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Fast forward scatter Shadow Inverse Synthetic Aperture Radar imaging algorithm based on phase compensation

Dianzi Yu Xinxi Xuebao/Journal of Electronics and information technology 2015年第10期37卷 2294-2299页

作者： Liu, Chang-Jiang Hu, Cheng Zeng, Tao Zhou, Chao School of Information and Electronics Beijing Institute of Technology Beijing100081 China Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing Institute of Technology Beijing100081 China

The numerical calculation of forward scatter Shadow Inverse Synthetic Aperture Radar (SISAR) imaging is usually performed by the Fresnel numerical integral which is complicated and time consuming. To improve the calculation speed, the fast SISAR imaging method is investigated. Firstly, a fast imaging method based on the Fast Fourier Transform (FFT) is proposed while the phase errors introduced by the FFT are compensated. Then, through the analysis of the spectrum on the motion compensated signal, the sampling law for SISAR imaging is given, indicating that signals used for imaging can be sampled at a rate much lower than the Nyquist sampling rate. Simulation results show that the proposed fast imaging method can give accurate profiles and significantly reduce the computation, which is of practical meaning in engineering application. ©, 2015, Science Press. All right reserved.

关键词： Fast Fourier transforms

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Fixed-point simulation technology for SAR real-time imaging system

Fixed-point simulation technology for SAR real-time imaging ...

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IET International Radar Conference 2015

作者： Zhou, Xin Xie, Yi-Zhuang Yang, Chen Du, Qing Deng, Yi Beijing Key Laboratory of Embedded Real-Time Information Processing Technology Beijing Institute of Technology Beijing100081 China Department of Electrical and Computer Engineering Virginia Polytechnic Institute State University ArlingtonVA United States

ISBN: (纸本)9781849199940

In this paper, a fast fixed-point simulation technology is proposed for a multi-channel synthetic aperture radar (SAR) imaging system. The overall computations in the SAR imaging algorithm is explicitly analysed. FFT operations account for most memory consumption in the imaging flow. Accordingly, a fixed-point FFT algorithm is adopted due to the trade-off between precision and memory occupation of the FPGA implementation. Furthermore, this paper describes an optimized word-length configuration method based on theoretical analysis of architecture of Radix-22 FFT. This methodology is verified in a SystemC development environment due to its superiority of fast and bit-accurate system-level simulation capability. Finally, the proposed SystemC based fixed-point imaging algorithm and the Matlab based floating-point imaging algorithm are both conducted to process point array target raw data. Peak side-lobe ratio (PSLR) and integrated side-lobe ratio (ISLR) is evaluated. Experimental results indicate that profiles in the two cases do not differ greatly, which validates that the proposed fixedpoint algorithm with less resources occupation has comparable accuracy and can meet system requirements.

关键词： Fast Fourier transforms

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TOA estimation for unkonwn signal under low SNR condition based on accumulation

TOA estimation for unkonwn signal under low SNR condition ba...

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IET International Radar Conference 2015

作者： J. C. Xu L. X. Ren Z. Y. Jiang E. K. Mao Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing

ISBN: (纸本)9781510822023

This paper presents a novel low complexity TOA estimation method for unknown signal under low SNR condition, especially for inner-pulse modulated signal. In this new method, received signal is firstly pre-processed by multiplying its delayed conjugation to reduce intra-pulse modulation. Then a refined coherent accumulation is applied to achieve a precise TOA estimation result. Simulation results show that this new method can achieve an accurate TOA estimation for unknown signal under low SNR condition.

关键词： TOA estimation coherent accumulation multiplication with delayed conjugation

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Improving tropical deforestation detection by fusing multiple SAR change measures

Improving tropical deforestation detection by fusing multipl...

