| 摘要 |
A method and apparatus provides instantaneous passive range measurement onboard an aircraft for determining the range between the aircraft and a target. The target may either be stationary and on the earth's surface, or a slower moving vehicle. Calculation of the desired range is achieved using the formula: Range=[Sin a/Sin b] V; where "a"=angle from aircraft heading to target, "b"=turning rate; and "V"=ground velocity. The apparatus consists of an automatic video tracker, a video camera, and a servo controlled aiming platform. A resolver on the aiming platform is utilized to determine the angle from the aircraft axis to the target. This angle is added to the aircraft drift angle to determine the total angle from the aircraft heading to the target. The video tracker is utilized to determine the turning rate of the aiming platform. Using the difference in contrast between the target and the background of the video scene, the tracker provides error signals (azimuth and elevation) to keep the aiming platform pointed at the target. The azimuth error signal determines the turning rate of the aiming platform. The total turning rate is determined by adding the aiming platform turning rate to the aircraft turning rate obtained from the aircraft inertial system.
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