LL Logo



An Overview of Issues In
Hot Clutter Mitigation

Thomas W. Miller and Janet M. Ortiz
Hughes Aircraft Company
P.O. Box 902
MS E1/J132
El Segundo, CA 90245
tel: (310) 616-8247
fax: (310) 355-6387
email: jortiz2@msmail2.hac.com

Abstract Because multipath jamming, or "hot clutter," consists of the coherent sum of weighted, time-delayed, Doppler-shifted versions of a common jammer waveform, mitigation techniques seek to exploit the commonality between the direct path waveform and the scattered signals. This is often done by obtaining a clean sample of the direct path jammer, then weighting it, through tapped delay lines and Doppler frequency weights, to cancel the scattered component. Other approaches exploit the commonality between separate areas on the ground to cancel the interference. In active radars, however, ground or "cold" clutter and target returns are also present, and the processing used to mitigate hot clutter can adversely affect standard STAP and radar signal processing. The five presentations in this session discuss issues in hot clutter mitigation, approaches to cancelling hot clutter including beam space, element space, and multiple linear constraint, and preliminary results in the simultaneous mitigation of hot clutter and ground clutter. In this overview, a brief discussion of the phenomenology of hot clutter is presented to motivate the development of alternate mitigation algorithms. Specific issues particular to the various mitigation approaches are presented, including general limitations on performance and the special requirements for simultaneous hot and cold clutter mitigation. Example performance using simulated data and selected Mountaintop samples is also shown. This presentation intends to summarize major work performed to date, introduce the subsequent current papers, and suggest areas that still remain to be studied.



LL Logo Disclaimer

Direct comments and questions to: webmaster@ll.mit.edu

MIT Lincoln Laboratory. All rights reserved.