Partial ambiguity resolution for reliable GNSS positioning — A useful tool?

In differential global navigation satellite system positioning applications with short to moderate observation time spans, carrier phase ambiguity resolution is required to obtain precise coordinate estimates. Depending on the length of the baseline, differential atmospheric delays between the two receivers may have to be considered, thus weakening the underlying system model. In this contribution, we study single-, dual-, and triple-frequency, single- and combined-system GPS/Galileo cases with short, medium-length, and long baselines with an emphasis on reliable (fixed failure rate) ambiguity resolution. The goal is to determine, if, when, and to what extent partial ambiguity resolution techniques are beneficial. Four different ambiguity resolution algorithms are compared: A purely model-driven scheme based on the bootstrapping failure rate and a data-driven scheme based on the difference test, each for full and partial ambiguity resolution, respectively. Simulation results show that partial ambiguity resolution can considerably extend the range for instantaneous real-time kinematic positioning, and clearly reduce the convergence time for long baselines.