Bearing intersection deghosting by altitude comparison system and methods

A system for detecting the location of a plurality of targets comprising:

• (a) a first antenna system having first and second planes of receipt which are inclined a fixed angle (.theta..sub.1) from one another, said first antenna system being located along the line of intersection of said first and second planes, said first antenna system including means for sweeping said line of intersection at a known rate of sweep (.tau..sub.1), and means for measuring the instantaneous azimuth angle (A.sub.R1) of said line of intersection;
• (b) a second antenna system spaced apart from said first antenna system a known distance (S), said second antenna system having third and fourth planes of receipt which are inclined a fixed angle (.theta..sub.2) from one another, said second antenna system being located along the line of intersection of said third and fourth planes, said second antenna system including means for sweeping said line of intersection at a known rate of sweep (.tau..sub.2), and means for measuring the instantaneous azimuth angle (A.sub.R2) of said line of intersection;
• (c) means for determining the azimuth angles A.sub.R1N and A.sub.R2N for each of N targets which are within the range of said first and second antenna systems;
• (d) means for measuring the delay T.sub.1R1N between receipt by said first antenna system of signals in said first and then in said second planes which are emitted from each of said N targets and received directly by said first antenna system;
• (e) means for measuring the delay T.sub.1R2N between receipt by said second antenna system of signals in said third and then in said fourth planes which are emitted from each of said N targets and received directly by said second antenna system;
• (f) means for measuring the delay T.sub.2R1N between receipt by said first antenna system of signals in said first and then in said second planes which are emitted from said N targets and received by said first antenna system after being reflected from a remote surface;
• (g) means for measuring the delay T.sub.2R2N between receipt by said second antenna system of signals in said third and then in said fourth planes which are emitted from said N targets and received by said second antenna system after being reflected from a remote surface;
• (h) means for measuring the heights R.sub.1H and R.sub.2H of said first and second antenna systems;
• and
• (i) for calculating, for each of N azimuth angle A.sub.R1N, the elevation (H.sub.1N) of the target associated with that angle in response to .theta..sub.1, .tau..sub.1, T.sub.1R1N, T.sub.2R1N, and R.sub.1H ;
• means for calculating, for each of N azimuth angle A.sub.R2N, the elevation (H.sub.2N) of the target associated with that angle in response to .theta..sub.2, .tau..sub.2, T.sub.1R2N. T.sub.2R2N, and R.sub.2H :
• and means for selecting N of the N.sup.2 possible locations of said targets as real target locations by determining the location of the intersection of lines defined by said azimuth angles A.sub.R1N and A.sub.R2N for which the associated elevations H.sub.1N and H.sub.2N are equal.