Bistatiske radarmålinger av helikopter

Abstract

A civilian helicopter was used for measurements with our bistatic CW radar. The flashes of the helicopter rotor blades as well as the helicopter body were detected. Detection of the helicopter body depended on the level of clutter interference whereas the flashes had a speed relative to the body and consequently stood out from the stationary clutter or direct signal. Dependent on geometry (bistatic angle and helicopter orientation) and distance, blade flashes of the main rotor and tail rotor were detected with different characteristics (speed and interval) that matched the specifications. Differences in RCS levels were found from energy returned from the front side and backside of the main rotor. Similar results were obtained from RCS calculations based on a model of a helicopter rotor made in a CAD program. This report does not cover measurements for all possible geometries and parameter setting but it shows the potential for detection and possible identification by a bi- or multi-static CW radar.