MOOS Vertically Mobile Instrument Node (Vertical Profiler)

The vertical profiling features of the MOOS system are currently poorly defined and decisions need to be made regarding the best path to follow in developing or purchasing the equipment required to enable the profiling capability. This document examines the implications of some of the functional requirements in the context of the MOOS architecture and assesses how well several available solutions meet these requirements.

Commercially available equipment by the name of vertical profiler is typically designed for relatively short deployments in which the device operates nearly autonomously, collecting and storing data for analysis upon recovery of the device. Within the MOOS architecture, there is the additional requirement that the equipment be capable of near real-time communication with the rest of the system. Also, it is desirable that the profiler be able to easily accept new instruments in a standardized manner. Because the MOOS “Remote Instrument Node” device (RIN) shares these requirements, a better name for the profiler in the MOOS architecture may be “Vertically Mobile Instrument Node” (VerMIN?). Adopting the point of view that ideally the MOOS vertical profiler would have all the capabilities of a RIN, and additionally be able to crawl up and down the riser cable, provides a starting point for specifying the profilers requirements. Determining what subset of the RIN’s capabilities the profiler is capable of, in accordance with size and power limitations, is the object of specifying the MOOS vertically mobile instrument node.

Functional Requirements – Upper Water Column Profiler

.1 User/High-Level Requirements

The MOOS system functional requirements documents makes several references to vertical profiling capabilities in the upper water column. The functional requirements presented here include those as well as other requirements that ...

• The profiler shall be deployable in conjuction with at least a subset of the mooring configurations that comprise MOOS.

• The profiler shall operate between a depth of 500 meters and the surface.

• The profiler shall be capable of performing 6 full profiles per day.

• The profiler speed shall be 30 cm/s.

• The profiler shall be capable of near real-time communications with the shore.

• The profiler shall support a 20 kg instrument payload.

.2 Derived Requirements

• The profiler shall be able to participate in the MOOS power and data architecture, providing the communications link outlined above in the high-level requirements section.

.3 Environmental Requirements

• The profiler shall be operational whenever the sea conditions are within the “90% design condition” for the MOOS mooring system. For the Outer Monterrey Bay site, these are:

1. Surface Currents ¡ 50 cm/s

2. Significant wave height = 5 meters

3. Average wind speed ¡ 20 kts

.4 Operational/Maintenance Requirements

• The profiler shall be capable of unattended service for one year. (2,190 profiles)