Joint Delay and Angle Estimation for GNSS Multipath Signals Based on Spatial and Frequential Smoothing

Multipath signals formed by signal reflecting from objects around the receiver in Global Positioning System result in tracking performance reduction and positioning error increase. Based on parameter estimation, multipath signals can be recognized, separated, restrained, and then position accuracy get improved. In this context, a two-step approach of joint multipath delays and direction of arrivals utilizing the characteristics of spatial and code domain in GNSS signals has been proposed: coarse estimation and fine estimation. To address the relative delays that may cause low resolution by similar DOAs, coarse estimation forms a spatial-frequential extended matrix and mainly adopts forward spatial and frequential smoothing. In order to enhance the performance, fine estimation is conducted by spatial filtering to separate each path and localized two dimension searching of fine delay and DOA which improve the precision within saving the complexity. Finally, simulation results and complexity analysis demonstrate that out schemes have excellent performance with low complexity, which make it attractive in practical project.