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A frequency domain estimation and compensation method for system synchronization parameters of distributed-HFSWR
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作者 WANG Hongyong SUO Ying +3 位作者 DENG Weibo WU Xiaochuan BAI Yang ZHANG Xin 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第5期1084-1097,共14页
To analyze the influence of time synchronization error,phase synchronization error,frequency synchronization error,internal delay of the transceiver system,and range error and angle error between the unit radars on th... To analyze the influence of time synchronization error,phase synchronization error,frequency synchronization error,internal delay of the transceiver system,and range error and angle error between the unit radars on the target detection performance,firstly,a spatial detection model of distributed high-frequency surface wave radar(distributed-HFSWR)is established in this paper.In this model,a method for accurate extraction of direct wave spectrum based on curve fitting is proposed to obtain accurate system internal delay and frequency synchronization error under complex electromagnetic environment background and low signal to noise ratio(SNR),and to compensate for the shift of range and Doppler frequency caused by time-frequency synchronization error.The direct wave component is extracted from the spectrum,the range estimation error and Doppler estimation error are reduced by the method of curve fitting,and the fitting accuracy of the parameters is improved.Then,the influence of frequency synchronization error on target range and radial Doppler velocity is quantitatively analyzed.The relationship between frequency synchronization error and radial Doppler velocity shift and range shift is given.Finally,the system synchronization parameters of the trial distributed-HFSWR are obtained by the proposed spectrum extraction method based on curve fitting,the experimental data is compensated to correct the shift of the target,and finally the correct target parameter information is obtained.Simulations and experimental results demonstrate the superiority and correctness of the proposed method,theoretical derivation and detection model proposed in this paper. 展开更多
关键词 distributed high-frequency surface wave radar(distributed-HFSWR) direct wave synchronization error curve fitting system synchronization parameter compensation
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Comparison of Precipitation Observations from a Prototype Space-based Cloud Radar and Ground-based Radars 被引量:6
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作者 刘黎平 张志强 +3 位作者 于丹茹 杨虎 赵崇辉 仲凌志 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2012年第6期1318-1329,共12页
A prototype space-based cloud radar has been a precipitation system over Tianjin, China in July developed and was installed on an airplane to observe 2010. Ground-based S-band and Ka-band radars were used to examine t... A prototype space-based cloud radar has been a precipitation system over Tianjin, China in July developed and was installed on an airplane to observe 2010. Ground-based S-band and Ka-band radars were used to examine the observational capability of the prototype. A cross-comparison algorithm between different wavelengths, spatial resolutions and platform radars is presented. The reflectivity biases, correlation coefficients and standard deviations between the radars are analyzed. The equivalent reflectivity bias between the S- and Ka-band radars were simulated with a given raindrop size distribution. The results indicated that reflectivity bias between the S- and Ka-band radars due to scattering properties was less than 5 dB, and for weak precipitation the bias was negligible. The prototype space-based cloud radar was able to measure a reasonable vertical profile of reflectivity, but the reflectivity below an altitude of 1.5 km above ground level was obscured by ground clutter. The measured refiectivity by the prototype space-based cloud radar was approximately 10.9 dB stronger than that by the S-band Doppler radar (SA radar), and 13.7 dB stronger than that by the ground-based cloud radar. The reflectivity measured by the SA radar was 0.4 dB stronger than that by the ground-based cloud radar. This study could provide a method for the quantitative examination of the observation ability for space-based radars. 展开更多
关键词 space-based cloud radar observational capability field experiment cloud observation
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Cramer-Rao bound and signal-to-noise ratio gain in distributed coherent aperture radar 被引量:7
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作者 Peilin Sun Jun Tang Xiaowei Tang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2014年第2期217-225,共9页
This paper studies the estimation performance of the coherent processing parameter (CPP), including time delay differences and phase synchronization errors among different apertures of the distributed coherent apert... This paper studies the estimation performance of the coherent processing parameter (CPP), including time delay differences and phase synchronization errors among different apertures of the distributed coherent aperture radar (DCAR). Firstly, three architectures of signal processing in the DCAR are introduced. Secondly, the closed-form Cramer-Rao bound (CRB) of the CPP estimation is derived and compared. Then, the closed-form CRB is verified by numerical simulations. Finally, when the next generation radar works in a fully coherent mode, the closed-form signal-to-noise ratio (SNR) gain of the three architectures is presented. 展开更多
关键词 Cramer-Rao bound (CRB) joint parameter estimation distributed coherent aperture radar (DCAR).
