Fractional Fourier transform-based chirp radars for countering self-protection frequency-shifting jammers

Self-protection deceptive jammers create at the radar receiver output multiple-false targets that are impossible to isolate in both time and frequency domains. In this paper, we introduce a novel technique based on fractional Fourier transform (FrFT) to discriminate between the true target echo and those false targets in the case of frequency-shifting jammers. In fact, we exploit the capability of the FrFT to resolve, in a matched manner, spectra that are overlapping in time and frequency. This is a property that cannot be achieved using a standard matched filter. The theoretical analysis of this technique is presented and its effectiveness is verified by simulation.

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The Weighted Fractional Fourier Transform and Its Application in Image Encryption

Mathematical Problems in Engineering ◽

10.1155/2019/4789194 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10

Author(s):

Tieyu Zhao ◽

Qiwen Ran

Keyword(s):

Fourier Transform ◽

Theoretical Analysis ◽

Image Encryption ◽

Fourier Transforms ◽

Fractional Fourier Transform ◽

Rapid Development ◽

Matrix Group ◽

Future Developments ◽

Security And Reliability ◽

Fractional Fourier Transforms

With the rapid development of information, the requirements for the security and reliability of cryptosystems have become increasingly difficult to meet, which promotes the development of the theory of a class of fractional Fourier transforms. In this paper, we present a review of the development and applications of the weighted fractional Fourier transform (WFRFT) in image encryption. Relationships between the algorithms are established using the generalized permutation matrix group in theoretical analysis. In addition, the advantages and potential weaknesses of each algorithm in image encryption are analyzed and discussed. It is expected that this review will provide a clear picture of the current developments of the WFRFT in image encryption and may shed some light on future developments.

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Key Validity Using the Multiple-parameter Fractional Fourier Transform for Image Encryption

10.21203/rs.3.rs-504295/v1 ◽

2021 ◽

Author(s):

Tieyu Zhao ◽

Yingying Chi

Keyword(s):

Numerical Simulation ◽

Fourier Transform ◽

Information Security ◽

Theoretical Analysis ◽

Image Encryption ◽

Fractional Fourier Transform ◽

Point Of View ◽

Multiple Parameter

Abstract Multiple-parameter fractional Fourier transform (MPFRFT) is proposed and applied to image encryption. The MPFRFT with two vector parameters has better security, which becomes the main technical means to protect information security. However, our study found that many keys of the MPFRFT are invalid, which greatly reduces its security. Theoretical analysis and numerical simulation verify our point of view.

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A review of self-protection deceptive jamming against chirp radars

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078717000708 ◽

2017 ◽

Vol 9 (9) ◽

pp. 1853-1861 ◽

Cited By ~ 4

Author(s):

Samer Baher Safa Hanbali ◽

Radwan Kastantin

Keyword(s):

Pulse Compression ◽

Matched Filter ◽

Coupling Property ◽

True Target ◽

Processing Gain ◽

Different Types ◽

Before And After ◽

Deceptive Jamming ◽

Pros And Cons ◽

Self Protection

The well-known range-Doppler coupling property of the chirp radar makes it more vulnerable to different types of deceptive repeater jammers that benefit from the pulse compression processing gain of the radar-matched filter. These jammers generate many false targets that appear before and after the true target. Therefore, the radar cannot distinguish the true target from the false ones. This paper reviews different self-protection repeater jammers and presents their pros and cons, in order to provide a reference for the study of jamming/anti-jamming methods.

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Countering a Self-protection Frequency-shifting Jamming against LFM Pulse Compression Radars

International Journal of Electronics and Telecommunications ◽

10.1515/eletel-2017-0019 ◽

2017 ◽

Vol 63 (2) ◽

pp. 145-150 ◽

Cited By ~ 4

Author(s):

S. Baher Safa Hanbali ◽

Radwan Kastantin

Keyword(s):

Pulse Compression ◽

Radar Signal ◽

True Target ◽

Processing Gain ◽

Before And After ◽

A New Technique ◽

Small Change ◽

Pulse Compression Radar ◽

Self Protection ◽

Frequency Shifting

Abstract the well-known range-Doppler coupling property of the LFM (Linear Frequency Modulation) pulse compression radar makes it more vulnerable to repeater jammer that shifts radar signal in the frequency domain before retransmitting it back to the radar. The repeater jammer, in this case, benefits from the pulse compression processing gain of the radar receiver, and generates many false targets that appear before and after the true target. Therefore, the radar cannot distinguish between the true target and the false ones. In this paper, we present a new technique to counter frequency shifting repeater jammers. The proposed technique is based on introducing a small change in the sweep bandwidth of LFM waveform. The effectiveness of the proposed technique is justified by mathematical analysis and demonstrated by simulation.

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A Secure Speech Content Authentication Algorithm Based on Discrete Fractional Fourier Transform

International Journal of Digital Crime and Forensics ◽

10.4018/ijdcf.2015070102 ◽

2015 ◽

Vol 7 (3) ◽

pp. 19-36 ◽

Cited By ~ 2

Author(s):

Fan Zhang ◽

Zhenghui Liu ◽

Hongxia Wang

Keyword(s):

Fourier Transform ◽

Theoretical Analysis ◽

Experimental Evaluation ◽

Fractional Fourier Transform ◽

Content Authentication ◽

Hybrid Domain ◽

Frame Number ◽

Discrete Fractional Fourier Transform ◽

Tamper Location ◽

Speech Content

Watermark schemes content-based provide one way to solve the veracity and integrity of speech content. Some existed content-based schemes are vulnerable to feature-analysed substitution attack. Aiming to solve the problems, a secure speech content authentication algorithm is proposed, on the basic of the undeterminate angle of discrete fractional fourier transform. In the paper, the definition and calculation of discrete fractional fourier transform are given. And the watermark generation method based on discrete fractional fourier transform is analyzed. Frame number and watermark bits are embedded into hybrid domain of scrambled signals. Compared with the existed watermark schemes, the features for watermark generation and embedding are secret, which improves the security of watermark system. Theoretical analysis and experimental evaluation results show that the proposed algorithm is inaudible, robust to desynchronous attacks and has the excellent ability of tamper detection and tamper location.

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