The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 24, 1996
Filed:
Nov. 27, 1981
John A Didomizio, Norwalk, CT (US);
Northrop Grumman Corporation, Los Angeles, CA (US);
Abstract
An AMTI radar employs a dual cancellation format to cancel the clutter in the radar returns received by the apertures of an interferometric radar antenna. Angle information generated on a first pass through the cancellation unit and the detection processor is recalculated in a second pass. Only those range doppler cells identified during the first pass as containing moving targets are used in the second angle calculation thereby enhancing the accuracy of this second angle measurement. This three-aperture system derives four data sets, L(t), C(t-.tau.), C(t) and R(T-.tau.) which represent samples taken over multiple pulse repetition intervals for each range interval or bin of interest. Fast Fourier transforms change the data sets into the frequency domain and phase compensations for the data sets are calculated in a triple interferometric signal calibration unit. Compensation phase is further adjusted in the maximized/minimized phase calculator allowing a much reduced phase quantity to be applied to the delayed data sets. Following subtraction of doppler filter outputs of the delayed data sets from the undelayed data sets in the cancellation unit, maximum clutter cancellation is achieved in the clutter region and optimal moving target response is obtained in the clutter-free region. The two-range maps-that result after subtraction of the doppler filter outputs are presented to a detection and validation processor to determine range, doppler, amplitude and angle measurements to the moving targets.