scholarly journals Assessment of RCS-specific SNR and Loglikelihood Function in Detecting Low-observable Targets and Drones Illuminated by a Low Probability of Intercept Radar Operating in Littoral Regions

2021 ◽  
Vol 9 (4) ◽  
pp. 1-22
Author(s):  
Perambur Neelakanta ◽  
Dolores De Groff
Keyword(s):  
Signal To Noise Ratio ◽  
Aspect Angle ◽  
Radar Echoes ◽  
Near Shore ◽  
Specific Geometry ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals ◽  
Loglikelihood Ratio ◽  
Kinetic Features

The objective of this study is to deduce signal-to-noise ratio (SNR) based loglikelihood function involved in detecting low-observable targets (LoTs) including drones Illuminated by a low probability of intercept (LPI) radar operating in littoral regions. Detecting obscure targets and drones and tracking them in near-shore ambient require ascertaining signal-related track-scores determined as a function of radar cross section (RCS) of the target. The stochastic aspects of the RCS depend on non-kinetic features of radar echoes due to target-specific (geometry and material) characteristics; as well as, the associated radar signals signify randomly-implied, kinetic signatures inasmuch as, the spatial aspects of the targets fluctuate significantly as a result of random aspect-angle variations caused by self-maneuvering and/or by remote manipulations (as in drones).  Hence, the resulting mean RCS value would decide the SNR and loglikelihood ratio (LR) of radar signals gathered from the echoes and relevant track-scores decide the performance capabilities of the radar. A specific study proposed here thereof refers to developing computationally- tractable algorithm(s) towards detecting and tracking hostile LoTs and/or drones flying at low altitudes over the sea (at a given range, R) in littoral regions by an LPI radar. Estimation of relevant detection-theoretic parameters and decide track-scores in terms of maximum likelihood (ML) estimates are presented and discussed.

scholarly journals Low Probability of Intercept Triangular Modulated Frequency Modulated Continuous Wave Signal Characterization Comparison using the Spectrogram and the Scalogram

2017 ◽  
pp. 37-47
Author(s):  
Daniel L. Stevens ◽  
Stephanie A. Schuckers
Keyword(s):  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Time Frequency ◽  
Novel Approach ◽  
Wave Radar ◽  
Time Frequency Localization ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals ◽  
Continuous Wave Signal

Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques for the purpose of analyzing low probability of intercept radar signals. This paper presents the novel approach of characterizing low probability of intercept frequency modulated continuous wave radar signals through utilization and direct comparison of the Spectrogram versus the Scalogram. Two different triangular modulated frequency modulated continuous wave signals were analyzed. The following metrics were used for evaluation: percent error of: carrier frequency, modulation bandwidth, modulation period, chirp rate, and time-frequency localization (x and y direction). Also used were: percent detection, lowest signal-to-noise ratio for signal detection, and plot (processing) time. Experimental results demonstrate that overall, the Spectrogram produced more accurate characterization metrics than the Scalogram. An improvement in performance may well translate into saved equipment and lives.

scholarly journals Low Probability of Intercept Frequency Hopping Signal Characterization Comparison using the Spectrogram and the Scalogram

2016 ◽  
pp. 13-23 ◽  
Author(s):  
Daniel L. Stevens ◽  
Stephanie A. Schuckers
Keyword(s):  
Signal To Noise Ratio ◽  
Frequency Hopping ◽  
The Novel ◽  
Time Frequency ◽  
Novel Approach ◽  
Time Frequency Localization ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals ◽  
Signal Characterization

Low probability of intercept radar signals, which are often problematic to detect and characterize, have as their goal ‘to see and not be seen’. Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques for the purpose of analyzing these low probability of intercept radar signals. This paper presents the novel approach of characterizing low probability of intercept frequency hopping radar signals through utilization and direct comparison of the Spectrogram versus the Scalogram. Two different frequency hopping low probability of intercept radar signals were analyzed(4-component and 8-component). The following metrics were used for evaluation: percent error of:carrier frequency, modulation bandwidth, modulation period, and time-frequency localization. Also used were: percent detection, lowest signal-to-noise ratio for signal detection, and plot (processing) time. Experimental results demonstrate that overall,theScalogram produced more accurate characterization metrics than the Spectrogram. An improvement in performance may well translate into saved equipment and lives.

