Vehicle-Mounted GNSS Receiver with Reflected Signals Suppression Based on Doppler Frequency Difference

Tsubasa Terada, Takeshi Amishima, Ryuhei Takahashi

Peer Reviewed

Abstract: Global Navigation Satellite System (GNSS) positioning technology is advancing rapidly. Consequently, GNSS applications require high accuracy and reliability. One of the major errors in positioning is due to multipath propagation. Error reduction methods for baseband processing include those that perform processing in the time domain using sampled data or correlator output, and methods that perform processing in the spatial domain using an array of antennas. However, there are several problems such as, huge computational complexity, difficulty in suppressing reflected waves with arrival time differences smaller than the correlator interval, and increase in cost of the antenna footprint and hardware. In recent years, several methods have been proposed to discriminate reflected waves in the Doppler frequency domain of vehicle-mounted GNSS receivers. If there is a certain Doppler frequency difference, even if the arrival time difference between the direct and reflected waves is almost the same, each arrival wave can be separated. However, conventional methods have problems such as high computational complexity. In this study, we propose an algorithm to improve pseudorange accuracy by separating and suppressing reflected waves in the Doppler frequency domain using the correlator output, assuming a vehicle-mounted GNSS receiver. The effectiveness of the proposed method is evaluated using computer simulations and experiments. In the simulation evaluation, the proposed method suppressed the reflected waves below the noise level and achieved a pseudorange accuracy approaching the theoretical value for the case where only direct waves arrived. When the direct wave C/N0 was 40 dB-Hz, and the reflected wave arrived with a C/N0 of 34 dB-Hz and a 0.1 chip delay from the direct wave, the improvement was 5 m. The experimental evaluation involved a proof-of-principle experiment using a single-axis actuator, and a driving experiment, which confirmed the effectiveness of the proposed method.
Published in: Proceedings of the 2024 International Technical Meeting of The Institute of Navigation
January 23 - 25, 2024
Hyatt Regency Long Beach
Long Beach, California
Pages: 883 - 897
Cite this article: Terada, Tsubasa, Amishima, Takeshi, Takahashi, Ryuhei, "Vehicle-Mounted GNSS Receiver with Reflected Signals Suppression Based on Doppler Frequency Difference," Proceedings of the 2024 International Technical Meeting of The Institute of Navigation, Long Beach, California, January 2024, pp. 883-897. https://doi.org/10.33012/2024.19546
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