A novel synthetic bandwidth method in BP image space for stepped-frequency SAR

Hu, Kebin; Wang, Hui; Shi, Jun

doi:10.1109/radar.2014.6875593

Cited by 2 publications

(1 citation statement)

References 9 publications

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“…To maintain the system performance, the transmitting sequence of frequency-stepped signal should be carefully designed. A general idea to solve the above problem is to transmit subband signals in different time intervals, but the inter-subband time offsets [8], [9], inter-subband errors of delay, amplitude and phase [10]- [12] will bring out difficulties to imaging algorithms especially the time-domain ones. Currently, a lot of researches have been conducted about stepped-frequency SAR imaging [13]- [16].…”

Section: Introductionmentioning

confidence: 99%

An Improved Ultrahigh-Resolution Stepped-Frequency Spaceborne SAR Imaging Algorithm

Li,

Ding,

Zhang

et al. 2024

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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Frequency stepping is a widely used technique for ultra-high-resolution synthetic aperture radar (SAR). Although reducing the burden of hardware, the technique increases the complexity of imaging algorithms due to the inter-subband time offsets and inter-subband errors of delay, amplitude and phase. To address the above problems, an improved ultra-highresolution stepped-frequency spaceborne SAR imaging algorithm is proposed in this paper. By generating subband images individually, performing inter-subband error estimation based on primary points, and then synthesizing the subband images in the imaging domain, the proposed algorithm effectively avoids the problem of time offsets and significantly improves inter-subband error compensation accuracy benefiting from the high SNR in the imaging domain. Besides, considering the characteristics of non-ideal factors in frequency-stepped SAR, a series of error compensation methods aiming at stop-and-go approximation, ionospheric error and tropospheric delay are integrated to the proposed algorithm. The effectiveness of the proposed algorithms is verified via computer simulations, and real data experiments are also conducted based on both an X-band spaceborne SAR system, Taijing 4-01, and a Ka-band spaceborne SAR system, Luojia 2-01.

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Section: Introductionmentioning

confidence: 99%

An Improved Ultrahigh-Resolution Stepped-Frequency Spaceborne SAR Imaging Algorithm

Li,

Ding,

Zhang

et al. 2024

IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing

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Research on Ultra-Wideband NLFM Waveform Synthesis and Grating Lobe Suppression

Liu

Jia

Liu

et al. 2022

Sensors

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Ultra-wideband (UWB) nonlinear frequency modulation (NLFM) waveforms have the advantages of low sidelobes and high resolution. By extending the frequency domain wideband synthesis method to the NLFM waveform, the synthetic bandwidth will be limited, and the grating lobe will grow as the number of subpulses increases at a fixed synthetic bandwidth. Aiming for the highly periodic grating lobes caused by equally spaced splicing and small subpulse time-bandwidth products (TxBW), a multisubpulse UWB NLFM waveform synthesis method is proposed in this paper. Random frequency hopping and spectral correction are utilized to disperse the energy of periodic grating lobes and optimize the matched filter of the subpulse, thereby reducing notches and Fresnel ripples in the synthesized spectrum. The results of the hardware-in-the-loop simulation experiment show that the peak sidelobe ratio (PSLR) and the integral sidelobe ratio (ISLR) of the NLFM synthetic wideband waveform (SWW) obtained by 50 subpulses with a bandwidth of 36 MHz are improved by 4.8 dBs and 4.5 dBs, respectively, when compared to the frequency domain wideband synthesis method, and that the grating lobe is suppressed by an average of 10.6 dBs. It also performs well in terms of point target resolution, and it has potential for 2D radar super-resolution imaging.

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A novel synthetic bandwidth method in BP image space for stepped-frequency SAR

Cited by 2 publications

References 9 publications

An Improved Ultrahigh-Resolution Stepped-Frequency Spaceborne SAR Imaging Algorithm

An Improved Ultrahigh-Resolution Stepped-Frequency Spaceborne SAR Imaging Algorithm

Research on Ultra-Wideband NLFM Waveform Synthesis and Grating Lobe Suppression

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