US 4,107,678 A · Polarization correlation target seeker

Abstract

A target seeker circuit contained in a projectile having a trajectory guidance mechanism cross-correlates returns of a cross-polarized antenna pattern to distinguish between target returns reflected by man-made targets and clutter returns reflected by naturally occurring articles to cause the trajectory guidance mechanism to direct the projectile towards the target. One coordinate of diversity in the cross-polarized returns is achieved by changing the RF frequency of the antenna pattern while a second coordinate of diversity is achieved by changing the aspect range of the clutter. The target returns are distinguished from the clutter returns either by comparison to a threshold value which is set in relation to the worst case clutter level or, alternatively, by comparison to an adaptive threshold which is responsive to the dynamic clutter level.

Claims19

Dependent claims

A seeker circuit comprising:

means for generating an illumination signal;
means for mixing first and second polarized return signals with the illumination signal to provide first and second intermediate frequency signals bounded by a predetermined bandwidth;
means for cross-correlating the first and second intermediate frequency signals of said mixing means to provide a cross-correlation product signal;
and
means for comparing a target threshold level in relation to the cross-correlation product signal of said cross-correlating means to provide a control signal.

2 more elements

A seeker circuit comprising:

means for generating a frequency modulated, continuous wave illumination signal;
means for mixing cross-polarized backscattering return signals with the illumination signal to provide intermediate frequency signals of predetermined bandwidth;
means for multiplying the intermediate frequency signal associated with a return of one polarization with the intermediate frequency signal associated with another return of a second polarization to provide a cross-correlation product signal;
means for integrating the cross-correlation product of said cross-correlating means over the frequency modulation of said illumination signal;
means for comparing the integrated cross-correlation signal of said integrating means with a target threshold level to provide a control signal.

2 more elements

Dependencies are inferred from the claim text.

Polarization correlation target seeker

Life of this patent

Polarization correlation target seeker

Life of this patent

Abstract

Claims19