Method for elevation measurement of a low-altitude target in a monopulse radar receiver, and monopulse radar receiver using such a method

Abstract

Abstract 1. A method for measuring the elevation of a low altitude target in a monopulse radar receiver associated to an antenna presenting sum S(x) and difference diagrams D(x), x being the adjusted elevation with respect to the axis of the antenna, this method comprising successively : - a first step of elaborating first elevation sum and difference signals on the basis of the signals received from the radar antenna, the axis of which is aligned along a first direction ; - a second step of calculating the complex ratio m1 between the first elevation difference signal and the first sum signal ; characterized in that the method further comprises : - a third step during which the axis of the radar antenna is dislocated to a second direction including with the first direction an angle theta while conserving its ground angle ; - a fourth step of elaborating second elevation sum and difference signals on the basis of the signals received from the radar antenna which is aligned along the second direction ; - a fifth step of calculating the complex ratio m2 between the second elevation difference signal and the second sum signal ; - and a sixth step of calculating the elevation angle alpha of the target and the elevation angle alpha' of its image expressed in relation to the 3 dB beam width of the radar antenna with respect to the first direction of the radar antenna axis by solving the following complex equation : A(alpha, alpha')m1 m2 + B(alpha, alpha')m1 + C(alpha, alpha')m2 + E(alpha, alpha') = 0 in which A, B, C, E are known real and symmetrical functions in alpha and alpha' of the radar antenna radiation on the sum channel S(x) and the difference channel D(x) in the elevation direction x with respect to the antenna axis, such that (alpha - alpha') . A(alpha, alpha') = S(alpha)S(alpha' + theta) - S(alpha + theta)S(alpha') (alpha - alpha') . B(alpha, alpha') = D(alpha + theta)S(alpha') - S(alpha)D(alpha' + theta) (alpha - alpha') . C(alpha, alpha') = S(alpha + theta)D(alpha') - D(alpha)S(alpha' + theta) (alpha - alpha') . E(alpha, alpha') = D(alpha)D(alpha' + theta) - D(alpha + theta)D(alpha').

Inventors

• 👤 Claude Aubry
• 👤 Daniel Casseau
• 👤 Joseph Roger
• 👤 Robert Vergnory-Mion

Bibliographic Details