GLONASS precise point positioning considering the influence of code inter-frequency biases

The current constellation of GLONASS uses frequency division multiple access (FDMA), meaning the code observations of different satellites have inter-frequency biases (IFB). The code IFB is usually included in the pseudo-range residuals when performing precise point positioning (PPP). However, it will affect the convergence of PPP when the value of code IFB is large. In this contribution, a GLONASS PPP algorithm considering the influence of pseudo-range IFB is presented. The unified model of the algorithm in the ionosphere-free combination PPP and original observation PPP is given. At the same time, the validity of this algorithm is verified through the GLONASS observation data. The results show that the algorithm can effectively weaken the influence of the code IFB and the convergence speed and residual distribution of the GLONASS PPP considering the influence of code IFB is better than traditional method.