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Resolving co- and early post-seismic slip variations of the 2021 MW 7.4 Madoi earthquake in east Bayan Har block with a block-wide distributed deformation mode from satellite synthetic aperture radar data 被引量:14
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作者 Shuai Wang Chuang Song +1 位作者 ShanShan Li Xing Li 《Earth and Planetary Physics》 CSCD 2022年第1期108-122,共15页
On 21 May 2021(UTC),an MW 7.4 earthquake jolted the east Bayan Har block in the Tibetan Plateau.The earthquake received widespread attention as it is the largest event in the Tibetan Plateau and its surroundings since... On 21 May 2021(UTC),an MW 7.4 earthquake jolted the east Bayan Har block in the Tibetan Plateau.The earthquake received widespread attention as it is the largest event in the Tibetan Plateau and its surroundings since the 2008 Wenchuan earthquake,and especially in proximity to the seismic gaps on the east Kunlun fault.Here we use satellite interferometric synthetic aperture radar data and subpixel offset observations along the range directions to characterize the coseismic deformation of the earthquake.Range offset displacements depict clear surface ruptures with a total length of~170 km involving two possible activated fault segments in the earthquake.Coseismic modeling results indicate that the earthquake was dominated by left-lateral strike-slip motions of up to 7 m within the top 12 km of the crust.The well-resolved slip variations are characterized by five major slip patches along strike and 64%of shallow slip deficit,suggesting a young seismogenic structure.Spatial-temporal changes of the postseismic deformation are mapped from early 6-day and 24-day InSAR observations,and are well explained by time-dependent afterslip models.Analysis of Global Navigation Satellite System(GNSS)velocity profiles and strain rates suggests that the eastward extrusion of plateau is diffusely distributed across the east Bayan Har block,but exhibits significant lateral heterogeneities,as evidenced by magnetotelluric observations.The block-wide distributed deformation of the east Bayan Har block along with the significant co-and post-seismic stress loadings from the Madoi earthquake imply high seismic risks along regional faults,especially the Tuosuo Lake and Maqên-Maqu segments of the Kunlun fault that are known as seismic gaps. 展开更多
关键词 Madoi earthquake Bayan Har block synthetic aperture radar data co-and post-seismic slip block-wide distributed deformation seismic risk
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Finite sensor selection algorithm in distributed MIMO radar for joint target tracking and detection 被引量:6
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作者 ZHANG Haowei XIE Junwei +2 位作者 GE Jiaang ZHANG Zhaojian LU Wenlong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第2期290-302,共13页
Due to the requirement of anti-interception and the limitation of processing capability of the fusion center, the subarray selection is very important for the distributed multiple-input multiple-output(MIMO) radar sys... Due to the requirement of anti-interception and the limitation of processing capability of the fusion center, the subarray selection is very important for the distributed multiple-input multiple-output(MIMO) radar system, especially in the hostile environment. In such conditions, an efficient subarray selection strategy is proposed for MIMO radar performing tasks of target tracking and detection. The goal of the proposed strategy is to minimize the worst-case predicted posterior Cramer-Rao lower bound(PCRLB) while maximizing the detection probability for a certain region. It is shown that the subarray selection problem is NP-hard, and a modified particle swarm optimization(MPSO) algorithm is developed as the solution strategy. A large number of simulations verify that the MPSO can provide close performance to the exhaustive search(ES) algorithm. Furthermore, the MPSO has the advantages of simpler structure and lower computational complexity than the multi-start local search algorithm. 展开更多
关键词 distributed MULTIPLE-INPUT multiple-output(MIMO)radar SUBARRAY selection TARGET tracking TARGET detection particle SWARM optimization(PSO)
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Human Respiration Rate Estimation Using Ultra-wideband Distributed Cognitive Radar System 被引量:2
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作者 Predrag Rapajic 《International Journal of Automation and computing》 EI 2008年第4期325-333,共9页
It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present... It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present a multi-ray propagation model for UWB signal,which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces,A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment.This model enables replication of time-varying multipath profiles due to the displacement of a human chest.Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate.The analytical framework can serve as a basis in the planning and evaluation of future rheasurement programs.We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture. 展开更多
关键词 Medical and patient monitoring sensing technologies and signal processing vital sign ULTRA-WIDEBAND distributed cog-nitive radar respiration rate estimation.
