Mobile Wireless Localization through Cooperation

TL;DR

This paper introduces COTAR, a cooperative localization method for mobile nodes using TOA and RSS data, achieving high accuracy in real-time scenarios with realistic channel modeling.

Contribution

It develops a new cooperative localization strategy combining TOA and RSS, with an optimal detector and low-complexity algorithm, using realistic channel models.

Findings

COTAR outperforms existing strategies in accuracy.

Achieves localization within a few tenths of a meter in ideal conditions.

Effective in both static and mobile environments.

Abstract

This paper considers N mobile nodes that move together in the vicinity of each other, whose initial poses as well as subsequent movements must be accurately tracked in real time with the assist of M(>=3) reference nodes. By engaging the neighboring mobile nodes in a simple but effective cooperation, and by exploiting both the time-of-arrival (TOA) information (between mobile nodes and reference nodes) and the received-signal-strength (RSS) information (between mobile nodes), an effective new localization strategy, termed cooperative TOA and RSS (COTAR), is developed. An optimal maximum likelihood detector is first formulated, followed by the derivation of a low-complexity iterative approach that can practically achieve the Cramer-Rao lower bound. Instead of using simplified channel models as in many previous studies, a sophisticated and realistic channel model is used, which can effectively account for the critical fact that the direct path is not necessarily the strongest path. Extensive simulations are conducted in static and mobile settings, and various practical issues and system parameters are evaluated. It is shown that COTAR significantly outperforms the existing strategies, achieving a localization accuracy of only a few tenths of a meter in clear environments and a couple of meters in heavily obstructed environments.