A clutter suppression method based on improved principal. The multiscale directional neighborhood filter and its. Radar horizon line of sight there are limits t o the reach of radar signals. It was based on single polarization signal and combined four discriminants for clutter detection. The velocity of rain clutter is generally that of the wind. The doppler frequency distributions of these effects and how they affect radar performance differ with. Several oth radar systems were deployed starting in the 1950s and 1960s as part of early warning radar systems, but. Meymaris national center for atmospheric research, boulder, colorado manuscript received 29 april 2008, in. An adaptive clutter suppression technique for moving target. An mti radar in an aircraft encounters problems not found in a ground based system of the same kind because the large undesired clutter echoes from. Clutter suppression for cooperative radar based on orthogonal. Bayesian statistical analysis of groundclutter for the. Model frequency agility techniques to counter the effects of interference in radar, communications, and ew systems. Since the clutter is one of the most limiting factor for the performance of a radar system, we start this section with a chapter on the statistical modeling and analysis of radar clutter data.
Land clutter is a function of many parameters including billingsley, 2002. Based on the analysis, the main influence to clutter build up in ground based radar is the wind speed as compared to others. Ground clutter with the narrow spectra can be used to monitor the system zdr. Mprf waveform for ground based radars to suppress returns. The phenomenon the radar antenna is a circular electronic scanning antenna. A similar example in matlab can be found in frequency agility in radar, communications, and ew systems. Pdf modeling the amplitude distribution of radar sea clutter. A clutter suppression method based on improved principal component selection rule for ground penetrating radar jichao zhu, wei xue, xia rong, and yunyun yu abstractprincipal component analysis is usually used for clutter suppression of ground penetrating radar, but its performance is in.
The 110 ghz model based on data available for grazing angles of 0. Sophisticated processing methods are employed to further process radar returns and extract target data even when heavily obscured by ground clutter or background returns surrounding the object s of interest. This is an important part of overall radar system design because land clutter coming into the sidelobes may cause the radar to use coherent waveforms and doppler domain processing instead of more time efficient noncoherent waveforms and processing. At the frequenc ies normally used for radar, radio waves usually travel in a straight line. Nov 06, 2014 as the inversions set in, anomalous propagation takes hold thanks to superrefraction and ground clutter lights up on the various radar sites going east to west with the setting sun. Groundbased coastal air surveillance wind turbineradar. The mission of a ground moving target indication gmti radar, as its name implies, is to detect and classify ground based vehicles, even ones with very low velocities. The analysis for existing facilities focused on block island wind farm, the first commercial offshore wind farm in the u. Greco and simon watts, describes how sea, ground, and rain clutter. Torres cooperative institute for mesoscale meteorological studies, the university of oklahoma, and noaaoar national severe storms laboratory, norman, oklahoma 1. Detection of ground clutter from weather radar using a. Radar equation for area clutter ground based radar again the received power from clutter is also calculated using eq. Blocks in gpu compute the clutter of each scattering unit in parallel, and threads in each block parallel compute the clutter of each differential unit in scattering unit. Antps59 longrange air surveillance radar fact sheet pdf.
This type of radar can provide a wide area of coverage and frequent updates of a specific area of interest if the radar is placed on a satellite with a low earth orbit. Clutter suppression for cooperative radar based on orthogonal polarization character maoqiang jing, zhuming chen, qianli wang, and qi jiang abstractin indoor scenario, radar echoes are interfered by clutter from walls, ceilings. Multimission capable with the ability to simultaneously detect ultralow to high altitude targets while performing its normal surveillance mission. It was based on single polarization signal and combined four discriminants for clutter. Master thesis groundbased sar imaging basics and land clutter effects in the focused image marc lort cuenca albert aguasca sole, master thesis advisor. For monostatic radar, received power prfrom a target with rcs. Mishra, an adaptive clutter suppression technique for mtd in pulse doppler radar an adaptive clutter suppression technique for moving target detector in pulse doppler radar amritakar mandal, rajesh mishra school of ict, gautam buddha university, yamuna expressway, greater noida, uttar pradesh 208, india. Since nf uses only range kernel of the wellknown bilateral filter, it is less complex and makes clutter removal method appropriate for realtime implementations.
Snr from the ground decreases and zdr increases in rain. Ground clutter article about ground clutter by the free. An array of 27 ground planes was fabricated for the clutter study. Polarimetric backscattering behavior of ground clutter at x. Extensive analysis of the new clutter measurement database led to a progression of increasingly accurate statistical clutter models for laying down the clutter strengths in visible regions of clutter occurrence 1, 2. Clutter modeling is based on the uncertainty of the environment as described probabilistically. Clutter signal is a nonstationary signal that received by the receiver. A study of ground clutter suppression at the chill doppler weather. It can rarely be described as spatially uniform except perhaps for local regions of woods, open fields or desert.
