An Emergency Seamless Positioning Technique Based on ad hoc UWB Networking Using Robust EKF.

Han Han,Liu Liu,Wang Wang,Li Li,Zhang Zhang,Yang Yang

doi:10.3390/s19143135

Abstract

In this paper, a new emergency positioning technique is proposed based on ad hoc GNSS/UWB (Global Navigation Satellite System/Ultra-Wideband) network. The main innovations of the program are reflected in two aspects. First of all, a unified coordinate frame for indoor and outdoor environments is constructed dynamically with GNSS/UWB integration. In the outdoor environments, the high accuracy positioning can be achieved with GNSS/UWB equipment. The high-accuracy indoor coordinate is obtained by measuring the range observations between adjacent network nodes and outdoor GNSS/UWB nodes, and the range information of the UWB network is transmitted to the cloud server center. A network adjustment algorithm is proposed to improve the positioning accuracy of the UWB network. Secondly, a UWB indoor location algorithm based on robust EKF (Extended Kalman Filter) is proposed. By analyzing the transfer characteristics of gross error in EKF model, a new robust EKF model is established. The model is constructed based on the statistical characteristics of redundant observation components and prediction residual. The robust equivalent gain matrix is constructed, and the robust positioning solution of UWB is obtained with iteration. The global test is carried out first to further improve the real-time operation efficiency. Finally, a field indoor and outdoor seamless positioning experiment was carried out to verify the effectiveness of the proposed algorithm. The results show that the positioning accuracy of UWB emergency network nodes (anchors) can reach 0.35 m. Based on the network, the positioning accuracy of the tag can reach 0.38 m by applying the improved robust EKF positioning algorithm, which is improved by 20.83% and 73.43% compared with standard EKF and least square method, respectively.

Highlights

People live and work indoors more than 90% of their lives [1]
In order to solve the above problems, this paper proposes an indoor and outdoor integrated seamless positioning technology based on GNSS/UWB network
In order to solve the problem of fast and accurate positioning of rescue workers under emergency conditions, a seamless indoor and outdoor positioning solution based on ad hoc GNSS/UWB network is proposed in this paper

Summary

Introduction

People live and work indoors more than 90% of their lives [1]. Every year, a large number of indoor people are killed and injured because of emergencies such as building fires [2], including many firefighters who lost their way or couldn’t find a safe exit in the fire. The outdoor positioning method based on GNSS Other seamless positioning methods based on GNSS and WLAN are researched by [18,19,20]. M. et al [21] propose a positioning solution that is based on BeiDou satellite navigation system and radiofrequency technology in indoor and outdoor scenic spots. This method needs the pre-deployment radiofrequency spots. A group of GNSS/UWB base stations are placed at the entrances and exits of the building. The coordinates of the base station of point and point are obtained by D-GNSS technique used as the outdoor positioning reference. The anchor should be kept within the line-of-sight with at least two surrounding anchors

Objectives

Results

Conclusion