CHARLESTON, W.Va. -- If Charleston residents get up early for the next week or so, they might catch a glimpse of a funny-looking truck driving up and down their street, with all kinds of high-tech cameras and other gear mounted on the back.
It's not the CIA or Homeland Security, spying on their neighborhoods. And it's not Google, gathering more images for its controversial Street View website.
The light blue Chevrolet Suburban, covered with graphics, is called a mobile LiDAR vehicle.
Like many other cities, Charleston is under federal and state mandates to map its storm sewers, city storm water manager Tom Elkins said.
But rather than map just the sewers, city leaders decided to map the entire city with LiDAR (Light Detection and Ranging) technology. Though a bit more expensive than the traditional GPS mapping the city first planned to use, LiDAR is many times faster and more accurate.
A consulting firm, Michael Baker Jr. Inc., is using the vehicle to help map the city's storm sewer system.
"We're going to create a full three-dimensional model of the city," said Aaron Morris, a vice president with Baker.
"We will create a system very similar to what Google does with its images, but we take it a step farther with LiDAR," Morris said during a demonstration of the LiDAR truck Wednesday afternoon.
Project Manager Scott Howell pointed out the various instruments mounted on the roof of the truck, starting with twin lasers at the rear corners -- the heart of the system. By aiming a laser beam at a spinning mirror, each unit can capture 200,000 points of information about the surrounding area, up to 200 meters away, every second.
Beside the lasers are two 5 megapixel digital cameras that can shoot pictures at up to three frames per second.
"On top is one of the GPS [global positioning system] units," Howell said. A second GPS unit -- a flattened dome about six inches in diameter -- was mounted on the roof above the driver's seat.
A distance measuring unit attached to the left rear wheel and an inertial measuring unit (IMU) round out the instrumentation. "The IMU measures pitch, roll and yaw," he said, especially handy on rough roads or when the entire instrument deck is removed and mounted on a boat or ATV.
Engineers have used LiDAR for a number of years, most often to map topography from airplanes. "This on-the-ground application is a new technology," Howell said. "This has only been out for two-plus years."