Analysis of Air-To-Ground Ranging (AGR) Mode on Airborne Multi-mode Fire-Control Radar

Abstract

Air-to-ground ranging (AGR) is one of the crucial functionalities of an Airborne multi-mode fire-control Radar. This mode provides precise bore-sight range measurements from the antenna to the point of intersection of the antenna bore-sight with the ground for weapon delivery. The bore-sight range is estimated by characterizing the sign cross-over point of the elevation monopulse curve. Conventional Range-Doppler processing is employed for signal processing and a range estimation scheme involving multi-level thresholding and cost minimization is proposed for estimating the actual bore-sight range. The performance of the algorithm is evaluated first on simulated data and then on actual radar data collected via an airborne multi-mode fire control radar system. The bore-sight range estimator is fine-tuned using moving average (MA) filtering to obtain a much accurate and more precise range estimate. The measurements are analyzed under stable roll conditions of the platform to determine the operational performance of the algorithm chain. The height of the terrain is measured from the estimated bore-sight range and is validated using the terrain Digital Elevation Model (DEM).