Coote, PaulTrumpf, JochenMahony, RobertWillems, Jan CConference Program Committee2015-12-07December 19781424438723http://hdl.handle.net/1885/18319We present a near-optimal deterministic filter for systems that evolve on the unit circle. Unlike suboptimal filtering algorithms that rely on approximations of the system, the proposed approach preserves the non-linear system model. This leads to an explicit bound on the optimality gap in terms of the tracking error. Specifically, the optimality gap is bounded by a term that is fourth-order in the tracking error. A simulation demonstrates that the filter can track a signal on the unit circle in the presence of large disturbances. An optimal algorithm for recursive estimation of static (non-dynamic) data on the unit circle appears as a special case of the proposed filter.200910.1109/CDC.2009.53999992015-12-07