Helicopter-Mounted Laser Beam Characterization Test 2.

Abstract

The effectiveness of a laser designator is dependent on the intensity and size of the beam placed on a target. This report describes a laser beam spread and wander test conducted at Holloman Air Force Base on August 18, 1994, by the Army Research Laboratory. To assess the performance of a helicopter-mounted laser, the beam was characterized by viewing and analyzing the diffuse reflections from a target board. The results are compared to a similar test conducted on June 7, 1994. Measurements were made to determine the impact of the platform (on which the laser designator was mounted) and environment on beam characteristics for a helicopter-mounted mid-infrared (IR) laser. A large reflective surface (2.44 by 2.44 m) target board was used to determine beam size and intensity. The board contained a hot blackbody (IR) source to guide the laser tracking system in directing the laser beam to its surface. The 30-Hz-frame- rate, mid-IR imager was used to characterize the diffuse reflections of the 1 OO-kHz, repetively pulsed, mid-IR laser beam. Data were recorded for the helicopter engine on/off, different hovering altitudes, and different ranges from the helicopter to the stationary reflective target board. When the helicopter was on the ground at 500-m range and with strong optical turbulence, there was some decrease in the beam spreading when the helicopter rotor was on, compared to when the rotor was off. When the helicopter was hovering and rotated so the exhaust and laser were pointed toward the target board, there was a bimodal beam geometry formed that changed shape with range and, presumably, is related to the air compression changes caused by the rotor downwash and refractive index changes in the exhaust plume.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1996
Accession Number
ADA304787

Entities

People

  • Daniel R. Billingsley
  • Fernando R. Palacios
  • Samuel B. Crow
  • Wendell R. Watkins

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force
  • Air Force Facilities
  • Diffuse Reflection
  • Environment
  • Exhaust Plumes
  • Geometry
  • Helicopter Engines
  • Helicopter Rotors
  • Hot Spots
  • Hovering
  • Intensity
  • Laser Beams
  • Laser Target Designators
  • Laser Tracking
  • Line Of Sight
  • Measurement
  • Military Research

Fields of Study

  • Physics

Readers

  • Aerospace Engineering
  • Optical Physics and Photonics.
  • Pulsed Power and Plasma Physics.

Technology Areas

  • Directed Energy