Accession Number:

AD0911216

Title:

An Active Optical Ground Sensor for a Parachute Retrorocket Airdrop System (Prads),

Descriptive Note:

Corporate Author:

HARRY DIAMOND LABS ADELPHI MD

Report Date:

1973-02-01

Pagination or Media Count:

45.0

Abstract:

An active optical ground sensor for a Parachute Retrorocket Airdrop System PRADS was evaluated. The sensor yields a fire pulse for retrorocket initiation when the sensor attached to a dropload platform is at a predetermined distance above the ground. The senor employs triangulation and geometric ranging with a gallium arsenide laser. A fire pulse is produced when the ground surface enters a well defined detection region of small spatial extent located at the desired function range from the sensor. Drop tests of a sensor unit with a 6-in. transmitter-to-receiver lens separation showed that the sensor functioned within or - 1 ft of the preset function height of 28 ft over a variety of ground surfaces including light dirt, sod, green shrub leaves, and sod covered with a light smoke screen. The accuracy with which the sensor indicates the function height to a point on the ground surface can be further improved by increasing the transmitter-to-receiver lens separation. Laboratory range-response measurements showed that a sensor with a 15-in. lens separation is capable of indicating a function height of 28 ft within or - 12 ft for any target whose reflectance at 0.9 micrometer is between rho 0.05 and rho 0.8

Subject Categories:

  • Military Operations, Strategy and Tactics
  • Optics
  • Rocket Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE