A super-resolution algorithm with FRFT towards GNSS TOA estimation for multipath channel

Abstract

Multipath channels can highly reduce the performance of global navigation satellite system (GNSS) time-of-arrival (TOA) estimations, as a non-line-of-sight (NLOS) signal can distort the estimating accuracy for the line-of-sight (LOS) signal in a conventional GNSS receiver. This paper firstly investigates the dynamic difference of the LOS and NLOS signals for a moving GNSS antenna. Then, the fractional Fourier transform (FRFT) algorithm is presented to match the signals with different Doppler rate values in a multipath channel. A long coherent processing interval (CPI) is also adopted to enhance the sensitivity and accuracy of the FRFT match filter. Simulating results demonstrate the high performance for detections towards the LOS/NLOS signals in the fractional Fourier domain (FRFD) based on the proposed FRFT super-resolution algorithm (SRA).