X. Sun
NextGen Imaging Technologies (NGIT), Inc,
United States
Keywords: remote sensing, mapping, airborne, instrument, system of systems, gimbal, photogrammetry
Summary:
NextGen Imaging Technologies (NGIT) inc designs and fabricates agile and precise gimballed imaging systems using NGIT’s advanced technologies and innovations in the fields of remote sensing system of systems, high-performance gimbal machine, and advanced photogrammetry. These systems are versatile, deployable on a range of rotary and fixed wing aerial vehicles and Lighter-Than-Air (LTA) aerostat and airship from low to high altitudes. High-resolution and high-precision geospatial information over wide areas can be fast collected and visualized. A specific system solution presented by this paper is a fully integrated gimballed imaging system adapted for a Cessna 182 airplane. The sensor payload of the system consists of two mid-format global-shutter industrial cameras, a Falcon4 86-MegaPixel (MP) CMOS camera with max 16 frames per second (fps), 2.75GB/s data throughput made by Teledyne Dalsa, and a 47MP ON semiconductor KAI−47051 CCD based camera made by SVS-Vistec with upto 7fps throughput, attached with an 80mm lens and a 210mm telephoto respectively. The roll, pitch, and yaw gimbal actuation subsystems agilely and precisely steer the sensor payload to collect high-resolution aerial photos into a mission-planned-tile-grid across a wide imaging swath. Each gimballed photo is precisely directly geo-referenced with real-time metadata that is compatible to Open Geospatial Consortium (OGC) standard. These aerial photos can be directly opened by Google Earth as ground overlay for immediate geospatial visualization. Advanced aerotriangulation algorithms are adaptable to exploit the dual resolution and multi-perspective imaging data of the collection and reveal various terrain, city infrastructure, and plain metric map features. A fast, high-resolution, and wide-swath aerial mapping has been experimented on September 30, 2018 over city of Lawrence, MA. The telephoto/sensor payload was agilely gimbaled in a 7-step Across-Track-Staring (ATS) exposure mode. The percentage side-overlap between two adjacent images within the ATS exposure sequence is 10%. A smaller percentage overlap allows a more efficient mapping area multiplication. The images collected with the ATS mode are presented on the Google Earth desktop. It shows that these images are precisely registered on a mission-planned-tile-grid and seamlessly mosaicked together to have the ground underfly completely covered without data holidays. This result demonstrates that 1) the imaging swathwidth of the 7-step ATS mode by one flypass is generally wider than the combined imaging swathwidth of 7 parallel fixed-Nadir-imaging flypasses because a higher than 10% side-overlap is required by latter; and 2) the photos collected by gimbal-aided ATS exposure mode are registered into mission-planned-tile-grid significantly better than those collected from multiple fixed-Nadir-imaging flypasses without gimbal aids. The demonstrated fast, high resolution and wide area airborne gimballed imaging system is valuable for many other applications. For example, it can be efficiently and effectively used for emergency response, search and rescue, fast change detection, homeland and board security, and environmental monitoring.