For the last five years, aerial surveying firm RME Geomatics has championed the development, testing, and application of LiDAR-equipped Unmanned Aerial Systems (UAS) throughout Canada.
According to Curtis Parks, general manager at RME Geomatics, the company’s goal is to fill a niche—deliver cost-effective aerial surveying solutions in small and remote areas. He adds, “These are surveys that have not been done previously because they were perceived as too small, too remote, or too expensive for conventional manned aircraft,” Parks says.
At the heart of the firm’s UAS capabilities is its Renegade™ LiDAR helicopter platform, a tightly integrated and optimized sensor system developed from the ground up to meet the surveying demands of owners in various markets, including agriculture, oil and gas exploration, mining, and forestry.
It was a good plan…with one significant issue. Early in the development of the Renegade™ solution, RME engineers struggled to find a position and attitude measurement system with the right combination of functionality, size, and cost. That all changed when RME’s engineering team shifted from a calibrated magnetometer to NovAtel’s latest small, power-efficient, and lightweight GNSS/Inertial Navigation System (INS) for improved reliability and capabilities at the right price point.
RME engineers tested a number of airframes of varying sizes. In 2012, the firm settled on the helicopter airframe and, over the next two years, focused extensively on operational capabilities, reliability, and flexibility.
Parks recalls, “Our goal in developing Renegade™ is to deliver a system that can gather the right data at the right time for the right cost. A mobile UAS can gather data with very little lead time and without delays common to satellites or manned aircraft.”
In comparison, manned aircraft typically take time to mobilize, and to achieve cost-effectiveness, typically cover large areas during a flight, i.e., hundreds of square kilometres. Similarly, satellite-based imaging systems are expensive due to large base fees, they may not provide the right resolution, and cannot see through clouds.
Parks observes, “In many cases, the owner only wants a small area covered, say a few square kilometres. Ours is a mobile system that is ready at a moment’s notice to map virtually any size area that is needed. It can fly at much lower altitude and at whatever speed; so, data quality is significantly higher than conventional manned systems.”
The Renegade™ has a maximum take-off weight of 35 kilograms and a stabilized sensor gimbal. The Unmanned Aerial Vehicle (UAV) has a one-hour flight time that is expandable to two hours with a modular payload of up to 11 kilograms. Optional professional grade sensors include LiDAR, six-band multispectral (450–1050 nanometres), sub-centimetre georeferenced RGB (red/green/blue) imagery, thermal infrared, and video. The UAV doesn’t need a runway and can take off and land in challenging conditions and locales. Data can be processed in near real-time.
At one time, the Renegade™ relied on a magnetometer compass for heading and positioning, a choice that eventually drove the engineers to seek an alternative solution. “We just had too many problems with errors in the autopilot’s heading reading,” explains Parks.
About a year ago, the firm began an extensive evaluation of available lightweight GNSS/INS solutions. Parks adds, “The NovAtel dual– antenna bearing system provided a perfect heading measurement solution and offered increased reliability, directional control and accuracy to the LiDAR system. It was the most capable system at the right price point.”