DETECTION TECHNIQUES FOR VALIDATING DOPPLER ESTIMATES IN HETERODYNE LIDAR

We investigate the ability of detection techniques based on the likeli hood ratio to discriminate between heterodyne lidar Doppler estimates at low signal levels using examples generated by simulation. The disti nction between estimates that are regarded as acceptable and as spurio us is based on the Cramer-Rao lower bound. The conditional false alarm probability, which ordinarily describes recording detection of a sign al when none is present, is then found to be an approximate upper boun d on the probability of selection of a spurious estimate. The method i s superior theoretically to similar techniques based on detection func tions other than the likelihood ratio. The likelihood ratio also provi des a basis for reprocessing rejected data in the light of contextual information provided by those estimates that are accepted. (C) 1997 Op tical Society of America.