Abstract: At present, slow convergence of traditional precise point positioning (PPP) with float ambiguity prevent the wide application in various fields. And the uncalibrated phase biases
originating in receivers and satellites prevent the integer ambiguity resolution of PPP, so it can not be directly fixed by using carrier wavelength. In order to solve this problem, an estimation model based on directional statistics is proposed. Then the validity of the phase bias correction for PPP fixed solution is analyzed in terms of the reliability of
ambiguity resolution, convergence speed and positioning accuracy. The results show that both reliability of ambiguity resolution and convergence speed of PPP with phase bias correction are improved, and the accuracy of PPP fixed solution can be improved by one order of magnitude.

Key words: Precise point positioning (ppp), Phase bias, Single-difference ambiguity fixing, Directional statistics