Spectral polarimetric radar clutter suppression to enhance atmospheric echoes christine unal delft university of technology, delft, netherlands manuscript received 9. Doerry prepared by sandia national laboratories albuquerque, new mexico 87185 and livermore, california 94550 sandia national laboratories is a multiprogram laboratory managed and operated. Clutter and interference tx rx target ground m u lti p a th d i r e c t p a t h c l u t t e r interference antenna main lobe ground sidelobe clutter in range gate range gate spherical wavefront in antenna far field target rain mainbeam clutter ground sidelobe clutter the point target approximation is good when the target extent radar clutter peter gerstoft1,l. Clutter is a term used for unwanted echoes in electronic systems, particularly in reference to. So, several works have developed models of clutter radar.
Performance limits for exoclutter ground moving target indicator gmti radar armin w. The classification procedure comprises the estimation of the parameters of the gc pdf. Modeling the amplitude distribution of radar sea clutter mdpi. Spectral polarimetric radar clutter suppression to enhance. 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. In the particular case of the compound k distribution model, the pdf of clutterplusnoise can be defined exactly 80. Clutter is spatially distributed and larger in physical size than the radar resolution cell. Radar clutter mitigation techniques tecnico lisboa. For a known clutter pdf, the pdf of clutterplusnoise will generally have to be calculated numerically. Noise was discussed earlier in detail concerning the radar basics. Finally, basic background material and sample problems are included on the detection of targets in the presence of noise and clutter.
When the clutter signal has gaussian probability distribution and is random from pulsetopulse, sc can be combined. Example rcs values applicable to aew are given for targets and clutter. Clutter reduction using background subtraction of ground. Radar modeling typically includes a system signal model which includes a state and an associated variance. However, if the surface has some roughness, the forward scatter component called coherent or specular reflection is reduced by diffuse, noncoherent scattering in other directions. Since radar clutter is generally highly correlated, the joint pdf cannot. Request pdf clutter reduction using background subtraction of ground penetrating radar for landmine detection gpr ground penetrating radar is an application of electromagnetics that has been. Some radars are required to detect small targets in the presence of much larger radar echoes from sea or land clutter in the radar s coverage. The distribution of clutter reflectivities is often so wide that. Geometry of illumination, namely, grazing depression angle. Wit hin a wnd ow f sme 60 x40, p aed rry radars can instantly switch their beam position to any position in azimuth and elevation. Radar spacetime processing for rangefolded spreaddoppler. Ieee new hampshire section radar systems course 1 pulse doppler 1112009 ieee aes society radar systems engineering lecture clutter rejection part 2 doppler filtering dr.
This also allows for much lower false alarm rates to be used when there is insuf. 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. When the radar is tasked with surveying its sector and tracking dozens of. Radar parameters, namely, frequency, polarisation and resolution. Meymaris national center for atmospheric research, boulder, colorado manuscript received 29 april 2008, in. Odonnell ieee new hampshire section guest lecturer 2. On the use of auxiliary receive channels for clutter.
Simon haykin et al uncovering nonlinear dynamics the case study of sea clutter pdfdatei. Therefore, in competition with the return from an aircraft, there are many sources of unwanted signals. Pdf cancellation of clutter and multipath in passive radar. Introduction to radar systems mit lincoln laboratory. Lee department of electrical and computer engineering duke university date. Radar systems course 3 airborne pd 112010 ieee new hampshire section ieee aes society outline introduction the airborne radar mission and environment clutter is the main issue different airborne radar missions pulse doppler radar in small fighter interceptor aircraft f14, f15, f16, f35 airborne, surveillance, early. Clutter model for vhf sar imagery julie ann jackson and randolph l. Moses the ohio state university, department of electrical and computer engineering 2015 neil avenue, columbus, oh 43210, usa abstract we present a physicallybased clutter model for low frequency synthetic aperture radar that includes both. Radar spacetime processing for rangefolded spreaddoppler clutter mitigation by william w. Also, the presence of a maritime target usually manifests itself in the tail of the radar distribution due to its higher amplitude return.
Feb, 2016 radar 2009 a clutter rejection doppler filtering 1. Radar detection of aircraft on a particular scan depends in large measure on the clutter return from the targets range cell. To derive a suitable processing scheme, we resort to the general theory of radar detection which applies to any type of pdf and autocorrelation function acf of the target and clutter. The paper deals with the cancellation of direct signal, multipath and clutter echoes in passive radar, where the transmitted waveform is not under control of the radar designer and the sidelobes of the ambiguity function mask even targets largely. For monostatic radar, clutter is the diffuse backscatter in the direction towards the radar. Clutter is a term used for unwanted echoes in electronic systems, particularly in reference to radars.
