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Modified frequency scaling algorithm for FMCW SAR Data Processing

Chinese Journal of Aeronautics 2007年第4期20卷 339-345页

作者： Jiang Zhihong Huang Fukan Wan Jianwei Cheng Zhu College of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China

This paper presents a modified frequency scaling algorithm for frequency modulated continuous wave synthetic aperture radar （FMCW SAR） data processing. The relative motion between radar and target in FMCW SAR during reception and between transmission and reception will introduce serious dilation in the received signal. The dilation can cause serious distortions in the reconstructed images using conventional signal processing methods. The received signal is derived and the received signal in range-Doppler domain is given. The relation between the phase resulting from antenna motion and the azimuth frequency is analyzed. The modified frequency scaling algorithm is proposed to process the received signal with serious dilation. The algorithm can effectively eliminate the impact of the dilation. The algorithm performances are shown by the simulation results.

关键词： FMCW radar SAR radar imaging frequency scaling algorithm

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The frequency scaling algorithm and interferometric spotlight SAR processing

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AEROSPACE SCIENCE AND TECHNOLOGY 2002年第2期6卷 147-158页

作者： Mittermayer, J Inst Hochfrequenztech & Radarsyst D-82230 Wessling Germany

Synthetic Aperture Radar (SAR) is a well-established technique for air- and spaceborne high resolution imaging. This paper demonstrates the phase preservation of the new frequency scaling algorithm for Spotlight SAR data processing and investigates differences between Stripmap and Spotlight illumination. The algorithm performs the range cell migration correction for non-chirped raw data without interpolation by using a novel frequency scaling operation. The azimuth processing is based on a spectral analysis approach that is made highly accurate by azimuth scaling. In almost all processing stages, a subaperture approach is introduced for efficient azimuth processing. The maximum scene size for air- and spaceborne spotlight parameter examples is estimated. A method is proposed, which shows how to process Stripmap mode raw data in the Spotlight mode. Point target simulations and real raw data processing, including the generation of Spotlight interferograms prove the phase preservation of the frequency scaling algorithm. The same SAR Stripmap raw data set of DLR's airborne system is processed in Stripmap and in Spotlight mode and the resulting detected images and interferograms are compared to each other. The differences due to the different range of squint angles used for the azimuth focusing are discussed. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.

关键词： SAR signal processing spotlight-SAR frequency scaling algorithm

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A Full-Aperture frequency scaling algorithm for Processing Dechirped Sliding Spotlight SAR Data

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IEEE ACCESS 2023年 11卷 92550-92564页

作者： Kang, Young-Geun Park, Seong-Ook Korea Adv Inst Sci & Technol Sch Elect Engn Daejeon 34141 South Korea

This paper proposes a full-aperture method for processing sliding spotlight synthetic aperture radar (SAR) data with dechirp-on-receive. The frequency scaling algorithm (FSA) efficiently processes the dechirped signals because the range cell migration correction (RCMC) process involves removing the residual video phase. However, the conventional FSA combined with the sub-aperture method is unsuitable for processing sliding mode data because the azimuth extent of the SAR image is limited by the system pulse repetition frequency. In addition, the azimuth compression performance deteriorates as the range displacement increases from the center of the SAR image. To address these problems, we developed a modified full-aperture FSA for sliding mode data processing. A complete signal model of the azimuth convoluted sliding mode data with the dechirp-on-receive is newly derived. Based on the signal model, the frequency scaling factor and azimuth-matched filter have been modified to accurately perform RCMC and azimuth compression. Point target simulations demonstrated two advantages of the proposed algorithm over the conventional sub-aperture approach;One is accurate and consistent azimuth compression performance regardless of range displacements, and the other is wide observable azimuth extent. The practicality of the proposed method is further verified through actual SAR raw data experiments. In addition, it is analyzed that the proposed algorithm is specialized in processing dechirped sliding mode data through a characteristic comparison with various traditional sliding spotlight processing methods.

