SYSTEMS AND METHODS FOR RESOLVING GPS PSEUDO-RANGE AMBIGUITY

摘要

Methods and systems for determining a position of a mobile terminal that includes a satellite radiotelephone and a GPS receiver using knowledge of the position of the communication satellite spot-beam in which the mobile terminal is located. Using this knowledge, the present invention can resolve the one-millisecond ambiguity, that arises from the code repeat length where relative code phase may be determined but absolute code phase could not. Trial positions, are selected to cover the spot-beam area, with spacing between trial positions accounting for the one-millisecond ambiguity. Pseudo-range measurements are generated for each trial position and used to generate position fixes. The best position fix, e.g. based on a self-consistency check, is selected. In an additional aspect of the invention, the number of trial positions is reduced by selecting an arc of positions within the spot-beam as trial positions based on timing delay information from the satellite communication system.