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IET International Radar Conference 2015

作者： Xichao, Dong Shaun, Quegan Liu, Wei Cui, Kai Lv, Xin School of Information and Electronics Beijing Institute of Technology Beijing100081 China Beijing Key Laboratory of Embedded Real-Time Information Processing Technology Beijing Institute of Technology Beijing100081 China CTCD University of Sheffield SheffieldS3 7RH United Kingdom

ISBN: (纸本)9781849199940

The paper studies tropical deforestation detection in Riau province, Indonesia with L-band ALOS PALSAR and C-band ENVISAT ASAR data. Multiple change measures as SAR image intensity, texture, and temporal variations of ScanSAR time series are extracted and employed for deforestation detection. These measures are then combined for improving the detection with subsequent performance evaluation by comparing with the World Wildlife Fund's land cover maps as reference data. When applied on the FBD scene overlaid by both the PALSAR and ASAR data, the detection rate achieves up to 83.2%(at a false alarm rate of 20%) with a significant improvement of over 18% compared with the detection based on the single measure.

关键词： Synthetic aperture radar

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An autofocusing imaging algorithm for wall penetrating SAR

An autofocusing imaging algorithm for wall penetrating SAR

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IET International Radar Conference 2015

作者： Wei Liu Meng Zheng Yin Xiang Zegang Ding Tao Zeng Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing Institute of Technology

ISBN: (纸本)9781510822023

The absence of wall's characteristic will smear and blur the image, shift the target position, and even defocus the imaging result. To solve the problems, a novel autofocusing imaging algorithm is proposed in this paper. Firstly, the electromagnetic field is employed as a 2-D matching filter during the imaging processing. Then, the electromagnetic field in the air-to-wall medium is replaced by that in the air-to-air medium. Thirdly, the mismatching error, which is proved to be an extra frequency gap at the shifted depth, is compensated by using the phase cross-correlation method. Finally, the correctness and efficiency of the proposed method are verified by the full wave simulation with data from CST.

关键词： Autofocusing technology Ground Penetrating Radar Near-Field Imaging Synthetic Aperture Radar

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Region of interests extraction based on visual saliency for remote sensing image

Region of interests extraction based on visual saliency for ...

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IET International Radar Conference 2015

作者： Ma, Long Xu, Bin Bi, Fukun Chen, He Yu, Ying Beijing Key Laboratory of Embedded Real-Time Information Processing Technology Beijing Institute of Technology Beijing100081 China Beijing Remote Sensing Information Institute Beijing100192 China School of Electronic Information Engineering North China University of Technology Beijing100144 China School of Information Science and Engineering Yunnan University Kunming650091 China

ISBN: (纸本)9781849199940

This paper proposes a novel region of interests extraction method for remote sensing image based on visual saliency analysis as well as the multi-scale saliency fusion mechanism. Firstly, under the theory of multi-scale and multiresolution analysis, the gaussian pyramid representation is generated. Then, various spatial features are exploited to compute saliency maps under different scales. Finally the saliency map could be calculated by the corresponding level fusing as well as the across-scale combination. The comparative experiments validate the effectiveness of the proposed model.

关键词： Extraction

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Subdomain clutter reduction method for imaging near surface target

Subdomain clutter reduction method for imaging near surface ...

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IET International Radar Conference 2015

作者： Meng Zheng Wei Liu Yin Xiang Zegang Ding Tao Zeng Xun Wang Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing Institute of Technology

ISBN: (纸本)9781510822023

Penetrating radar for detecting near surface target is a kind of radar which can be used to detect, discern and image the small targets buried in the shallow surface of nonmetallic medium. The main clutter of this radar mechanism is the reflection wave transmitted between radar antennas and the surface of the non-metallic medium. If it cannot be reduced, the image of the small targets will be submerged. This paper presents a clutter reduction method which bases on the idea of subdomain mean cancellation to suppress the reflection wave of non-uniform surface of the medium. Experimental results prove that subdomain mean cancellation method can effectively repress the reflection wave of the medium surface and significantly improve the quality of the image.

关键词： clutter reduction near surface target penetrating radar subdomain mean cancellation

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A new reconfigurable methodology to implement the shiftand-correlate (SAC) algorithm for real-time SAR autofocusing

A new reconfigurable methodology to implement the shiftand-c...

