Tracking and positioning using phase information from estimated multi-path components

High resolution radio based positioning and tracking is a key enabler for new or improved cellular services. In this work, we are aiming to track user movements with accuracy down to centimeters using standard cellular bandwidths of 20-40 MHz. The goal is achieved by using phase information from the multi-path components (MPCs) of the radio channels. First, an extended Kalman filter (EKF) is used to estimate and track the phase information of the MPCs. Each of the tracked MPCs can be seen as originating from a virtual transmitter at an unknown position. By using a time difference of arrival (TDOA) positioning algorithm based on a structure-of-motion approach and translating the tracked phase information into propagation distances, the user movements can be estimated with a standard deviation of the error of 4.0 cm. The paper should be viewed as a proof-of-principle and it is shown by measurements that phase based positioning can be a promising solution for movement tracking in cellular systems with extraordinary accuracy.