Radar system for detecting slowly moving targets

Abstract

A bistatic radar system for detecting the presence of a slowly moving target by the use of an arrangement which provides a reduction in the frequency spread of the reflected clutter energy. A radar transmitter and a radar receiver are located aboard separate aircraft which fly with a predetermined speed and direction about the target area. The speed and direction of the two aircraft are such that the angular velocities of the aircraft about the target area are substantially equal and opposite. This arrangement reduces the spread of the reflected clutter energy caused by motion of the radar transmitter and receiver relative to the target area. The radar return signals are filtered and processed to determine when a signal is present which has been shifted in frequency due to the motion of the moving target. In one embodiment, the two aircraft fly directly toward each other at the same speed. In another embodiment, the two aircraft fly directly away from each other at the same speed. Apparatus is included which determines the position of the moving target both with respect to the two aircraft and with respect to the ground.

Dependencies are inferred from the claim text.