Inside Unmanned Systems

JUN-JUL 2019

Inside Unmanned Systems provides actionable business intelligence to decision-makers and influencers operating within the global UAS community. Features include analysis of key technologies, policy/regulatory developments and new product design.

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46   June/July 2019 unmanned systems inside DIRECT GEOREFERENCING Joseph Hutton has been with Applanix—part of the Trimble family—since its inception in 1991 and has more than 25 years of experience in the development and ap- plication of GNSS-aided inertial navigation systems for mobile mapping and positioning. He focused his presen- tation on Direct Georeferencing (DG) on UAVs. Applanix offers a number of OEM products for high-accuracy DG on such unmanned vehicles, including the Applanix APX-15-EI UAV, Applanix APX-18 UAV and Applanix APX-20 UAV. Direct Georeferencing with the systems allows the location of image elements collected by LiDAR and hyperspectral sensors to be accurately computed without extensive networks of ground control points, reducing costs while maintaining accuracy to produce maps. "Our DG solutions are designed to make airborne mapping, whether from a manned or unmanned platform, be completed faster, more eff iciently and with greater accuracy," Hutton said. Hutton explained that Applanix uses data from the position orientation system, along with sensor data, to directly decode each pixel or point on the ground. This can be done without any ground control points. It's important to realize though that DG can be used with any type of imaging sensor but it must be used with scanning-type sensors such as LiDAR and spectral scanners. In terms of necessary components needed for DG, Hutton said that first you need a high-performance, multi-frequency, multi-constellation type of a receiver, to be used in an inertial measurement unit computing orientation, such as that addressed by Wheeler. Again, it's important to select a high-performance low-noise unit antenna, as well as the algorithms needed for post- processing, to blend the data together. "But very importantly you need a GNSS augmenta- tion system to correct the errors down to that posi- tioning that you need to do to direct your efforts," said Hutton, who then elaborated on the benefits of some of Trimble's high-accuracy DG products mentioned previously. Additiona lly, Tr imble's CenterPoint RTK (Rea l T i me e Xt ende d) pr ov ide s h ig h- a c c u r a c y GNS S positioning ser vices via satellite or cellular deliver y worldw ide. It's ideal for jobs requiring the highest accuracy, Hutton stated. "So with this technology we've been able create this high-accuracy position without actually having base stations. It's a cloud-based service and it's global, and all you need is an internet connection, and it's avail- able within minutes after the mission," he said. "The accuracy is typically better than four centimeters RMS horizontal and six centimeters RMS vertical. So we start to talk about beyond visual line of sight. These types of augmentations methods become more and more relevant." Trimble RTX also offers a back-up service that features satellite delivered xFill designed to seamlessly engage if RTK radio or cellular connectivity is lost, allowing longer-duration work with fewer interruptions. Hutton also covered post-processing, noting that it de- livers high accuracy and reliability, and that, with map- ping, users don't typically need real-time results. ONE AND DONE My-Linh Truong discussed RIEGL's high-end product line, explored the benefits of the company's unmanned LiDAR solutions, and offered best-for-the-job analysis of platforms, scanners and cameras. Webinar attendees gained insight into rich-data capture and reference databases for base maps. She addressed a variety of RIEGL UAS LiDAR payloads, including the VUX-SYS (VUX-1UAV/VUX- 1LR), the miniVUX-1UAV and the miniVUX-1DL, which was released in 2017. These systems offer integration with Applanix sensors. RIEGL's UAS platforms include the RiCOPTER (with RiCC)/BathyCopter and the RiCOPTER-M (with RiCC). These models prov ide multi-purpose/multi-sensor benefits, stronger, more powerful engines and impressive f light times that vary with the weight of the payload. A new integrated camera control and time stamp- ing for up to four cameras are now available, Truong said, along with a new mechanical and electrical inter- face for the INS/GNSS integration APX-20 UAV INS/ GNSS system. "What you're looking for is something that provides high data acquisition rates, and you're looking for a one-and-done mindset," she said. "You want to make sure that in your lengthy f light time you have the data storage capacity. You don't want to have a lot of user interaction where you might accidentally not record your data. So with the RIEGL system it's our acquisi- tion software running onboard the sensor. It records the full data stream stored on board the SSD storage on the sensor until you land." The aircraft will then do an auto-shutdown, so users have their full point cloud from start to finish. Hogan capped off the panelists' presentations by explaining how Microdrones integrates the webinar's showcased technologies using its aerospace platforms and expertise and its workf low and software knowledge to create a fully integrated system. In talking about BVLOS, Hogan said: "Everybody WEBINAR RECAP LiDAR AND BVLOS UAVS

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