外文翻译比幅单冲雷达二阶判别函数.docxVIP

外文资料原文 SECOND ORDER DISCRIMINANT FUNCTION FOR AMPLITUDE COMPARISON MONOPULSE Elsayed E. Agrama, Onsy A. Abdel-Alim, and Mohamed A. Ezz-El-Arab Faculty of Engineering,Alexandria University,Alexandria,Egypt A new three receiving elements amplitude comparison monopulse Direction Finding (DF) technique is introduced. An appropriate second order discriminant function is chosen for this technique. Then, simulation is used to compare its accuracy to that of the two receiving elements direction finding technique. Different sources of error were taken into consideration, such as, for example, receiver noise, pattern errors, amplitude imbalance, mechanical and quantization errors. Introduction and theory The term amplitude comparison monopulse direction finding technique is used to calculate the angle of arrival of a radio frequency signa1, usually a radar signa1, at a receiving antenna array using the output signal amplitudes from TWO adjacent antenna elements. In this technique, the angle of arrival is related to a discriminant function which is a first order function in the output signal amplitude and is given by: where A and A, are the output signal amplitudes from the two receiving adjacent antenna elements i and i+l respectively, is the field patterns of the above two antenna elements which are assumed to be identical with pattern beam width but squinted from each other by an angle : Here we introduce the principle of the second order amplitude comparison monopulse direction finding technique in which the output signals from THREE adjacent antenna elements are used to calculate the angle of arrival of the incident signal. For this technique, a second order discriminant function is introduced such that: Where is a second order function in the output signal amplitude ;and A are as defined before. Figure (1) illustrates (a) antenna arrays geometry (b) antenna elements field patterns;(c) the function and (d) the function for equals 45° and = 80°. 2-elements system