Apparatus for combining data produced from multiple radars illuminating a common target area
First Claim
1. An apparatus for combining radar signals from a plurality of radars which illuminate a common target at different PRF, providing multiple samples of a plurality of range bins representing an increment of radial distance to said target comprising:
- first, second and third analog-to-digital converters for respectively converting each radar signal to a digital signal representation;
first, second and third complex discrete Fourier transform filters for respectively receiving the digitized signals, said filters providing from said digitized signals first, second and third groups of velocity range bins, representing substantially the same velocity increment of said common target;
first means for unfolding said second group of velocity range bins to be identical in number to each of said first group of velocity range bins;
second means for unfolding said third group of velocity range bins to be identical in number to each of said first group of velocity range bins; and
,means for combining said first group of velocity range bins with corresponding velocity range bins from said first and second means for unfolding, whereby a single group of velocity range cells are provided.
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Abstract
An apparatus for combining signals from a plurality of radar installations is described. A methodology for combining signals from a pluraltiy of radar installations/sensors has been developed. This methodology provides enhanced target detection performance by properly fusing together the commensurate range-Doppler filter bins of each sensor. In this methodology, the processing of each of the individual radars in the Doppler frequency domain is provided such that a common velocity domain is obtained from each of the radars. Using a zero fill discrete Fourier transform, the velocity domain obtained from each radar is further normalized to have a common bin size. Additionally, for the higher frequency radars, the normalized velocity bins are unfolded so that each radar signal produces the same number of velocity bins in its respective velocity domain. Once the common velocity coordinate has been obtained a vector addition of the resulting velocity bins produces a common radar velocity signal which can be detected and processed. Combining radar signals before detection results in a gain in sensitivity over systems which combine signals after detection.
34 Citations
14 Claims
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1. An apparatus for combining radar signals from a plurality of radars which illuminate a common target at different PRF, providing multiple samples of a plurality of range bins representing an increment of radial distance to said target comprising:
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first, second and third analog-to-digital converters for respectively converting each radar signal to a digital signal representation; first, second and third complex discrete Fourier transform filters for respectively receiving the digitized signals, said filters providing from said digitized signals first, second and third groups of velocity range bins, representing substantially the same velocity increment of said common target; first means for unfolding said second group of velocity range bins to be identical in number to each of said first group of velocity range bins; second means for unfolding said third group of velocity range bins to be identical in number to each of said first group of velocity range bins; and
,means for combining said first group of velocity range bins with corresponding velocity range bins from said first and second means for unfolding, whereby a single group of velocity range cells are provided. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for combining radar signals from two or more radar receivers, having a different PRF and different carrier frequency illuminating a common target comprising:
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means connected to each radar receiver for respectively digitizing a plurality of reflection signal samples of a corresponding plurality of radial range bins; means for deriving from each digitized sample of each of said radial range bins a plurality of respective velocity range bins corresponding to each digitized sample; means for compressing the velocity range bins from the respective radars having the lower PRF and lower frequency to represent an increment of velocity which corresponds to the higher PFR, higher frequency range bins, whereby common velocity corrdinates are obtained for each of said radars; means for unfolding the respective velocity range bins obtained from the higher PRF higher frequency radars to obtain a corresponding number of compressed velocity range bins produced by said lower PRF lower frequency radar; and
,means for combining said unfolded velocity range bins with corresponding compressed velocity range bins from said lower PRF radar. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification