关键词: Android手机, GNSS原始观测值, 载波相位, 多普勒, 平滑伪距

Abstract: To improve the accuracy of GNSS positioning in Android mobile phone, the pseudorange observation is smoothed by carrier phase and Doppler. Firstly, the acquisition method of GNSS raw measurement at Android mobile phone is given. Then the carrier phase smoothing pseudorange and Doppler smoothing pseudorange algorithm models are derived. An reasonable and effective experiment is designed to evaluate the accuracy of the algorithms. The result shows that in the static test both carrier phase and Doppler smoothing algorithm can improve the positioning accuracy of the original pseudorange, and the Doppler smoothing algorithm performs better. In the dynamic test, the Doppler smoothing algorithm can obtain better positioning accuracy than the original pseudorange, but the carrier phase smoothing algorithm is worse than the original pseudorange. Due to the restriction of hardware, the rate of cycle slip and signal losing lock accounting for more than 50%. The availability of carrier phase in the mobile phone is low. The optimal smoothing time constant of Doppler smoothing algorithm is less than or equal to 10 seconds, which has great potential for real-time dynamic positioning.

Key words: Android mobile phone, GNSS raw observations, carrier phase, Doppler, smooth pseudorange