Short baseline acoustic positioning system

When operating from a smaller vessel where transducer spacing is limited (i.e. when the baseline is short), the SBL system will exhibit reduced precision.

Rather than tracking both vehicles with a positioning system from the surface which would result in degraded accuracy as the pair's deployment distance, the SBL baseline transducers are mounted on MEDEA.

The reported accuracy is 0.09m[5] SBL systems are also available commercially for positioning of small ROVs and other subsea vehicles and equipment.

SCINI (figure 2) is a small, torpedo-shaped tethered vehicle (ROV) designed for rapid and uncomplicated deployment and exploration of remote sites around Antarctica, including Heald Island, Cape Evans and Bay of Sails.

SCINI system is designed to be compact and light-weight so as to facilitate rapid deployment by helicopter, tracked vehicle and even man-hauled sleds.

The mission's science goals[7] however demand high accuracy in navigation, to support tasks including running 10-m video transects (straight lines), providing precise positions for still images to document the distribution and population density of benthic organisms and marking and re-visiting sites for further investigation.

The SBL navigation system (figure 3) consists of three small, 5 cm diameter sonar baseline transducers (A, B, C) that are linked by cable to a control box (D).

Figure 4A is an improvised ROV control room, in this case in a cabin hauled on top of an ice hole at Cape Armitage.

The scientist types written or speaks audible observations into the computer to provide a context for the data, note objects or evens of interest or designate the start or conclusion of a video transect (figure 4B).