April 2006

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An off-shore firing range in the middle of an expanse of featureless ocean. Precision guided munitions. Microsecond margins of error. The objective: measuring test results with meters of accuracy in real-time. How are you going to do it? An array of acoustic sensors on buoys, RTK GPS, and precisely timed triangulation. Here’s their story.

GNSS satellites orbit around the Earth. That about says it all, right? Not quite. Professor Ashkenazi puts on two hats and declaims on a subject of gravity - with a little levity.

The commander of a new operational support facility located near the GPS Master Control Station is employing off the shelf software solutions to help military personnel in t he field anticipate the performance of their GPS equipment under a variety of conditions.

Today, three centers of excellence — the GPSOC, the NAVCEN, and the FAA’s National Operations Control Center (NOCC) — privately referred to as the Big Three, provide a supporting “port of entry” to any GPS user on the globe.

The chief designers of Russia's modernized GLONASS-M satellite provide a look at the new capabilities being brought on line at the world's second-oldest GNSS.

GNSS is all about positioning, sure. But for most automotive applications we need a map to help make sense of the GNSS data. A mapbase, however, can be more than a static background for location. Applied dynamically, map data can act as a sensor, providing context and situation awareness to in-vehicle systems and drivers.

Over the last couple of years, a series of papers coauthored by members of the European Commission (EC) Galileo Signal Task Force have laid out elements of the frequency plan and signal structure: RF bands, lengths and types of codes, data rates, and so forth. What had remained missing were the Galileo codes and the navigation message structure.

Over the years, researchers have advanced the use of GPS receivers to measure water vapor content in the troposphere and model its effects on signal propagation. However, these techniques typically employ stationary GPS receivers. This column describes a method for measuring water vapor by GPS receivers on moving platforms and determining the associated atmospheric effects.