Pseudorange Double Difference Algorithm Based on Duty-Cycled Carrier Phase Smoothing on Low-Power Smart Devices

摘要

In recent years, due to the open access to raw GNSS measurements, it is possible to study other PVT algorithms to improve the positioning accuracy on smartphones. In this paper, we first give the analysis of the characteristics of the smartphone observations and measurement error sources, then focus on the con-tinuous cycle slip of carrier phase with duty cycle mode. Then, we propose an improved Hatch filtering algorithm in order to use the carrier phase observations which have continuous loss of cycles to reduce the measurement noise of pseu-doranges. Finally, we give a comparison of several pseudorange positioning algorithms, the model of pseudorange double difference algorithm and the parameter selection principle of Kalman filter. Experiments based on a real smartphone in the open sky environment and the post-processing of the collected data is discussed in detail later. The results show that the proposed carrier smoothing algorithm can effectively reduce the noise of pseudorange observations and the positioning accuracy of the pseudorange double difference algorithm with carrier smoothing technique is less than 5 m, which shows obvious improvement compared with the positioning accuracy of the traditional positioning method on smartphones.