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Joint resource allocation scheme for target tracking in distributed MIMO radar systems 被引量:1
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作者 ZHENG Na’e SUN Yang +1 位作者 SONG Xiyu CHEN Song 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第4期709-719,共11页
A joint resource allocation scheme concerned with the sensor subset,power and bandwidth for range-only target tracking in multiple-input multiple-output(MIMO)radar systems is proposed.By selecting an optimal subset of... A joint resource allocation scheme concerned with the sensor subset,power and bandwidth for range-only target tracking in multiple-input multiple-output(MIMO)radar systems is proposed.By selecting an optimal subset of sensors with the predetermined size and implementing the power allocation and bandwidth strategies among them,this algorithm can help achieving a better performance within the same resource constraints.Firstly,the Bayesian Cramer-Rao bound(BCRB)is derived from it.Secondly,a criterion for minimizing the BCRB at the target location among all targets tracking in a certain range is derived.Thirdly,the optimization problem involved with three variable vectors is formulated,which can be simplified by deriving the relationship between the optimal power allocation vector and the bandwidth allocation vector.Then,the simplified optimization problem is solved by the cyclic minimization algorithm incorporated with the sequential parametric convex approximation(SPCA)algorithm.Finally,the validity of the proposed method is demonstrated with simulation results. 展开更多
关键词 distributed MULTIPLE-INPUT multiple-output(MIMO)radar target tracking JOINT RESOURCE alloction sensor SUBSET selection(SSS) optimal power and bandwidth allocation(OPBA)
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Modified OMP method for multi-target parameter estimation in frequency-agile distributed MIMO radar 被引量:3
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作者 XING Wenge ZHOU Chuanrui WANG Chunlei 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2022年第5期1089-1094,共6页
Introducing frequency agility into a distributed multipleinput multiple-output(MIMO)radar can significantly enhance its anti-jamming ability.However,it would cause the sidelobe pedestal problem in multi-target paramet... Introducing frequency agility into a distributed multipleinput multiple-output(MIMO)radar can significantly enhance its anti-jamming ability.However,it would cause the sidelobe pedestal problem in multi-target parameter estimation.Sparse recovery is an effective way to address this problem,but it cannot be directly utilized for multi-target parameter estimation in frequency-agile distributed MIMO radars due to spatial diversity.In this paper,we propose an algorithm for multi-target parameter estimation according to the signal model of frequency-agile distributed MIMO radars,by modifying the orthogonal matching pursuit(OMP)algorithm.The effectiveness of the proposed method is then verified by simulation results. 展开更多
关键词 distributed multiple-input multiple-output(MIMO)radar multi-target parameter estimation frequency agility modified orthogonal matching pursuit(OMP)method
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Distributed inverse synthetic aperture radar imaging of ship target with complex motion 被引量:2
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作者 ZHANG Junqiu WANG Yong LU Xiaofei 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第6期1325-1337,共13页
For ship targets with complex motion,it is difficult for the traditional monostatic inverse synthetic aperture radar(ISAR)imaging to improve the cross-range resolution by increasing of accumulation time.In this paper,... For ship targets with complex motion,it is difficult for the traditional monostatic inverse synthetic aperture radar(ISAR)imaging to improve the cross-range resolution by increasing of accumulation time.In this paper,a distributed ISAR imaging algorithm is proposed to improve the cross-range resolution for the ship target.Multiple stations are used to observe the target in a short time,thereby the effect of incoherence caused by the complex motion of the ship can be reduced.The signal model of ship target with three-dimensional(3-D)rotation is constructed firstly.Then detailed analysis about the improvement of crossrange resolution is presented.Afterward,we propose the methods of parameters estimation to solve the problem of the overlap or gap,which will cause a loss of resolution and is necessary for subsequent processing.Besides,the compressed sensing(CS)method is applied to reconstruct the echoes with gaps.Finally,numerical simulations are presented to verify the effectiveness and the robustness of the proposed algorithm. 展开更多
关键词 complex motion distributed inverse syntheic aperture radar(ISAR) parameters estimation compressed sensing(CS)
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New Solution on Distributed Hardware-in-the-Loop Radar System Simulation on HLA
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作者 刘伟 曾涛 李海 《Journal of Beijing Institute of Technology》 EI CAS 2003年第S1期81-85,共5页
