Advanced STAP for TSI
Modulated Clutter



Daniel J. Rabideau
MIT Lincoln Laboratory
244 Wood Street, Room J-118D
Lexington, MA 02173-9108
tel: (781) 981-2892

Abstract This paper addresses the problem of adaptively canceling both conventional clutter and terrain-scattered jamming (TSJ) in airborne radar systems. Many traditional algorithms for this problem have involved first adapting in space/fast-time to cancel TSJ, then adapting in space/slow-time to cancel conventional clutter. Unfortunately, the rapid updating required to cancel the nonstationary TSJ will modulate the clutter and targets, making the cancellation of conventional clutter extremely difficult and reducing the metric accuracy of the reported target locations. In this paper, we build on the foundation laid in [1] to give detailed descriptions of several novel algorithms for handling modulated clutter and targets. First a multi-stage beamformer is described which prevents the modulated clutter from degrading system performance. Second, a reduced DOF 3 dimensional STAP algorithm is employed to cancel TSJ and clutter together. Third, we compare conventional pre and post-Doppler STAP algorithms and show that pre-Doppler STAP is better suited to modulated clutter, but that a modified post-Doppler STAP algorithm employing detached bins can also perform well. Finally, we propose a multidimensional sidelobe target editing algorithm which can be used to find the correct target location from many modulated target echoes. In each case, a formulation of the processor is presented and its properties are described. Examples showing the application of these proposed structures to site-specific simulated data sets are used to illustrate their performance.

[1] D. Rabideau, "Signal Modulation in Pulse-By-Pulse Adaptive Nulling Systems," Proc. Adaptive Sensor Array Proc. Workshop, 1997.



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