A New Reassigned Spectrogram Method in Interference Detection for GNSS Receivers

Abstract

Interference detection is very important for Global Navigation Satellite System (GNSS) receivers. Current work on interference detection in GNSS receivers has mainly focused on time-frequency (TF) analysis techniques, such as spectrogram and Wigner–Ville distribution (WVD), where the spectrogram approach presents the TF resolution trade-off problem, since the analysis window is used, and the WVD method suffers from the very serious cross-term problem, due to its quadratic TF distribution nature. In order to solve the cross-term problem and to preserve good TF resolution in the TF plane at the same time, in this paper, a new TF distribution by using a reassigned spectrogram has been proposed in interference detection for GNSS receivers. This proposed reassigned spectrogram method efficiently combines the elimination of the cross-term provided by the spectrogram itself according to its inherent nature and the improvement of the TF aggregation property achieved by the reassignment method. Moreover, a notch filter has been adopted in interference mitigation for GNSS receivers, where receiver operating characteristics (ROCs) are used as metrics for the characterization of interference mitigation performance. The proposed interference detection method by using a reassigned spectrogram is evaluated by experiments on GPS L1 signals in the disturbing scenarios in comparison to the state-of-the-art TF analysis approaches. The analysis results show that the proposed interference detection technique effectively overcomes the cross-term problem and also keeps good TF localization properties, which has been proven to be valid and effective to enhance the interference detection performance; in addition, the adoption of the notch filter in interference mitigation has shown a significant acquisition performance improvement in terms of ROC curves for GNSS receivers in jamming environments.

Frequency tracking and mitigation method based on CPHD filter and adaptive multiple linear Kalman notch filter for multiple GNSS interference

“…Several mitigation methods for the effect of cross‐terms were recently studied . One of the simple methods is a pseudo‐WVD (PWVD) and can be expressed as where x r ( t ) is the complex received signal which contains the interference signal, GNSS signal, and measurement noise.…”

Performance analysis of different interference detection techniques for navigation with Indian constellation

“…In [13, 14], if the interference‐like jammer is a sine wave with unknown amplitude, phase and frequency then spectrogram is the best detector. So, in‐band interference signals are observed using the PSD based on Welch analysis.…”

A New GNSS Interference Detection Method Based on Rearranged Wavelet–Hough Transform

“…Although GNSS has a certain capability to be immune from interference, due to the reception of the very low GNSS signal power, intentional or unintentional radio frequency interference (RFI) can cause serious performance degradation of a GNSS receiver; for instances, RFI may cause degradation of GNSS signal quality, serious errors in navigation and timing results, and even completely loss lock of the receiver [ 2 , 3 , 4 , 5 , 6 ]. Therefore, interference detection has become a critically important role for GNSS applications [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ].…”

“…Presently, the research topic on time-frequency (TF) transforms in GNSS interference detection has obtained increasing attention [ 4 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. For example, the spectrogram and Wigner–Ville distribution (WVD) were used for interference detection in GNSS receivers, due to the limitation of Heisenberg’s uncertainty principle, the spectrogram method has a TF resolution trade-off problem, thereby providing poor TF localization characteristics; although WVD presents good time-frequency aggregation property, in the case of multi-component signals, serious cross-interference terms occur in the TF plane [ 7 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ].…”