In the large-scale distributed hardware-in-the-loop radar simulation system based on HLA, a new solution of processing after acquisition is proposed, which separates the software subsystem from the hardware jammer sub... In the large-scale distributed hardware-in-the-loop radar simulation system based on HLA, a new solution of processing after acquisition is proposed, which separates the software subsystem from the hardware jammer subsystem by a response database, so as to settle the problem, that the software subsystem can not meet the real-time need of the hardware, with very little increment of code. And the data completeness and feasibility of this solution are discussed. 展开更多
关键词 distributed simulation hardware-in-the-loop (HITL) HLA radar
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Weather Radar Data and Distributed Hydrological Modelling: An Application for Mexico Valley
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作者 Baldemar Méndez-Antonio Ernesto Caetano +3 位作者 Gabriel Soto-Cortés Fabián G. Rivera-Trejo Ricardo A. Carvajal Rodríguez Christopher Watts 《Open Journal of Modern Hydrology》 2013年第2期79-88,共10页
The frequent occurrence of exceptionally very heavy rainfall in Mexico during the summer causes flash floods in many areas and major economic losses. As a consequence, a significant part of the annual government budge... The frequent occurrence of exceptionally very heavy rainfall in Mexico during the summer causes flash floods in many areas and major economic losses. As a consequence, a significant part of the annual government budget is diverted to the reconstruction of the disasters caused by floods every year, resulting hold up in the country development. A key element to mitigate the flash flood hazards is the implementation of an early warning system with the ability to process the necessary information in the shortest possible time, in order to?increase structural and non-structural resilience in flood prone regions. The real-time estimation of rainfall is essential for the implementation of such systems and the use of remote sensing instruments that feed the operational rainfall-runoff hydrological models is becoming of increasing importance worldwide. However, in some countries such as Mexico, the application of such technology for operational purposes is still in its infancy. Here the implementation of an operational hydrological model is described for the Mixcoac river basin as part of the non-structural measures that can be applied for intense precipitation events. The main goal is to examine the feasibility of the use of remote sensing instruments and establish a methodology to predict the runoff in real time in urban river basins with complex topography, to increase the resilience of the areas affected by annual floods. The study takes data from weather radar operated by the National Meteorological Service of Mexico, as input to a distributed hydrological model. The distributed unit hydrograph model methodology is used in order to assess its feasibility in urban experimental basin. The basic concepts underlying the model, as well as calibration and validation are discussed. The results demonstrate the feasibility of using weather radar data for modeling rainfall-runoff process with distributed parameter models for urban watersheds. A product resulting from this study was the development of software Runoff Forecast Model (ASM), for application in distributed hydrological models with rainfall data in real time in watersheds with complex terrain, which are usually found in Mexico. 展开更多
关键词 radar distributed Hydrologic Modeling RESILIENCE
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Distributed Radar Target Tracking with Low Communication Cost
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作者 Rui Zhang Xinyu Zhang +1 位作者 Shenghua Zhou Xiaojun Peng 《Journal of Beijing Institute of Technology》 EI CAS 2022年第6期595-604,共10页
In distributed radar,most of existing radar networks operate in the tracking fusion mode which combines radar target tracks for a higher positioning accuracy.However,as the filtering covariance matrix indicating posit... In distributed radar,most of existing radar networks operate in the tracking fusion mode which combines radar target tracks for a higher positioning accuracy.However,as the filtering covariance matrix indicating positioning accuracy often occupies many bits,the communication cost from local sensors to the fusion is not always sufficiently low for some wireless communication chan-nels.This paper studies how to compress data for distributed tracking fusion algorithms.Based on the K-singular value decomposition(K-SVD)algorithm,a sparse coding algorithm is presented to sparsely represent the filtering covariance matrix.Then the least square quantization(LSQ)algo-rithm is used to quantize the data according to the statistical characteristics of the sparse coeffi-cients.Quantized results are then coded with an arithmetic coding method which can further com-press data.Numerical results indicate that this tracking data compression algorithm drops the com-munication bandwidth to 4%at the cost of a 16%root mean squared error(RMSE)loss. 展开更多
关键词 distributed radar distributed tracking fusion data compression K-singular value decomposition(K-SVD)algorithm sparse coding least square quantization(LSQ)
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Suppression of Log-Normal Distributed Weather Clutter Observed by an S-Band Radar
