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This article presents the authors’ experience in setting up an airborne pseudolite (UAVlite) with the needed ground-based infrastructure to perform code and phase ranging performance analysis. UAVlites transmit GNSS-like signals free from any local transmitter multipath (in contrast to ground-based transmitters) and can in principle be localized in real-time through a synchronized network of ground stations which may also broadcast the UAVlite positions in real-time.
One of the great engineering successes of the International Civil Aviation Organization (ICAO) and its expert panels is the standardization of globally harmonized Communication, Navigation and Surveillance (CNS) systems. These standards, sometimes supported by more detailed industry standards, provide safe and interoperable services between aircraft and the ground and space systems supporting them.
Rightfully, the GNSS community almost universally considers reflected signals to be problematic (the field GNSS reflectometry being an obvious exception). Reflected or non-line-of-sight (NLOS) signals combine with line-of-sight (LOS) signals to produce multipath effects, or if the LOS signal is absent NLOS signals can produce large ranging biases. Both phenomena increase measurement error and decrease positioning accuracy, especially in areas with lots of reflecting surfaces such as deep urban canyons.
From the Scandinavian farmlands to the hallowed halls of academia, Dr. Anna Jensen has traveled a remarkable road. She has now spent more than 20 years in GNSS research, development, teaching and consulting, focusing on GPS, Galileo, EGNOS, and GLONASS.
While threats to American defense satellites were climbing sharply, the costs and schedules of U.S. military space programs were on the same unsustainable trajectory — prompting lawmakers last year to begin trying to reorganize Air Force’s military space programs by creating a Space Corps. A move that, so far, has failed.