Evaluation of Compass Ambiguity Resolution Performance Using Geometric-Based Techniques with Comparison to GPS and Galileo

The Chinese GNSS system, Compass, is expected to be operational in the near future. The system will provide open and authorized service on four frequency bands. One of the important application areas involving Compass will be carrier-phase based precise positioning. However, the associated ambiguity resolution performance of Compass has not been discussed in the literature to date. In this paper, the ambiguity resolution performance of Compass is evaluated in terms of probability of correctly fixing ambiguities with different combinations of measurements using geometry-based covariance analysis. Simulation results presented in this paper show that using Compass B1 and B1-2 for dualfrequency positioning with slant ionospheric error estimation is not optimal since the center frequencies of two signals are too close making ionospheric observation difficult. Comparisons of ambiguity resolution performance among Compass, Galileo and GPS are also carried out in this investigation. Results show that Compass has poorer performance in terms of ambiguity resolution compared to GPS and Galileo due to the fact that Compass signals have larger measurement noise and are more susceptible to multipath effects.