Track model constraint for GPS position (Patent)
A track model is created for use with a GPS receiver. In one embodiment, the track model is a set of planar surfaces which approximate the contiguous surface on which navigation takes place. The GPS receiver searches for an appropriate planar surface associated with its approximate position. Having found the appropriate planar surface, the GPS receiver constrains its position using the planar surface associated with its approximate position. Using the track model improves the accuracy of the computed position at the time and improves the ambiguity estimation process so that positions with greatly improved accuracy are available sooner.