A Study on GPS Ranging Based on Signal Subspace Method in Frequency Selective Fading Channels

摘要

Multipath mitigation is a major challenge in satellite-based navigation systems. Most of the available methods to mitigate multipath relies on the estimation of amplitude, phase, delay time of multipath, and narrowing down the correlators position. In order to simplify, we propose a signal subspace method based on singular value decomposition (SVD) that only requires the information of the delay time of each multipath component. In principle, this method depends on the calculation of orthogonal null subspace from a designed signal matrix using the information of the delay time of multipath. This subspace is used to nullify the channel effect completely at the correct direct signal delay time. Computer simulations demonstrate that the performance of this method is better in severe multipath scenario compared to conventional methods.