NovAtel’s OEM617D GNSS receiver card delivers a high-accuracy GNSS positioning and ALIGN® heading solution in real-time, and offers a high-level of performance and reliability in a lightweight, compact, and low-power package. The GNSS card uses a selectable combination of GPS, GLONASS and Beidou to maximize solution accuracy and availability, even in difficult operating environments. The ALIGN heading firmware generates a precise carrier phase positioning solution between two fixed antennas to generate a very accurate heading/pitch solution. RME integrates the OEM617D directly into the Renegade™ autopilot electronics package, replacing the magnetometer and eliminating the previous issues with heading and positioning stability.
RME Geomatics next developed a custom survey payload that includes a NovAtel Synchronized Position Attitude Navigation (SPAN®) GNSS/INS system, which delivers enhanced positioning performance and advanced processing capability. The custom integration consists of the high-end OEM638 GNSS/SPAN receiver for primary positioning and IMU data processing, the OEM615 GNSS receiver for ALIGN heading, and the KVH1750 IMU for high-rate aircraft attitude.
The OEM638/OEM615 dual-board, dual-antenna GNSS receiver pair delivers ALIGN heading, which is important for both autopilot operations and aided alignment of the SPAN INS solution.
“Align gives us heading using dual antennas,” says Parks. “It eliminates issues with having to change magnetic declination in different parts of Canada, interference from ferrous materials on the aircraft, and external environmental factors. Ultimately, it is more reliable than basing everything on a magnetic compass.”
The tightly–coupled OEM638/KVH1750 GNSS/IMU SPAN solution provides a survey payload and sensor package with the high-rate position and attitude information that is needed for direct geo-referencing and high-precision survey data collection. The OEM638/OEM615/KVH1750 components are directly integrated into the custom Renegade™ UAS payload that is optimized for long-duration UAS operations.
RME Geomatics also coupled its LiDAR sensor to the Renegade™ UAS autopilot and used the OEM638/OEM615/KVH1750 for processing. The combined system can gather LiDAR data to an absolute accuracy of 5-15 centimetres with several hundred points per square metre. The system also incorporates integrated direct geo-referencing for simultaneous LiDAR and sub-centimetre resolution imagery without the need to use ground targets or by using fewer targets than other GNSS/INS solutions.
“We use the OEM617D if we are only dealing with autopilot functions and the 638/615 option when we need processing power,” adds Parks.
RME Geomatics also use NovAtel’s Waypoint® Inertial Explorer® software to post-process the collected UAS SPAN survey data. By using Inertial Explorer as part of their survey workflow, the RME Geomatics team has an optimized post-processed position solution with the best possible accuracy for any survey location (using a local base station, CORS network or Precise Point Positioning (PPP)) and with complete quality control of the final combined GNSS/INS trajectory.
Parks points to three benefits of the NovAtel receivers. He says, “First, the NovAtel receivers are reliable. It’s a more robust aircraft-like system. I can take the GPS system anywhere as compared to the magnetometer which had to be calibrated. A second benefit is the precision of the system and third is customer service. This is not plug and play technology. Technical support is critical and NovAtel is the best in terms of support.”
To-date, the Renegade™ UAS has been used on an extensive range of projects from mapping oil fields to LiDAR forest surveys to variable rate application crop mapping to thermal IR mapping and 6-band spectral imaging mine aggregate pits and tailing ponds.
RME Geomatics is the first company to receive Health Canada and Transport Canada for airborne laser payloads in Ontario. Today, RME Geomatics has an unspecified-location Special Flight Operations Certificate (SFOC) issued by Transport Canada for all regions in Canada.