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Fractional OAM Vortex SAR Imaging Based on chirp scaling algorithm

RADIO SCIENCE 2025年第3期60卷 1-14页

作者： Liu, Yu Du, Yongxing Li, Baoshan Qin, Ling Li, Chenlu Inner Mongolia Univ Sci & Technol Baotou Peoples R China

Vortex electromagnetic wave carries orbital angular momentum. Combined with Doppler information provided by radar platform movement, vortex electromagnetic wave can achieve higher resolution target imaging in SAR Imaging technology. In this paper, fractional order OAM vortex SAR imaging is studied. Firstly, the side-looking strip SAR imaging model is established. Then, the scattering echo equation of fractional order OAM is derived. Finally, the imaging simulation of multi-point target and single point target under Gaussian SNR is carried out by chirp scaling algorithm. The experimental results show that compared with the integer order OAM Vortex SAR Imaging, the fractional order OAM Vortex SAR Imaging in this paper has stronger robustness in Multi-target and Noise environment, which proves the effectiveness of the fractional order Vortex SAR Imaging.

关键词： fractional OAM vortex SAR imaging chirp scaling algorithm

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chirp scaling algorithm for GEO SAR based on fourth-order range equation

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ELECTRONICS LETTERS 2012年第1期48卷 41-U115页

作者： Bao, M. Xing, M. D. Li, Y. C. Xidian Univ Natl Lab Radar Signal Proc Xian 710071 Shaanxi Peoples R China

For a synthetic aperture radar (SAR) onboard a geosynchronous-earth-orbit (GEO) satellite, the track can be curvilinear. Thus, the validity of imaging algorithms based on the conventional hyperbolic range equation (CHRE) becomes questionable. A fourth-order range equation is adopted to improve the accuracy in the approximation of the range history for GEO SAR and a modified chirp scaling algorithm (CSA) is proposed. Simulation results show that the presented algorithm has better performance than the CHRE-based CSA in the GEO case, implying good application prospects.

关键词： GEO SAR artificial satellites chirp scaling algorithm conventional hyperbolic range equation fourth-order range equation geosynchronous-earth-orbit satellite hyperbolic equations imaging algorithm radar imaging spaceborne radar synthetic aperture radar synthetic aperture radar

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Focusing bistatic forward-looking synthetic aperture radar based on modified Loffeld's bistatic formula and chirp scaling algorithm

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JOURNAL OF APPLIED REMOTE SENSING 2014年第1期8卷 083586-1-083586-12页

作者： Ma, Chao Gu, Hong Su, Weimin Li, Chuanzhong Chen, Jinli Nanjing Univ Sci & Technol Inst Elect Engn & Optoelect Technol Nanjing 210094 Jiangsu Peoples R China Nanjing Univ Informat Sci & Technol Inst Elect & Informat Engn Nanjing 210044 Jiangsu Peoples R China

A focusing solution for bistatic forward-looking synthetic aperture radar (BFSAR) is presented. Forward-looking imaging is highly desirable in some potential applications, such as self-landing in bad weather, military surveillance, and navigation. Unfortunately, monostatic synthetic aperture radar reaches its limit when it is used in a forward-looking configuration. BFSAR can provide a high-resolution image in the forward-looking direction. However, due to the special forward-looking geometry, many proposed methods of deriving a bistatic point target reference spectrum (BPTRS) cannot handle the BFSAR data well. A modified Loffeld's bistatic formula (MLBF) for a forward-looking configuration is proposed first;it can get an accurate BPTRS of BFSAR. Then, a chirp scaling algorithm (CSA) based on MLBF is derived. CSA without interpolation allows high performance. Numerical simulations show that the proposed focusing solution can handle the BFSAR data well and achieve a high-resolution focused image. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

关键词： bistatic forward-looking synthetic aperture radar modified Loffeld's bistatic formula chirp scaling algorithm

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Azimuth-Invariant Motion Compensation and Imaging chirp scaling algorithm for Multiple-Receiver Synthetic Aperture Sonar

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IEEE ACCESS 2022年 10卷 114060-114076页

作者： Tian, Zhen Zhong, Heping Tang, Jinsong Zhang, Jiafeng Naval Univ Engn Naval Inst Underwater Acoust Technol Wuhan 430030 Hubei Peoples R China

