Accession Number : ADA262472


Title :   Ground Clutter Measurements for Surface-Sited Radar


Descriptive Note : Technical rept.


Corporate Author : MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB


Personal Author(s) : Billingsley, J B


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a262472.pdf


Report Date : 01 Feb 1993


Pagination or Media Count : 88


Abstract : A large volume of radar ground clutter measurement data has been collected from many sites that are widely dispersed over the North American continent. At each site backscatter was recorded from all the terrain within the field of view, typically to ranges extending to 25 or 50 km. As a result, in most of these measurements the angle of illumination of the earth's surface was usually very low, typically within a degree or so of grazing incidence, with much intermittent shadowing of low regions. This report examines the nature of low-angle radar ground clutter as it has come to be understood through analysis of this extensive new base of measurements. Depression angle, that is, the angle below the horizontal at which the backscattering terrain point is observed at the radar antenna, is shown to be the principal parametric influence on clutter amplitude statistics, even for the very low angles and small (i.e., typically fractional) variations in angle that occur in surface-sited radar. This principal role of depression angle is the result of its effect on shadowing in a sea of patchy visibility and discrete or localized scattering sources. Following this understanding, a general predictive model for ground clutter spatial amplitude statistics is developed based on very precise computation of depression angle but on only relatively gross specification of terrain type. The important radar parameters entering the model are rf frequency as it affects mean strength of clutter amplitude distributions and spatial resolution as it affects spread in these distributions.... Radar ground clutter, Terrain reflectivity, Land clutter, electromagnetic propagation Clutter measurements, Low-angle, Radar clutter, Multipath clutter models, Multifrequency.


Descriptors :   *RADAR CLUTTER , *RADAR ANTENNAS , *GROUND CLUTTER , FREQUENCY , ANGLES , PROPAGATION , MEASUREMENT , SCATTERING , COMPUTATIONS , MODELS , DISTRIBUTION , SPECIFICATIONS , PARAMETERS , SITES , RESOLUTION , STATISTICS , TERRAIN , BACKSCATTERING , ILLUMINATION , REGIONS , VARIATIONS , SURFACES , VISIBILITY , MEAN , OCEANS , REFLECTIVITY , AMPLITUDE , DEPRESSION ANGLES , LOW ANGLES , GRAZING


Subject Categories : Electrical and Electronic Equipment
      Active & Passive Radar Detection & Equipment


Distribution Statement : APPROVED FOR PUBLIC RELEASE