Monday, February 23, 2015

GPS and "dead reckoning"

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We are frequently asked how well the Motion Computing tablets' GPS performs when mounted in apparatus or when leaving the station.  The concern is that it will take too much time for the GPS to acquire a signal from the satellites before allowing the driver/officer to map a route to the emergency.

With almost all modern GPS antennas this is not an issue.  Sometimes referred to as "dead reckoning" but in the industry it's called an "almanac" or internal memory to record the recent satellites used by the GPS.  For example, the almanac can predict satellite positions up to 3 days in advance.  This results in signal acquisition in less than 15 seconds and usually within just a few seconds.

The bottom line: use a modern GPS receiver connected via USB to your Motion Computing vehicle dock and you'll be in great shape to respond quickly.

At Allegiance Technology, we don't sell the GPS receivers but one of our partners recommends the USGlobalSat BU-353-S4 which can be found on the web for under $65.  It mounts with a magent.  You can find more information on exact specs at the USGlobalSat website.