Dual Beam Single Axis Tracking Antenna for Tracking Telemetry Instrumented Airborne Vehicles

Abstract

A dual-beam, single-axis, tracking antenna capable of receiving and tracking telemetry data from an instrumented airborne vehicle is described. The dual-beam, single-axis, tracking antenna system consists of both a high-gain and a low-gain antenna positioned by the same antenna pedestal/servo electronics. Automatic switching between the high-gain and the low-gain antennas, based on received signal strength, permits tracking from maximum range (using the high-gain antenna) to close-in nearly overhead passes (using the low-gain antenna) by exploiting the wide-beam characteristics of the low-gain antenna when space losses are at a minimum. The wide beamwidth of the low-gain antenna permits its use as an acquisition aid for the high-gain antenna during initial acquisition, while its wide beamwidth also precludes locking on to a side lobe. The use of only one tracking axis rather than two reduces cost and improves reliability.