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New GPS Standard Published

Posted by michael on from the dont-need-no-stinking-directions dept.

jeffy124 writes: "The Dept of Defense has released a new standard for GPS. The new standard will go into become available for use starting in 2003 when the first satellites are launched. Full completion is estimated to 2014. The new standard allows for greater horizontal accuracy of 36 meters instead of 100 meters, and also sets a new baseline for transmission protocols that circumvent ionic interference."

2 of 111 comments (clear)

  1. Current GPS can do better than that... by Cerlyn · · Score: 5, Informative

    A civilian differential GPS reciever always was able to do better than what selective availabilty should have allowed. These units gave (and still give) accuracies within 15 meters or so. Given a Loran compensation reciever (used to pick up posititioning signals meant for boats), one can improve on this accuracy by using additional known transmitters located at ground-based reference points.

    If you want "new" GPS units that were recently releaesd in the past year or so, look for units with the Wide Area Augmentation System (WAAS). Implemented alongside with the FAA, these units rely on two additional satilite signals for an average accuracy of three meters.

    Obligatory manufactuers links: Garmin's GPS description page and Magellan, another GPS supplier.

  2. Re:Furthermore this won't change non military use by nathanm · · Score: 3, Informative
    Despite these artificial limitation posed by the the US and Australian DoD, apparently everyone who's wanted to has been able to get accuracy to within fifteen meters for quite some time now.
    It's not an "artificial" limitation. When they say GPS has a 36 m accuracy, they mean there is a 95% Circular Error of Probability (CEP) that it will locate your horizontal position on the Earth's surface any day within a 36 m sphere. It's quite possible that the position is more accurate. Some days, the accuracy with a 95% CEP has been as low as 7.8 m, and the 50% CEP as low as 2.9 m (both with only single frequency receivers).

    Do the sattellites give bad readings which can be easily re-set to their true value, is some kind of interpretarion of multiple results possible (a kind of triangulation)? Either way, this has been the case for over five years.
    Before May 1, 2000 "Selective Availibility" introduced a timing error that limited the 95% CEP accuracy to 100 m for civilian receivers. It's been turned off for good now, but the DOD has reserved the right to degrade the signal in a specific region, probably by jamming it.