Global Navigation Satellite Systems Engineering, Policy, and Design
The advent of large LEO constellations is a game-changer for navigation. A key feature of these constellations is their potential to allow simultaneous measurement of Doppler shifts from a large number of satellites.
A framework to seamlessly navigate people from urban road traffic to indoor foot traffic uses the phone’s inertial measurement unit, GNSS chipset and camera, aided by an extended Kalman filter and ORB-SLAM. Tests show the framework performing well in both phases, guiding the phone’s user, behind the wheel on a city street, to a spot in an underground parking garage and walking to a meeting inside a large building.
By astral definition, every dawn is new. In the human condition, we see its possibility, its growing brightness bringing hope. Or, in our best selves, we bring hope to it.
By Alan Cameron
The United States Federal Aviation Administration’s (FAA) Wide Area Augmentation System (WAAS) uses Hexagon | NovAtel technologies, including reference receivers and signal generators, to provide the accuracy and integrity necessary to safely operate civil aircraft. Here’s a look at the updated technologies and how they enable GPS as a safety of life service for aviation.
Ambiguity resolution combined with multiple constellations and multiple frequencies proves very effective in reducing Precise Point Positioning convergence time. Such a solution with a 30° mask has a shorter convergence than a float multi-GNSS solution without any obstructions, despite the latter using more satellites.
By Inside GNSS
Research has focused on methods to analytically determine bounding probability distributions and parameters and identify the conditions under which such bounds are guaranteed to hold. This column summarizes several important examples from this research to highlight the most useful principles and techniques.
By Sam Pullen
As a significant number of people and robotics venture into space, infrastructures providing critical services such as GNSS must be considered on a large extra-terrestrial scale to support these explorations and settlements.
By Inside GNSS
Laboratory tests explore how commercially available receivers respond to meaconing and spoofing, with the goal of developing useful test methodologies and metrics to assess receiver robustness and resilience to real-world spoofing threats.
There are interesting tradeoffs to consider in placing navigation satellites at various orbital heights, including signal power, availability, cost, orbit prediction, receiver computational load and manufacturer motivation.
By Inside GNSS
Innovative European developers use emerging GNSS-based Internet of Things technologies to create more power-efficient solutions for a range of logistics, maintenance and other applications.
By Peter Gutierrez
It has become fashionable of late in U.S. government circles to undermine the U.S. defense forces. The General Accounting Office (GAO), the Federal Communication Commission (FCC) and the White House (POTUS) have all pitched in, doing their share to weaken the capability and downgrade the tools with which our warfighters enter conflict.
A favorable GAO ruling discounted Congressional allegations that the FCC skipped a key legal step before granting Ligado’s controversial application. This positions the broadband company closer to its target and to ongoing interference with GPS signals.
By Dawn M.K. Zoldi (Colonel, USAF, Ret.)
The digital outputs of a four-channel antenna processing chain consisting of a four-element squared phased array and a 4-coherent channels front-end are processed to identify the presence of a jamming signal. The processing unit then implements a spatial filter to minimize jammer impact. The reconstructed signal is input to a COTS/SDR receiver designed to work in a typical railway environment.
