Design and Performance Evaluation of the Improved INS-Assisted Vector Tracking for the Multipath in Urban Canyons

Abstract

Dynamic short-delay multipath in increasing dense urban canyons is a challenge to the global navigation satellite system-based (GNSS-based) positioning systems. However, the performance of existing multipath methods for a stand-alone receiver is limited on dealing with short-delay multipath. Vector tracking-based deep coupling with an inertial navigation system (INS) has the potential to suppress multipath errors by tracking direct signals using more accurate and robust positions. But in the typical deep couplings reported, the unmodeled multipath error is generally regarded as noise with other errors, and consequently their capacity for multipath suppression is not satisfying. To solve these problems, an improved deep coupling structure with a multipath error estimator is proposed and implemented in two schemes. Different from other methods, this modification creates nearly no extra complexity and computation cost. In this way, the inner correlation caused by multipath interference between channels can be decoupled, and the underlying requirements for modeling the errors accurately to construct vector feedback are fulfilled. Besides, for comparison analysis, a software-defined platform including different tracking and integration approaches is designed. Finally, the proposed methods are evaluated in weak signal, short-delay multipath, dynamic multipath, and the real-life multipath scenarios, and their superiority in positioning, measurement improvement, and tracking robustness are validated.