###### Abstract  
This article details the preliminary design and testing of a Resetting Anchor/Antenna Tether Mechanism (RAATM) for an autonomous underwater vehicle (AUV). The proposed mechanism is intended to enable an AUV to secure itself to the seabed, ascend, descend, transmit and receive signals via the tether, retract the anchor, and re-anchor again as required. The ability of an AUV to passively loiter on station for extended periods preserves power and may otherwise expand mission capabilities for a variety of underwater vehicles. If they are capable of communication through electromagnetic transmission, AUVs equipped with such technology may be utilized to form mobile networks that may, in turn, receive external communications from above the surface. Spherical AUV (SAUV) capabilities may be especially enhanced through the integration of the proposed mechanism. The RAATM was designed for integration with the Wreck Interior Exploration Vehicle (WIEVLE), a small SAUV designed for operations in entanglement-prone, extreme environments, but the RAATM may be used in any suitably-sized underwater vehicle capable of safely contacting the ocean floor. A prototype of the anchoring portion of the mechanism was constructed, and anchoring strength was tested repeatedly in three types of sediment, under varied configurations and loading angles, with promising results.  
RAATM; AUV; UUV; SAUV; WIVELE; tether; robotic anchoring mechanism; underwater electromagnetic communications; mobile networks +
Footnote †: journal: Applied  
Article  
Preliminary Design and Testing of a Resetting Combination Anchor, Antenna, and Tether Mechanism for a Subscribed Antenna, Antenna, and Tether Mechanism for  
floating on the surface of the water or at various depths (in some cases gliding) to resting freely on the sea floor [3].  
Most traditional methods of anchoring rely on the weight of the anchor and the portion of the anchor node (the rope, chain, cable, or combination thereof that connects the anchor to the vessel) that lies on the seabed, along with the rigid projections of the anchor itself, to drag along the seabed, increasing friction and thereby resisting the movement of the vessel. Some anchoring methods use an auger to screw into the seafloor for small, lightweight applications. To our knowledge, no existing anchoring methods combine an auger with an array of wire roots that can reset between deployments for multiple anchoring operations throughout an AUV mission.  
Of particular interest to our work with the RAATM is its potential integration with the Wreck Interior Exploration Vehicle (WIEVLE) AUV [4]. The WIEVLE is a spherical AUV designed to operate in highly complex environments such as littoral zones, inside shipwacks, and other environments with a high risk of entanglement. To maximize utility in a variety of mission capacities that require a long loitering time in a specific operating area, an anchor system is sought. Furthermore, periodic communication between the WIEVLE and command and control (C2) infrastructure would expand mission capability while loitering in a given operating area. Thus, the RAATM may be useful to expand the range of missions that the WIEVLE and similar AUVs can perform successfully.