May/Jun 2019
Online News, Articles, and Features
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Global Navigation Satellite Systems Engineering, Policy, and Design
Global Navigation Satellite Systems Engineering, Policy, and Design
The problem of Position Determination based on Low Earth Orbit (LEO) satellites signal of opportunity in uncovered and denied GNSS areas such as oceanic regions, north regions and deserts can be significant one. How to maintain tracking information of airlines especially during distress and emergency? To achieve that, a new design for Search and Rescue (SAR) positioning information is developed. Position and speed of the transceiver could be estimated based on distributed Doppler information fusion from LEO satellites.
Novel protection level formulas, combining RAIM with solution separation and Precise Point Positioning, are applied to static, automotive, and flight scenarios. The authors of this article demonstrate that protection levels below 2 meters are achieved with reduced computational loads.
With the rethinking of the Galileo Commercial Service (CS), the E6B signal will disseminate Precise Point Positioning (PPP) corrections whereas the E6C component will be encrypted for authentication purposes. Different processing options for the E6 signals are investigated and it is shown that the sensitivity gap between data and pilot processing can be bridged by introducing non-coherent integrations and inter-frequency aiding. Extended integrations mitigate the impact of noise while inter-frequency aiding reduces the dynamics perceived by the E6B tracking loop.
Curtis Hay is a Technical Fellow at General Motors, where he develops precise GNSS and map technology for safe and reliable autonomous and semi-autonomous vehicles. He has appeared on many international stages, but while he very much enjoys traveling and meeting people in faraway lands, both for work and for pleasure, he knows where home is.
Improvements to GPS performance are often incremental, achieved by squeezing better performance out of existing systems with clever tweaks, smarter analysis and sharper receivers. Then again, every once in a while, there’s a huge leap in the capabilities of the system itself—an advance so big that it makes you appreciate all over again the elegant wizardry of satellite navigation.
Hostile cyber operations such as jamming and spoofing of GNSS signals are a growing concern. While they do not cause major damages to the satellite navigation system as such, they can have severe effects on critical national infrastructures and many other systems. Here, we address how international telecommunications law as well as the international law on the prevention of war apply in this context.
In the past few months, there have been articles in the press providing information and misinformation in advance of the GPS week rollover that occurred on April 6. Readers were warned to retire obsolete receivers, update software, check with manufacturers, and even perform testing of critical devices.
