POSIDONIA

Attention:

The mounting of USBL antenna is executed by ships crew, the operation of the system must be executed by experienced scientific staff. The need of the system has to be announced in cruise planning docment "Einsatzplanung" prior to the cruise.

In case of sea ice conditions the system must be operated with no ship speed but following ROV or drifting is allowed. In free ice conditions moving of ship is allowed up to 5 knots speed using deployable antenna or maximum ship speed using flush antenna or Thomson Marconi antenna. In case of deployable antenna or Thomson Marconi antenna preparation takes ca 45 minutes: removing ice protection of moon pool and lowering antenna. The reverse procedure for deinstallation takes the same time. In case of flush antenna the ice protection window must be opened which takes a few moments.

Opening angle for transponder detection amounts to 60 degrees. The detection range amounts to 8000m.

Posidonia system is not compatible with USBL system Global Acoustic Positioning System (GAPS), which is also available on board.

Summary

POSIDONIA II is an ultra-short baseline (USBL) acoustic positioning system for tracking of subsea vehicles.

Manufacturer	iXblue
Model	POSIDONIA II
Serial No.	n/a
Type	ultra short baseline positioning systems

Contacts

Name	Institution	Role
Ralf Krocker	Alfred-Wegener-Institute for Polar and Marine Research	Engineer In Charge
Ralf Krocker	Alfred-Wegener-Institute for Polar and Marine Research	Data Provider

Components

On board Polarstern there are three different antennas available, which can be used alternatively but not at the same time. First antenna is flush and permanently mounted in ships keel at ca 11m depth. The antenna is protected by window, which can be opened during operation. Second antenna named deployable antenna is lowered through the moon pool. Third antenna from Thomson Marconi is fixed mounted at a device carrier for moon pool. Active antenna is connected to electronic device named USBL-Box in room E-525a. The control and operation of the system is performed via web-Interface.
For Posidonia system are two transponders of type Oceano ET861 and two releasers of type Oceano RT 861 B1S (RT2500 S-Side Bar) on board available. The maximum depth amounts to 6000m.
Online data stream of Posidonia is broadcasted via UDP, which can be used by alternative visualisation tools (e.g. PosiView) or for seperately logging.

Position

No local frame definition found in sensor.awi.de.

Data logging, storage and archiving

Logged parameters

Parameter	Sensor Output Type	Unit
day	date and time	unknown
month	date and time	unknown
year	date and time	unknown
latitude	latitude	degree
longitude	longitude	degree
raw time	date and time	s
x-position	distance	m
y-position	distance	m
z-position depth	distance	m
transponder number	index	unknown

Central geographical ship's position and time standard

Time synchronising for USBL-Box is provided by TRIMBLE GPS receiver.
Geographical ship's position and orientation is provided by MRU Ixblue Hydrins.

Rawdata storage on board

Storage of data in DShip system is established for transponders with number 0 (=antenna), 1, 2, 3 and 4.

Dship

Reduced measurement data.

Device name	POSIDONIA
Parameters	day; EW; month; NS; position_latitude [°]; position_longitude [°]; raw_time [secs]; transponder_No; transponder No (rel); x [m]; y [m]; year; z (depth) [m]

Data archiving on land

After the cruise the DShip data set can be extracted from https://dms.awi.de.

File format(s)	*.txt
Calibration certificates	NO

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