Trenz Electronic GmbH Support Forum
Archived Boards and Threads => Archived Boards => FAQ GlobalTop GPS Receivers and Modules => Topic started by: Horsa on September 11, 2010, 01:11:06 PM

Q: Can I improve GPS distance accuracy against GPS position accuracy?
You cannot improve the accuracy of the GPS distance between two points with respect to the accuracy of the GPS position of two points by computing the difference between the GPS positions of the two points, because the GPS position error of the two points will not necessarily be the same.
If we knew the amount of error that can occur between two unknown points for distance calculation, then we could essentially obtain very precise GPS location through some basic filtering. But unfortunately this is not the case, because the variables that affect the satellite signal reception is constantly shifting, and the position estimates from calculations based on the random pseudo code will always have a reasonable amount of error.
GlobalTop GPS modules and receivers are specified at 3 m accuracy 95% of the time, so the maximum amount of error between two points is around 6 m (for 95% of the time). There will be spikes and oddities that occur every now and then, but GlobalTop GPS modules and receivers will try to filter them out using, for instance, the proprietary NavSpeed threshold feature.