Moving object ISAR imaging method based on random frequency modulation stepping waveform designing

Abstract

The invention belongs to the technical field of high-resolution imaging in radar confrontation, and discloses a moving object ISAR imaging method based on random frequency modulation stepping waveform designing. The method comprises steps of firstly, designing an ISAR emission waveform based on random frequency modulation and pulse recurrence interval pre-designing; then, using matching filtering, dechirping or a compression sensing method to carry out sub-pulse compression processing so as to acquire a coarse resolution distance image sequence; constructing an equivalent measurement matrix and using the compression sensing method to carry out interpulse compression processing so as to obtain a high resolution distance image of the target; and after obtaining high resolution distance image sequences in different observation angles, carrying out azimuth processing through the compression sensing method so as to obtain a two-dimensional ISAR image of the target. According to the invention, effects on interpulse compression and synthesis of high resolution distance images imposed by moving of the target are effectively avoided; and the method is free from prior information of target moving parameters and is insensitive to the size of target speed, so when the data quantity required for imaging is reduced, the imaging quality is also improved.

Description

technical field [0001] The invention belongs to the technical field of high-resolution imaging in radar countermeasures, and provides an ISAR imaging method for moving targets based on random frequency modulation step waveform design, which is especially suitable for high-resolution imaging of space / air moving targets. Background technique [0002] Inverse Synthetic Aperture Radar (ISAR) imaging technology plays an extremely important role in the field of radar target recognition, especially in space detection and ballistic missile defense. ISAR imaging obtains high resolution in the range direction by compressing broadband radar echoes, further utilizes the rotation of the target, and uses aperture synthesis technology to achieve high resolution in the azimuth / pitch direction. It is usually used to detect moving targets such as aircraft, ships, missiles, and satellites. , celestial bodies, etc. for imaging. Generally speaking, high-resolution radar imaging of moving target...

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Problems solved by technology

Literature "Compressive sensing and stretch processing" (Krichene HA, Pekala M J, Sharp M D, et al. IEEE Radar Conference, Georgia, USA, 2011:362–367.), "Reconstruction of Moving Target'sHRRP Using Sparse Frequency-Stepped ChirpSignal" (Zhu F, Zhang Q, Lei Q, et al. IEEE Sensors Journal, 2011, 11(10): 2327–2334.), "A novel cognitive ISAR imaging method with random stepped frequency chirp signal" (Zhu F, Zhang Q, Luo Y, et al.SCIECE CHINA Information Sciences,2012,55(8):1910–1924.), "High-resolution ISAR imaging method based on random frequency modulation step signal" (Lv Mingjiu, Li Shaodong, Yang Jun, etc. Electronics and Journal of Information Science, 2016, online publication: http: / / www.cnki.net / kcms / detail / 11.4494.TN.20161017.1102.006.html) and others have conducted research on CS-based step-FM ISAR imaging methods, but all assume The echo has completed ideal motion compensation, without considering the influence of target motion on the synthetic range image

Random CFS (RCFS) signal has strong anti-jamming and anti-interception capabilities, but the existence of radial velocity will cause the broadening of the target range image and the divergence of energy, making the target echo signal not sparse enough, directly using CS reconstruction of the signal will bring reconstruction bias

Literature "Stochastic linear frequency modulation stepping radar waveform design and imaging algorithm research" (He Jin, Luo Ying, Zhang Qun, et al. Journal of Electronics and Information Technology, 2011,33(9):2068–2075.), "Based on sparse linear frequency modulation ISAR Imaging of Stepping Signals" (Wang Hongxian, Liang Yi, Xing Mengdao, et al. Chinese Science: Information Science, 2011, 41(12):1529–1540.), "High-Resolution ISAR Imaging With Sparse Stepped-Frequency Waveforms "(Zhang L, QiaoZ J, Xing M D, et al.IEEE Trans.Geosci.Remote Sens.,2011,49(11):4630–4651.) considered motion parameter estimation and compensation, but the principle is more complicated, The implementation steps are relatively cumbersome, and for high-speed motion, the effectiveness is difficult to ensure

In general, the current high-resolution radar imaging methods for moving targets still need further research

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