Position and Orientation Estimation in Radio Network With Groups of Locally Synchronized Nodes

Abstract

This article presents a positioning system with groups of locally synchronized nodes. A mobile object is equipped with a group of several synchronized receivers that are able to measure the difference in the time of arrival of signals from reference transmitters. The reference transmitters are synchronized only in local groups, with no global synchronization between groups. It is assumed that the synchronous operation of transmitters and receivers in groups does not allow for the phase-coherent emission and reception of signals, making beamforming and angle of arrival estimation impossible. The structure of the positioning system and the equations for estimating the position and orientation angle are presented, along with the Gauss-Newton algorithm for iteratively estimating the coordinates and orientation of the mobile object. The possible accuracy of the proposed solution is evaluated using dilution of precision and the Cramer-Rao lower bound. The analysis showed that although the quality of the position estimation in the proposed solution is highly dependent on the mutual location of the reference transmitters and the mobile object, the orientation angle can be estimated highly accurately, almost regardless of the mobile object location.

Keywords

• Asynchronous positioning
• Cramer-Rao lower bound
• Gauss-Newton algorithm
• radio localization
• radio navigation