Accession Number : ADA117161

Title :   Active Imaging of Range Targets at 1.2 Millimeters.

Descriptive Note : Conference paper,


Personal Author(s) : Johnson,John Lamar ; Herren,Kenneth A ; Morgan,Robert L ; Tanton,George A

PDF Url : ADA117161

Report Date : 18 Jun 1982

Pagination or Media Count : 9

Abstract : Several years ago investigators showed that for detection and tracking of 'obscured' targets at ranges up to 3 km, submillimeter wavelengths in the atmospheric windows between 0.74 - 1.3 mm offer great potential advantages over wavelengths in both the optical and in the microwave regions. At submillimeter wavelengths a significant reduction over the conventional microwave antenna size needed for a given resolution can be realized. Submillimeter waves also penetrate fogs and aerosols much more effectively than do the shorter optical and IR wavelengths. We have demonstrated active target imaging through the atmosphere with a submillimeter wave laser operated at a wavelength of 1.2 mm. Copper corner cube targets were imaged over a maximum atmospheric path of 650 meters (two-way) using an 0.3 meter antenna. The system used in that demonstration has a CO2 pumped SMMW gas laser which is passed through a beam expander to a 0.3 meter diameter f/5 primary mirror and then to a computer controlled two-axis scan mirror which directs the beam down a target range adjacent to the laboratory building. The return beam is collected through the same optics and sent by a beamsplitter to the detector, and the signal is sent to the computer from a lock-in amplifier. The targets consisted of a trio of copper corner cubes at 100 meters from the primary, and a single copper corner cube at 325 meters.

Descriptors :   *Radar targets, Images, Submillimeter waves, Lasers, Scanning, Obscuration, Weather, Visibility

Subject Categories : Active & Passive Radar Detection & Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE