Joseph L Mccray

US Patent:

43896472, Jun 21, 1983

Filed:

Dec 22, 1980

Appl. No.:

6/219455

Inventors:

Michael A. Fanuele - Toms River NJ
Joseph A. McCray - Freehold NJ
Otto F. Rittenbach - Neptune NJ

Assignee:

The United States of America as represented by the Secretary of the Army - Washington DC

International Classification:

G01S 1352
G01S 1300

US Classification:

343 77

Abstract:

Two discriminator circuits are used with Doppler radars to indicate the t of aircraft in the radar beam based on the modulating effect of the aircraft rotor or propeller on the Doppler return signal. The increase in the Doppler signal when a rotor or propeller becomes orthogonal to the incident radar beam causes a spike in the detected Doppler signal. The frequency of such spikes is an indication of the make and model aircraft being observed and the circuitry comprises means for sensing such frequency and operating one of a plurality of indicators if such frequency corresponds to that of a known rotor or propeller frequency of a particular make and model aircraft corresponding to that indicator.