To improve the imaging quality of conventional imaging algorithms without motion compensation (MOCO) and the efficiency of point-by-point MOCO algorithms for multiple-receiver synthetic aperture sonar (SAS) with azimuth-invariant six-degree of freedom (DOF) motion errors, an azimuth-invariant MOCO and imaging chirp scaling (CS) algorithm is presented in this paper. Taylor series approximation is used to process the range history in double square root form, while considering the fourth-order and inner terms with respect to the azimuth time. Using the method of series reversion and Fourier transform (FT) properties, the analytical two-dimensional frequency spectrum of the point target response of each receiver is derived. On this basis, the azimuth-invariant MOCO and imaging CS algorithm is proposed for six-DOF motion error compensation and multiple-receiver SAS imaging. Because it considers the azimuth-invariant six-DOF motion errors, the proposed algorithm has better imaging quality than conventional imaging algorithms without MOCO. Additionally, it has a significantly higher efficiency than point-by-point MOCO algorithms because the CS algorithm is a fast FT-based algorithm and does not require interpolation processing. The imaging simulation and experimental results verified the effectiveness and efficiency of the proposed algorithm.

关键词： Imaging Synthetic aperture sonar Receivers chirp modulation Transmitters Approximation algorithms Taylor series Underwater communication Sonar navigation Sonar equipment chirp scaling algorithm motion compensation series reversion synthetic aperture sonar underwater imaging technology

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A chirp scaling algorithm based on the method of series reversion for bistatic SAR

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ELECTRONICS LETTERS 2022年第25期58卷 999-1001页

作者： Wu, Haoran Cha, Hao Ning, Mingqiang Zhang, Peng Naval Univ Engn Wuhan Hubei Peoples R China

For the problem that the existing chirp scaling algorithm based on the method of series reversion (MSRCSA) needs to approximate the range cell migration (RCM) into a linear term of range and causes a larger range cell migration correction (RCMC) error, we propose an improved MSRCSA, which is able to focus azimuth-variation bistatic SAR. Firstly, to avoid the linear approximation for RCM, this paper derives a new curvature factor varying with the azimuth frequency and range, utilizing to describe RCM without any approximation. Secondly, since the new curvature factor is different with the traditional curvature factor varying only with the azimuth frequency, a new scaling function is given to modulate the echo signal so that the required range-variant RCMC shift can be implemented by using phase multiplies. Thirdly, the proposed MSRCSA is implemented by utilizing three phase multiplications and four fast Fourier transforms (FFTs). Finally, the good performance of the proposed MSRCSA is examined by comparing the imaging result of the proposed MSRCSA with that of the existing MSRCSA.

关键词： improved MSRCSA scaling function echo signal range-variant RCMC shift series reversion echo bistatic SAR linear approximation chirp scaling algorithm larger range cell migration correction error azimuth-variation bistatic SAR traditional curvature factor fast Fourier transforms phase multiplies synthetic aperture radar RCM azimuth frequency radar signal processing

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Improved chirp scaling algorithm integrated motion compensation for parallel-track bistatic synthetic aperture radar

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Journal of Beijing Institute of Technology 2011年第4期20卷 536-539页

作者：齐春东曾涛李枫 School of Information and Electronics Beijing Institute of Technology

To compensate motion errors of images from the parallel-track bistatic synthetic aperture radar（BiSAR）,an improved chirp scaling algorithm（CSA） is *** velocity vector of the moving aircrafts in the parallel-track BiSAR system can not remain invariant in an aperture,an actual aperture is divided into subapertures so that it is reasonable to assume that the aircrafts move with constant acceleration vector in a *** on this model,an improved CSA is *** new phase factors incorporate three-dimensional acceleration and *** motion compensation procedure is integrated into the CSA without additional operation *** simulation results show that the presented algorithm can efficiently resolve motion compensation for parallel-track BiSAR.

关键词： chirp scaling algorithm parallel-track bistatic synthetic aperture radar motion compensation

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Focusing Bistatic Forward-looking SAR using chirp scaling algorithm

Focusing Bistatic Forward-looking SAR using Chirp Scaling Al...

