载波/多普勒平滑伪距在Android手机中的定位实现

针对Android手机GNSS伪距定位精度较低的问题，利用手机端观测信息，通过载波相位/多普勒平滑伪距改善手机端伪距观测值的质量，从而达到提高定位精度的效果。首先给出了Android手机GNSS原始观测量的获取方法，然后推导了载波相位平滑伪距和多普勒平滑伪距算法模型，并设计合理有效的试验对算法的精度进行评定。试验结果表明：在手机端静态定位中载波相位和多普勒平滑算法均可提高原始伪距的定位精度，且多普勒平滑算法表现更优；在手机端动态定位中多普勒平滑算法可获得比原始伪距更优的定位精度，但是载波相位平滑算法较原始伪距更差；由于硬件的制约手机端周跳和信号失锁严重，占比超过50%，载波相位在手机端的可用性较低；多普勒平滑算法的最优平滑时间常数小于等于10 s，具有实时动态定位的巨大潜力。

Carrier/Doppler smooth pseudorange in Android mobile phone

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.