Fast Ambiguity Resolution for Pulsar-Based Navigation by Means of Hypothesis Testing

The problem of the global navigation satellite system carrier-phase ambiguity resolution (AR) has drawn a lot of attention and to some extent been well solved in the past. However, the pulse-phase AR in the pulsar-based navigation has not been fully investigated due to its special feature that the source pulsars are far away enough to be considered stationary relative to the observers. In this paper, the indeterminate AR problem is proposed to describe this AR situation by a group of indeterminate measurement equations and a new method is developed that enables faster estimation of pulse-phase ambiguities. This method is based on the hypothesis testing that helps one to construct the ambiguity acceptance space at a certain significance level. The acceptance space is then reformulated as a linear form via singular value decomposition that is much easier to search for. Besides, the search algorithm is redesigned that uses particle swarm optimization to quickly find an initial solution and employs a new parameter to compress the search space. As a result, the ambiguity search can be performed much more efficiently especially at big problem sizes.