An Autonomous GNSS/MEMS-Based INS Integrated System for Unmanned Mapping Operations

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The evolution of small unmanned surface vehicles (USVs) and unmanned aerial vehicles (UAVs) in recent years has opened the door for the development of low-cost systems that can be used for many critical applications. These include seafloor and topographic mapping, disaster monitoring, search and rescue, public safety, precision agriculture, open-pit mining, road inspection, and others. The use of USVs and UAVs in these critical applications, however, often requires continuous high accuracy positioning and attitude information. Unfortunately, existing positioning and attitude systems are either very expensive and bulky or very inaccurate. The former system types, which typically integrate differential global positioning system (GPS) and high-end inertial sensors, cannot be used on small unmanned mapping systems due to their weight and cost. The latter types, on the other hand, often rely on low-cost GPS systems, which cannot provide accurate positioning and attitude information and are susceptible to signal blockage and interference, especially in urban areas. To overcome the above limitations, a low-cost autonomous positioning and orientation system will be developed in this research. The proposed system integrates multi-constellation global navigation satellite systems (GNSS) and emerging micro-electro-mechanical system (MEMS)-based inertial sensors. Although autonomous, the proposed system will be built on the concept of precise point positioning (PPP) currently being developed by the applicant’s research group, which provides accuracy level comparable to that of complex differential real-time kinematic technique (i.e., centimetre to decimeter level). In addition, the proposed system will be developed using tightly coupled mechanization, which is carried out in the raw measurements domain. As such, the GNSS signal can still be used even if the number of satellites drops to below four, which is not the case with GPS-alone system. Moreover, MEMS sensors are relatively environment independent, small, inexpensive, light, and consume very low power. This means that the proposed system, in addition to meeting the required accuracy, reliability and availability, will be inexpensive, small and flexible. As such, it offers significant advantages over existing systems. The technological outcome of the proposed research project includes algorithms and estimation methodologies for an autonomous, low-cost integrated GNSS/MEMS-based inertial system as well as a software and a prototype system to support commercial next generation small USV and UAV mapping operations. The developed software can be used as a standalone product or can be integrated with another system, for example, on-board imaging systems. This in turn could lead to the development of a smart system that can automate the entire USV or UAV mission. Such an innovative system has not been developed elsewhere.