Study and Analysis of GDOP for Pseudolite Based Navigation System for Test Range Applications

摘要

This work aims at studying various geometric configurations/constellations of pseudolites and estimating the corresponding PDOP associated with Pseudolite based navigation. Exhaustive study has been conducted out of which few representative cases have been presented. As a result, the paper demonstrates that a properly chosen pseudolite configuration on ground can give equivalent accuracy of that configuration installing satellites in troposphere. It is further demonstrated that when the user is at lower altitudes, a set of pseudolites near the launch pad is required to counter earth curvature effects. Another set of distant pseudolites are required to have improved PDOP for the user at higher altitudes. Thus, a combination of two set of pseudolite systems can give improved performance for the whole range of the test vehicle. In the current study, the accuracy of pseudolite based and GPS-augmented-pseudolite based navigation have been studied and found that the latter gives better accuracy.