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VSAR: a high resolution radar system for ocean imaging 总被引:1,自引:0,他引:1
The velocity synthetic aperture radar (VSAR) is a conceptual synthetic aperture radar (SAR)-based sensor system for high resolution ocean imaging. The VSAR utilizes data collected by a multielement SAR system, to extract information not only about the radar reflectivity of the observed area, but also about the radial velocity of the scatterers in each pixel. This is accomplished by making use of the phase information contained in multiple SAR images, and not just the magnitude information as in conventional SAR. Using this velocity information, the VSAR attempts to compensate for the velocity distortion inherent in conventional SAR and to reconstruct the ocean reflectivity. We present the basic theory of the VSAR system and its performance. We also provide an analysis of the VSAR imaging mechanism for a statistical model of the radar returns, designed to capture the effects of speckle and of resolution degradation due to the decorrelation of the radar returns 相似文献
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A data compression technique is developed for synthetic aperture radar (SAR) imagery. The technique is based on an SAR image model and is designed to preserve the local statistics in the image by an adaptive variable rate modification of block truncation coding (BTC). A data rate of approximately 1.6 bit/pixel is achieved with the technique while maintaining the image quality and cultural (pointlike) targets. The algorithm requires no large data storage and is computationally simple. 相似文献
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设计并实现了一种基于PCI总线的高速数据采集系统,主要包括模拟输入、信号调理、模数转换、数据传输存储以及计算机接口等部分.此系统可用于对某型号电子舱信号群进行实时高速采集,其性能和指标均满足要求. 相似文献
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弹载合成孔径雷达(Synthetic Aperture Radar,SAR)的目标距离、视线角由于高速逼近目标而快速变化,这导致传统的固定脉冲重复频率(Pulse Repetition Frequency,PRF)(简称重频)波形难以兼顾弹载SAR雷达在成像各方面的约束条件,故需要根据当前弹体运动和弹目关系变化情况实时计算重频。详细分析了影响重频选择的各项因素,包括避免距离模糊、方位模糊、高度杂波、发射遮挡影响及SAR成像分辨率、系统相参性要求等影响因素,并设计了自适应重频计算的工作流程。某SAR雷达系统实验表明,该设计能够在实际飞行弹道条件下根据实际弹目关系自适应调整脉冲重复频率,从而更好地实现SAR雷达系统的工作性能,有效解决了固定重频波形不能适应弹载SAR工作条件的难题。 相似文献
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针对固液动力探空火箭在进行测试、飞行试验时,需要实时测量并记录推力、燃料供给速率以及吹除系统工况信息的问题,设计并工程实现了对箭载重要设备输出信号进行监控和采集记录的数据采集系统.以STM32F103RB微控制器为核心,完成了数据采集、存储、传输等电路的设计,并在Real View MDK集成开发环境下,运用C语言完成了控制、测试程序的编写.最后,通过Real View ULINKR仿真器实现了软硬件的联合测试,验证了系统的供电控制、采样频率、工况记录等功能都满足设计要求,完成了对箭载重要设备监控和采集记录的任务.只需修改微控制器内的操控程序,就可将此数据采集系统应用于不同型号的固液动力探空火箭. 相似文献
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Durand R. Ginolhac G. Thirion L. Forster P. 《IEEE transactions on aerospace and electronic systems》2009,45(1):221-236
This paper deals with a new synthetic aperture radar (SAR) Processor based on a subspace detector designed for man-made target (MMT) detection. As MMTs are more accurately decribed by a set of canonical elements than with isotropic points, we develop a new algorithm which aims at using new models, instead of the isotropic point model commonly used in SAR processors. A subspace detector matched to canonical elements is included in the SAR processing. The implementation and the optimization of subspace detector SAR (SDSAR) algorithm is described. Simple examples of MMT detection in simulations and real data with a target hidden in a forest show the power of our approach. The SDSAR algorithm is shown to be the first robust and tractable algorithm relying on realistic scattering assumptions about the target. 相似文献
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根据火箭发动机地面试验对测量与控制的要求,设计了一套用于火箭发动机地面试验数据采集与控制的便携式测控系统.测控系统硬件基于NI(National Instruments)公司的USB(universal serial BUS)数据采集与控制设备开发,集测量与控制功能于一体,便携性好,通用性强;软件基于模块化设计思想,采用LabVIEW编程环境开发,人机交互界面友好,通用性强,可扩展性好.该测控系统平台已成功应用于多次发动机地面试验,能满足多种类型的火箭发动机试验对测控的需求. 相似文献
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合成孔径雷达(SAR)具有高分辨率、全天候等优点,是提高精确制导武器制导精度的有力工具。制导精度是精确制导武器的重要性能指标,影响SAR制导系统精度的主要因素有实时图的获取误差及预处理误差、图像匹配误差、惯导测量误差、SAR制导特殊弹道引起的导航制导的误差。概述了SAR图像匹配制导系统精度的相关研究,对比和分析了这些研究和结论,指出了该研究存在的问题和发展方向。 相似文献
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Birk R. Camus W. Valenti E. McCandless W. Jr. 《Aerospace and Electronic Systems Magazine, IEEE》1995,10(11):15-23
This paper presents profiles of 12 airborne and spaceborne Synthetic Aperture Radar (SAR) imaging systems. This information is intended to help potential users evaluate the systems for specific applications. The systems profiled in this article can be used for commercial purposes; some have been built specifically for commercial use while others also serve as science and research tools, Both domestic and foreign systems designed for government agencies and private industry are profiled. Nine of these systems are currently operational; two systems are scheduled to begin service in the near future. A third system is no longer active, but archive data are commercially available 相似文献
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Fornaro G. Sansosti E. Lanari R. Tesauro M. 《IEEE transactions on aerospace and electronic systems》2002,38(2):441-454
Synthetic aperture radar (SAR) systems require that a focusing operation be performed on the received backscattered echoes (raw data) to generate high-resolution microwave images. Either due to platform attitude instabilities, or to Earth rotation effects, the SAR raw data may be acquired in "squinted" geometries, i.e., with the radar beam directed with an offset angle (squint angle) from the broadside direction. This research investigates the impact of the focusing operation carried out on squinted raw data acquisitions performed by SAR sensors operating in the stripmap mode. To this end the 2D frequency SAR processing approach is generalized with respect to conical, i.e., nonorthogonal, reference systems. This allows analysis of the geometric, spectral, and phase aberrations introduced in the images by the chosen processing geometry with respect to the acquisition, and identification of the focusing procedure that minimizes these aberrations. The whole theory is validated by experimental results carried out on simulated data. Moreover, the extension of this analysis to the interferometric case where these aberrations may have a significant role is also investigated 相似文献