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作者 Shuji Sayama Seishiro Ishii 《Wireless Engineering and Technology》 2013年第3期125-133,共9页
We have observed weather clutter containing targets (ships) using an S-band radar with a frequency 3.05 GHz, a beam width 1.8°, and a pulsewidth 0.5 μs. To investigate the weather clutter amplitude statistics, w... We have observed weather clutter containing targets (ships) using an S-band radar with a frequency 3.05 GHz, a beam width 1.8°, and a pulsewidth 0.5 μs. To investigate the weather clutter amplitude statistics, we introduce the Akaike Information Criterion (AIC). We have found that the weather clutter amplitudes obey the log-normal, Weibull, and log-Weibull distributions with the shape parameters of 0.308 to 0.470, 4.42 to 4.51, and 15.91 to 16.44, respectively, for small data within the beam width of an antenna. We have proposed the log-normal/CFAR circuit modified a Cell-Averaging (CA) LOG/CFAR circuit. It is found that weather clutter is suppressed with improvement of 51.58 dB by log-normal/CFAR. As a result, we have showed that weather clutter observed by S-band radar does not obey the Rayleigh distribution and our log-normal/CFAR circuit has an effect on suppression of clutter and detection of target, while conventional LOG/CFAR circuit does not. In addition, if our circuit can be realized, we will have an advantage economically. 展开更多
关键词 CFAR S-BAND radar WEATHER CLUTTER Log-Normal distribution
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Distributed Computation Models for Data Fusion System Simulation
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作者 张岩 曾涛 +1 位作者 龙腾 崔智社 《Journal of Beijing Institute of Technology》 EI CAS 2001年第3期291-297,共7页
An attempt has been made to develop a distributed software infrastructure model for onboard data fusion system simulation, which is also applied to netted radar systems, onboard distributed detection systems and advan... An attempt has been made to develop a distributed software infrastructure model for onboard data fusion system simulation, which is also applied to netted radar systems, onboard distributed detection systems and advanced C3I systems. Two architectures are provided and verified: one is based on pure TCP/IP protocol and C/S model, and implemented with Winsock, the other is based on CORBA (common object request broker architecture). The performance of data fusion simulation system, i.e. reliability, flexibility and scalability, is improved and enhanced by two models. The study of them makes valuable explore on incorporating the distributed computation concepts into radar system simulation techniques. 展开更多
关键词 radar system computer network data fusion SIMULATION distributed computation
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GS-orthogonalization OMP method for space target detection via bistatic space-based radar
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作者 Shuyu ZHENG Libing JIANG +2 位作者 Qingwei YANG Yingjian ZHAO Zhuang WANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第7期333-351,共19页
A space-based bistatic radar system composed of two space-based radars as the transmitter and the receiver respectively has a wider surveillance region and a better early warning capability for high-speed targets,and ... A space-based bistatic radar system composed of two space-based radars as the transmitter and the receiver respectively has a wider surveillance region and a better early warning capability for high-speed targets,and it can detect focused space targets more flexibly than the monostatic radar system or the ground-based radar system.However,the target echo signal is more difficult to process due to the high-speed motion of both space-based radars and space targets.To be specific,it will encounter the problems of Range Cell Migration(RCM)and Doppler Frequency Migration(DFM),which degrade the long-time coherent integration performance for target detection and localization inevitably.To solve this problem,a novel target detection method based on an improved Gram Schmidt(GS)-orthogonalization Orthogonal Matching Pursuit(OMP)algorithm is proposed in this paper.First,the echo model for bistatic space-based radar is constructed and the conditions for RCM and DFM are analyzed.Then,the proposed GS-orthogonalization OMP method is applied to estimate the equivalent motion parameters of space targets.Thereafter,the RCM and DFM are corrected by the compensation function correlated with the estimated motion parameters.Finally,coherent integration can be achieved by performing the Fast Fourier Transform(FFT)operation along the slow time direction on compensated echo signal.Numerical simulations and real raw data results validate that the proposed GS-orthogonalization OMP algorithm achieves better motion parameter estimation performance and higher detection probability for space targets detection. 展开更多
关键词 Bistatic space-based radar High-speed maneuvering space targets detection Range Cell Migration(RCM) Doppler Frequency Migration(DFM) Gram Schmidt(GS)-orthogonalization Orthogonal Matching Pursuit(OMP)algorithm
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A synthetic aperture radar sea surface distribution estimation by n-order Bézier curve and its application in ship detection 被引量:3