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IET International Radar Conference 2015

作者： Li, Bingyi Xie, Yizhuang Liu, Xiaoning Deng, Yi Beijing Key Laboratory of Embedded Real-Time Information Processing Technology Beijing100081 China Research Institute of Radar Technology School of Information and Electronics Beijing Institute of Technology Beijing100081 China ECE Department of Virginia Polytechnic Institute State University Falls ChurchVA United States

ISBN: (纸本)9781849199940

Doppler Frequency Rate (FDR) is an essential parameter in the procedure of Synthetic Aperture Radar (SAR) processing. In this paper, we investigate an achievable autofocus algorithm, shift-and-correlate (SAC), and design the implementation of FDR estimation. The proposed method can dramatically improve the accuracy of imaging and reduce the time delay of the SAR imaging process. Depth-of-focus theory and linear fitting theory are discussed in this paper for decreasing the computation-consumption and the preserving precision. We verify the proposed method in a 16384∗16384 SAR imaging process at 100 MHz system clock on a dedicated designed Field Programmable Gate Array (FPGA) tested. To testify the feasibility of the proposed method, we compared our run-out results with existing implementations using traditional DSP and MATLAB methods in terms of real-time performance and imaging quality.

关键词： Synthetic aperture radar

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A selection method of frequency combination in MF-InSAR system

A selection method of frequency combination in MF-InSAR syst...

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IET International Radar Conference 2015

作者： Qi, Yalin Zhang, Qi Yang, Wenfu Yang, Shuangjing Liu, Tiandong Beijing Key Laboratory of Embedded Real-Time Information Processing Technology Radar Research Lab. School of Information and Electronics Beijing Institute of Technology Beijing100081 China China Academy of Launch Vehicle Technology Beijing100076 China Beijing Institute of Spacecraft System Engineering CAST Beijing100094 China

ISBN: (纸本)9781849199940

As an extension of the Interferometric Synthetic aperture radar (InSAR), the multi-frequency InSAR can realize high-accuracy elevation extraction of the steep terrain. Though the maximum likelihood estimation (MLE) is widely used in the signal processing of multi-frequency InSAR, the performance of this method can be influenced by the selection of frequency combination. At the beginning, this paper analyses the elevation estimated effectiveness of different frequency combinations from the aspect of Cramer-Rao Lower Bound (CRLB). Then, it calculates the ambiguity cycle as a further filter for the optimal frequency combination. Finally, this paper discusses the adaptability to the phase noise with the help of Monte Carlo simulation strategy. In consideration of these three aspects, a selection method of frequency combination is proposed, and further simulation results are provided in quantity. Relevant researches can be used in the design of multi-frequency InSAR system.

关键词： Phase noise

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Pulse repetition frequency design for geosynchronous SAR in ellipcial orbit

Pulse repetition frequency design for geosynchronous SAR in ...

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IET International Radar Conference 2015

作者： Yin, Wei Yang, Wenfu Ding, Zegang Liu, Wei Zhang, Qingjun Ren, Jingjing Beijing Key Laboratory of Embedded Real-Time Information Processing Technology Radar Research Lab. Beijing Institute of Technology Beijing100081 China China Academy of Launch Vehicle Technology Beijing100076 China Beijing Institute of Spacecraft System Engineering CAST Beijing100094 China

ISBN: (纸本)9781849199940

Elliptical orbit and squint mode are widely used in the system design of geosynchronous synthetics aperture radar (GEO SAR) to improve the coverage performance. In this paper, the effects of orbit height variation and squint mode to pulse repetition frequency (PRF) design are analyzed. The orbit height variation causes the variation of nadir interference and beam illumination region, and squint mode produces large range cell migration (RCM). These can induce invalidations of the designed PRF. Based on this, the constraints of nadir interference and transmit interference are updated for GEO SAR, and the effective time for the designed PRF is derived. PRF number required for imaging in one orbital period is analyzed.

关键词： Synthetic aperture radar

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