Clutter mitigation techniques for spacebased radar. This method builds a backscattering coefficient model based on groundbased radars and is not suitable to describe the clutter characteristics of. Advanced feature based techniques for landmine detection using ground penetrating radar zhenhua ma dr. The clutter is extended in space domain continuous in adjacent range bins. Ground clutter signals are typically statistically station. Surface clutter ground or sea returns are typical surface clutter. This introduces noises that are considered as clutter that will create doppler effect and can be detected by the receiver. For a radar system, clutter refers to the received echoes from environmental scatters other than targets, such as land, sea or rain.
In these bands, phenomena associated with clutter 2 interfere with. However because of the large footprint of the radar on the. Polarimetric backscattering behavior of ground clutter at. By way of example, a groundbased radar may capture range cells near the horizon a certain distance from the radar based on the height of the radar above the surface e.
Clutter echoes can be many orders of magnitude larger than target echoes. Real radar databases acquired by a dvbt based passive radar pr system were characterized considering the crossambiguity function output as the observation space. Ground based radars receive clutter from many sources. Sep 22, 2016 clutter computation becomes a bottleneck of radar simulation. Pdf highfidelity inhomogeneous ground clutter simulation of. Introduction radar backscatter from the ground can contaminate. In principle, all that is required to estimate the radar return backscatter from a region of clutter is a knowledge of the volume or surface illuminated and the echo per unit volume. The hh and vvpolarized backscattering behavior of homogeneous ground clutter has been investigated by measuring the radar cross section per unit area of rough surface terrain. It should be noted that the clutter pdf of phv depends on. Spectral polarimetric radar clutter suppression to enhance. To solve this problem, a parallel simulation method for clutter computation is introduced based on gpu platform. It is demonstrated by the simulation results that the performance of the proposed airborne moving target indication amti algorithm is comparable to that of the conventional mti processing approaches used in the surface.
Overthehorizon radar, or oth sometimes called beyond the horizon, or bth, is a type of radar system with the ability to detect targets at very long ranges, typically hundreds to thousands of kilometres, beyond the radar horizon, which is the distance limit for ordinary radar. We can use this kind of radar in sea and ground environments. Ground clutter in weather radar observations causes degradation of data. Significant gaps remain in the published data, especially for groundbased radars viewing the terrain at grazing incidence, and for bistatic situations where one. Weibull probability density function the weibull and log normal distributions are used to model ground clutter, because they are too parameter distributions which will allow for skewness long tails in the distribution of ground clutter. The performance of a radar system can be judged by the following. They can also be classified into n umerous categories based on the specific radar characteristics.
Ground based radar example formulating the problem p. Highfidelity inhomogeneous ground clutter simulation of airborne. Groundclutter signal and statistics vary widely since groundclutter targets are very diverse. Pdf this paper presents a highfidelity inhomogeneous ground clutter. Such echoes are typically returned from ground, sea, rain, animalsinsects, chaff and atmospheric turbulences, and can cause serious performance issues with radar systems. Pdf the ground clutter canceller based on the clutter. The doppler frequency distributions of these effects and how. The factors such as weak target reflection energy, ground clutter, and. The simulation of ground clutter is the key and knot problem in radar simulation system. Certain commercial equipment and materials are identified in this report to specify adequately the technical aspects of the reported results. Using simulink, a scenario is created with a ground based radar and an approaching aircraft who can also emit jamming signals.
Synthetic ground clutter simulation sgcs an initial proof of concept version of an sgcs has been designed and implemented. Utilize stateoftheart technology in all our radar products leader in solidstate electronically steered phased array technology over 175 longrange ground based radars delivered world wide greater than any other proven operational performance under all environmental conditions clutter resistant pencil beams detect lowflying. It is recognized as the worlds most capable longrange groundbased radar for tactical ballistic missile defense with proven performance during live fire tests. This clutter gets also a doppler speed by the wind.
Since clutter results mainly from scatterers in the radarresolutioncell,itisminimizedbyusingsmallradarangleresolution narrowbeamwidth,andsmallrangeresolutionwidesignalbandwidth. Main beam of antenna illuminates the ground antenna sidelobes illuminate clutter over a wide range of viewing angles altitude return reflects from the ground directly below the radar. It is still a challenging issue to detect ground clutter and mitigate its effects on weather observations. The doppler frequencies of the weather clutter might be nonzero, but are relatively small. Radars can be classified as ground based, a irborne, space born e, or ship based radar systems. Returns from geographical land masses are generally stationary, however, the effect of wind on. Clutter is a term used for unwanted echoes in electronic systems, particularly in reference to radars. The clutter in these range cells is representative of the clutter reflecting back from the horizon.
