Time-of-Arrival (TOA) measurements is acquired from Round Trip Time (RTT) of the packet. Using Timestamp, correlation, and ranging counter, precise ranging measurements could be acquired. The position of the tag is estimated using those measurements from known anchor positions. On the other hands, anchor positions are hardly known in the environment without infrastructure. To solve this problem, this paper suggests large-scale based TOA localization system. Each anchor takes TOA measurements from other anchors and position of all anchors could be calculated using all of this TOA measurement. All measurement is centralized in the location server for this system. On the other hands, this method conceives position ambiguity as not knowing the absolute position of the anchors. This paper utilizes constraints from known information. In this paper, large-scale based TOA localization system is introduced and derived from TOA measurements. The performance of this system and error is analyzed. Moreover, the method of making constraints from known information is further studied. The simulation result shows that large-scale based TOA localization system and the method of adding constraint would be good alternative for TOA localization without infrastructure, even if there is observability problem remained.

Keywords: time of arrival (TOA), large-scale based localization system, Gauss-Newton (GN)