General design methodology of code multi‐correlator discriminator for GNSS multi‐path mitigation

Abstract

Multi-path becomes a main source of positioning errors in new-generation global navigation satellite systems (GNSS). Code multi-correlator discriminators (MCD), represented by narrow early-minus-late (NEML) and double delta (DD) discriminators which are designed for binary phase offset keying (BPSK) signals, are one of the main multipath mitigation techniques. However, because of the complicated auto-correlation function and intricate relationships among multiple correlators, it is hard to implement a trial and error approach, which is the conventional design method of discriminator structures, to specifically design code MCD structures for new GNSS signals which have complicated spreading waveforms. In this article, instead of a trial and error approach, a general design methodology for designing code MCD structures based on heuristic optimisation for multi-path mitigation is proposed. The proposed method can specifically design code MCD structures for signals with various modulations and receivers with different bandwidths, indicating the adaptability of the proposed method. Multi-path mitigation performances of such designed structures are better than those of traditional code discriminator structures with strong tracking robustness and slight degradation of thermal noise performance. Designed code MCD structures are also insensitive to multi-path relative amplitudes and bandwidths of receivers, ensuring the practicality of the designed code MCD structures. | INTRODUCTIONGlobal navigation satellite systems (GNSS) provide positioning, navigation and timing service. To promote the accuracy of positioning, on one hand, several new signals are employed in the new generation GNSS. Compared with the binary phase shift keying (BPSK) signal, which was first used in GNSS, binary offset carrier (BOC) [1] signals and multiplexed BOC (MBOC) [2] signals have more complicated autocorrelation functions (ACFs) and greater potential to improve the accuracy of positioning. On the other hand, with the development of various GNSS receiving and processing techniques, such as high precision differential techniques, performance of positioning is significantly improved. Nevertheless, there are still several non-negligible factors that reduce positioning accuracy, such as multi-path, which has become one of the main sources of positioning errors.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Anti-Multipath Underwater Acoustic Time-Delay Detection Algorithm Based on Dual-Delta Correlators

“…Where L B is loop bandwidth. When tracking loop reaches steady state, the discriminator output error is considered to be very small [8]. the discriminator function can be re-expressed as:…”

Pseudorange error prediction for adaptive tightly coupled GNSS/IMU navigation in urban areas

“…The cost and bulky size of the antennas limit the applications for ITS in urban environments, however. Signal processing methods can be used to reduce certain kinds of multipath error by improving the form of the receiver correlator structure design or correlator function, but they are not able to address NLOS effects (Yang 2016;Chen et al 2020;He et al 2020;Kumar and Singh 2020;Qi et al 2021).…”