scholarly journals Low Probability of Intercept Triangular Modulated Frequency Modulated Continuous Wave Signal Characterization Comparison Using the Wigner Ville Distribution and the Choi Williams Distribution

2019 ◽  
pp. 35-44
Author(s):  
Daniel L. Stevens
Keyword(s):  
Continuous Wave ◽  
Signal To Noise Ratio ◽  
Time Frequency ◽  
Novel Approach ◽  
Wave Radar ◽  
Time Frequency Localization ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals ◽  
Continuous Wave Signal

Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time frequency analysis techniques for the purpose of analyzing low probability of intercept radar signals. This paper presents the novel approach of characterizing low probability of intercept triangular modulated frequency modulated continuous wave radar signals through utilization and direct comparison of the Wigner Ville Distribution versus the Choi Williams Distribution. The following metrics were used for evaluation: percent error of: carrier frequency, modulation bandwidth, modulation period, chirp rate, and time-frequency localization (x and y direction). Also used were: percent detection, lowest signal-to noise ratio for signal detection, and plot (processing) time. Experimental results demonstrate that overall, the Wigner Ville Distribution produced more accurate characterization metrics than the Choi Williams Distribution. An improvement in performance may well translate into an increase in personnel safety.

Detection and Parameter Extraction of Low Probability of Intercept Frequency Hopping Signals using the Spectrogram and the Reassigned Spectrogram

2020 ◽  
pp. 11-20
Author(s):  
Daniel L. Stevens
Keyword(s):  
Frequency Analysis ◽  
Parameter Extraction ◽  
Frequency Hopping ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Analysis Techniques ◽  
Time Frequency Localization ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals

Low probability of intercept radar signals, which are often problematic to detect and characterize, have as their goal ‘to see and not be seen’. Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques for the purpose of analyzing these low probability of intercept radar signals. Although these classical time-frequency analysis techniques are an improvement over existing Fourier-based techniques, they still suffer from a lack of readability –which can be caused by poor time-frequency localization (such as the spectrogram), which may in turn lead to inaccurate detection and parameter extraction. In this study, the reassignment method, because of its ability to improve time-frequency localization, is proposed as an improved signal analysis technique to address the poor time-frequency localization deficiency of the spectrogram. This paper presents the novel approach of characterizing low probability of intercept frequency hopping radar signals through utilization and direct comparison of the spectrogram versus the reassigned spectrogram.

scholarly journals Detection and Parameter Extraction of Low Probability of Intercept Radar Signals using the Hough Transform

2016 ◽  
pp. 9-25
Author(s):  
Daniel L. Stevens ◽  
Stephanie A. Schuckers
Keyword(s):  
Hough Transform ◽  
Continuous Wave ◽  
Parameter Extraction ◽  
Time Frequency ◽  
Low Snr ◽  
Analysis Technique ◽  
Shift Keying ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals

Digital intercept receivers are currently moving away from Fourier-based analysis and towards classical time-frequency analysis techniques, such as the Wigner-Ville distribution, Choi-Williams distribution, spectrogram, and scalogram, for the purpose of analyzing low probability of intercept radar signals (e.g. triangular modulated frequency modulated continuous wave and frequency shift keying). Although these classical time-frequency techniques are an improvement over the Fourier-based analysis, they still suffer from a lack of readability, due to cross-term interference, and a mediocre performance in low SNR environments. This lack of readability may lead to inaccurate detection and parameter extraction of these radar signals. In this paper, the use of the Hough transform, because of its ability to suppresscross-term interference, separate signals from cross-terms, and perform well in the presence of noise, is proposed as an improved signal analysis technique. With these qualities, the Hough transform has the potential to produce better readability and consequently, more accurate signal detection and parameter extraction metrics.