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IEEE Radar Conference (RADAR)

作者： Wu, Junjie Yang, Jianyu Huang, Yulin Yang, Haiguang Univ Elect Sci & Technol China Sch Elect Engn Chengdu 611731 Sichuan Peoples R China

ISBN: (纸本)9781424489022

With appropriate geometry configurations, bistatic Synthetic Aperture Radar (SAR) can break through the limitations of monostatic SAR on forward-looking imaging. Thanks to such a capability, bistatic forward-looking SAR (BFSAR) has extensive potential applications. However, the current BFSAR imaging algorithms always involve the time-consuming interpolation to carry out range migration correction. This paper develops a chirp scaling type imaging algorithm, which just needs the complex multiplication and FFT, for BFSAR with two parallel moving stations. The simulation results validate the effectiveness of the method.

关键词： Azimuth BFSAR imaging algorithm chirp Doppler effect FFT Imaging Power capacitors Receivers Transmitters bistatic forward looking SAR focusing bistatic synthetic aperture radar chirp scaling algorithm chirp scaling type imaging algorithm fast Fourier tran

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A new method for Doppler centroid estimation for spaceborne SAR based on chirp scaling algorithm

A new method for Doppler centroid estimation for spaceborne ...

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IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Zhang, Yunhua Zhai, Wenshuai Chinese Acad Sci Ctr Space Sci & Appl Res Microwave Remote Sensing Lab Beijing Peoples R China Grad Univ Chinese Acad sci Beijing Peoples R China

ISBN: (纸本)9781424412112

We introduce a new method to estimate the Doppler centroid accurately based on chirp scaling algorithm after investigating the performances of curvature factor Cs and the effective FM rate Ks regarding to Doppler ambiguity number (DAN) and finding that Cs and Ks will lose their functions if a wrong DAN is used and the generated image definition will be degraded. So relations between definition evaluation functions (such as entropy and variance) and the DAN can be used to find the correct DAN which makes the entropy minimum or the variance maximum. Radarsat raw data is used to test the proposed method and find that the performance of using variance is better than that of using entropy.

关键词： Doppler centroid Synthetic Aperture Radar (SAR) chirp scaling algorithm image entropy image variance

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Improved chirp scaling algorithm for Processing Squinted Mode Synthetic Aperture Sonar Data

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CYBERNETICS AND INFORMATION TECHNOLOGIES 2016年第6期16卷 111-122页

作者： Fan, Naiqiang Wang, Yingmin Lv, Yarong Northwest Ploytech Univ Engn Practice Training Ctr Xian Peoples R China Northwest Ploytech Univ Sch Marine Sci & Technol Xian Peoples R China Northwest Ploytech Univ Ming De Coll Xian Peoples R China

The conventional chirp scaling algorithm is mainly used in side looking or small squint angle mode of synthetic aperture imaging. In application of synthetic sonar, the large squint angle imaging is often required and the range-azimuth coupling is serious. On the basis of studying the principle of the conventional chirp scaling algorithm, we improved the imaging algorithm in large squint mode. We analysed the structure of the echo frequency spectrum and the compensation of phase factor. The improved imaging algorithm designs a more precision of phase compensation factor, and eliminates the high order degree of range and azimuth coupling in the specific mapping band. Any target point is simulated in imaging region by using the improved algorithm. The simulation conclusion showed that the improved chirp scaling algorithm is able to meet the imaging focus and is more suitable to slant imaging as compared with the traditional algorithm.

关键词： Synthetic aperture sonar chirp scaling algorithm range-azimuth coupling secondary range compression Taylor series Fresnel assumption

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An Improved chirp scaling algorithm with Capability Motion Compensation for SAR

An Improved Chirp Scaling Algorithm with Capability Motion C...

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2010 2nd International Conference on Signal Processing System(2010年信号处理系统国际会议 ICSPS 2010)

作者： Chundong Qi Tao Zeng Feng Li Liang Chen School of Information and Electronics Beijing Institute of Technology Beijing China

Since a motion error is the main phase error source in the aircraft synthetic aperture (SAR), the motion errors have to properly be compensated during the SAR image reconstruction. The chirp scaling (CS) algorithm is one of the best algorithms in the practice system. An improved CS algorithm which can compensate motion error is proposed. Specially, the proposed method is based on the constant acceleration movement and the sub-aperture technique.

关键词： motion error motion compensation chirp scaling algorithm

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