GPS 비가용 환경을 고려한 점검 무인비행체의 보조 측위센서 설계 개념

Abstract

This paper suggests a novel localization sensor for substation inspection UAVs carrying out their missions under a GPS-denied environment. The proposed sensor consists of a transmitter located at the known position and a cruciform receiver array which enables the UAV to measure the time difference of arrivals. For such case, the UAV localization problem can be cast into a passive nonlinear state estimation using the range difference (RD) information expressed by a nonlinear function of the UAV position of interest. To avoid the performance degradation due to the inherent nonlinearity of the problem, we reformulate the localization problem in the setting of a linear robust state estimation. Ensuring the robustness against imperfect RD measurement noise statistics which is cruicial for determining filter design parameters, a modified robust weighted least squares estimator is designed by considering the geometric constraint between the state variables as an additional information. Experimental results show that the proposed design concept of a UAV localization sensor is applicable in practice.