Study On The Principles And Models Of Single Frequency BDS Precise Positioning

Beidou satellite navigation system(BDS) is the satellite navigation and positioning system developed by China. BDS has officially provided regional services since December 27, 2012. The current BDS high precision applications mostly use triple or dual frequency receivers, and the cost is very high. This has greatly limited the development and applications of BDS in precision agriculture, lane level positioning and navigation, deformation monitoring and other related fields. So the study of the single frequency BDS receiver to achieve high precision navigation and positioning is needed to promote the theory and technology of BDS related disciplines and progress. The key to solve the problem of high precision positioning of single frequency BDS was studied in the dissertation, including cycle slip detection, single frenquency single epoch ambiguity resolution, multi-path error modeling and single frequency positioning reliability analysis etc.. The main contribution of this dissertation is rephrased as follows:(1) The single frequency carrier phase cycle slip detection methods are studied in this chapter, and a new method based on Kalman filtering is proposed for the single frequency BDS cycle slip real-time detection.(2) A least squares concatenated single epoch ambiguity method was proposed, which adopts BDS single epoch single frequency code pseudorange and carrier phase observations to construct the double difference observation equation and baseline length constraint equations of least squares solution. The ambiguity float solution variance covariance matrix is obtained. Then double difference ambiguity is fixed based on the Par-Lambda algorithm to improve the success rate and searching efficiency. A Kalman based ambiguity resolution method is proposed using a similar idea, and some interesting results are obtained.(3) The operation cycle of BDS satellite constellation was studied. It was found that the GEO's orbit cycle is fluctuating with a maximum fluctuation of 40 seconds. The MEO and IGSO satellites are comparatively more stable. GEO satellites have a good repeatability between the running track of any two adjacent days. For the MEO satellites, there is no correlation in the adjacent two days, but 7 days cycle trajectory shows a strong relevance.(4) For the BDS multi-path effect, the single difference residuals method was used to extract the same visible satellite single difference residuals between the adjacent two days. A correlation coefficient method was adopted to calculate the correlation coefficient. It was found that the lead cycle is approximately the same between the adjacent two days with the maximum correlation coefficient.(5) The influence characteristics between success rate of single frequency BDS carrier phase solution and the visible satellites was studied. Under the same conditions, the simulation results of GPS and BDS system are compared and simulated. The success rate of biased estimation is simulated in the case of gross errors and cycle slip.