Implementation and analysis of GPS ambiguity resolution strategies in single and multiple reference station scenarios.

摘要

The Global Positioning System (GPS) double-difference (DD) operations can effectively reduce or eliminate many errors innate to raw undifferenced carrier-phase observables, such as the atmospheric effects and satellite orbital error. Ambiguity resolution under the influence of the ionosphere has been under extensive investigation for the past decade, and numerous resolution strategies have been proposed.;These eight strategies include the L1-only ambiguity resolution, widelane (WL) ambiguity resolution, combined L1 and L2 ambiguity resolution, ambiguity resolution using of ionosphere-free (IF) combination, and stochastic ionosphere modelling ambiguity resolution. All eight strategies are tested on three baselines ranging from 13 km to 43 km. In general, strategies that take the ionospheric error into account in their estimation models give much better position and ambiguity results than those that do not, and the stochastic ionosphere modelling ambiguity resolution strategies give best performance in both the ambiguity and position domains. The impact of the different parameterization schemes is also investigated and it is found that parameterizing the L1 and L2 observables with respect to L1 and WL ambiguities versus L1 and L2 ambiguities does not bring significant gain in the ambiguity domain, while it does in the position domain. (Abstract shortened by UMI.)