High resolution MMW seeker fuse processing

The authors describe a new signal processing technique for phased arrays that can be used in near-field target imaging. This processing technique is useful to millimeter wave seekers employing planar phased arrays as a new approach to performing warhead fusing. The array operation and signal processing are similar to synthetic sampled aperture radar (SSAMAR). Through a coherent integration of all echoes, a two-dimensional information sequence is synthesized. The array pattern is computed as the amplitude spectrum of the information sequence (which is twice the size of the actual array). Thus, the angular resolution is doubled, and the sidelobes are significantly attenuated. A new mathematical model for the round trip delay based on a Taylor series expansion of the phase is also introduced. This model allows correction for the nonlinearity associated with two-array phase. It follows that near field target tracking (with a focused image) is possible through correction for the dominant second-order phase terms. Examples through computer simulation are used to validate and verify the theory.<
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