Abstract:Aiming at the problems of low accuracy, poor stability, and packet loss of agricultural machines indoor localization when the signal transmission of global navigation satellite system (GNSS) was obstructed. The research of indoor and outdoor cooperative agricultural machines localization algorithm for ultra-wideband (UWB) frequency modulation technology was carries out. Firstly, the three base-station multilateral ranging and localization model was constructed, the absolute localization solve of the main base station and the transformation of the coordinates of the auxiliary base station were realized. Meanwhile, the weighted least squares high double sided two-way ranging (WLS-HDS-TWR) with the full center mass was proposed, and the WLS estimation algorithm based on Taylor series expansion solved for the center of mass of the triangle formed by the intersection of the base station ranging circles, i.e., the localization of the active vehicle. The indoor deployment mode of UWB positioning module for multi-state base station combination was innovatively proposed. The distance information of master and slave vehicle was obtained by time of flight (TOF) method. By integrating GNSS calibration position information, master vehicle coordinates information, and distance measurement information, master-slave vehicle cooperative localization was achieved. Finally, a joint simulation platform was built based on Prescan/Simulink to verify the reliability of the proposed algorithm. The indoor and outdoor collaborative localization experiments were carried out by agricultural tracked vehicles. The experiments showed that the full center mass of WLS-HDS-TWR collaborative positioning algorithm can effectively solve the problem of indoor GNSS signal loss, and the positioning accuracy was improved by 26.98% and 22.03% compared with the HDS-TWR and the full center mass of LS-HDS-TWR algorithms, meeting the needs of intelligent agricultural machines collaborative positioning.
