A Tension-based Position Estimation Solution of a Moored Structure and its Uncertain Anchor Positions*

:Thruster-assisted position mooring (TAPM) is an attractive stationkeeping solution for long-term operation. Due to the complex environmental loads and system structure, increasing attention has been paid to improve the redundancy and reliability. This paper summaries the key research results when introducing the simultaneous localization and mapping algorithm to moored structures, which can provide an additional position reference system with uncertain anchor positions. It is especially cost-efficient for some applications alleviating the need for special sensors, such as, hydroacoustic sensors. The line-of-sight range mapping from tension measurements is discussed. Fairleads, the turret dynamics, and loading effects are considered to provide a more realistic and robust solution. A sensor network scheme and a state-space model are proposed, and an extended Kalman filter (EKF) is employed to estimate the uncertain anchor position.