The IFFT-based SQM method against digital distortion in GNSS signals

Sun, Chao; Zhao, Hongbo; Zhuang, Chen; Feng, Wenquan

doi:10.1007/s10291-017-0622-9

Cited by 7 publications

(6 citation statements)

References 7 publications

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“…All the positive chips of digital-distorted signals have a falling edge that leads or lags relative to the correct end-time for that chip [20]. Some detection methods have been developed for this kind of distortion [21], [22].…”

Section: The Damping Factor Associatedmentioning

confidence: 99%

Detection and Classification of GNSS Signal Distortions Based on Quadratic Discriminant Analysis

et al. 2020

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Satellite signal distortions, or so called ''evil waveforms'' (EWFs), may cause severe distortions of the cross-correlation function in receivers. Undetected EWFs could result in large range errors and threaten the integrity of Global Navigation Satellite System (GNSS). Analog distortion and digital distortion are two classical types of signal distortions. With the advent of modernized GNSS signals, more failure types are considered to cover potential EWFs of Binary offset carrier (BOC) modulated signals, such as codeonly distortion and subcarrier-only distortion. Different failure types affect the correlation functions and the tracking precision in different ways. Therefore, it is useful to identify the failure type of a detected distortion. Conventional multi-correlator method can detect signal distortions; however, it is infeasible to identify the failure types. We developed a novel multi-correlator method based on Quadratic Discriminant Analysis (QDA). The QDA-based method also uses correlation-domain detection metrics but performs distortion type classification by supervised learning algorithm. Experimentally measured results on Beidou B1C data signals are presented, which show the effectiveness and robustness of proposed method. Compared with conventional multi-correlator method, the QDA-based signal quality monitoring (SQM) method shows better performance on detecting EWFs and provides an extra capability to identify the failure types accurately. INDEX TERMS Evil waveforms (EWFs), quadratic discriminant analysis (QDA), signal quality monitoring (SQM), multi-correlator method.

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Section: The Damping Factor Associatedmentioning

confidence: 99%

Detection and Classification of GNSS Signal Distortions Based on Quadratic Discriminant Analysis

et al. 2020

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“…Since the correlation peak is still normalized to "1", it is required to be modified with the associated loss of the signal. The correlation peak of the included noise is shown in (16).…”

Section: Simulation Of Correlation Peaks Under the White Gaussian Noise (Wgn)mentioning

confidence: 99%

“…In [15], correlation peaks monitoring was introduced in detail, and a virtual correlation pair for MDE computation was proposed. In [16], an IFFT-based SQM method against digital distor-tion was addressed. Although these literature provide some positive results for monitoring distorted signals, they do not analyze the effects of signal distortion on the accuracy of pseudo-range measurement, and are not suitable for practical applications.…”

Section: Introductionmentioning

confidence: 99%

Quality monitoring and biases estimation of BOC navigation signals

Zhao

Zhang

Luo

et al. 2019

JSEE

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Many safety-critical applications that utilize the global navigation satellite system (GNSS) demand highly accurate positioning information, as well as highly integrity and reliability. Due to GNSS signals are easily distorted by the interferences or disturbances, the signal quality monitoring (SQM) is necessary to detect the presence of dangerous signal distortions. In this paper, we developed an SQM software for binary offset carrier (BOC) modulated navigation signals. Firstly, the models of BOC signal with ideal and distortion are presented respectively. Then the architecture of SQM software is proposed. Moreover, the effect of the white gaussian noise (WGN) and the front-end filter on the correlation peak of the receiver is analyzed. Finally, the biases induced by the signal distortion are evaluated. The experiments simulate the relationships between the code phase shift and the normalized correlation value in the case of the signal digital distortion and the analog distortion. The simulation results demonstrate that the proposed SQM method can effectively monitor the signal distortion and accurately estimate the correlation peak deviation caused by the distortion.

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“…We mainly take measures of segmentation and averaging to minimize the impact of noise. Similar way of processing can also be used for signal quality monitoring [30]. An interleaver is used here to store the consecutive baseband signal in rows and extract each column of rows for parallel computing.…”

Section: Multipath Parameter Estimate Algorithmmentioning

confidence: 99%

A Frequency-Domain Multipath Parameter Estimation and Mitigation Method for BOC-Modulated GNSS Signals

Sun

Zhao

Feng

et al. 2018

Sensors

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As multipath is one of the dominating error sources for high accuracy Global Navigation Satellite System (GNSS) applications, multipath mitigation approaches are employed to minimize this hazardous error in receivers. Binary offset carrier modulation (BOC), as a modernized signal structure, is adopted to achieve significant enhancement. However, because of its multi-peak autocorrelation function, conventional multipath mitigation techniques for binary phase shift keying (BPSK) signal would not be optimal. Currently, non-parametric and parametric approaches have been studied specifically aiming at multipath mitigation for BOC signals. Non-parametric techniques, such as Code Correlation Reference Waveforms (CCRW), usually have good feasibility with simple structures, but suffer from low universal applicability for different BOC signals. Parametric approaches can thoroughly eliminate multipath error by estimating multipath parameters. The problems with this category are at the high computation complexity and vulnerability to the noise. To tackle the problem, we present a practical parametric multipath estimation method in the frequency domain for BOC signals. The received signal is transferred to the frequency domain to separate out the multipath channel transfer function for multipath parameter estimation. During this process, we take the operations of segmentation and averaging to reduce both noise effect and computational load. The performance of the proposed method is evaluated and compared with the previous work in three scenarios. Results indicate that the proposed averaging-Fast Fourier Transform (averaging-FFT) method achieves good robustness in severe multipath environments with lower computational load for both low-order and high-order BOC signals.

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The IFFT-based SQM method against digital distortion in GNSS signals

Cited by 7 publications

References 7 publications

Detection and Classification of GNSS Signal Distortions Based on Quadratic Discriminant Analysis

Detection and Classification of GNSS Signal Distortions Based on Quadratic Discriminant Analysis

Quality monitoring and biases estimation of BOC navigation signals

A Frequency-Domain Multipath Parameter Estimation and Mitigation Method for BOC-Modulated GNSS Signals

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