GPS satellites usually transmit their signals with constant power. However, a so-called “Flex Power” is foreseen to increase the strength of individual signals to better fulfill operational constraints. Flex power operations can be detected in carrier-to-noise density ratio (C/N0) observations provided by GNSS receivers of the global tracking network of the International GNSS Service (IGS).
Critical infrastructure has a compelling need to infer the assurance of PVT estimates—as do users in general. However, traditional PNT platforms do not offer a principled way to infer assurance from multiple anti-spoofing (A-S) techniques, situational awareness (SA) information, and other auxiliary sources such as network data. Here we introduce, a PNT Trust Inference Engine (PNTTING) that can assess PNT trust according to probabilistic models with rigorous semantics.
Readers of this website are familiar—perhaps overly familiar!—with the threats to resilient positioning and navigation that are posed by interference, intentional and unintentional. Timekeeping applications for critical infrastructure using GNSS must also protect themselves against jamming and spoofing.
Though the pandemic impacts federal workers and contractors across the country, the early-March testing of GPS backup technologies finished on time and the analysis is expected to be completed on schedule.
An assisted GPS direct positioning estimation (DPE) technique for urban environment copes with a full spectrum of direct-line-of-sight and non-line-of-sight or multipath conditions. A new approach using signal visibility and specular reflection predictions within the DPE shows the potential to reduce positioning error from approximately 30 to 10 meters.
EMCORE Corporation, a provider of advanced mixed-signal products serving the aerospace, defense and broadband communications markets, received the 2019 Raytheon Integrated Defense Systems (IDS) 5-Star Supplier Excellence Award for performance and partnership.
The U.S. Army’s Rapid Capabilities and Critical Technologies Office’s (RCCTO) selected TRX Systems to deliver a prototype tactical electronic warfare (EW) kit for dismounted soldiers. TRX is also one of 11 firms selected by the Department of Transportation to demonstrate GPS backup technologies, with tests to take place in March.
[This story is the third in a series of 11 detailing technology from firms selected by the Department of Transportation (DOT) in August 2019 to demonstrate technologies that could be used to back up the services provided by GPS should GPS signals be jammed, spoofed or unavailable. See also Echo Ridge and Seven Solutions.]
TRX Systems will provide a portable kit that generates alerts when electronic jamming or spoofing is detected and will provide a “rewind” navigation feature to estimate the user’s probable current position after jamming or spoofing has occurred. The company has developed NEON, a GPS-denied location technology, providing 3D mapping and GPS-denied personnel tracking for warfighters, first responders, security and industrial personnel that operate indoors, underground, and in areas without GPS.
Neon Command User Interface. Courtesy TRX Systems
NEON delivers ubiquitous, low-cost, GPS-denied location through the use of advanced sensor fusion, ranging, and patented dynamic mapping algorithms. The algorithms fuse inertial sensor data, Wi-Fi readings and inferred building data to deliverreliable 3D location. Optional use of geo-referenced ultra-wideband or Bluetooth beacons enhances positioning accuracy
Neon User Interface. Courtesy TRX Systems
TRX’s NEON Location Service provides position data that enables tracking and navigation when satellite technology is unavailable or unreliable. NEON detects GPS interference and delivers continuous location during such events; NEON also delivers 3D personnel location indoors, outside, and underground. NEON provides PNT assurance with commercial-grade solutions that integrate with present and future military satellite assurance and location capabilities.
“The EW Kits provide an easy to use and real-time assessment of GPS integrity for the warfighter, integrated with existing military applications and systems,” said Carol Politi, President and CEO of TRX Systems.
In a 2017 case study, TRX Systems’ NEON Personnel Tracker solution provided 3D tracking of law enforcement, EMS Personnel and other first responders during a critical incident training exercise at Grand Central Terminal in New York City, hosted by the Department of Homeland Security (DHS).
Beijing’s municipal government released a three-year plan to promote the innovation and development of industries related to the BeiDou Navigation Satellite System. The total output of BeiDou navigation and location service industry in the Beijing region will exceed 100 billion yuan ($14.4 billion U.S. dollars) by 2022, according to the plan document.
In late February, Northrop Grumman’s Mission Extension Vehicle MEV-1 autonomously docked with another satellite in geostationary orbit in space, making navigation history. It simultaneously took the next step in satellite operation by extending Intelsat 901’s lifetime beyond its original plan. The so-called “rescue satellite,” built by Northrop Grumman subsidiary Space Logistics, used a combination of traditional ranging, optical orbit determination from ground, and on-board sensors (visible, infrared, and LiDAR) for relative navigation in space to make its ultra-precise rendezvous 35,786 km above Earth.
The successful operation means a potential sea change in satellite operation: their lifetimes can be extended, and defunct satellites can be moved to safer orbit even after their fuel supplies are exhausted.
The complex series of maneuvers to bring the two satellites together began with an October 2019 launch of the MEV-1. Northrop Grumman controllers undertook a series of engine burns to raise MEV-1’s orbit from its highly elliptical geostationary transfer orbit up to a circular orbit 300 km above the geosynchronous belt. Shortly thereafter, Intelsat decommissioned its satellite 901, and it used the last of its propellant to move into the GEO graveyard orbit.
MEV-1 approached.
For 19 days, MEV-1 advanced upon and withdrew from Intelsat 901, calibrating its navigation sensors: optical cameras, infrared cameras and side-scanning LiDAR to orient and position itself relative to Intelsat 901.
Images courtesy Northrop Grumman.
For the final delicate and very precise maneuver, on February 25 MEV-1 autonomously flew to 20-meter distance, pausing before resuming travel to the critical 1-meter docking position. It autonomously extended a docking probe, engaging an engine nozzle aboard Intelsat 901. A nozzle, by the way, that was never designed for docking purposes.
MEV-1 then extended a group of internal grippers to anchor the two satellites together.
The satellite duo are now jointly performing stack on-orbit checkouts. Later this month, MEV-1 will relocating the two of them to a GEO spot over the central Atlantic, where Intelsat 901 will take over services for another Intelsat satellite, providing C-band service in the Americas, Europe, and Africa.
MEV-1 will then, like the Lone Ranger, bid farewell to Intelsat 901 and move on to a new mission.
A new GNSS-centric application programming interface (API) library for Android and IoT developers is on the verge of appearing, and is now accepting registrations for its software development kit. The Fulfilling Enhanced Location Accuracy in the Mass Market through Initial Galileo Services (FLAMINGO) reportedly achieves half-meter accuracy in a smartphone.
Apple has filed an application to patent a machine-learning system for correcting GNSS positions based on consumer location estimates gathered from the setting. The technology could be applied to the company’s mobile mapping app.
“I’ve been a revolutionist for 47 years,” Brad Parkinson began a recent invited lecture at Google, “with this stealthy revolution. GPS is indeed a stealthy revolution.” In his lecture “GPS and Humanity” he described how GPS has “stealthily” crept into the fabric of global society and created dependencies that did not exist before.
Keeping a mapping drone at a safe distance from rugged vertical terrain during its mission requires intense planning and a GNSS-enabled technology called “terrain following.” A new online video series and free webinar document the real-life challenges and hazards that professional surveyors encounter in their work, this among them.
