Position Control Between GNSS and Non-GNSS Environments Using High Precision IMU

UAVs such as multi-copters use GNSS to obtain position information for position control; when RTK-GNSS is used, the position accuracy is within a few centimeters. However, if a UAV enters an environment where satellite signals cannot be received, such as under a bridge or in a tunnel, position control becomes impossible. To cope with such cases, we propose a system that combines RTK-GNSS and a high-precision IMU. In this study, a multi-copter is equipped with RTK-GNSS and an IMU. When the multi-copter enters under a bridge or a short tunnel and the RTK-GNSS positioning state becomes RTK-Float, the system switches to inertial navigation using the IMU. It was confirmed that the UAV could fly with high accuracy for about 30 s after entering this state. The maximum error in position after disconnecting the RTK-GPS antenna was about 2.83 m. Then, when the RTK-GNSS positioning state returns to RTK-Fixed, it switches to flight using RTK-GNSS positioning information. The effectiveness of the proposal was confirmed through actual flight experiments.