The Dredging Tool Driver calculates a relative X, Y, and Z between the ROV and a Dredge Head.
It is not a real USBL system, but actually a pseudo USBL system.
It receives via an A/D converter a horizontal and a vertical angle.
The driver has a user-interface, so online a range (between the ROV and the dredge head) can be entered.
The driver will use this range and the two angles to calculate the dX, dY and dZ.
The driver receives an ASCII datastring, containing four values, each one representing a channel.
The user may define in the driver which channel provides the horizontal and which channel the vertical angle.
The unit of this incoming data can be defined: degrees or radians (default).
The user may enter an (C-O) value for each angle, which will be applied to the observation.
The entered value should always be in degrees.
The definitions of the angles and range are as follows:
- The range must be the slant range.
- The horizontal angle is the gyro angle relative to the ROV heading. Zero degrees being in the direction of the heading of the ROV.
A positive angle (clockwise to the right) will result in a positive dX.
- The vertical angle is the pitch angle of the dredging pipe. Zero degrees being horizontal, positive angle being downwards, resulting in a positive dZ.
To decode the X, Y and Z observations, create an new object, e.g. "Dredging Head"; this will automatically add a reference node, which will be our "transponder".
Do not enter a shape, since its rotation is not defined.
Add a "USBL" system, and select driver "Dredging Tool (dX, dY, dZ)".
There is no need to define the three observation separately, since they are automatically added and connected to the system.
On the Parameters tab sheet, set the Sign convention for Z-axis data to positive downward and the three alignments should be set to "No".
The vessel location should be the ROV object. If you do not enable the reduction to ship's reference point, you must select a node, located on the ROV object, on the Corrections tab sheet.
The calculated X/Y/Z will be relative between this node and the "transponder".
So define this transponder on the Targets tabsheet: Add a node from the Dredging Head object as a transponder.
There is no need to set a slot number.