Real-time carrier phase multipath detection based on dual-frequency C/N0 data

摘要

Since carrier phase multipath cannot be easily captured or mitigated, especially in real-time and kinematic applications, it is necessary to assess the multipath significance. We propose a real-time multipath detection method using dual-frequency carrier-to-noise-power-density ratio (C/N0). The proposed method takes full account of the relationship between the multipath and C/N0. Specifically, when the multipath effects are significant, the C/N0 behaviors not only deviate from the nominal values, but also differ in frequencies. Therefore, a combination test consisting of two statistics is developed. One is based on the C/N0 and the other is based on the differenced C/N0 between frequencies (C/N0). In addition, as an indispensable component of the multipath detection, a procedure for modeling the nominal C/N0 and C/N0 functions is proposed. This procedure is based on a rigorous evaluation in terms of statistical properties. To validate the effectiveness of the proposed method, both static and kinematic experiments were carried out under environments with distinct levels of reflective and diffractive multipath. The results show that this method can effectively detect the multipath significance, and the two statistics are both indispensable. In addition, the modeling procedure improves the reliability of multipath detection with the minimal detectable multipath as small as 0.05 cycles, providing a great potential in high-precision applications.