RIEGL LMS-Q780 Demonstration in Colorado
In May 2013, a demonstration took place at Black Canyon of the Gunnison National Park and the Red Mountains near Telluride, Colorado, to test and showcase the capabilities of the full-waveform digitizing RIEGL LMS-Q780 airborne laser scanner.
The purpose of this demonstration was to test the maximum range of the laser, to test the performance of the laser on snow and ice fields in mountainous terrain, and to map areas with large changes in elevation to examine the performance of RiMTA, RIEGL’s cutting edge technology for automatic resolution of range ambiguities, with the LMS-Q780. This was made possible through collaboration between two project partners and RIEGL USA .
The configured system of the RIEGL LMS-Q780 and an Applanix POS AV510 was flown in a DeHavilland Twin Otter by two pilots and one operator who utilized the RIEGL acquisition software, RiACQUIRE.
Maximum altitude (MSL) during the demonstration was 23,000 feet and the speed flown during the demonstration was between 130 to 160 knots.
Data acquisition of the Black Canyon of the Gunnison National Park included two passes flown over the canyon to examine the altitude effects on the data captured. The first pass was flown at an average speed of 105 knots at an altitude of 6500 meters MSL (21,000 feet) while the second pass was flown at an average speed of 165 knots at 5000 meters (16,000 feet). The density of the data was 0.5 to 1 point per square meter.
The data acquisition through the Red Mountains included ten passes flown over the area for a combined density of about 2.5 to 5 points per square meter over the 200 square kilometer area flown. Six of the passes were flown north and south at a speed of 130 to 160 knots at an altitude of 6000 to 6500 meters MSL (19,000 to 21,000 feet). Four of the passes were flown east to west at a speed of 140 knots at an altitude of 5000 meters.
Once the scan data was acquired and the crew was back on the ground, the data was processed through the RIEGL processing software suite comprised of RiWORLD, RiPROCESS, and RIANALYZE with the integrated module RiMTA. The post processing of the entire, accumulated data set was accomplished in only two hours by one person.
Over the course of the demonstration, roughly 400 square kilometers of topographic area were scanned with terrain height variations captured between 2400m to 4000m (8000 feet to 13000 feet) with a maximum altitude flown of 23000 feet MSL. Approximately five hundred million data points were collected with the point density on the ground at approximately 0.5 to 1 point per square meter.
The maximum altitude that the LMS-Q780 was operated at was 17000 feet AGL over terrain with no snow. The acquired data at 17000 feet showed both excellent point distribution and excellent signal strength. The coverage of data throughout the mountainous terrain flown was exceptional; exceeding the expectations of those involved with the demonstration, due to the high flight altitudes flown.
The system was able to handle over ten simultaneous pulses in the air, which resulted in excellent ground data coverage, as well as safe flying conditions for the aircraft without the need for terrain following. Parallel scan lines and equally spaced laser footprints provided excellent topographic coverage. Deep canyons, crevices, and other demanding topographic areas were mapped and generated the optimal spatial sampling frequency needed for the demonstration and project at hand.
The detail collected from the Black Canyon proved that the RIEGL LMS-Q780 provides precise data at high altitudes and high collection speeds. The average point density on the ground that was collected during these passes was 0.5 points/square meter at 6500m (21,325 feet) altitude. The excellent dynamic range of the system with regard to intensity proved to be exceptionally useful for snow identification methods.
The test and demonstration of the RIEGL LMS-Q780 Airborne Laser Scanning System in Colorado have shown that the system is capable of accomplishing complex terrain, such as mountains or urban areas, and wide area mapping. The proof is seen that the user is able to accomplish simple and safer flight planning and flying, even for difficult terrain, and can achieve faster project processing with exceptional data quality as the result.