Isis uses the Coverage Map feature to compute the towfish position, Coverage Map must be running, Tools>Coverage Map and Mosaic:
Hit OK to display the Coverage Map window. This window MUST be open:
The map window re-sizes itself automatically as the survey size increases.
Go to View>Layback
In this example the we are using a single value of layback entered manually. NOTE that layback can also be computed automatically by Isis see this link
Hit Accept to display the Current Value, this is the value that will be used to compute the towfish position.
BOTH THE LAYBACK WIDOW AND THE COVERAGE MAP WINDOW MUST BE OPEN.
Click Tools>ASCII Report, then check Form 1 and Setup form 1
In Report Form 1 click MVP data
The following message is displayed:
Hit Yes.
Select GLL and HDT (the information for the vessels Position and Heading), click OK
Setup the rest of ASCII report form 1 as shown below:
In this setup we are using the new Network Port method, you may also use the older serial port setup.
Check Output to a Network Port, enter 1 (the first port) then Configure port:
Enter the IP address of the machine running Triton Nav and a port number, turn the port On and click OK
Tools > ASCII Report Form2
Check Fish Layback Position
Setup a second Network Port:
Note that the IP address will be the same IP address (192.168.2.103 in this example) of the Triton Nav PC but the port number must be different (5556)
To check what is actually being sent by Isis check Output to a Window and then Open Window for both ASCII reports:
NOTES:
The ASCII report string for the towfish position is a standard NMEA $GPGGA sentence.
If instead of entering the exact address of the Triton Nav PC the final group of numbers is entered as 255 (In this case 192.168.2.255) then any PC connected to the sub net 192.168.2.xxx will be able to receive the information on Ports 5555 and 5556
There are many UDP pots available and in theory you might be able to use any number from 1 - 65535, however some lower numbers <1024 have special designations and are not available - choose higher numbers if in doubt, or if a "Port in Use" message occurs.
Start Triton Map, make sure the Survey Control Panel is available on the right side, if you do not see it go to View and click Survey Control Panel
On the lower right side Click the Acquisition Setup Button:
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Use the left/right arrows to select Sock 1, click Navigation and select NMEA0183, entering NOCLOCK in the options prevents the PC clock being set to the time of the incoming nav string.
Click Show Server to display the Network Socket server:
Select Socket 1 (blue) and then Setup
Click Datagram and enter the Port Number for the Vessel and Vessel heading as configured in Isis.
Repeat the procedure for Socket 2 entering the Port number for the towfish:
Hit OK
When all ports are setup turn on each port, you can click the Spy button to view samples of the incoming data:
NOTE: The Spy button is only active for a few seconds, the message "Time Out on Port" will be displayed if data is not refreshed within 2 secs.
Use the Shape Tab to configure different shapes and to have a Swath be displayed.
You may also enter offsets and have them displayed on the vessel icon, check Show Offsets Icon
To display the vessel and towfish position in the main map window click the Connect button:
Initially you will need to determine the correct Projection for the survey area:
In general choose Universal Transverse Mercator and pick the correct hemisphere (N / S) and Zone depending on your Longitude.
Click the compass button to display the compass for the Master object (M) right click in the Compass window for some options including choosing True Heading.this causes the vessel icon to be correctly orientated with the vessel gyro, if True COG is chosen then the vessel icon will orientate itself using navigation updates.
