Dual-space Ambiguity Resolution Approach Theory and Application

Abstract

In real time kinematic (RTK) GPS positioning the reference station(s) is (are) static, and the moving receivers must not be far from the reference station(s). But in some cases, such as formation flying, satellite-tosatelliteorbit determination, etc, it is difficult to establish a static reference station. GPS kinematic-to-kinematic positioning (KINRTK) will meet such requirements. The key work of ambiguity resolution for KINRTK is to obtain an ambiguity float solution rapidly. The float solution can be estimated using either the “Geometrybased”(GB) or “Geometry-free”(GF) approach, requiring the construction of a “GB” or “GF” ambiguity search space. These two spaces are different but have the same true integer ambiguity result. Searching in two spaces at the same time, referred to here as Dual-space Ambiguity Resolution Approach (DARA), will be faster than in the individual spaces because only a few ambiguity candidates meet the conditions of both spaces simultaneously. It can be shown that DARA can dramatically reduce ambiguity candidates even if the C/A-code pseudo-range observables are used. The results of a vehicle test confirm that our approach is promising, resulting in millimeter-level misclosure of the KINRTK run.