Space-Time-Frequency Adaptive Processor for Multiple Interference Suppression in GNSS Applications

Qiang Guo,Lian-Gang Qi,Jianhong Xiang

doi:10.1155/2018/2301052

Abstract

To enhance the multiple interference suppression performance of global navigation satellite system (GNSS) receivers without extra antenna elements, a space-time-frequency adaptive processor (STFAP) is investigated. Firstly, based on the analysis of the autocorrelation function of the multicomponent signal, we propose a common period estimation and data block technique to segment the received signal data into blocks. Secondly, the signal data in each block are short-time Fourier transformed into time-frequency (TF) domain, and the corresponding TF points with similar frequency characteristics are regrouped to structure space-time-frequency (STF) data matrixes. Finally, a space-time-frequency minimum output power- (STF-MOP) based weight calculation method is introduced to suppress multiple interfering signals according to their sparse characteristics in TF and space domains. Simulation results show that the proposed STFAP can effectively combat more wideband periodic frequency-modulated (WBPFM) interferences even some of them arriving from the same direction as GNSS signals without increasing the number of antenna elements.

Highlights

In recent years, with the rapidly increasing complexity of the electromagnetic environment, interference suppression techniques for global navigation satellite system (GNSS) receivers have become an increasingly prominent role [1]
The single-antenna interference suppression methods, such as frequency-domain filtering [2], adaptive time-domain filtering [3, 4], and time-frequency (TF) filtering [5], have the advantages of small volume and low hardware complexity; they can only deal with the interferences with sparse characteristics in time and frequency domains and are not able to cope with multiple interferences [6] effectively
By combining time and spatial processing, it increases the number of suppressed narrowband interferences (NBI) without extra elements in the array; it still cannot deal with the scenario in which the number of wideband interferences (WBI) exceeds that of antenna elements

Summary

Introduction

With the rapidly increasing complexity of the electromagnetic environment, interference suppression techniques for global navigation satellite system (GNSS) receivers have become an increasingly prominent role [1]. The number of interferences coped with by spaceonly-based methods is limited to the number of antenna elements To deal with this shortcoming, the space-time adaptive processing (STAP) is introduced in GNSS applications and widely studied [8,9,10]. By combining time and spatial processing, it increases the number of suppressed NBI without extra elements in the array; it still cannot deal with the scenario in which the number of WBI exceeds that of antenna elements. To avoid the degradation of interference suppression performance when the number of interferences falling into a TF point exceeds the limitation that an antenna array can cope with, we propose a space-time-frequency minimum output power- (STFMOP) based interference suppression method to modify the conventional weight calculation formula by using a reference TF point

Signal Model

The Proposed STFAP

MHz 2 MHz 2 MHz 2 MHz 2 MHz 2 MHz

Experiments and Simulation Results

Conclusions