Cloud recognition system watching over Pentagon.

• Jurisdiction: United States
• Date: 01 July 2004
• Author: Pappalardo, Joe

A laser system designed to identify and track chemical or biological attacks on the Pentagon is providing a glimpse into the future of long-range threat detection equipment.

Perched on top of a raised elevator shaft on the roof of the Pentagon's Navy annex, one kilometer from the main building, a pencil-thin laser beam constantly sweeps the air. The light waves bounce off particles, which arc analyzed based on changes in the frequency of the returning waves.

The light detection and ranging (LIDAR) system, called "Wind-Tracer," was developed by CLR Photonics. It is used internationally in airports and atmospheric research laboratories.

Across the highway, CLR technicians ensconced in a hotel room near the Pentagon examine real-time displays of wind direction and speed. Another monitor displays a shimmering white mist--the usual pattern of background dust, pollution and water normally found in the D.C. air. The goal is to create computer models in determine the direction a toxic plume could drift if released near the Defense Department's headquarters.

LIDAR is one...