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REVERSE-RANGE-DOPPLER METHOD FOR AUTOMATED geoCODING SAR IMAGES

Journal of Electronics(China) 2012年第3期29卷 242-247页

作者： Liu Jiayin Hong Wen Key Laboratory of Technology on Geo-spatial Information Processing and Application System Chinese Academy of SciencesBeijing 100190China National Key Laboratory of Microwave Imaging Technology Beijing 100190China Institute of Electronics Chinese Academy of SciencesBeijing 1001q0China

Range-Doppler (RD) method and Reverse-Range-Doppler (RRD) method are combined together to achieve automatic geocoding of Synthetic Aperture Radar (SAR) image quickly and accurately in the paper. The RD method is firstly used to locate the four corners of the image, then the other pixels of the image can be located by Reverse-Range-Doppler (RRD) method. Resampling is performed at last. The approach has an advantage over previous techniques in that it does not require ground control points and is independent of spacecraft attitude knowledge or control. It can compensate the shift due to the assumed Doppler frequency in SAR image preprocessing. RRD simplifies the process of RD, therefore speeds up the computation. The experimental results show that a SAR image can be automated geocoded in 30 s using the single CPU (3 GHz) with 1 G memory and an accuracy of 10 m is attainable with this method.

关键词： Range-Doppler (RD) Reverse-Range-Doppler (RRD) geolocation Automated geocoding Space-borne Synthetic Aperture Radar (SAR)

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geostationary autonomous trajectory determination technology based on enhanced inter-satellite links of the Beidou medium earth orbit constellation

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Aerospace Science and technology 2025年 163卷

作者： Fangtan Jiao Yuxin Hu Xiaodong Yu Haihong Wang Qiuli Chen Aerospace Information Research Institute Chinese Academy of Sciences Beijing 100094 China Key Laboratory of Geo-spatial Information Processing and Application System Technology Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing 100049 China Institute of Telecommunication and Navigation Satellite CAST Beijing 100094 China

Trajectory determination is critical for autonomous operations in geostationary Orbit (geo). However, the existing methods cannot satisfy the need for stability and accuracy in short-cycle scenarios. Since the emerging method based on the Ka-band Inter-Satellite Link (ISL) of the Beidou satellite navigation system medium Earth orbit constellation has the advantages of high accuracy and anti-interference, this paper applies it to the autonomous operations of geo satellites and analyzes the feasibility and link characteristics. Different from previous ISL-related studies about long-term orbit determination, there is an issue of periodic failure of priori orbital data caused by frequent maneuvers in short-cycle autonomous operations for ISL-based applications. In this paper, by fusing the priori clock bias information and multiple ISL observation data under the constraint of a sub-hour period, we propose an ISL-based fractional steps filtering method containing rapid contraction and precise tracking, assisted by an optimized satellite selection strategy, to address the issue above. The result indicates that thanks to an average number of 12.16 visible navigation satellites for geo users, the proposed method with dispersed and diversified satellite selection scheme gives excellent results, with convergence to sub-meter accuracy in 10 min on average that satisfies the constraint of a sub-hour period and shows a 41.1 % improvement in average convergence time efficiency compared to the traditional method. Moreover, regarding trajectory determination accuracy in short-cycle autonomous operations, the root-mean-square error achieves about 0.38 m, which is better than the result of existing applications of about 10–20 m precision, demonstrating the advantages of the proposed method.

关键词： Autonomous trajectory determination Beidou satellite navigation system geostationary orbit Inter-satellite link

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Deep amended COPERT model for regional vehicle emission prediction

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Science China(information Sciences) 2021年第3期64卷 238-240页

作者： Zhenyi XU Yu KANG Yang CAO Zerui LI Department of Automation University of Science and Technology of China Key Laboratory of Technology in Geo Spatial Information Processing and Application System Chinese Academy of Sciences

Dear editor,The existing methods for regional vehicle emission prediction can be roughly categorized into the classes of classical dispersion models and satellite remote sensing *** plume models, operational street ca...

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Multi-aspect Tomographic SAR Imaging Approach via Distributed Compressed Sensing and Joint Sparsity

Multi-aspect Tomographic SAR Imaging Approach via Distribute...

