Lidar Technique & Specification
Technique
Lidar (laserscanning) systems operate on a similar principal to radar. A laser ranger in the aircraft transmits a series of laser pulses, each of which is returned from the ground in the path of the laser. Along with the ground, targets may include vegetation or man-made structures. Precise target elevation and horizontal co-ordinates are obtained by combining:
- Aircraft to target range, from the laser ranger
- Scanner look angle
- Aircraft x,y,z positions, from differential GPS measurements
- Aircraft roll, pitch and yaw orientation, from the Inertial Navigation System
Specification
- at 850 metres altitude provides a ground density point of 1 metre, a swath of 600 metres and a typical height accuracy of +/- 15 cm (1 sigma)
- Can operate day or night (subject to safety considerations) and in weather that would preclude the acquisition of traditional aerial photography
- Is ideal for acquiring data over extensive areas including block and linear features
- Provides simultaneous first and last-pulse capability giving ranges to trees and the ground in a single pass
- Is relatively compact and capable of flying on both fixed-wing and helicopter platforms