Analysis of fast accurate low ambiguity beam forming for non lambda/2 ultrasonic arrays

Two-dimensional ultrasonic measuring systems have found applications in a n umber of fields including robotics and process control. To provide two-dime nsional ranging, an array of receiving and/or transmitting elements are req uired, which have traditionally required spacing at sub-lambda /2 intervals . The lambda /2 limitation has been removed by new processing methods but t he process still remains computationally intensive. This paper describes a method of reducing the computational effort significantly whilst increasing the accuracy of measurement. In order to optimise the system further, an a nalysis of the effect of different receiving element distributions within t he array on systematic and random errors is also presented. (C) 2001 Elsevi er Science B.V. All rights reserved.