March/April 2012

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GNSS jammers used as personal privacy devices can interfere with nearby aircraft approach and landing systems. In some cases, use of these devices can take multiple reference receivers off-line due to integrity issues within the broadcast position message. This article describes incidents at Newark International Airport and other aviation facilities as examples of the adverse effects of such devices and discusses possible mitigations.

What is the endpoint of ever cheaper, ever smaller, and ever more sensitive GPS receivers? It’s the GPS dot: a miniature GPS tracking device that we’ll buy in bulk and stick on almost everything of value that we own. But the dot has a dark side: the secret and potentially malicious tracking of others. The need to protect ourselves from invasive tracking could lead to more GPS jamming and spoofing . . . and a showdown between privacy and GPS integrity.

Precise point positioning is available now via the ground segment of GNSS systems. Websites give us nearly real-time correction data for civil uses. So, why can’t the satellite segment provide this service? The author argues that this can be done and that not doing it is the equivalent of “Selective Unavailability.”

Cooperative positioning among clusters of GNSS users allows for faster computation of positions with higher reliability. Its performance is similar to that of assisted GNSS, but without any infrastructure requirement. Peer-to-peer cooperative positioning could be a promising addition to fixed augmentation systems of the future.

The regulatory phase of the GPS/LightSquared controversy appears to be winding down, and the litigation phase warming up.

In this issue: GPS trackers at sea, location-aware music, lonely places, launch strain and QZSS

As the world’s GNSS systems gain traction in building out constellations with new capabilities, what can be done to achieve maximum benefits?