Doppler beam sharpening dbs is a next stage and is an effective method to improve the azimuth resolution of airborne pulse doppler radar in its airtoground. The efficient scan moving target indication mti mode is implemented in the widearea ground mti systems for the purpose of widearea surveillance. This was a camdriven reflector in a trough which introduced a frequency shift at if. Doppler beam sharpening commonly refers to the method of processing unfocused realbeam phase history to achieve better resolution than could be achieved by processing the real beam without it. Application of doppler beam sharpening for azimuth. Doppler beam sharpening dbs is a next stage and is an effective method to improve the azimuth resolution of airborne pulse doppler radar in its airto ground. Range bin output plots demonstrate the effective ness of these techniques. Volume iii, issue v, may 2016 ijrsi issn 2321 to improve. As an important mode of modern airborne firecontrol radar, doppler beam sharpening dbs imaging can provide a large area of radar images in front of airborne radar with high resolution in its airtoground mode. The nps institutional archive theses and dissertations thesis collection 199303 resolution in radar mapping anderson, michael d. Accordingly, airborne or spaceborne was radar is widely applied in civilian and military. Monopulse ground mapping with doppler beam sharpening, weather and turbulence detection, air target detection, windshear detection, beacon mode for dropzone identi. Range bin output plots demonstrate the effectiveness of these techniques. In this case, each range bin is pro cessed to resolve targets in doppler which correspond to azimuth.
A new generation of airborne pulse doppler radar with dbs can provide a. Today it is an airborne scanning mode in which the echoes from the. In figure1, aircraft is moving along the velocity v a. Semantic scholar extracted view of terminal guidance using a doppler beam sharpening radar by jeremy hodgson et al. In conventional dbs technology, the narrowband doppler filter groups formed by. Terminal guidance using a doppler beam sharpening radar. Ultimately this is to improve radar image quality in the azimuth plane to complement the excellent range resolution and thus improve object classification in lowthz radar imaging systems for autonomous platforms. This paper focuses on the use of a particular form of sar known as doppler beam sharpening dbs to generate images that can be used to guide a missile onto a target. Several beam sharpening techniques are illustrated with radar images. However, because of the scanning movement of the radar antenna, it is difficult to acquire enough coherent pulses in a single azimuth direction in the doppler beam sharpening dbs, so the sharpening. Doppler beam sharpening relied on the processing of doppler shift, so was only available at angles between 15 and 60 degrees off the aircrafts velocity vector.
In the proposed kadbs framework, the dbs imaging model for was radar is constructed and the crossrange resolution is analyzed. Ultimately this is to improve radar image quality in the azimuth plane to complement the excellent range resolution and thus improve object classification in low. Pdf terminal guidance using a doppler beam sharpening. American institute of aeronautics and astronautics 12700 sunrise valley drive, suite 200 reston, va 201915807 703. Basically, the ground mapping is done using real beam ground mapping. Doppler beam sharpening dbs is a next stage and is an effective method to improve the azimuth resolution of airborne pulse doppler radar in its airtoground mode. Doppler beam sharpening article about doppler beam. Knowledgeaided doppler beam sharpening superresolution. A new heightestimation method using fmcw radar doppler. The synthetic beamwas scanned by use ofan ultrasonic compensator. Realtime implementation of doppler beam sharpening technique dbs doppler beam sharpening technique which increase cross range resolution. Doppler beam sharpening dbs is a technique that uses the relative motion between the target and the radar platform to resolve targets, or dominant scatterers, within the same target in crossrange by exploiting the doppler effect 1.
This technique was originally known as doppler beam sharpening, but later became known as synthetic aperture radar sar. Doppler beam sharpening dbs synthetic aperture radar sar mapping modes real beam ground map rbm and prime detection spotlight sp mode. Therefore, dbs radar imaging has been used in many fields such as military reconnaissance, ground match. Airborne radars are used to provide highresolution ground mapping. Several families of codes are investigated emphasizing matched filter output and doppler tolerance. It also discusses the principle and the processing method of dbs according to the requirement of keeping constant resolution. This paper analyses the basic principle of doppler beam sharping radaf imaging and its reallime signal processing procedure,on the basis of doppler resolution theory,then, a realtime digital signal processing scheme of dopoler beam sharping is developed. Superresolution doppler beam sharpening method using fast. Computer simulation results show that the doppler beam sharpened ratio of the system can reach 17. In 1952, doppler beamsharpening system was developed by. Airborne fire control radar pulse doppler beam sharpening. In this paper, dbs method is implemented to enhance azimuth resolution from the moving platform aircraft by discriminating the different doppler shifts. This paper deals with the problem of high crossrange resolution doppler beam sharpening dbs imaging for airborne widearea surveillance.
