Radiometric Measurements of Powerline Cables at 94 GHz

摘要

When pilots are flying at low altitudes, they need a sensor that can help them detect and avoid wires; this need remains a high priority for all U.S. military services. Many different sensors have been considered to fulfill this need. This report presents data that were collected on powerline wires of various diameters with the use of a 94-GHz radiometer. These measurements were conducted at short range in an effort to quantify the wire signatures and to determine if a millimeter-wave radiometer could be used to help pilots avoid wires. Data are presented for seven sizes of wire as well as for the horizon background of each wire. The results show that wires down to 1/4 in. in diameter can probably be detected reliably at ranges up to 200 m with a 94-GHz radiometer that uses a 3-ft antenna, provided that the signature of the horizon background can be characterized during flight. Beyond 200 m, the results show that an image-enhancement algorithm, if proven to be adequate, or a larger antenna will probably be necessary to reliably detect most standard powerline wires.