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Rosen P.A. Hensley S. Wheeler K. Sadowy G. Miller T. Shaffer S. Muellerschoen R. Jones C. Madsen S. Zebker H. 《Aerospace and Electronic Systems Magazine, IEEE》2007,22(11):21-28
NASA's Jet Propulsion Laboratory is currently building a reconfigurable, polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track SAR data for differential interferometric measurements. Differential interferometry can provide key deformation measurements, important for studies of earthquakes, volcanoes, and other dynamically changing phenomena. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly pre-defined paths with great precision. The expected performance of the flight control system will constrain the flight path to be within a 10 m diameter tube about the desired flight track. The radar will be designed to be operable on a Unpiloted Arial Vehicle (UAV) but will initially be demonstrated on a NASA Gulfstream III. The radar will be fully polarimetric, with a range bandwidth of 80 MHz (2 m range resolution), and will support a 16 km range swath. The antenna will be electronically steered along track to assure that the antenna beam can be directed independently, regardless of the wind direction and speed. Other features supported by the antenna include elevation monopulse and pulse-to-pulse re-steering capabilities that will enable some novel modes of operation. The system will nominally operate at 45,000 feet (13,800 m). The program began as an Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO). 相似文献
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Zaorski R.W. Voss R.A. Nunn E.C. 《IEEE transactions on aerospace and electronic systems》1971,(6):1068-1077
This paper discusses the concept, design, and design verification of the White Sands Range and Range-Rate System. Development of the system has been completed only through the design phase. The system is designed to meet requirements for high-accuracy midcourse tracking under severe target dynamics at the White Sands Missile Range. It is a multistatic Doppler and range tracker which operates at X band and incorporates transmitter, transponder, receiver, and baseline subsystems. The transmitter includes specially designed digital circuitry to synthesize test signals for target simulation during checkout of the system. The transponder signal is processed by a receiver which has been established theoretically to be the optimum realizable processor of continuous tracking data. The receiver incorporates specially designed carrier acquisition circuitry and digital VCO, and directly provides digital Doppler and tone phase data to facilitate real-time processing. The system utilizes data from other tracking systems at the Range for spatial acquisition, for aiding carrier acquisition in the receiver, and for resolving range ambiguities. 相似文献
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A system impulse response with low sidelobes is critical in synthetic aperture radar(SAR) images because sidelobes contribute to noise and interfere with nearby scatterers. However,the conventional tricks of sidelobe suppression are unable to be exactly applied to the case of spaceborne sliding spotlight SAR due to great azimuth shifts in both time and frequency domains. In this paper, an extended chirp scaling algorithm is presented for spaceborne sliding spotlight SAR data imaging. The proposed algorithm firstly uses the spectral analysis(SPECAN) technique to avoid the azimuth spectrum folding effect and then employs the chirp scaling(CS) algorithm to achieve data focusing, i.e., the so-called two-step approach. To suppress the sidelobe level, an efficient strategy for the azimuth spectral weighting which only involves matrix multiplications and short fast Fourier transformations(FFTs) is proposed, which is a post-process executed on the focused SAR image and particularly simple to be implemented. The SAR image processed by the proposed extended CS algorithm is very precise and perfectly phase-preserving. In the end, computer simulation results verify the analysis and confirm the validity of the proposed algorithm. 相似文献
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飞机外场试验和飞行训练的需求使得采集系统成为飞机的重要设备。为检测外场环境下某型飞机上
的采集系统的工作状态,本文以便携式计算机为硬件基础,以Qt 为软件平台,针对某型采集系统设计了地面
遥测检测专用设备,实现了多类数据的实时解析。检测结果表明,该设备具有数据处理能力强、安全可靠性好、
易维护等优点,能够为某型飞机上的某型采集系统检测提供工程保障。 相似文献
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Adams G.F. Ausherman D.A. Crippen S.L. Sos G.T. Williams B.P. Heidelbach R. 《Aerospace and Electronic Systems Magazine, IEEE》1996,11(12):31-35
The Environmental Research Institute of Michigan (ERIM) and Horizons, Inc. have completed the development, calibration and evaluation of the Advanced Research Projects Agency (ARPA)/US Army Topographic Engineering Center (TEC) funded IFSARE (Interferometric Synthetic Aperture Radar for Digital Terrain Elevations) system. This system rapidly produces geocoded SAR imagery and digital terrain elevation data. The dual-channel, X-band SAR is installed in the ERIM Learjet 36. The ground processor was developed in collaboration with the NASA Jet Propulsion Laboratory. The system produces 1.5 to 3.0 meters (1 sigma) absolute accuracy three-dimensional terrain elevation data over large areas without the use of ground control points. Several examples from recent data collections are presented 相似文献