초록 ▼

A radar system mounted on a moving vehicle uses a displaced phase center antanna (DPCA) and associated processing for taking the difference between the two signals received by the displaced antennas to provide moving target indication (MTI) by cancellation of the returns from stationary targets. The

A radar system mounted on a moving vehicle uses a displaced phase center antanna (DPCA) and associated processing for taking the difference between the two signals received by the displaced antennas to provide moving target indication (MTI) by cancellation of the returns from stationary targets. The presence of moving targets is identified by threshold processing within discrete frequency bands. DPCA processing ordinarily results in amplitude nulls or “blind speeds”for targets moving at particular radial velocities. According to the invention, the two signals received by the displaced antennas are summed, weighted and divided into frequency bands which extend through the expected null region in a form of Doppler processing. Threshold processing is performed on DPCA processed signals within certain frequency bands outside of the null regions and on Doppler processed signals within other frequency bands, thereby substantially eliminating the blind speeds.

대표청구항 ▼

A method for processing first and second signals, defining at least one wavelength and received at different times by first and second mutually displaced antennas carried on a vehicle movable relative to terrain, said first and second signals together defining a pulse recurrence interval, which sign

A method for processing first and second signals, defining at least one wavelength and received at different times by first and second mutually displaced antennas carried on a vehicle movable relative to terrain, said first and second signals together defining a pulse recurrence interval, which signals include components representing returns from said terrain which are modified by Doppler components resulting from motion of said vehicle, comprising the steps of: multiplying each of said first and second signals by a first weighting signal for reducing frequency sidelobes attributable to the pulsatory return of said first and second signals to produce first and second weighted signals; dividing said first weighted signals into frequency components lying within a plurality of predetermined first frequency bands to produce first spectral band signals; dividing said second weighted signals into frequency components lying within said plurality of predetermined first frequency bands to produce delayed second spectral band signals which are delayed relative to said first spectral band signals; taking the difference between said first spectral band signals and said delayed second spectral band signals to produce MTI signals, in which the effects of said motion of said vehicle on said returns from said terrain are reduced to thereby relatively enhance returns from moving targets, but reducing the effective amplitude of said returns from those of said moving targets having radial velocities within certain limits; summing said first and second signals to produce second sum signals; multiplying said second sum signals by second weighting signals for reducing frequency sidelobes attributable to the pulsatory nature of said first and second signals, thereby producing third weighted signals; and dividing said third weighted signals into frequency components lying within predetermined second frequency bands, at least most of which are higher in frequency than the highest of said predetermined first frequency bands.