A Theoretical Error Analysis on Indoor TOA Localization Scheme Using Unmanned Aerial Vehicles

Unmanned aerial vehicle (UAV) is attractive for indoor localization where conventional localization means are unavailable such as global positioning system (GPS) satellites and pre-installed wireless anchor nodes. The advantage of indoor localization using UAVs is that even when only few UAVs are available, if each of them ranges a target node many times from different locations while flying around, the localization accuracy can be improved, because it virtually increases the number of UAVs, namely, anchor nodes. However, the locations of UAVs are also estimated by GPS, so they can contain some errors in themselves. Furthermore, the channels between UAVs and a target node are likely to be in non-line-of-sight (NLOS) conditions, so the NLOS range biases worsen the localization accuracy. In this paper, for time-of-arrival (TOA) localization scheme, we theoretically analyze the effects of UAV location errors and NLOS range errors on the indoor localization error. Using perturbation method in the theoretical analysis, we derive a simple equation connecting these errors and localization error, and discuss dominant factors and achievable accuracy using realistic system parameters.