RADAR DOPPLER FOR THE DETECTION AND LOCATION OF HELICOPTERS.

摘要

P This Doppler radar for detecting and locating helicopters using blade flashes operates in a band between 300 MHz and 20 GHz and identifies blade flashes by the width of their frequency spectrum and their duration. In reception, it uses a multi-lobe antenna associated with several parallel signal processing chains specialized in the detection of helicopters allowing detection over a wider area and precise location. Each chain includes a DAP phase amplitude detector (10, 10 ') followed by a VCM Doppler filter (20, 20') selecting broad frequency spectrum echoes, a module calculation circuit (30, 30 ') , a contrast circuit (40, 40 ') eliminating excessively long echoes, a threshold circuit (50, 50') and a false alarm reduction circuit RFA (60, 60 ') eliminating the too short echoes. The chains lead to a field calculation circuit (100) carrying out deviations when possible. /P