’s new Airpeak line, the small S1 drone can be equipped with the company’s full-size mirrorless interchangeable-lens Alpha camera. Its proprietary motor, propeller, control system and sensing technology allow it to fly at high speed (a maximum speed of 55 mph) with stable wind resistance. Propulsion technology using a combination of devices developed by Sony provides wind resistance in strong wind speeds up to 44.7 mph. The Airpeak S1 includes obstacle detection, automatic flight control via sensing, and increased safety via cloud management of the aircraft.
At 80 grams, George is a low SWaP certifiable solution for enterprise operations and those wishing to type certify their UAS. Built around the open-source autopilot Cube from CubePilot, George combines Cube with Design Assurance Level C (DAL-C) hardware and safety and sensor monitoring, enabling customers to meet the type certification and safety case requirements for BVLOS operations. Its triple-redundant IMU includes three accelerometers, three gyroscopes, three magnetometers and three barometers. The hardware platform is designed and built to RTCA DO-254 DAL-C and meets rigorous DO-160G and MIL-810H power and environmental qualifications.
In January, BAE Systems announced its intent to buy the Collins Aerospace Military GPS division. In April, Raytheon finalized its merger with United Technologies Corp. (UTC) to officially form Raytheon Technologies Corp. The U.S. Department of Justice approved the Raytheon/UTC merger in March, but only on the condition the companies divest UTC’s military GPS and large space-based optical systems businesses, as well as Raytheon’s military airborne radios business.
Collins Aerospace’s military GPS business will be integrated into BAE Systems’ Electronic Systems sector.
“This partnership will enable us to build on our market leadership and bring new discriminating capabilities to our customers, including the U.S. Department of Defense and its allies,” said Greg Wild, director of Military GPS. “We’re excited to be joining the BAE Systems family. They appreciate our legacy of innovation and will provide opportunities for continued business growth and success.”
Based in Cedar Rapids and Coralville, Iowa, the military GPS business has a workforce of approximately 700 employees. The business designs and produces advanced, hardened and secure GPS products with a range of form factors, including products designed for space-constrained and harsh environments.
