
Accession Number : AD0699150
Title : TRIMMEDMEAN DETECTOR FOR NONCOHERENT DISTRIBUTIONS.
Descriptive Note : Interim rept.,
Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C
Personal Author(s) : Trunk,G. V.
Report Date : 11 DEC 1969
Pagination or Media Count : 16
Abstract : Seaclutter measurements using highresolution radar indicate that clutter crosssection returns do not usually follow a Rayleigh distribution. The lognormal and contaminatednormal descriptions of sea clutter have been considered, and detection curves for these distributions have been generated for both the mean and median detectors  the median being better for the lognormal distribution and the mean being slightly better for the contaminatednormal. In this report, the trimmedmean detector is proposed as a detector against these clutter distributions. By using a Monte Carlo technique, equations are obtained for the threshold values, and curves of probabilities of detection (P sub d) are drawn for falsealarm probabilities (P sub fa) ranging from 0.01 to 10 to the minus 9th power. When one compares the mean, median, and trimmedmean detectors, the conclusion is that the trimmedmean is the better detector against either of the two distributions considered. In fact, for the lognormal distribution, when 10 samples are available, the trimmedmean requires 5 dB less S/N ratio than the mean in order to obtain P sub d = 0.9 and P sub fa = 10 to the minus 8th power. Unfortunately, whereas the mean and median are easily implemented, the implementation of the trimmedmean is very difficult because of the necessity of ordering the samples. (Author)
Descriptors : (*DEMODULATORS, *RADAR RECEIVERS), TARGET ACQUISITION, PROBABILITY, RADAR CLUTTER, MONTE CARLO METHOD, PROBABILITY DENSITY FUNCTIONS
Subject Categories : Active & Passive Radar Detection & Equipment
Distribution Statement : APPROVED FOR PUBLIC RELEASE