Test Report on the November 2005 NATO RTG-40 Active Imager Land Field Trials

Abstract : The NATO Research Technology Group 40 (RTG-40) was established in 2003 to develop improved models of active imaging system performance to include the effects of atmospheric optical turbulence. Supporting the development of these models is the performance of naval and land field trials to provide data bases of system performance under varying turbulence conditions. In support of the land trials, the U.S. Army Research Laboratory s (ARL) Computational and Informational Sciences Directorate s Battlefield Environment Division (CISD/BED) provided extensive instrumentation as well as range sponsorship and coordination of the measurement program. This report documents the major accomplishments by the ARL group in preparation for and during the trials. The experiment was conducted at and sponsored by the High Energy Laser Systems Test Facility, located on White Sands Missile Range, NM. The test occurred 7 18 November, 2005. Weather conditions were typical for a southern NM in November; with temperatures ranging between 0-30 C, variable winds, and clear to moderate cloud cover. Data were collected during four lasing periods spanning morning or evening neutral events, with additional passive data collected whenever possible. Data collected by the ARL team included 20 Hz U-V-W wind speed and temperature data from 4 RM Young sonic anemometers mounted at 2.5, 4.5, 6.5, and 8.5 m heights on a mid-range met tower, and 2/3 Hz turbulence (Cn 2) data collected by 4 sets of Lockheed scintillometers set up in pairs (one at 2 m AGL, the other at 4 m) two pairs measuring between 0 and 1 km and another pair between 1 and 2 km. In this report we describe the instrumentation, the test, the data collected, and discuss the initial analysis performed on the meteorological data collected.