The OxTS xNAV550 GNSS-aided inertial system and Z+F PROFILER® 9012 were mounted on a vehicle roof and connected to each other using a custom interface cable. This provided an accurate 1PPS time stamp and regular NMEA messages in real-time for the Z+F PROFILER® 9012. Once configured, the Z+F system was set to record and the xNAV550 was left to log automatically.
Once the driving tests were complete, the raw data from the xNAV550 INS/GNSS was downloaded and processed using our free post-processing software with OxTS’ own gx/ix navigation algorithms. RINEX correction data was downloaded from the local service and used to achieve 2 cm position accuracy, while forwards/backwards (combined) processing was also used to achieve the best results during GNSS blackout. The output measurements could then be used to fully-georeference the Z+F PROFILER® 9012’s measurement data into an accurate point cloud via Z+F’s post-processing software suite.
As well as providing users with an integration guide, the test also highlights the benefit of a GNSS-aided inertial navigation system for georeferencing. As sections of the real-world route included urban canyons and tunnels, it was important for the xNAV to maintain its outputs during GNSS blackouts, and to resist the effects of multipath, otherwise the LiDAR measurements would be unusable. This is why the GNSS and IMU combination is essential.
While an xNAV550 was used for the purposes of this test, any of our survey systems with real-time output can be integrated with Z+F products, and are already used in several types of land and air-based survey applications where accuracy, reliability and resilience are required. OxTS has also developed a number of technologies to further enhance the coupling of GNSS within an INS system, such as our gx/ix technology, which intelligently utilises deep coupling methods to blend inertial measurements with GNSS updates to produce the most reliable navigation output possible.
For more information on our survey systems, please contact sales@oxts.com.
Details on Z+F LiDAR equipment, including the Z+F PROFILER® 9012, can be found on Z+F’s website.
Data and images courtesy of Z+F
