Moving target imaging synthetic aperture radar

US5122803A · kind A · utility

Assignee

• The United States of America as represented by the Secretary of the Army · US

Inventors

• Barry L. Stann · Silver Spring, US
• Peter Alexander · Winter Garden, US

Key dates

• Filing date: Nov 6, 1991
• Grant date: Jun 16, 1992
• Expiry date: Nov 6, 2011

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S13/9029
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and apparatus of imaging moving targets with an aircraft mounted complex radar system has a plurality of independent, but synchronized synthetic aperture radars (SARs) positioned on the aircraft at equal separation distance .DELTA.x along the flight velocity vector V.sub.p of the aircraft. Frequency modulated (or otherwise coded) pulses are transmitted therefrom with an interpulse period T.sub.p, where 1/T.sub.p is an integral multiple of V.sub.p /.DELTA.x. The pulse repetition frequency, platform velocity, and spacing between adjacent SARs are all chosen to create the effect of a stationary radar momentarily fixed in space. A two dimensional complex IF (intermediate frequency) output signal is recovered by the first SAR on the aircraft. This signal is identical to that recovered by a conventional SAR. The two dimensions are fast time and downtract position. If only one point target is present, the IF output signal is the point target's phase history. Typically, many point targets are simultaneously present, and the IF output signal is the sum of point target phase histories. Each additional SAR on the platform recovers a different two dimensional complex IF output signal.…