In LiDAR (Light Detection And Ranging), a pulsed laser ranging system is mounted in an aircraft equipped with a precise kinematic GPS receiver and an Inertial Navigation System. Accurately timing the laser pulses gives the distance to reflecting features.
The located return pulses create a 3-dimensional "point cloud" consisting of reflections off a variety of features, which are classified into ground and other features. LiDAR ground point coverage in forested areas typically has a patchy distribution, characterised by gaps under large trees.
LiDAR surveys undertaken by mineral exploration companies over rain forested areas in western Tasmania in 2008-12 produced relatively poor DEMs (Digital Elevation Models), characterised by a ground point spacing of much greater than the 2m necessary to reveal high resolution geological features such as bedding traces. However recent advances in LiDAR instrumentation promise improved DEMs in heavily forested areas.
The Luina survey was contracted to AAM, and was flown over a 100 km2 area using a newly released instrument, the Optech Pegasus HD500.
- Demonstrate the practicality of obtaining a high quality LiDAR DEM in heavily forested areas by using newly available technology.
- Efficiently create a geological map in an area difficult to access by using geological features identified from the LiDAR.
- Evaluate LiDAR survey specifications to optimise the canopy penetration of LiDAR pulses and maximise the proportion of pulses returned from the ground.
An acquisition and processing report and the digital data will be made available in late 2014.