Accession Number : ADD017360

Title :   Apparent Size Passive Range Method.

Descriptive Note : Patent Filed 15 Jul 93, patented 13 Dec 94,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Harriman, Walter L

Report Date : 13 Dec 1994

Pagination or Media Count : 8

Abstract : 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 or a slower moving vehicle. Calculation of the desired range is achieved using the formula: Range = (S/S')V(Cos a)(Cos b) where S=apparent target size; S' =rate of change of apparent size; V=ground velocity; a= azimuth angle from aircraft heading to target; and b= elevation angle from the aircraft heading to the target. The apparatus consists of an automatic video tracker, a video camera, and a servo controlled aiming platform. The video tracker provides target size data. Resolvers on the aiming platform are utilized to determine the azimuth and elevation angles from the aircraft axis to the target. The azimuth angle is added to the aircraft drift angle to determine the total azimuth angle from the aircraft heading to the target. The drift angle and ground velocity are obtained from the aircraft inertial system. (AN)

Descriptors :   *RANGE FINDING, *PATENTS, VELOCITY, ANGLES, TARGET ACQUISITION, MOTION, PASSIVE SYSTEMS, DRIFT, CAMERAS, AIRCRAFT EQUIPMENT, CALIBRATION, AIMING, INERTIAL SYSTEMS, ELEVATION, RANGE(DISTANCE), VIDEO SIGNALS, AZIMUTH, SURFACE TARGETS, TARGET POSITION INDICATORS, SERVOMECHANISMS, VIDEO RECORDING, AUTOMATIC TRACKING

Subject Categories : Target Direction, Range and Position Finding

Distribution Statement : APPROVED FOR PUBLIC RELEASE