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2021 CIE International Conference on Radar, Radar 2021

作者： Du, Bang Zhang, Zhe Qiu, Xiaolan Lei, Bin Ding, Chibiao Key Laboratory of Technology in Geo-spatial Information Processing and Application System Beijing China Beijing China University of Chinese Academy of Sciences Beijing China Aerospace Information Research Institute Chinese Academy of Sciences Suzhou China

ISBN: (纸本)9781665498142

Synthetic aperture radar (SAR) tomography (TomoSAR) is a novel technique that enables three-dimensional (3-D) imaging and plays an important role in urban remote sensing by utilizing multiple observations of the same target scene from various baselines. Canonical TomoSAR observations are from a single aspect, which has been well studies already. However, modern SAR sensors such as Unmanned Aerial Vehicle (UAV) allow us to achieve multi-aspect TomoSAR data of the same target scene. This paper proposes a novel framework named 'Multi-aspect TomoSAR,' which takes advantage of rich TomoSAR data from multiple observation aspects. We derive the multi-aspect TomoSAR signal model using distributed compressed sensing (DCS) and adopt a simultaneous sparse approximation algorithm named SOMP to solve the joint sparsity model. Numerical results on synthetic simulated data show that the multi-aspect estimation can provide more accurate estimation, yield a promising perspective. Experimental results on real airborne data will be reported in the journal version of this work later. © 2021 IEEE.

关键词： Distributed compressed sensing Joint sparsity model Multi-aspect TomoSAR

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First assessment of Noise-Equivalent Sigma-Zero in GF3-02 TOPSAR mode with sea surface wind speed retrieval

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Acta Oceanologica Sinica 2023年第10期42卷 84-96页

作者： Junxin Yang Lihua Zhong Xinzhe Yuan Xiaochen Wang Bing Han Yuxin Hu Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China Key Laboratory of Technology in Geo-Spatial Information Processing and Application Systems Chinese Academy of SciencesBeijing 100190China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China National Satellite Ocean Application Service Beijing 100081China

Gaofen-3-02(GF3-02)is the first C-band synthetic aperture radar(SAR)satellite with terrain observation with progressive scans of SAR(TOPSAR)imaging mode in China,which plays an essential role in marine environment *** the weak scattering characteristics of the ocean,the system thermal noise superimposed on SAR images has significant interference,especially in cross-polarization ***-Equivalent Sigma-Zero(NESZ)is a measure of the sensitivity of the radar to areas of low *** NESZ is defined to be the scattering cross-section coefficient of an area which contributes a mean level in the image equal to the signal-independent additive noise *** TOPSAR,NESZ exhibits the shape of the SAR scanning gain curve in the azimuth and the shape of the antenna pattern in the ***,the accurate measurement of NESZ plays a vital role in the application of spaceborne SAR sea surface cross-polarization *** paper proposes a theoretical calculation method for the NESZ curve in GF3-02 TOPSAR mode based on SAR noise inner calibration data and the imaging algorithm.A method for correcting the error existing in the theoretical curve of NESZ is also proposed according to the relationship between sea surface backscattering and wind speed and the same characteristics of target scattering in the overlapping area of adjacent *** to assessment with wide-swath TOPSAR cross-polarization data,the GF3-02 TOPSAR mode has a very low thermal noise level,which is better than−33 dB at the edge of each beam,and controlled below−38 dB at the center of the *** two-dimensional reference curves of the NESZ of each beam are provided to the GF3-02 TOPSAR *** discussing the relationship between normalized radar cross section(NRCS)and wind speed,we provide a formula for NRCS related to wind speed and radar incidence *** with the NRCS derived from this formula and the NESZ-subtracted NRCS of SAR images,the bias is−0.0048

关键词： GF3-02 TOPSAR Noise-Equivalent Sigma-Zero(NESZ) cross-polarization normalized radar cross section(NRCS) sea surface wind

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An Energy Efficient Carry-Free Inner Product Unit

An Energy Efficient Carry-Free Inner Product Unit

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2019 IEEE International Conference on Signal, information and Data processing, ICSIDP 2019

作者： Yan, Wen Ercegovac, Milos D. Key Laboratory of Technology in Geo-spatial Information Processing and Application System Institute of Electronics Chinese Academy of Sciences Beijing China University of California Computer Science Department Los AngelesCA United States

ISBN: (纸本)9781728123455

An energy efficient truncated inner product unit is proposed in this paper. The proposed unit is pipelined and processes the m pairs of n-bit operands in serial, so that only one unit is required and it can be reused in each recurrence. Truncated inner product is produced so that no accumulation is needed for the lower part. The array reduction unit is bit-level pipelined to improve throughput and reduce the initial delay. A two-level [4:2] adder is proposed to accumulate redundant vectors with non-uniform input arrival. The proposed inner product is compared with other truncated inner product units using fully merged arithmetic, partially merged arithmetic and the counter based inner product for different precision and vector length. Our proposed inner product unit has significant reduction in area, power and energy. © 2019 IEEE.

关键词： Pipelines

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Dominant Physical Scattering Mechanism Analysis for GF-3 Typical Ground Objects by Polarimetric Decomposition

Dominant Physical Scattering Mechanism Analysis for GF-3 Typ...

