Multipath Insensitive Delay Lock Loop in GNSS Receivers

Abstract

The code measurement suffers from multiple error sources and especially multipath. The latter is unpredictable and changes in space and over time. Many interesting multipath mitigation techniques have been proposed. Most of them are not sufficiently effective for precise positioning using the code measurement. This paper presents a multipath insensitive delay lock loop that aims to improve the pseudorange measurement precision in the presence of multipath. This code loop is simple and does not require postprocessing of observables. Simulation and real implementation results showed that the proposed code loop dramatically improves the tracking error due to multipaths. Tracking error is limited to 1 m on pseudorange in typical multipath environments. This loop is more sensitive than the standard delay lock loop to thermal noise and applies predominantly to strong GNSS signals.