Improved Back-Projection Algorithm on Small Time Bandwidth Product SAR Imaging

Han, Liguo; Suo, Zhiyong; Zheng, Chengxin; Li, Zhenfang; Zhang, Qingjun

doi:10.1109/lgrs.2020.3018588

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…Synthetic aperture radar (SAR) serves as a highly influential and widely used remote sensing system, functioning as a high-resolution microwave imaging radar capable of operating nearly full-time and in almost all weather conditions [1][2][3]. As a significant approach to aerial remote sensing, airborne SAR is extensively utilized in Earth observation, environmental monitoring, strategic target surveillance, disaster monitoring, ground moving target indication (GMTI), and other applications [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

A Novel Real-Time Processing Wideband Waveform Generator of Airborne Synthetic Aperture Radar

Chen,

Wei,

et al. 2024

Remote Sensing

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This paper investigates a real-time process generator of wideband signals, which calculates waveforms in a field-programmable gate array (FPGA) using the high-level synthesis (HLS) method. To obtain high-resolution and wide-swath images, the generator must produce multiple modes of large time-bandwidth product (TBP) linear frequency modulation (LFM) signals. However, the conventional storage method is unrealistic as it requires huge storage resources to save pre-computed waveforms. Therefore, this paper proposes a novel processing approach that calculates waveforms in real-time based simply on parameters such as the sampling frequency, bandwidth, and time width. Additionally, this paper implements predistortion through the polynomial curve to approximate phase errors of the system. The parallelizing process in the FPGA is necessary to satisfy the high-speed requirement of a digital-to-analog converter (DAC); however, repeatedly multiplexing real-time calculation consumes extensive logic and DSP resources, potentially exceeding FPGA limitations. To address this, this paper proposes a piecewise linear algorithm to conserve resources, which processes the polynomial only once, acquires the difference in two adjacent values through the register and pipeline, and then adds this increment to facilitate parallel computations. The performance of this proposed generator is validated through simulation and implemented in experiments with an X-band airborne SAR system.

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Section: Introductionmentioning

confidence: 99%

A Novel Real-Time Processing Wideband Waveform Generator of Airborne Synthetic Aperture Radar

Chen,

Wei,

et al. 2024

Remote Sensing

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“…Airborne SAR is widely used in Earth observation, disaster monitoring, and other applications. SAR transmits linear frequency modulation (LFM) signal in range orientation, in order to obtain high‐resolution and wide swath image, which normally needs a large time‐bandwidth product (TBP) LFM signal [1, 2]. In addition, some airborne SARs demand many work modes which compose different bandwidth and pulse width signals.…”

Section: Introductionmentioning

confidence: 99%

A novel linear frequency modulation signal generator in real‐time processing of airborne synthetic aperture radar

Chen

Wei

et al. 2023

The Journal of Engineering

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Generally, synthetic aperture radar(SAR)generates linear frequency modulation (LFM) signals by method of look-up table (LUT), which requires calculating different LFM signals and storing these waveforms in advance. With the demand for multi-mode, high-resolution and wide swath of airborne SAR systems, the method of LUT is not available, because that requires huge storage resources. In order to solve these drawbacks in limited hardware resources, this letter proposes a novel LFM signal generator in real-time processing. By taking advantage of high level synthesis (HLS) on FPGA, the proposed generator calculates the LFM signal simply using parameters of pulse width, bandwidth, and sampling frequency. Meanwhile, in order to compensate for the SAR system phase error, the proposed generator calculates phase error using a linear polynomial algorithm, which can compensate for the phase error in real time. The simulation results prove that this approximation can achieve a good effect. The performance of this method is implemented by experiments with an X-band airborne SAR system.

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“…As a host platform, the helicopter presents some challenges for highresolution SAR imaging [3][4][5]. Currently, most research in helicopter SAR imaging focus on the platform vibration [6][7][8][9]. Some mathematical models of the platform vibration are established.…”

Section: Introductionmentioning

confidence: 99%

Rotor blades blockage modulation suppression algorithm for helicopter‐borne SAR

Gao

Liu

et al. 2021

IET Signal Processing

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There exists periodic modulation problem in radar echoes due to the main rotor blades periodic blockage in helicopter-borne fire-control radar which is mounted atop the main rotor mast of the helicopter. Such modulation echo induces a set of ghosts in synthetic aperture radar (SAR) image, further resulting in a poor performance of subsequent tracking and striking. To address this problem, this article proposes a method on rotor blades blockage modulation suppression for helicopter-borne SAR. By decomposing the blocked echo into the form of Fourier series in the azimuth direction, a reference function could be constructed to suppress the modulation directly by adopting an iterative approximation strategy. This method effectively avoids the complex blocked data recovery methods, and thus can be used to suppress various kinds of periodic modulation components without requiring certain distribution models. Both simulated and realmeasured data are processed to demonstrate the effectiveness of the proposed algorithm.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Improved Back-Projection Algorithm on Small Time Bandwidth Product SAR Imaging

Cited by 5 publications

References 10 publications

A Novel Real-Time Processing Wideband Waveform Generator of Airborne Synthetic Aperture Radar

A Novel Real-Time Processing Wideband Waveform Generator of Airborne Synthetic Aperture Radar

A novel linear frequency modulation signal generator in real‐time processing of airborne synthetic aperture radar

Rotor blades blockage modulation suppression algorithm for helicopter‐borne SAR

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