Development and investigation of algorithm of integration of TOF/AOA UWB local navigation system with long baseline and IMU

At present, solutions for a number of indoor positioning tasks, such as monitoring of personnel and equipment at production facilities, providing access control and management at sensitive facilities, etc., are being actively researched and developed. Positioning local navigation systems (LNS) based on ultra-wideband (UWB) signals can be attributed to the most promising option for solving such problems. However, the cost and labor intensity of deployment of such systems grows in proportion to the number of used radio navigation reference points (RNRPs), usually placed along the perimeter of the room. It is possible to achieve the required accuracy while reducing the number of RNRPs used with the help of hybrid UWB LNS capable of measuring several different types of navigation parameters, which include ToF/AoA UWB LNS. There is a possibility to increase the accuracy of estimates of the user’s coordinates by reducing the fluctuation component of AoA error by increasing the distance between the antenna elements of the ToF/AoA LNS. However, for single-base phase direction finders this method of error reduction leads to phase ambiguity of measurements. To resolve the phase ambiguity, an additional information about the user’s heading angle is obtained from an additional sensor, which can be an inertial measurement unit (IMU). In addition to resolving phase ambiguity, the integration of UWB LNS with IMU improves the accuracy of coordinate estimates.