Towards Reliable and Precise BeiDou Positioning with Stochastic Modelling

The China's BeiDou system is the first global satellite navigation system to broadcast the three frequency signals for full constellation. A lot of studies have been done recently for positioning and navigation by using BeiDou three frequency signals, but mostly based on the GPS-like empirical stochastic model. This paper aims to study the stochastic modelling of BeiDou observations and then analyze its impact on the ambiguity resolution and precision positioning. To generalize the stochastic model, the satellite-dependent precisions, cross correlations between arbitrary two frequencies and time correlations for each frequency are set up. The results indicate that comparing with empirical stochastic model, the realistic stochastic model can improve the ambiguity resolution and positioning precision. Besides, the derived variance matrix of parameters with realistic stochastic model can objectively reflect the actual precisions of parameter estimates, which is rather important for solution evaluation in real applications.