Patent ID: 6515613
Filing Date: 2003-02-04
Classification: G01S

Abstract:
A method for operating a helicopter mounted ROSAR system for detecting objects located in an area to be imaged, vertically below the helicopter, said method comprising:providing a transmitting antenna which is located in a fixed position or near the tip of a rotor blade on said helicopter, and which transmits a signal that is one of a pulse frequency and an FM constant wave signal; providing a receiving antenna for receiving reflections of said transmitted signal, said receiving antenna being situated remote from and rotating about a center of rotation which is fixed relative to said helicopter; and processing received reflections to generate coordinate information defining a range and angular position of said objects; wherein angular coordinate information is determined for a plurality of concentric circular range rings situated in the area to be imaged, each range ring comprising a plurality of pixels situated therein; a proper coordinate-specific doppler signal is generated as a reference signal of each coordinate of a center point of a pixel in the area to be imaged; and only a single said reference signal is determined for each range ring.