Moving Baseline RTK-based Ground Vehicle-Drone Combination System

The unmanned aerial vehicle (UAV) market has expanded following the Fourth Industrial Revolution. However, limitations persist, particularly flight duration and operation range due to battery constraints. To overcome these limitations, combining UAVs with other moving vehicles has been proposed, and these approaches typically rely on camera information. However, the narrowing field of view during the landing process on moving platforms can cause the target to exit the camera's limited range, necessitating a restart of the land process, which is detrimental impacting on mission performance given the drone's limited operating time window. To address this, Real-Time Kinematics (RTK) has been applied to effectively complement the weaknesses of camera-based approach systems by improving the position accuracy of both drones and target platforms. RTK computes the user's precise position by mitigating common errors in global navigation satellite system (GNSS) signals through double-differentiating measurements between the user and a fixed reference station whose exact location is known. Nevertheless, this solution is constrained by the operating range around the reference station. This study introduces a novel combination system for ground vehicles and drones, using only GNSS without reliance on cameras. The system employs Moving Baseline RTK (MBRTK) technology, which extends the benefit of RTK by sending correction data from a moving reference station, thereby eliminating the dependency on stationary and additional ground infrastructures, and widening the operational range. Prior research has validated that MBRTK technology can achieve cm-level accuracy, which significantly reduces the complexity and infrastructure for system construction. However, this precision requires the use of specialized receiver modules or the development of proprietary software implementations. In contrast, our developed system is designed for ease of integration, utilizing readily available commercial off-the-shelf (COTS) components. It is engineered to be compatible with standard message protocols and hardware configurations used in existing technologies, such as RTK or Pixhawk autopilots. This compatibility allows for minimal modifications during implementation, significantly lowering barriers to adoption and facilitating a more straightforward upgrade path for systems seeking to incorporate MBRTK capabilities. Our proposed system utilizes the relative position provided by MBRTK to synchronize the drone's movement with those of the ground vehicle, thereby streamlining the control process without additional commands.