Indoor High-precision Fusion Positioning Method for Agricultural Robots Based on UWB

Addressing the high-precision positioning requirements in agricultural indoor greenhouse scenarios, the method of ranging and positioning based on UWB (Ultra-Wideband) electromagnetic signals using the TOF (Time of Flight) approach has been adopted by numerous engineers currently. However, due to significant variations in temperature and humidity within greenhouse structures, as well as obstructions from plant steel frameworks, the acoustic ranging and positioning method based on TOF is constrained by difficulties in calibrating the speed of sound, low ranging frequency, and short ranging distance, making it challenging to apply in practical positioning scenarios. In contrast, UWB offers long ranging distance and high frequency, satisfying the demands of practical positioning applications, yet its positioning accuracy is relatively low. To address this issue, this paper proposes a fusion positioning algorithm that integrates UWB ranging information with IMU (Inertial Measurement Unit) information. This algorithm fuses UWB and IMU information through a loosely coupled approach based on an EKF (Extended Kalman Filter) and calculates the final two-dimensional positioning coordinates using the trilateration algorithm. Experimental results demonstrate that the UWB-IMU fusion positioning algorithm effectively enhances positioning accuracy in complex indoor greenhouse scenarios compared to a standalone UWB positioning system.