Communications: directive radio wave systems and devices (e.g. – Synthetic aperture radar
Patent
1999-09-07
2000-12-26
Sotomayor, John B.
Communications: directive radio wave systems and devices (e.g.,
Synthetic aperture radar
342 99, 342152, 342159, 342192, 342194, 342196, G01S 7292, G01S 1390
Patent
active
061666785
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. The operation is allowed principally because of over-sampling; the FOPEN III A/D rate of 500 MHz exceeds the receiver bandwidth of 200 MHz by more than a factor of 2.
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Auton William G.
Sotomayor John B.
The United States of America as represented by the Secretary of
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