The ALS Technology

Airborne laser scanning is achieved by measuring the time delay between the transmission of a laser pulse and the return reflection signal from the object scanned. 

The position of the aircraft is referenced by using integrated GPS-INS technology. The equipment will detect multiple returns from each emitted pulse allowing it to record the top of vegetation canopy as well as the ground surface below the vegetation.

During post processing Surtech can remove all laser strikes returned from vegetation and to retain points from the true ground surface. This true ground data is then used to produce Digital Terrain Models (DTM).

Combined with the ALS technology is a medium-format digital camera. This allows Surtech to utilize the LiDAR derived DTM to automatically create ortho-rectified imagery of the survey site.