GB1294851A - - Google Patents

Abstract

1294851 Pulse radar NORTH AMERICAN ROCKWELL CORP 2 Oct 1967 44812/67 Heading H4D In a low-flying aircraft, the effective field of view of the terrain-following radar, of the type described in Specification 1,118,961, is restricted during turning of the aircraft so as to view only the terrain in the predicted curved flight path. The craft is navigated in azimuth so as to fly between terrain prominences to prevent detection by "flying-up" over obstacles. The craft, 12, turns along the flight path, 15, by turning the bore sight axis, 16, in azimuth towards, 15, so as to. make an angle, 7, with the craft axis. The angle, 7, is a function of the craft forward velocity and the bank angle. Additionally, the antenna range is restricted, or range gated, to the valve R1, as a function of 7, to prevent upwards pitching of the craft in response to obstacles, 13, not in the predicted flight path. Signals from the vertical gyro (or turn indicator), 25, control the antenna, 20, in azimuth and the range gate, 23, the range gate limit decreasing with craft turning rate. In the range gating signal generator, Fig. 7, the aircraft forward speed, U; the bank angle, #, and the angle, #, are applied to the signal function generator 37 and the multiplier, 38 to produce the gating range R1. To the latter, as the signal combining means 40, is added a safety term, #R, to allow for variations in the predicted flight path due to craft side slip. The output from 40 is applied to the gate, 23, through the pulse position modulator, 41.