| 摘要 |
FMCW Radiation of two polarizations (e.g. circular or plane) is transmitted simultaneously. Beacons 3 may be arranged around the area of interest. They each comprise a double cone surrounded by vertical wires 9, so that horizontally polarized radiation is retroreflected whilst vertically polarized radiation is specularly (i.e. more weakly) reflected. The amplitudes of returns of the two polarizations are then compared to determine whether they are from a beacon or not. The transmitted radiation is in the form of a vertical fan beam; the direction of targets may be used to yield vehicle position, or changes in target position may be used to determine vehicle movement. <IMAGE> |