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作者 LANG Haitao ZHANG Jie +2 位作者 WANG Yiduo ZHANG Xi MENG Junmin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第9期117-125,共9页
To dates,most ship detection approaches for single-pol synthetic aperture radar(SAR) imagery try to ensure a constant false-alarm rate(CFAR).A high performance ship detector relies on two key components:an accura... To dates,most ship detection approaches for single-pol synthetic aperture radar(SAR) imagery try to ensure a constant false-alarm rate(CFAR).A high performance ship detector relies on two key components:an accurate estimation to a sea surface distribution and a fine designed CFAR algorithm.First,a novel nonparametric sea surface distribution estimation method is developed based on n-order Bézier curve.To estimate the sea surface distribution using n-order Bézier curve,an explicit analytical solution is derived based on a least square optimization,and the optimal selection also is presented to two essential parameters,the order n of Bézier curve and the number m of sample points.Next,to validate the ship detection performance of the estimated sea surface distribution,the estimated sea surface distribution by n-order Bézier curve is combined with a cell averaging CFAR(CA-CFAR).To eliminate the possible interfering ship targets in background window,an improved automatic censoring method is applied.Comprehensive experiments prove that in terms of sea surface estimation performance,the proposed method is as good as a traditional nonparametric Parzen window kernel method,and in most cases,outperforms two widely used parametric methods,K and G0 models.In terms of computation speed,a major advantage of the proposed estimation method is the time consuming only depended on the number m of sample points while independent of imagery size,which makes it can achieve a significant speed improvement to the Parzen window kernel method,and in some cases,it is even faster than two parametric methods.In terms of ship detection performance,the experiments show that the ship detector which constructed by the proposed sea surface distribution model and the given CA-CFAR algorithm has wide adaptability to different SAR sensors,resolutions and sea surface homogeneities and obtains a leading performance on the test dataset. 展开更多
关键词 Bézier curve nonparametric method ship detection sea surface distribution synthetic aperture radar
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GF-3 data real-time processing method based on multi-satellite distributed data processing system 被引量:5
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作者 YANG Jun CAO Yan-dong +2 位作者 SUN Guang-cai XING Meng-dao GUO Liang 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第3期842-852,共11页
Due to the limited scenes that synthetic aperture radar(SAR)satellites can detect,the full-track utilization rate is not high.Because of the computing and storage limitation of one satellite,it is difficult to process... Due to the limited scenes that synthetic aperture radar(SAR)satellites can detect,the full-track utilization rate is not high.Because of the computing and storage limitation of one satellite,it is difficult to process large amounts of data of spaceborne synthetic aperture radars.It is proposed to use a new method of networked satellite data processing for improving the efficiency of data processing.A multi-satellite distributed SAR real-time processing method based on Chirp Scaling(CS)imaging algorithm is studied in this paper,and a distributed data processing system is built with field programmable gate array(FPGA)chips as the kernel.Different from the traditional CS algorithm processing,the system divides data processing into three stages.The computing tasks are reasonably allocated to different data processing units(i.e.,satellites)in each stage.The method effectively saves computing and storage resources of satellites,improves the utilization rate of a single satellite,and shortens the data processing time.Gaofen-3(GF-3)satellite SAR raw data is processed by the system,with the performance of the method verified. 展开更多
关键词 synthetic aperture radar full-track utilization rate distributed data processing CS imaging algorithm field programmable gate array Gaofen-3
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Raindrop Size Distribution Parameters Retrieved from Xinfeng C-Band Polarimetric Radar Observations 被引量:4
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作者 DING Yan WAN Qi-lin +3 位作者 YANG Ling LIU Xian-tong XIA Feng FENG Lu 《Journal of Tropical Meteorology》 SCIE 2020年第3期275-285,共11页
