On-the-fly Ambiguity Resolution without Requirements of Priori Position Information for Passive Pseudolite Receiver

摘要

Ambiguity resolution is an indispensable step in high precision pseudolite based positioning. Since linear truncation error cannot be completely ignored in pseudolite systems, existing ambiguity resolution methods require a meter-level priori position information for initialization. Commonly the priori position relies on code measurements. However, in some constraint environments, such as urban canyons and container terminals, accurate code measurements are difficult to achieve due to the effect of multipath propagation, which presents a great challenge to existing ambiguity resolutions. To solve problems mentioned above, an 'on-the-fly' (OTF) ambiguity resolution algorithm for the pseudolite positioning system based on alternating batch least squares estimation is proposed in this paper. Since linearization is avoided in the proposed algorithm, the initial state does not affect the convergence of the algorithm. Therefore, it has no requirement for accurate prior information. Simulation results prove that the float point ambiguity solution for decimetre-level accuracy can be estimated via proposed algorithm even without any priori position information. It is suitable for estimating carrier phase ambiguity under the condition of missing a priori position information.