Impact of GPS/GLONASS Positioning on GPS Ambiguity Resolution and Positioning Result

Although GPS has an absolute advantage in real-time precise positioning at present, researching GLONASS system's function and contribution on real-time precise positioning, however, is also of great importance on improving its precision, reliability and initialized time. Due to the multiple frequencies of GLONASS satellites carrier phases, GLONASS ambiguity resolution is a complicated task. This paper analyses the mathematic model of integrated GPS/GLONASS relative positioning, and adopts GLONASS float ambiguity solution strategy. Using some observation data, it processes integrated GPS/GLONASS observables with pseudo-range and carrier phase at each epoch. By comparing the difference of initialized time and fixed rate of ambiguity and the precision of positioning between integrated GPS/GLONASS positioning and GPS positioning, the impact of GLONASS observables on GPS ambiguity resolution and positioning precision are analyzed. The experience indicates that, when adding GLONASS observation data, the initial time of GPS ambiguity becomes shorter and fixed rate of ambiguity is the same as GPS positioning. However, the precision of positioning isn't as good as GPS positioning because of the precision of GLONASS observable and float ambiguity.