AAMHatch Pty Limited, Australia
This article discusses Airborne Laser Scanning technology in context of its application in electricity transmission line survey. The results of such a survey helps to determine the maximum safe loading for each line, allowing each line to run at capacity without endangering the integrity of a network
Airborne Laser Scanning is a remote sensing technology, which allows closely spaced co-ordinates of ground and non-ground points to be obtained from a fixed or rotary wing aircraft. A highly detailed definition of the ground, together with features on or above it can be gathered.
A series of discrete laser light points is directed towards the ground approximately at right angles to the aircraft’s line of flight. The time taken for each reflected light point to return to the aircraft is accurately measured. From this, the distance can be calculated.
The attitude (dislevelment) and velocity of the aircraft are measured using an Inertial Measurement Unit (IMU). The position of the aircraft is computed using GPS instruments placed on the ground and in the aircraft. Using data from all three sources, the absolute position of each laser point can be computed to accuracies as high as 0.1 metre. The system configuration is depicted in Figure 1.
Fig 1 System configuration