NovAtel's Annual Journal of GNSS Technology Solutions and Innovation

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geomatics 2014 For more Solutions visit velocity 25 a Northrup-Grumman LN-200 IMU. The SPAN receiver is used to automatically and ac- curately correct for crab angle as well as photo- grammetric processing. Kathofer says, "In the old days, the operator would have to adjust for cross winds manually. The SPAN technology provides data to make the drift correction automatically." The modular nature of SPAN products is also invaluable. Having separate GNSS and IMU en- closures, allows the IMU to be mounted at the most suitable location, while the GNSS receiver is mounted where it is most convenient. The customer also uses the SPAN-CPT™ re- ceiver with its large format RC30 film camera in a Cessna C210 to correct for crab angle. SPAN- CPT is a compact, single enclosure GNSS+INS receiver capable of delivering up to centimetre- level accuracy. The IMU components, within the SPAN-CPT, include Micro-Electrome- chanical System (MEMS) accelerometers—a key development in recent years that is helping airborne mapping specialists take advantage of GNSS+INS systems. In fact, MEMS IMU accelerometers and gy- roscopes integrated with GNSS+INS systems are ideal for embedded navigation and mapping applications. Kathofer says, "Not long ago, the possibili- ties of GPS/IMU combinations were much more limited. The MEMS IMUs didn't provide enough accuracy as compared to the bigger high-performance IMUs with fiber optic gyros. That's not really the case anymore. The indus- try has come a long way in the performance of small IMUs over the years. The medium perfor- mance sensors have a great price/performance ratio and work very well in terms of accuracy for a wide range of applications." A MEMS GNSS+INS navigation system can be embedded with a range imaging of sensors without having to spend a huge amount of mon- ey, as they would for comprehensive and more complex systems. "It simply doesn't make sense to put on an ex- pensive system if the customer is only going to use 10% of the capabilities," explains Kathofer. "MEMS technology fit within the modular SPAN solution allows me to match customer needs with the most appropriate system capa- bilities, and to keep the costs reasonable." Suitable Speed Sometimes speed and accuracy of imagery is vital to saving lives, property and the environment. Discovery Air Fire Services (DAFS) is a pre- mier provider of special-mission aircraft working in the field of fire services, in Ontario, Canada, has an Imaging Division that provides low-level infrared services with its Hawkeye Units and high-level infrared with its Eagleye Units. Not long ago, DAFS sought to develop a high- level aerial infrared imaging service that could be operated from a low cost aerial platform. The system would provide accurate thermal and visual imagery, which can be used to effec- tively map and fight wildfires. The camera uses bolometer technology which does not require cooling like other IR cameras. GPS data accom- panies every image for projection onto flat topo- graphic or 3D terrain maps. DAFS selected the NovAtel SPAN-SE and IMU-CPT on its FireMapper sensor to connect with an RGB thermal camera to produce near real-time orthophotogrammetric photos. Kathofer says, "Crews must process the im- agery as quickly as possible. In this case, the challenge was to synchronize the FireMap- per sensors to the GPS/IMU axis. As with any customer, the goal is to find the most suitable GPS/IMU for the purpose, in terms of accu- racy and price." He concludes, "That's the beauty of the No- vAtel family of GPS/IMU products—flexibility. Within their GPS/IMU navigation product line, I can find a solution that fits the lower-end UAV small format cameras to higher end large format systems." NovAtel SPAN-SE with IMU-CPT on FireMapper sensor and RGB camera used for environmental monitoring at Discovery Air Fire Services, Sudbury ON, Canada. " " That's the beauty of the NovAtel family of GPS+INS products— flexibility.

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