关键词： Azimuth convolution dechirp-on-receive frequency scaling algorithm full-aperture method sliding spotlight mode synthetic aperture radar

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Squint LFMCW SAR Data Processing Using Doppler-Centroid-Dependent frequency scaling algorithm

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2008年第11期46卷 3535-3543页

作者： Jiang, Zhi-Hong Huang-Fu, Kan Natl Univ Def Technol Signal Proc Lab Sch Elect Sci & Engn Changsha 410073 Hunan Peoples R China

A linear frequency-modulated continuous-wave (LFMCW) synthetic aperture radar (SAR) is a highly miniaturized SAR that is suitable for use on a small unmanned aerial vehicle. In squint stripmap mode, the LFMCW SAR image quality is degraded by the presence of nonlinearities in the transmitted signal, combined with the large bandwidth introduced by the frequency scaling in the nonlinear frequency scaling (NLFS) algorithm. This paper proposes an extension of the NLFS algorithm called the Doppler-centroid-dependent frequency scaling algorithm. The algorithm introduces a new Doppler-centroid-dependent scaling factor to decrease the introduced bandwidth, effectively removing the range frequency aliasing, without extra computational load. Nonlinearity correction is performed at the same time as range cell migration correction. The validity of the proposed algorithm is demonstrated with point target simulation results.

关键词： Doppler centroid frequency scaling algorithm linear frequency-modulated continuous-wave (LFMCW) radar synthetic aperture radar (SAR)

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Non-linear frequency scaling algorithm for FMCW SAR data

Non-linear frequency scaling algorithm for FMCW SAR data

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3rd European Radar Conference (EuRAD 2006)

作者： Meta, Adriano Hoogeboom, Peter Ligthart, Leo P. Delft Univ Technol Int Res Ctr Telecommun & Radar Delft Netherlands TNO Def Secur & Safety The Hague Netherlands

ISBN: (纸本)9782960055177

This paper presents a novel approach for processing data acquired with frequency Modulated Continuous Wave (FMCW) dechirp-on-receive systems by using a non-linear frequency scaling algorithm. The range frequency non-linearity correction, the Doppler shift induced by the continuous motion and the range migration removal are performed at the same time in the wavenumber domain with a very efficient solution. The cross-range focusing is then achieved with conventional matched filtering. Real data have been acquired with the FMCW SAR demonstrator system built at the Delft University of Technology. Stripmap images processed with the proposed method are presented in order to show the validity of the non-linear frequency scaling algorithm.

关键词： synthetic aperture radar (SAR) frequency modulated continuous wave (FMCW) range frequency nonlinearity frequency scaling algorithm

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A Deramp frequency scaling algorithm for Processing Space-Borne Spotlight SAR data

A Deramp Frequency Scaling Algorithm for Processing Space-Bo...

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IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Pengbo, Wang Zhou, Yinqing Chen, Jie Li, Chunsheng Yu, Ze Min, He Beihang Univ Sch Elect Informat Engn Beijing 100083 Peoples R China

ISBN: (纸本)9780780395091

Reduced the data rate is one of the difficulties in high-resolution space-borne spotlight synthetic aperture radar (SAR). Based on Deramp Chirp scaling (DCS) algorithm and frequency scaling (FS) algorithm, a Deramp frequency scaling (DFS) algorithm for processing high-resolution space-borne spotlight SAR data is presented. The algorithm stars with raw data dechirped in range. First, the azimuth spectral folding phenomenon is overcome by using azimuth deramp processing. Secondly, the precise Range cell migration correction is achieved by frequency scaling processing and phase compensation. Lastly, the azimuth compression is performed by match filter. Based on the squinted equivalent range model, the complete derivation of the algorithm is presented and the realizing approach is given. Finally, the computer simulation shows the validity of the algorithm.

关键词： synthetic aperture radar frequency scaling algorithm high resolution

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Near-Field Three-Dimensional Planar Millimeter-Wave Holographic Imaging by Using frequency scaling algorithm

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SENSORS 2017年第10期17卷 2438页

作者： Zhang, Ye Deng, Bin Yang, Qi Gao, Jingkun Qin, Yuliang Wang, Hongqiang Natl Univ Def Technol Coll Elect Sci Changsha 410073 Hunan Peoples R China

