Jen King Jao

US Patent:

61666785, Dec 26, 2000

Filed:

Sep 7, 1999

Appl. No.:

9/389734

Inventors:

Jen King Jao - Wayland MA

Assignee:

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

International Classification:

G01S 7292
G01S 1390

US Classification:

342 25

Abstract:

A signal process is provided for radar interference mitigation in SAR data and to perform several functions. Initially, the algorithm separately removes the average range bias of the I-channel and the Q-channel data. Next, I- and Q-channels are equalized by properly compensating their phase difference and gain imbalance due to either constant or random timing jitters. The current implementation well compensates relative I/Q timing jitters within two sampling time intervals which, for the FOPEN III receiver, are 4 nanoseconds. Graceful performance degradation of the algorithm is expected when timing jitter exceeds two sampling intervals. For example, phase jitter on the order of 5 sampling intervals will be partially but not perfectly corrected. Following the I/Q equalization, adaptive RFI rejection is performed. The FOPEN III data bandwidth may also be reduced 50% with hardly any information loss.