This doppler beamsharpening concept was exploited by goodyear and by a group at the university of illinois. This paper deals with the problem of high crossrange resolution doppler beam sharpening dbs imaging for airborne widearea surveillance was radar under short dwell time situations. Since the lobe has an open angle for example 3 degree beam width the returns come from different angles and have different doppler velocities with in beam. An echo simulation method for dbs of missileborne radar that considers environmental. Because the real aperture of the radar antenna is so small compared to the wavelength in use, the radar energy spreads over a wide area usually many degrees wide in a direction orthogonal at right angles to the direction of the platform aircraft. Doppler beam sharpening dbs is a critical technology for airborne radar ground mapping in forwardsquint region. A commonly used technique for sar systems is called doppler beam sharpening. The doppler beam sharpening performs the cross range resolution improvement by analyzing the doppler difference inside the lobe. Technique of doppler beam sharpening dbs 16 for enhancing radar azimuth resolution divides the echoes in the same beam into a set of doppler beams by doppler analysis, and the ratio of the original beam width to the doppler beam width is called the sharpen ratio. Pdf analysis of beam sharpening effectiveness in broadband. Azimuth resolution is improved through beam sharpening. In the airbased radar, a completely new form of lateral angle measurement with the help of the doppler frequency, the socalled doppler beam sharpening, was developed in the 1970s. A synthetic aperture radar sar apparatus adapted to provide deadahead beam sharpening in a moving craft 10, comprising. Because the real aperture of the radar antenna is so small compared to the wavelength in use, the radar energy spreads over a.
In the airsurface mode the radar supports ranging, mapping and tracking of moving targets, the radar supports realbeam, doppler beam sharpening. Simulations of repeat jamming against antiship missile. Request pdf realtime implementation of doppler beam sharpening technique with simple motion estimation first page of the article find, read and cite all. In this study, the authors investigate the application of the doppler beam sharpening dbs technique for angular refinement to the emerging area of lowterahertz thz radar sensing. Request pdf resolution enhancement for doppler beam sharpening imaging the efficient scan moving target indication mti mode is implemented in the widearea ground mti systems for the purpose. Doppler beam sharpening is a method of processing received radar returns to radarimage. Several beam sharpening techniques are illustrated with radar images provided by hughes aircraft. One major problem was implementation of a practical data processor that could accept wideband signals from a storage device and carry out the necessary dopplerfrequency analysis at each resolvable picture element pixel. Synthetic aperture radar with deadahead beam sharpening. Since radar pulses propagate at the speed of light, the range to the target is proportional. A doppler correction to eliminate background clutter when aircraft radar aerial points in a direction other than straight ahead and consequently the computer breaks each reading into small pieces and reassembles them as. Pdf terminal guidance using a doppler beam sharpening radar. The problem with realbeam mapping is the relatively poor resolution provided by the radar antenna. The paper presents the processing technique of doppler beam sharpening which can improve the resolution of radar azimuth.
Realtime implementation of doppler beam sharpening technique. In this case, each range bin is processed to resolve targets in doppler which correspond to azimuth. Sar systems that are gen erally concerned with improving azimuth resolution are often referred to as doppler beamsharpening dbs sars. This shift movedthe various doppler shifts in the real beam back to a fixed filter frequency. The resolution available from doppler beam sharpening is limited by the antenna dwell timethe length of time for which the patch of terrain being observed is illuminated by the radar. Pdf the paper presents results of the research on beam. However, because of the scanning movement of the radar antenna, it is difficult to acquire enough coherent pulses in a single azimuth direction in the doppler beam sharpening dbs, so the sharpening ratio is greatly limited. In the scanning movement of the antenna, the dwell time at each azimuth angle is very short to guarantee a high revisit radio. With these techniques, nearsari quality output can be obtained. Resolution enhancement for doppler beam sharpening imaging. An echo simulation method for dbs imaging that considers environmental factors gaosheng li1, gui gao1, yang bai2, dongming zhou1, wei liu1, and jianghua cheng1 abstractdbs doppler beam sharpening imaging for scene matching terminal guidance is investigated. To improve the azimuth resolution in ground mapping radar using. In conventional dbs technology, the narrowband doppler filter groups formed by fast fourier transform fft method suffer from low spectral resolution and high side lobe levels. Technique of doppler beam sharpening for enhancing adar.
In modern radar sets, the doppler frequency is used for a variety of purposes. Doppler beam sharpening was used to create a coarse resolution image allowing the normalised bistatic clutter rcs of the stationary surface clutter to be analysed. Analysis of beam sharpening effectiveness in broadband radar on inland waters. According to one embodiment of the invention, the autonomous landing guidence system utilizes the monopulse beam sharpening technique described below. A knowledgeaided dbs kadbs imaging algorithm is proposed. Doppler beam sharpener how is doppler beam sharpener. Pdf to improve the azimuth resolution in ground mapping. An echo simulation method for dbs imaging that considers.
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