Columns and Editorials

September 25, 2018

Innovative Test System for GNSS Signal Performance Analysis in Real Environments | Part 1

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.

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By Günter W. Hein

GNSS Spoofing and Aviation: An Evolving Relationship

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.

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By Gerhard (Gary) Berz
September 24, 2018

Change Is Coming: 
The Space Force and SMC 2.0

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.

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By Dee Ann Divis

Are Reflected Signals Always Undesirable?

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.

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By Mark Petovello
August 29, 2018

Ligado Fight Comes Down to Choice of Interference Standard

There was a flurry of filings July 9 just as the window closed for public comment on Ligado Networks’ proposal to repurpose satellite frequencies for a terrestrial network — a plan with the potential to interfere with GPS receivers.

The comments emerged as speculation swirled around a July 3 bid by EchoStar for Ligado spectrum supplier INMARSAT. The bid was rejected and, as of press time, EchoStar will have to wait six months before trying again.

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By Dee Ann Divis
June 15, 2018

GNSS IoT Positioning: From Conventional Sensors to a Cloud-Based Solution

The advent of the Internet of Things (IoT) has considerably increased the number of services and applications that require positioning information. In this sense, IoT positioning sensors usually obtain and deliver their position to a central node where it is further managed and analyzed by a user or scheduler. Nonetheless, the stringent requirements of low-cost IoT sensors in terms of low power consumption to achieve larger battery lifetime are pushing current technologies to their limits.

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By Inside GNSS
June 12, 2018

The Cospas-Sarsat MEOSAR System: A Solution to Support ICAO GADSS Autonomous Distress Tracking Recommendation

Today, it appears that the Cospas-Sarsat MEOSAR system, relying on payloads deployed on GNSS constellations (Galileo, GPS, GLONASS), offers all the conditions to meet the new recommendation of ICAO for ADT-system for Commercial Aviation, with a new generation of in-flight triggered beacons, identical to the current ELT in terms of aircraft integration, but capable of receiving triggers and cancellation events from the avionics, from the crew or from internal sensors, and of detecting and managing their inhibitions to maintain the capability to raise alerts and be localized in any situation.

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By Inside GNSS
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