B. Etzlinger, F. Meyer, F. Hlawatsch, A. Springer and H. Wymeersch, “Cooperative Simultaneous Localization and Synchronization in Mobile Agent Networks,” in IEEE Transactions on Signal Processing, vol. 65, no. 14, pp. 3587-3602, July15, 15 2017. DOI: 10.1109/TSP.2017.2691665.
Cooperative localization in agent networks based on interagent time-of-flight measurements is closely related to synchronization. To leverage this relation, we propose a Bayesian factor graph framework for cooperative simultaneous localization and synchronization (CoSLAS). This framework is suited to mobile agents and time-varying local clock parameters. Building on the CoSLAS factor graph, we develop a distributed (decentralized) belief propagation algorithm for CoSLAS in the practically important case of an affine clock model and asymmetric time stamping. Our algorithm is compatible with real-time operation and a time-varying network connectivity. To achieve high accuracy at reduced complexity and communication cost, the algorithm combines particle implementations with parametric message representations and takes advantage of a conditional independence property. Simulation results demonstrate the good performance of the proposed algorithm in a challenging scenario with time-varying network connectivity.