On-the-fly accuracy enhancement for civil GPS receivers

Abstract

A method and means for enhancing the position accuracy of a civil or degraded accuracy GPS receiver by compensating for errors in its position solution with data derived from a military, or precise accuracy, GPS receiver, wherein the civil GPS receiver may be disposed in a mobile expendable vehicle and the military receiver in a mobile launch vehicle. The compensating data is obtained by a comparison of the pseudorange measurements of the military GPS set and another civil GPS set disposed with it in the launch vehicle and attached to the same antenna. Two embodiments are disclosed involving variations of calibration, 1) an On-the-Fly Relative Navigation technique, applicable when the expendable receiver tracks the same satellites as the military and civil sets are tracking, wherein the position bias determined from the measurements of the two launch sets is transferred to the expendable receiver and used to offset its solution, and 2) an On-the-Fly Differential Navigation system, used when the expendable receiver is not tracking the same satellites as the launch sets, wherein the correction process is performed relative to the military set's GPS position solution.

Dependencies are inferred from the claim text.