Patent ID: 6895358

Claim:
A method of locating, in a reference plane, an edge that is disposed at the junction between two surfaces that are substantially plane, said reference plane being substantially perpendicular to the surfaces, said method comprising the following stages: a) transmitting waves from at least one transmitter disposed in the reference plane, said transmitter having a transmit solid angle that enables at least some transmitted waves to reach both of the surfaces on either side of said edge; b) receiving the echoes of the waves transmitted by the transmitter in at least two receivers which are disposed in the reference plane such that one of the receivers essentially receives the waves reflected by one of the surfaces while the other receiver essentially receives the signals reflected by the other surface, the positions of the receivers and of the transmitter in the reference plane being known by construction; c) analyzing the energy of the signal received by each receiver to determine the value of the angle of inclination between the main transmit axis of the transmitter and the normal to the surface that has reflected the waves picked up by said receiver; d) computing the position in the reference plane of the point of impact of the waves on each surface by measuring the travel time of the signal transmitted by the transmitter and received by each receiver; and e) locating said edge in the reference plane by computing the point corresponding to the intersection of the straight lines passing through the two points of impact and forming respective angles with the main transmit axis of the transmitter.