An Extended Robust Estimation Method Considering the Multipath Effects in GNSS Real-Time Kinematic Positioning

Outliers and multipath effects significantly affect the positioning accuracy and reliability of the global navigation satellite system (GNSS), which must be handled properly in real-time kinematic (RTK) positioning, especially for low-cost devices. In this study, an extended robust estimation method (EIGG3) considering the multipath effects is proposed for RTK positioning. The carrier-to-noise power density ratio (
$C/N0$
) template function is introduced, and then, an extended shrinking factor of the bifactor equivalent weight is proposed, where one five-segment processing strategy considering the multipath effects is used. Two dedicated experiments, including one static experiment and one kinematic vehicle experiment, were carried out to evaluate the performance of the EIGG3 method in terms of positioning availability, accuracy, and ambiguity resolution. For the static experiment, the improved percentage of the EIGG3 method is 62.7%, 61.6%, and 52.1% compared to the traditional robust estimation method for the positioning accuracy in the
$E$
-,
$N$
-, and
$U$
-directions, respectively. Also, the EIGG3 method can further improve the performance of ambiguity resolution. For the kinematic vehicle experiment, the EIGG3 method 15.4% improvements for positioning accuracy in an urban environment, and even 23.9% improvements can be obtained in some typical scenarios.