The objective of this research was to acquire a raindrop size distribution(DSDs)retrieved from C-band polarimetric radar observations scheme for the first time in south China.An observation period of the precipitation... The objective of this research was to acquire a raindrop size distribution(DSDs)retrieved from C-band polarimetric radar observations scheme for the first time in south China.An observation period of the precipitation process was selected,and the shape-slope(μ-Λ)relationship of this region was statistically analyzed using the raindrop sample observations from the two-dimensional video disdrometer(2DVD)at Xinfeng Station,Guangdong Province.Simulated data of the C-band polarimetric radar reflectivity ZHHand differential reflectivity ZDRwere obtained through scattering simulation.The simulation data were combined with DSD fitting to determine the ZDR-Λand log10(ZHH/N0)-Λrelationships.Using Xinfeng C-band polarimetric radar observations ZDRand ZHH,the raindrop Gamma size distribution parametersμ,Λ,and N0were retrieved.A scheme for using C-band polarimetric radar to retrieve the DSDs was developed.This research revealed that during precipitation process,the DSDs obtained using the C-band polarimetric radar retrieval scheme are similar to the 2DVD observations,the precipitation characteristics of rainfall intensity(R),mass-weighted mean diameter(Dm)and intercept parameter(Nw)with time obtained by radar retrieval are basically consistent with the observational results of the 2DVD.This scheme establishes the relationship between the observations of the C-band polarimetric radar and the physical quantities of the numerical model.This method not only can test the prediction of the model data assimilation system on the convective scale and determine error sources,but also can improve the microphysical precipitation processes analysis and radar quantitative precipitation estimation.The present research will facilitate radar data assimilation in the future. 展开更多
关键词 C-band polarimetric radar 2DVD raindrop size distribution DSDs retrieval precipitation characteristics
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Phase synchronization processing method for alternating bistatic mode in distributed SAR 被引量:1
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作者 Zhihua He Feng He +2 位作者 Junli Chen Haifeng Huang Diannong Liang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2013年第3期410-416,共7页
In the distributed synthetic aperture radar (SAR), the alternating bistatic mode can perform phase reference without a synchronization link between two satellites compared with the pulsed alternate synchronization m... In the distributed synthetic aperture radar (SAR), the alternating bistatic mode can perform phase reference without a synchronization link between two satellites compared with the pulsed alternate synchronization method. The key of the phase synchronization processing is to extract the oscillator phase differences from the bistatic echoes. A signal model of phase synchronization in the alternating bistatic mode is presented. The phase synchronization processing method is then studied. To reduce the phase errors introduced by SAR imaging, a sub-aperture processing method is proposed. To generalize the sub-aperture processing method, an echo-domain processing method using correlation of bistatic echoes is proposed. Finally, the residual phase errors of the both proposed processing methods are analyzed. Simulation experiments validate the proposed phase synchronization processing method and its phase error analysis results. 展开更多
关键词 distributed synthetic aperture radar (SAR) alternating bistatic mode phase synchronization sub-aperture processing echo-domain processing.
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Diurnal Variation in the Vertical Profile of the Raindrop Size Distribution for Stratiform Rain as Inferred from Micro Rain Radar Observations in Sumatra
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作者 Ravidho RAMADHAN MARZUKI +3 位作者 Mutya VONNISA HARMADI Hiroyuki HASHIGUCHI Toyoshi SHIMOMAI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2020年第8期832-846,共15页
The diurnal variation in the vertical structure of the raindrop size distribution(RSD)associated with stratiform rain at Kototabang,West Sumatra(0.20°S,100.32°E),was investigated using micro rain radar(MRR)o... The diurnal variation in the vertical structure of the raindrop size distribution(RSD)associated with stratiform rain at Kototabang,West Sumatra(0.20°S,100.32°E),was investigated using micro rain radar(MRR)observations from January 2012 to August 2016.Along with the MRR data,the RSD from an optical disdrometer and vertical profile of precipitation from the Tropical Rainfall Measuring Mission were used to establish the microphysical characteristics of diurnal rainfall.Rainfall during 0000–0600 LST and 1800–2400 LST had a lower concentration of small drops and a higher concentration of large drops when compared to rainfall during the daytime(0600–1800 LST).The RSD stratified on the basis of rain rate(R)showed a lower total concentration of drops and higher mass-weighted mean diameter in 0000–0600 LST and1800–2400 LST than in the daytime.During the daytime,the RSD is likely governed by a riming process that can be seen from a weak bright band(BB).On the other hand,during 0000–0600 LST and 1800–2400 LST,the BB was stronger and the rainfall was associated with a higher concentration of midsize and large drops,which could be attributed to more active aggregation right above the melting layer with minimal breakup.Diurnal variation in the vertical profile of RSD led to a different radar reflectivity(Z)–R relationship in the rain column,in which Z during the periods 0000–0600 LST and1800–2400 LST was larger than at the other times,for the same R. 展开更多
关键词 diurnal variation raindrop size distribution micro rain radar stratiform rain Kototabang
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