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IEEE International Symposium on geoscience and Remote Sensing (IGARSS)

作者： Jin Yan Qiu Xiaolan Lijia Huang Laboratory of Spatial Information Intelligent Processing System Institute of Electronics Chinese Academy of Sciences Suzhou China Key Laboratory of Technology in Geo-spatial Information Processing and Application System CAS

The dominant scattering mechanism is of great significance for the application of ground objects classification and target detection. It can also verify the quality of the polarimetric data by check the dominant scattering mechanism of known ground objects. In order to improve the application performance, this paper studies the dominant scattering mechanism of GF-3 typical ground objects based on a large number of data slices. The GF-3 fully polarimetric data slices are classified based on the MODIS global classification map, and the GF-3 slice library of typical ground objects is constructed. Based on large amounts of GF-3 samples, we carry out the statistical analysis of dominant scattering mechanism separation results for typical GF-3 ground objects (building, woodland, cultivated land, grassland and waters) of by means of h/alpha/A decomposition. The quantitative results reveal the polarimetric scattering feature of different ground objects, and provide reference for fully polarimetric SAR application.

关键词： Scattering Synthetic aperture radar Entropy Buildings Statistical analysis Radar polarimetry Sensors

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A space-based radar nonlinear tracking method for air targets based on VB-PHD filter 2

A space-based radar nonlinear tracking method for air target...

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2nd IEEE International Conference on Signal, information and Data processing, ICSIDP 2024

作者： Fang, Linlin Zhong, Lihua Han, Bing Hu, Yuxin Aerospace Information Research Institute Chinese Academy of Sciences Beijing China Key Laboratory of Technology in Geo-Spatial Information Processing and Application Systems Chinese Academy of Sciences Beijing China

ISBN: (纸本)9798331515669

Space-based radar has better coverage and is not limited by the curvature of the earth. Aircraft target tracking is particularly important in space-based radar system. However, the long observation distance and strong nonlinear observation increases the challenge of target tracking. Therefore, we proposed a space-based radar nonlinear tracking method for air targets based on variational Bayesian probability hypothesis density (VB-PHD) filter. The relationship between state and observation is established. Then, the VB method is adopted to deal with uncertainty of measurement noise variances. Besides, the cubature filter is introduced to deal with the strongly nonlinear models, and the recursion process is completed by using the third-order spherical radial volume rule. Finally, simulation scenarios with different measurement noise parameters were constructed, and the tracking result comparisons show that it effectively solves nonlinear problems, and tracking precision can be significantly improved. © 2024 IEEE.

关键词： Space-based radar

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Perceptual Evaluation of Pre-processing for Video Transcoding

Perceptual Evaluation of Pre-processing for Video Transcodin...

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IEEE Visual Communications and Image processing (VCIP)

作者： Shiyu Huang Ziyuan Luo Jiahua Xu Wei Zhou Zhibo Chen CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System University of Science and Technology of China Hefei China

ISBN: (纸本)9781728173221

Recently, the pre-processed video transcoding has attracted wide attention and has been increasingly used in practical applications for improving the perceptual experience and saving transmission resources. However, very few works have been conducted to evaluate the performance of pre-processing methods. In this paper, we select the source (SRC) videos and various pre-processing approaches to construct the first Pre-processed and Transcoded Video Database (PTVD). Then, we conduct the subjective experiment, showing that compared with the video sent to the codec directly at the same bitrate, the appropriate pre-processing methods indeed improve the perceptual quality. Finally, existing image/video quality metrics are evaluated on our database. The results indicate that the performance of the existing image/video quality assessment (IQA/VQA) approaches remain to be improved. We will make our database publicly available soon.

关键词： Measurement Codecs Databases Visual communication Image processing Buildings Bit rate

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AutoDerain: Memory-efficient Neural Architecture Search for Image Deraining

AutoDerain: Memory-efficient Neural Architecture Search for ...

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IEEE Visual Communications and Image processing (VCIP)

作者： Jun Fu Chen Hou Zhibo Chen CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System University of Science and Technology of China Hefei China

ISBN: (纸本)9781728173221

Learning-based image deraining methods have achieved remarkable success in the past few decades. Currently, most deraining architectures are developed by human experts, which is a laborious and error-prone process. In this paper, we present a study on employing neural architecture search (NAS) to automatically design deraining architectures, dubbed AutoDerain. Specifically, we first propose an U-shaped deraining architecture, which mainly consists of residual squeeze-and-excitation blocks (RSEBs). Then, we define a search space, where we search for the convolutional types and the use of the squeeze-and-excitation block. Considering that the differentiable architecture search is memory-intensive, we propose a memory-efficient differentiable architecture search scheme (MDARTS). In light of the success of training binary neural networks, MDARTS optimizes architecture parameters through the proximal gradient, which only consumes the same GPU memory as training a single deraining model. Experimental results demonstrate that the architecture designed by MDARTS is superior to manually designed derainers.

关键词： Training Visual communication Image processing Memory architecture Neural networks Graphics processing units

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