Models of land clutter vs grazing angle, spatial distribution. Pdf radar detection of aircraft on a particular scan depends in large measure on the clutter return from the targets range cell. Radar land clutter constitutes the unwanted radar echoes returned from the earths surface that compete against and interfere with the desired echoes returned by targets such as aircraft and other moving and stationary targets. Radar returns are produced from nearly all surfaces when illuminated by radar. On the use of auxiliary receive channels for clutter mitigation with phased array weather radars khoi d. Theory of radar detection in coherent weibull clutter iet. Ground clutter processing for airborne radar in a compressed. Radar performance in clutter is summarized by two parameters.
Radar clutter modeling and analysis pdf free download. Pdf radar sea clutter suppression and target detection with. Implications for physics, signal processing, and control, iee proc. Modeling the amplitude distribution of radar sea clutter. Torres, member, ieee abstractphased array radars pars are attractive in weather. Similarly, the pdf of the envelope of targetplusclutterplusnoise is required to calculate pd. The results show radar clutter can be mitigated either by reducing the ground area illuminated by the antenna, in the case of surface clutter, or by reducing the pulse duration, in the case of volume clutter. This signaltoclutter ratio, sc, depends on the target rcs, the amount of clutter illuminated, the clutter re. Performance limits for exoclutter ground moving target.
Classification of high resolution radar echoes is carried out using the generalized compound probability density function gc pdf. Adjusting sea clutter on the radar screen manually. The goal is to assist with the studies being performed by members of the set185 panel. Radar detection performance in medium grazing angle x.
Illustration of a mimo radar system with m 3 and n 4. The system noise, usually referred to as thermal noise, is incorporated in the model. A perfectly smooth and flat conducting surface acts as a mirror. Land clutter is a function of many parameters including billingsley, 2002.
Us7903024b2 adaptive moving target indicator mti clutter. When this model is not valid, the performance of the algorithm will degrade. On a large area of rain clutter, falling from a welldefined rain cloud, for instance, the reflected signal would rise suddenly and then remain high over a. The chapter titled radar clutter modeling and analysis, coauthored by maria s. The ability to accurately predict the effects of land clutter in surface radar has been an unsolved problem for many. Statistical target and clutter models that have proved useful for radar system analyses are also discussed. One way to overcome this might be to estimate the clutter subspace by using a combination of both the assumed geometry and the received data. Pdf sea clutter refers to the radar returns from a patch of ocean surface. When a radar detects targets on or above the sea surface, it has to. Clutter refers to radio frequency rf echoes returned from targets which are uninteresting to the radar operators and interfere with the observation of useful signals.
High grazing angles are typically defined to be above 10. Clutter detection in pulsedoppler radar systems a thesis submitted to the department of electrical and electronics engineering and the institute of engineering and sciences. Spectral polarimetric radar clutter suppression to enhance atmospheric echoes christine unal delft university of technology, delft, netherlands manuscript received 9 may 2008, in. Adjusting sea clutter on the radar screen automatically. It is a problem for the user of the radar because the generally increased levels of the total radar return caused by precipitation clutter can mask other targets, as shown in figure 2. Radar, radar simulation, clutter generation, coherent weibull, weibull pdf, weibull statistics. Greco and simon watts, describes how sea, ground, and rain clutter. Classification of radar clutter in an air traffic control environment. Unwanted signals in a search radar are generally described as noise and clutter. Banks an abstract of a dissertation submitted in partial ful llment of the. Greco dipartimento di ingegneria dellinformazione university of pisa via g. Gini 2000, performance analysis of two structured covariance matrix estimators in compoundgaussian clutter, signal processing 802, pp.
The concept of radar crosssection, waveform design, antennas, transmitter and receiver characteristics, and the detection of radar signals in the presence of noise are presented. The phrase subclutter visibility scv describes the radar s ability to detect nonstationary targets embedded in a strong clutter background with a given signalto clutter ratio scr, for some probabilities of detection and false alarm. Apparatus for providing moving target indicator mti filtering in the presence of clutter for a radar receiver employing digital pulse compression to provide at an output a compressed digital pulse for application to the input of a mti digital filter, including a digital adaptive filter of the same weight as the mti filter and operative to receive the compressed pulse to provide at outputs of. Such echoes are typically returned from ground, sea, rain, animalsinsects, chaff and atmospheric turbulences, and can cause serious performance issues with radar systems. Pdf classification of radar clutter in an air traffic. Section 7 presents case studies to an innovative csmdsc scheme and show how the mdsc can be improved and be functional under heavy clutter background scenarios.
Some radars are required to detect small targets in the presence of much larger radar echoes from sea or land clutter in the radars coverage. Clutter includes echoes from land, sea, weather, and animals. Palmer, senior member, ieee, boon leng cheong, tianyou yu, guifu zhang, senior member, ieee, and sebastian m. Clearly the pdf must account for the different elements of the seaclutter as well as the thermal noise in the radar.
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