关键词: 全球定位系统, 多径信道, 自适应滤波器, 递归数字滤波器, 信噪比

Abstract: This article studies global positioning systems (GPS) multipath signal estimation. Through analyzing the principle of adaptive filters, a model is built of processing the intermediate frequency signals, and a new multipath signal estimation method is proposed utilizing the adaptive filters which can realize the estimation of amplitude, code phases and carrier phase. The scheme takes a series of correlation values for the desired signal of the adaptive filter which are obtained from dispreading, demodulation and accumulation using pseudo-range random noise codes with different latencies. A theoretical comparison with three other possible schemes demonstrates that the scheme possesses high signal-to-noise ratio (SNR) with good performance as well as code phase estimation information with no carrier phase ambiguity. According to the characteristics of various adaptive algorithms and the demands of the application, a recursive least-squares algorithm is adopted. Simulations show that the method can estimate the multipath signals of GPS L1 with code delay resolution of one sampling interval and carrier phase precision of 0.005 cycle at a SNR of 14 dB.

Key words: global positioning systems, multipath channel, adaptive filters, recursive digital filter, signal-to-noise ratio