Detection Of Stationary Ground Targets By Airborne MMW Radars

Abstract

In recent years detection of stationary ground targets such as tanks and trucks by airborne MMW radars mounted on helicopters have received significant technical attention [1, 2, 3]. This detection should take place in the presence of ground clutter return and under adverse weather conditions such as fog and rain. Since the detection ranges are not very long (in the order 5 kilometers) MMW radars are well suited for this application. The primary reason is the fact that these radars, because of their higher frequencies (i.e., smaller beamwidths), subtend smaller ground clutter areas in which the target is located. This gives a better target to clutter signal ratio. Similarly, again because of their smaller beamwidths, they subtend smaller rain volumes, reducing the effect of increased noise due to rain backscattering. In this paper, basic radar search equations are given for detection of targets in the clear (non clutter environment). The increased noise level due to ground clutter and atmospheric disturbances such as rain is also calculated. Additionally, methods of calculating atmospheric attenuation are outlined and applied to example problems. Two MMW (35 and 95 GHz) radar parameters are used in the detection of ground targets. It has been shown that for a given an-tenna size, the higher frequencies (i.e., 95 GHz) result in better detection ranges of stationary ground targets than the lower frequency (35 GHz). The reason is the smaller beamwidth and thereby the smaller clutter area coverage.© (1985) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.