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FOURTH ANNUAL
ASAP '96 WORKSHOP

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Signal Subspace Issues in
TSI Mitigation

Robert A. Gabel
MIT Lincoln Laboratory
244 Wood Street
Lexington, MA 02173-9108
tel: (617) 981-1035
email: gabel@ll.mit.edu

Abstract Terrain-Scattered Interference (TSI) cancellation architectures have been shown to be effective in mitigating the effects of TSI from both ground-based and airborne jammers. Techniques have been devised for weight training in the presence of monostatic clutter. The approach has been extended to both beam-space and element-space TSI mitigation as preprocessing for subsequent clutter-nulling STAP algorithms. However, the computation cost of TSI mitigation can be high, especially in the presence of the large delay and Doppler dispersions often associated with aircraft-based jammers. This presentation develops approaches to minimizing the cost of TSI mitigation weight training. Algorithm modifications, weight pruning, and trade-offs in the Doppler tracking of weights across a CPI is related to the associated cancellation performance. A portrait of TSI power is displayed as a function of delay, azimuth, Doppler, and time; this is used to motivate the selection of mitigation weights to be implemented. Resulting performance is displayed in terms of the residual jammer power, system SINR, and net array patterns using field data collected under the Mountaintop Program.

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