USA As Represented by Secretary of the Navy

The United States of America As Represented by the Government of the

Clifford L Temes

William M Waters

George J Linde

John A Pavco

A radar system for generating a three-dimensional image includes a radar transmitter which is operable to produce a radar signal of a frequency of at least three gigahertz. A plurality of radar receiving antennas from an antenna array. The antenna array is aerially translatable. For example, in one embodiment, the antenna array is disposed along the wings of an aircraft which, in operation, flies over the intended target area. A three-dimensional image is generated from a reflected radar signal returned from the surface of an object in response to the transmitted radar signal. The radar system may be incorporated into an aircraft and adapted to detect subsurface objects such as mines buried beneath the surface of the ground as the aircraft traverses over a target area.

Three-dimensional synthetic aperture radar for mine detection and other uses

A method to enhance target detectability on a radar plan position indicator s described which includes the receiving of coherent pulse-burst waveforms from a target so that at least one complete burst is included in each dwell of a scanning surveillance fan beam. A fast fourier transform is performed on each returned coherent burst to form Doppler channels in predetermined range cells. The largest signal of the Doppler channels in each range cell is then selected and color coded. The color coded signals are applied to a plan position indicator whereby target images are viewable. Preferably, the Doppler channels are color coded over a rainbow spectrum so that a white background is produced and target images appear as tracks on a microprocessor-based raster-type plan position indicator. A continuity test and threshold test are also utilized so that target velocity and position are determined.

Color-coded radar plan position indicator

This invention reduces the weight and bulk of shipboard-mounted microwave antenna systems by achieving horizontally and vertically polarized radar return signals without the need for a rotary joint.

Two-beam scanning antenna requiring no rotary joints

An improved transmission line or waveguide that can tolerate damage from ordnance fragments without severe degradation of performance. Ordnance fragment penetration into a waveguide tends to produce jagged inward protrusions or loose metal chips of the type which can cause arc-over and high standing wave ratios. The present invention provides a transmission line or waveguide made of a brittle nonconductive material such as plastic or composite material which is coated on the surfaces bordering the interior volume with a solder, conductive paint, or other conductive material. Thus, any penetration of the waveguide will leave a clean hole without jagged protrusions which could precipitate arcing and degrade the waveguide VSWR. An alternative embodiment comprises the construction of the waveguide walls from a brittle conductive material which would leave a clean hole after penetration.

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Alexandria, VA, United States of America

Clifford L Temes