Correlation domain residuals based multipath detection for a direct position estimation receiver

Abstract

Direct Position Estimation (DPE) enables the direct estimation of the GNSS receiver’s position, velocity, and timing (PVT) within the navigation domain by jointly utilizing signals from all satellites at the sample level, thereby bypassing the intermediate step of computing observables. This paper aims to effective multipath detection for a DPE receiver, which serves for further relieving multipath induced navigation solution bias. To achieve this goal, two multipath detection statistics are established based on correlation domain residuals. The DPE navigation solution, affected by multipath, is first used to compute the code delay of all in-view satellites. Subsequently, these code delays are used to derive the signal amplitudes from pre-calculated correlations. Using the code delays and amplitudes, we reconstruct the correlations of the line-of-sight (LOS) signals and subtract them from the pre-calculated correlations to derive the correlation domain residuals. In the popular DPE receiver implementations, correlation values for all code delays are pre-calculated, thus the established multipath detection statistics do not require additional correlators. The effectiveness of the established multipath detection statistics is first validated with numerical simulations based on a semi-analytic DPE receiver. Subsequently, a software-based DPE receiver is employed to verify the established statistics with both simulated and field-collected satellite signals.