Method of processing the signal issued by a radar of detection of an approach of an individual, and the radar device implementing this process

摘要

The invention relates to an acoustic radar operating on the "sonar" principle, i.e. measuring the time of return of short periodically emitted pulses. The analysis of these pulses yields an instantaneous image of the scene under surveillance. This instantaneous image is compared 20 with a previously acquired reference image 10 and, in the event of a disagreement between them, the newly-formed echo is studied 30 more thoroughly in such a way as either to trigger an alarm 40 or possibly to update 50, 60 the reference image. The device can be used particularly outside in order to keep watch on the porch of a dwelling, by virtue of the excellent rejection of outside disturbances (air movements, swaying of branches, temperature variations, etc) which reduces the number of false alarms to a minimum. IMAGE