Unified Approach to GPS Code and Carrier Solutions

Recent advances in dealing with Anti-Spoofing (A-S) make the dual-frequency P-code receivers much more attractive because they provide the most complete set of observables. The epoch solution for dual-frequency P-code receivers is described. The eUipses of standard deviations for the undifferenced ambiguities and for the wide-lane and narrow-lane ambiguities are very narrow and are oriented closely along the 45· or 90· azimuth respectively. The epoch solutions are studied for one satellite moving from the zenith to setting. Controlling multipath becomes important if the wide lane ambiguity or the undifferenced ambiguities are to be computed from individual or a sma1l number of single-epoch solutions. The epoch solutions are subjected to the double difference operation to yield relative positions. The coordinates of the moving receiver are estimated for each epoch or for a specified time interval. thus combining kinematic GPS, static GPS. and the so-called ambiguity fixing On-The-Fly (OTF) technique in a unified approach which applies equally well to dynamic and static situations and requires no antenna swaps.