Spectral polarimetric radar clutter suppression to enhance atmospheric echoes christine unal delft university of technology, delft, netherlands. Groundclutter characteristics have been studied extensively and excellent summaries and discussion of clutter and clutter statistics are given by long 2001 and billingsley 2002. For rough ground surface, the surface clutter components in different ascan traces are not aligned on the depth axis. This paper explores a lowrank and sparse representation based technique to remove the clutter produced by rough ground surface for aircoupled ground penetrating radar gpr. Lockheed martins long range and medium range radars set the industry standard for groundbased air surveillance. Groundbased air surveillance radars lockheed martin. Ground moving target detection for airborne radar using. The low, slow, and small lss target detection has always been a problem for both ground based and airborne radar systems. Clear areas of the map identify regions of the radar product that are not likely to be contaminated by persistent ground clutter returns. Detection of ground clutter for dualpolarization weather. That matrix wont have strictly a low rank but it will admit an enough decreasing singular value decomposition, so that 3 may be applied to our radar context.
Radar parameters, namely, frequency, polarisation and resolution. Eca filter effects on ground clutter statistics in dvbt. Since radar clutter is generally highly correlated, the joint pdf cannot. These errors are shown for a surfacebased radar with a normal daytime ionosphere vs. The system can simulate clutter returned from ground surfaces and vegetation, for a stationary ground based radar platform with a constant look direction. Marine corps to provide a mobile longrange surveillance radar capability. The x, ka, and wband behavior was investigated by analyzing isar imagery of 116th scale terrain collected in compact radar ranges operating at 160 ghz, 520 ghz, and 1. Radar clutter modeling and analysis pdf free download. Modeling the amplitude distribution of radar sea clutter mdpi.
The gaussian model was proved to be suitable for high doppler shifts. Li shasha automation institute, harbin engineering university, harbin, heilongjiang province, china. Al sumiadaee department of computer techniques engineering, alyarmouk university college, diyala, iraq abstract the purpose of this paper is to study and evaluate some types of clutter which causes the degradation of radar performance. Therefore, clutter suppressing is one of the key problems for indoor radar. Considering that radar signals from ground clutter have a much longer correlation time than that from weather, a scantoscan dual. Ground clutter mitigation with moving target indication. The chapter titled radar clutter modeling and analysis, coauthored by maria s. However, in this case the clutter rcs is computed differently. These data sets cover a wide range of frequencies l, s, and xband, and different collection geometries and sea conditions. Utilize stateoftheart technology in all our radar products leader in solidstate electronically steered phased array technology over 175 longrange groundbased radars delivered world wide greater than any other proven operational performance under all environmental conditions clutterresistant pencil beams detect lowflying.
We present a novel neighborhood filter nf based clutter removal algorithm in ground penetrating radar gpr images. Radar factors affecting radar performance britannica. Land clutter models for radar design and analysis ieee xplore. Provided n 1, the probability density function of the real and imaginary parts of y will be gaussian, through the application of the central limit theorem clt. Pdf on jan 1, 2017, jian zhou and others published the ground clutter canceller based on the clutter recovery in airborne mimo radar find, read and cite all the research you need on researchgate. Sea clutter are disturbing radar echoes of sea wave crests. Radars for the detection and tracking of cruise missiles.
The clutter may fill a volume such as rain or be confined to a surface like land. For surface based mtimtd radar, the ground clutter is stationary with zerodoppler frequency. Advances in the realtime simulation of synthetic clutter. Ho, thesis supervisor abstract landmine detection is an important and yet challenging problem that remains to be. Because the method requires constancy of the pdf of the clutter reflectivity we. Radar pulsed rf applications have unique design, performance and reliability challenges relative to other high power rf applications. However, with automotive radar, the range can be as short as a. Master thesis groundbased sar imaging basics and land. Detection of ground clutter from weather radar using a dual. Rough ground surface clutter removal in aircoupled ground.
Weather conditions detected by the radar are measured in six levels of intensity conforming to the icao and u. Mprf waveform for ground based radars to suppress returns from windmills and rain clutter abstract. The method has also shown promise for any groundbased radar that has. Us8947294b1 method and system for adaptively cancelling. Billingsley, lowangle radar land clutter measurements and empirical models. Renewable energy sources such as wind parks are more and more shaping our environment. The waves may be obstructed by w eather or shadowing, and interference may come from other aircraft or from reflections from ground objects figure 1. Pdf radar detection of aircraft on a particular scan depends in large measure on. Mitigation measures, including radar network fusion, radar upgrades, and infill systems, are also discussed.
Modeling the amplitude distribution of radar sea clutter. Geometry of illumination, namely, grazingdepression angle. Antenna sidelobes illuminate clutter over a wide range of viewing angles altitude return reflects from the ground directly below the radar. This example shows the design of a moving target indication mti radar to mitigate the clutter and identify moving targets. Ground based radar systems operate in the 12141400mhz band with the common 200. The simulation of ground clutter based on dem is studied. Us6771207b1 establishing radar coverage, blockage, and. For weather radar, ground clutter is the undesired echoes from scatterers on the ground, which can significantly bias the polarimetric weather radar measurements. Pdf ddma mimo radar system for low, slow, and small target.
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