scholarly journals Low Probability of Intercept Frequency Hopping Signal Characterization Comparison Using the Wigner Ville Distribution and the Choi Williams Distribution

2018 ◽  
pp. 1-10
Author(s):  
Daniel L. Stevens ◽  
Stephanie A. Schuckers
Keyword(s):  
Frequency Hopping ◽  
The Novel ◽  
Modulation Bandwidth ◽  
Time Frequency ◽  
Novel Approach ◽  
Time Frequency Localization ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals ◽  
Signal Characterization

Low probability of intercept radar signals, which are often challenging to detect and characterize, have as their objective ‘to see and not be seen’. Digital intercept receivers are currently moving from Fourier-based techniques to classical time-frequency techniques for the analysis of low probability of intercept radar signals. This paper presents the novel approach of characterizing low probability of intercept frequency hopping radar signals through utilization and direct comparison of the Wigner Ville Distribuion versus the Choi Williams Distribution. Two different frequency hopping low probability of intercept radar signals were analyzed (4-component and 8-component). The following metrics were used for evaluation: percent error of:carrier frequency, modulation bandwidth, modulation period, and time-frequency localization. Also used were: percent detection, lowest signaltonoise ratio for signal detection, and plot (processing) time.

Anti-Jamming and LPI Radar with Spread Spectrum Technology

2011 ◽  
Vol 219-220 ◽  
pp. 57-60
Author(s):  
Lian Qing Fu ◽  
Li Sheng Yang ◽  
Ya Ning Ma ◽  
Tao Wang
Keyword(s):  
Computer Simulations ◽  
Spread Spectrum ◽  
Signal To Noise Ratio ◽  
Radar System ◽  
Signal To Noise ◽  
Detection Range ◽  
Emission Signal ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Spread Spectrum Signals

In order to enhance the capability of anti-jamming and Low Probability of Intercept (LPI) of radar system, spread spectrum signals are designed for modern radar system. Emission signal is coded with PN codes at the transmitting terminal. Spectrum of signal is spreaded and multi-signal mixed together, so it is not easy to intercept. At the receiving terminal, undesired signals are spreaded when dispreading desired signal. Signal to noise ratio (SNR) of the received signals is raised after despreading, so the detection range broadens. Computer simulations verify the good performance of the proposed approach.

scholarly journals A Novel Approach for the Characterization of Triangular Modulated Frequency Modulated Continuous Wave Low Probability of Intercept Radar Signals via Application of the Wigner-Ville Distribution

2021 ◽  
pp. 19-28
Author(s):  
Daniel L. Stevens
Keyword(s):  
Signal Processing ◽  
Continuous Wave ◽  
Processing Technique ◽  
Signal Processing Technique ◽  
Time Frequency ◽  
Novel Approach ◽  
Wave Radar ◽  
Low Probability ◽  
Low Probability Of Intercept ◽  
Radar Signals

Digital intercept receivers are changing from Fourier-based analysis to classical time-frequency analysis techniques for analyzing low probability of intercept radar signals. This paper presents a novel approach of characterizing low probability of intercept triangular modulated frequency modulated continuous wave radar signals through utilization and direct comparison of the signal processing techniques Wigner-Ville Distribution versus the Reassigned Smooth Pseudo Wigner-Ville Distribution. The following metrics were used for evaluation: percent error of: carrier frequency, modulation bandwidth, modulation period, chirp rate, and time-frequency localization (x and y direction). Also used were: percent detection, lowest signal-to-noise ratio for signal detection, and plot (processing) time. Experimental results demonstrate that overall, the Reassigned Smooth Pseudo Wigner-Ville Distribution signal processing technique produced more accurate characterization metrics than the Wigner-Ville Distribution signal processing technique.

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