Doppler radar detection system

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG.
1 illustrates the principal features of the invention.
A doppler radar receiver provides received signal A which is filtered by doppler processor 1 and processed by magnitude detector 2 to provide a doppler filtered unipolar signal B in response to received signal A.
Signal B along with signal C and reference voltage G are supplied as input to block 100.
Block 100 contains thresholding and logic circuitry that: (1) if signal B is due principally to a target, it is gated on to pass as output signal T; but (2) if signal B is dominated by noise and/or clutter, it is gated off and signal T is rejected for not being due to a target.
It is to be recognized that block 100 is continuously responding to signal A via its inputs: signal B, signal C, and reference voltage G.
Thus, for a pulse radar, signal A varies with time corresponding to radar range.
Then, the processing by block 100 is accomplished by making separate thresholding and logic decisions for each radar range cell.
Now described is the method by which the thresholding and logic circuitry, block 100, effects.
Block 100 comprises two thresholders that function in operative association: block 10 is for clutter and is called a clutter thresholder, and block 20 is for noise and is called a noise thresholder.
It is subsequently explained how the logic of block 100 causes blocks 10 and 20 to function in operative association, so as to effectively output target signals yet reject both clutter and noise in a mixed noise/clutter/target environment.
As noted from FIG.
1, signal A is processed via two channels: the one that contains signal B and another, wherein signal A is input to magnitude detector 3 that provides unipolar signal C.
It is to be noted that (1) signal C is proportional to the magnitude of signal A, and (2) signal B is responsive to the magnitude of signal A because it is obtained after being doppler filtered by doppler processor 1.
A doppler processor operates as follows: 1