A Unified Focusing Algorithm for Several Modes of SAR Based on FrFT

Sun, Guang-Cai; Xing, Mengdao; Xia, Xiang-Gen; Yang, Jun; Wu, Yirong; Bao, Zheng

doi:10.1109/tgrs.2012.2212280

Cited by 39 publications

(21 citation statements)

References 45 publications

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“…where is the speed of light (3 × 10 8 m/s) and max and min represent the maximum and minimum range for processing, respectively. Correlating the reference signal in (8) with the received signal in (7), we have [29,30]…”

Section: Problem Formulationmentioning

confidence: 99%

“…A processing chain based on stretch processing (SP) [25][26][27], modified fractional Fourier transform (FrFT) [25,26], and superresolution algorithm (such as MUSIC [28]) is proposed to make discrimination between the subtargets. For radar system exploiting linear frequency modulation (LFM) signal, SP is another efficient approach to realize the matched filter by looking for the echoes within a predefined range interval of interest [29][30][31]. SP is usually used in the wide band processing in synthetic aperture radar (SAR), reducing the bandwidth requirement of the subsequent processing.…”

Section: Introductionmentioning

confidence: 99%

“…By exploiting FrFT with a proper rotation factor, a chirp signal becomes a signal with single frequency in an alternative mapping U domain. The energy-focusing characteristic of the FrFT makes it a powerful tool in the field of matched filtering, target detection, and parameter estimation for radar systems utilizing chirp signals [32,33]. FrFT algorithm is utilized in this paper to compensate for the distortion caused by Doppler effect for transmitted signals in LFM form.…”

Section: Introductionmentioning

confidence: 99%

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High Range Resolution Profile Construction Exploiting Modified Fractional Fourier Transformation

Feng

Jiang

Chen

2015

Mathematical Problems in Engineering

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This paper addresses the discrimination of closely spaced high speed group targets with radar transmitting linear frequency modulation (LFM) pulses. The high speed target motion leads to range migration and target dispersion and thereby the discriminating capability of the high range resolution profile (HRRP) deteriorating significantly. An effective processing approach composed of stretch processing (SP), modified fractional Fourier transform (FrFT), and multiple signal classification (MUSIC) algorithm is proposed to deal with this problem. Firstly, SP is adopted to transform the received LFM with Doppler distortions into narrow band LFM signals. Secondly, based on the two-dimensional range/velocity plane constructed by the modified FrFT, the velocity of the high speed group target is estimated and compensated with just one single pulse. After the compensation of range migration and target dispersion simultaneously, the resolution of the HRRP achieved by single pulse transmission improves significantly in the high speed group targets scenarios. Finally, MUSIC algorithm with superresolution capability is utilized to make a more explicit discrimination between the scatterers in comparison with the conventional SP method. Simulation results show the effectiveness of the proposed scheme.

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Section: Problem Formulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

High Range Resolution Profile Construction Exploiting Modified Fractional Fourier Transformation

Feng

Jiang

Chen

2015

Mathematical Problems in Engineering

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“…Due to its compressed sampling ability, compressed sensing has found many attractions in radar remote sensing and branched out to many new fronts. R. Baraniuk et al proposed the radar imaging system based on CS for the first time and a high resolution imaging method is presented in for SAR sparse targets reconstruction based on CS theory [7][8][9][10][11][12][13][14][15]. In the above researches, it has been shown that a successful recovery of a compressible signal depends on the presence of sparse dictionary and these works have made a great contribution to the future research of radar signal processing.…”

Section: Introductionmentioning

confidence: 99%

SAR Imaging Based on Compressive Sensing via Fractional Fourier Transform

Li¹,

Liu²,

Zhao³

et al. 2016

Proceedings of the 2016 6th International Conference on Machinery, Materials, Environment, Biotechnology and Computer

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Abstract.To reduce the amount of measurements, compressive sensing (CS) has been introduced to synthetic aperture radar (SAR). In this paper a novel synthetic aperture radar (SAR) imaging algorithm based on compressive sensing (CS) is proposed. In the range plane, the echo signal is reconstructed in fractional Fourier domain for the sparsity, and matched filtering is used in the azimuth to obtain the image. Taking into account the large peak signal to noise ratio (PSNR), raising compression ratio can enhance the resolution, improve the range ambiguity and possess benign focusing ability. Simulation results show that by using the method this paper proposed it outperforms the existing Range Doppler algorithm demonstrating the superior performance of the proposed approach.

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“…An efficient two-step approach is proposed to process the raw data in the spotlight and sliding-spotlight modes [28], [29]. The essence of this approach is the fractional Fourier transform (FrFT) or the rotation of time-frequency diagram (TFD) [30]. However, the squint angle and acceleration would lead to the skewing and ambiguity of the 2-D spectrum [31], and one-dimensional (1-D) deramping operation cannot decrease the pulse repetition frequency (PRF) to a minimum.…”

Section: Introductionmentioning

confidence: 99%

Acceleration Model Analyses and Imaging Algorithm for Highly Squinted Airborne Spotlight-Mode SAR with Maneuvers

Tang

Zhang

Guo

et al. 2015

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

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Synthetic aperture radar (SAR) imaging is usually performed along a straight path. In practice, variations from the ideal caused by maneuvers with acceleration are inevitable. The main problem is the complex signal processing, particularly in the highly squinted spotlight mode. In this paper, acceleration model is analyzed in more details. Impacts are obtained how the acceleration influences the Doppler parameters and space-variant terms, including the SAR resolution and azimuth bandwidth. According to the special signal properties of the acceleration case, an approximation of the range history is made to avoid using the method of series reversion (MSR) to obtain an accurate spectrum. Based on the high-accurate spectrum, a spotlight algorithm with a modified two-step approach is given. Simulation results show the effectiveness of the modified algorithm.Index Terms-Acceleration model, highly squinted, maneuvers, omega-K algorithm (OKA), spotlight synthetic aperture radar (SAR), two-step approach.

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A Unified Focusing Algorithm for Several Modes of SAR Based on FrFT

Cited by 39 publications

References 45 publications

High Range Resolution Profile Construction Exploiting Modified Fractional Fourier Transformation

High Range Resolution Profile Construction Exploiting Modified Fractional Fourier Transformation

SAR Imaging Based on Compressive Sensing via Fractional Fourier Transform

Acceleration Model Analyses and Imaging Algorithm for Highly Squinted Airborne Spotlight-Mode SAR with Maneuvers

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