Patent ID: 6384718
Filing Date: 2002-05-07
Classification: G01S

Abstract:
A method of detecting the presence of an obstacle in the vicinity of an object, comprising the steps ofemitting a pulsed signal from a predetermined location of the object; receiving echoes of such a pulsed signal as reflected from the obstacle at at least two locations of the object; measuring respective time intervals elapsing between said emitting and receiving steps; establishing the presence of the obstacle in a first environmental region of the object when at least one of said time interval to a first one of said two locations is smaller than a first threshold and said time interval to a second one of said two locations is smaller than a second threshold; selecting a third and a fourth threshold to exceed by predetermined amounts said first and second threshold, respectively; and establishing the presence of the obstacle in a second environmental region of the object when said time interval to said first location is smaller than said third threshold and said time interval to said second location is simultaneously greater than said fourth threshold.