Multiple target 3D location airborne ultrasonic system

Beam-forming techniques are widely used to determine 2D and 3D position of targets. One of the main restrictions is the requirement for lambda /2 dist ance between element to avoid ambiguities due to sidelobes. This requiremen t can be eliminated when short pulses are used and the beam-forming process is applied to the envelope of the received signals only. In airborne ultra sound, the information available from the envelope received signals, is the time of flight. To calculate 3D position of targets, a non-linear equation system has to be solved. The solution to this system can be found by sever al numerical methods, mainly iterative processes. In this paper, a new 3D u ltrasonic 3D target location system is presented which uses the Broyden met hod in conjunction with coarse beam forming. The operation of the system ha s been demonstrated using simulated data based on the characteristics of th e 2D ultrasonic target location system developed at Nottingham University. (C) 2001 Elsevier Science B.V. All rights reserved.