In this paper, a fast three-dimensional (3-D) frequency scaling algorithm (FSA) with large depth of focus is presented for near-field planar millimeter-wave (MMW) holographic imaging. Considering the cross-range range coupling term which is neglected in the conventional range migration algorithm (RMA), we propose an algorithm performing the range cell migration correction for de-chirped signals without interpolation by using a 3-D frequency scaling operation. First, to deal with the cross-range range coupling term, a 3-D frequency scaling operator is derived to eliminate the space variation of range cell migration. Then, a range migration correction factor is performed to compensate for the residual range cell migration. Finally, the imaging results are obtained by matched filtering in the cross-range direction. Compared with the conventional RMA, the proposed algorithm is comparable in accuracy but more efficient by using only chirp multiplications and fast Fourier transforms (FFTs). The algorithm has been tested with satisfying results by both simulation and experiment.

关键词： frequency scaling algorithm near-field millimeter-wave 3-D holographic imaging

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Bistatic SAR Data Focusing using an Analytical Spectrum Based frequency scaling algorithm in Tandem Configuration

Bistatic SAR Data Focusing using an Analytical Spectrum Base...

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2011 CIE International Conference on Radar(RADAR 2011)

作者： Chen Shichao 1 Liu Ming 2 Yang Lei 1 Xing Mengdao 1 Bao Zheng 1 1 National Lab of Radar Signal Processing,Xidian University,Xi’an 710071,China 2 School of Electronic Engineering,Xidian University,Xi’an 710071,China

A bistatic frequency scaling algorithm (FS) is proposed based on an exact analytical bistatic point target (PT) spectrum obtained by a geometry-based bistatic formula (GBF) method in tandem configuration. Since numerical calculation is no longer needed when calculating the important parameter- the half quasi bistatic angle (HQBA), fast imaging process is achieved. Unlike the existing algorithms, it avoids the influence of the baseline to range ratio because of its precise spectrum, it can handle the bistatic data with a large baseline. The proposed method has been proved by using simulated data. By comparing the experimental results between the proposed method and the numerical calculation method which has a heavy computational burden, the images were almost the same, which further proves the advantages and correctness of the proposed method.

关键词： bistatic synthetic aperture radar (BiSAR) exact analytical PT spectrum frequency scaling algorithm baseline to range ratio

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Unparallel trajectory bistatic spotlight SAR imaging

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Science in China(Series F) 2009年第1期52卷 91-99页

作者： ZHANG Lei JING Wei XING MengDao BAO Zheng Key Laboratory for Radar Signal Processing Xidian University Xi'an 710071 China

A new approach for unparallel trajectory bistatic spotlight SAR imaging is proposed. The approach utilizes the concept of instantaneous Doppler wavenumber and introduces two variants, the sum-range and subtraction-range, to develop the 2D frequency analytical formula. Based on the assumption of plane wavefront, the transmitting and receiving Doppler are separated and formulated via series reversion. And frequency scaling is applied to focus image. The algorithm is with high computational efficiency, and provides well focus for limited scene imaging. Simulation result confirms the validity of the approach.

关键词： unparallel trajectory bistatic SAR instantaneous Doppler wavenumber series reversion frequency scaling algorithm unparallel trajectory bistatic SAR instantaneous Doppler wavenumber series reversion frequency scaling algorithm

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Study on imaging algorithm for missile-borne side-looking SAR

Study on imaging algorithm for missile-borne side-looking SA...

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1st Asian and Pacific Conference on Synthetic Aperture Radar Proceedings

作者： Yi Yu-Sheng Zhang Lin-Rang Liu Xin Liu Nan Shen Dong Xidian Univ Natl Key Lab Radar Signal Proc Xian Shaanxi Peoples R China

ISBN: (纸本)9781424411870

A SAR image problem for missile-borne based on the platform anomaly movement is discussed in this paper. In this paper, a approximate illumination geometry has been defined and a new image model is presented. Image formation from missile-borne synthetic aperture radar (SAR) is limited by image degradations caused by missile's non-level straight line movement. In this paper we assume that the missile is uniformity and beeline motion in a synthetic aperture time due to the missile's high speed. A different reference range is adopted to cope with the range-dependent secondary range compression (SRC) to different synthetic aperture. By this approach, the SRC error can be reduced effectively. Finally, simulation results verb the correctness and validity of the proposed methods.

关键词： missile borne frequency scaling algorithm synthetic aperture radar

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