Simulation of Onboard Helicopter Radar Signals for Surface Elevation Measurements

The stage of landing a helicopter on unequipped fields in low visibility or adverse weather conditions is particularly dangerous for pilots and passengers. One of the possible ways to reduce risks is to use additional safe landing systems. Among the variety of such systems the terrain radars that use space-time signal processing and operate effectively in various environmental conditions deserve special attention. An important and relevant task in developing and analyzing these radars is a preliminary assessment of their general performance and accuracy. To solve this problem, simulation models of the surface and reflected signals that are detected by a two-antenna onboard radar are developed. The surface is represented as a two-dimensional random process with a given correlation function of elevation variation. The models of space-time fields after their sum and difference processing in the receiver channels are shown and analyzed in detail. The modeling results are the input data for the approbation of heuristic and optimal algorithms for measuring elevation of the surface selected for a safe landing. The performance and accuracy of the developed model are researched on the example of a three-dimensional surface with a spatially extended obstacle.