Assessment of a Multipath Mitigation Approach for GNSS/INS Ultra-Tightly Coupled Integration System

The GNSS/INS ultra-tightly coupled integration system addresses the shortcomings of both the GNSS and INS (Inertial Navigation System) individual systems, but due to the inherent limitations of the GNSS, the integrated system is still affected by jamming, multipath effects, or non-line-of-sight (NLOS) issues in urban environments. Recently, a multipath mitigation method based on DLL (Delay-Locked Loop) has been proposed. This approach is called the absolute position aiding (APA) method, which utilizes the positioning results to estimate the missing absolute code phase, thereby improving the quality of pseudorange measurements. This method highlights its advantages and complements the integrated system when applied with the GNSS/INS integration system. Results from vehicle dynamic tests reveal that the APA method offers distinct advantages in multipath environments compared to other conventional multipath mitigation methods, such as the narrow correlator and strobe correlator methods.