Naming Different Connections for Tracking other Vessels (Buddy)

[sea_rescue]

Hi,
I am using open CPN to monitor the locations and tracks of our rescue vessels. They each transmit their gps data via the internet (UDP) to the Operations Centre which currently display their locations and names on Google Earth, but I would like to display them on Open CPN. I can add each feed on the connection manager easily, but I would like each vessel to have its name alongside it so I can see which rescue vessel is where. Sorry if this is covered elsewhere but the search function didn't locate anything similar for me.

Thanks

[bcn]

Which data do you receive via UDP?
The AIS related messages AIVDM and AIVDO?

And have a look at Options|Ships|AIS targets:
here you can select to show ships names, defining the scale from which on this happens. (Helps to unclutter the screen)

bcn

[sea_rescue]

Hi,
Thanks for the reply. I currently transmit the GPS NMEA stream from the vessels laptops over the internet using the GPSGate software and receive it at the Ops Centre via the GPS Gate software. It then takes each vessels NMEA stream and outputs them on different Virtual Com Ports, which OpenCPN plots via Connection Manager.
Cheers

[nohal]

sea_rescue...
The important question is what does it output in the NMEA stream...

If it is FRPOS with the buddy data, there should (or could? - I really don't know and just read the code in https://github.com/OpenCPN/OpenCPN/b...coder.cpp#L678) be the name of the vessel and you can use the standard features to show the AIS target names.

Same if it sends the AIS data.

If it sends GP* sentences, then everything will be a total mess and a completely different approach is needed.

Can you record a bit of the data using the VDR plugin or otherwise and post it here?

Pavel

[sea_rescue]

Hi, it is $gp sentences but will get some on the weekend and post

[bcn]

In case you receive just the $GP sentence how will you identify the sender?

There is no reference to the MMSI (or the name of the vessel) in the $GP NMEA messages (GGA, GLL).

bcn

[sea_rescue]

Yeah, that is pretty much my question. When entering the source of data in connections, there is no where to name it. I can view multiple gps sources on google earth currently, but wanted to on OpenCPN if it could. No biggie, just wondering if it did. Thanks.

[bcn]

So just let's see your data after the weekend. If there are just the plain $GP sentences and nothing else there will be no easy solution.

bcn

[sea_rescue]

Great, thanks

[seandepagnier]

Maybe you can make a small program which translates the gps sentences into ais sentences and appends vessel information.

[PjotrC]

Such a program is attached in the recent thread on Flight Simulator as NMEA generator...

The Python script at2vdm.py takes a stream of GPRMC and outputs a stream of AIVDM, assuming an MMSI value given as option. Another option selects, if a Type 9 (SAR Aircraft) or Type 1 (Ship position report) is produced.

I use it with multiple computers, each producing a stream for a separate SAR aircraft...

[sea_rescue]

Hi, I have been looking for something that will convert the NMEA to AIS if I add some details to make it AIS. How can I run this program please? It looks like any NMEA coming in via a certain port can me assigned a MMSI which will allow it to be separated...

[sea_rescue]

OK, google has pointed me in the right direction for Python.... thanks

[sea_rescue]

Hmmmmm having trouble getting it to happen for me. Have installed Python, save the script as .py but can't get the udp data coming in to go back out as AIS....

[PjotrC]

sea_rescue...

Not sure what your platform is...

One thing that is easily missed is that in order to have the options evaluated in Python, one should call the script as

python at2vdm.py -listen....

Just calling it as

at2vdm.py -listen...

will run, but only with default option values.

You have 3 methods:

1. change the address/port number/etc options defaults in the source

2. make a link/shortcut to the .py script, and set the options in the properties window of this link

3. open a command line window and type the calling command starting with "python at2vdm.py -listen...."

You might set the "-verbose 3" and/or "-loglevel 3" to see if the data is coming through.

You will then see something like that:

C:\Python33\python.exe E:\Dokumenty\at2vdm.py -listen 127.0.0.1:5500 -forward 127.0.0.1:5501 -seconds 2 -mmsi 111303123 -loglevel 3 -verbose 3

listening on 127.0.0.1:5500
loglevel: 3
logging to file: rmc2vdm.log
forwarding to 127.0.0.1:5501
including static data :
$GPRMC,122228,A,0000.000,N,00000.000,E,000.0,000.0,1706114,0.000,E*4B
$GPGGA,122228,0000.000,N,00000.000,E,1,,,00,F,,,,*13
altitude = 0
$GPRMC,122228,A,0000.000,N,00000.000,E,000.0,000.0,1706114,0.000,E*4B
$GPGGA,122228,0000.000,N,00000.000,E,1,,,00,F,,,,*13
altitude = 0
$GPRMC,122228,A,0000.000,N,00000.000,E,000.0,000.0,1706114,0.000,E*4B
$GPGGA,122228,0000.000,N,00000.000,E,1,,,00,F,,,,*13
altitude = 0

(...)

$GPRMC,122229,A,3609.094,N,00520.375,W,003.1,267.6,1706114,0.000,E*58
$GPGGA,122229,3609.094,N,00520.375,W,1,,,09,F,,,,*0E
altitude = 2
$GPRMC,122230,A,3609.094,N,00520.375,W,003.0,267.6,1706114,0.000,E*51
lat = 36.1515666667
lon = -5.33958333333
sog = 3
cog = 267.6
a_cog = 2680
!AIVDM,1,1,,A,91b9Ilh0P3wWSbnDcr?:N2P20000,0*5A
$GPGGA,122230,3609.094,N,00520.375,W,1,,,09,F,,,,*06
altitude = 2
$GPRMC,122230,A,3609.094,N,00520.376,W,003.0,267.5,1706114,0.000,E*51
$GPGGA,122230,3609.094,N,00520.376,W,1,,,09,F,,,,*05
altitude = 2

(...)

$GPRMC,122231,A,3609.094,N,00520.376,W,003.0,267.5,1706114,0.000,E*50
$GPGGA,122231,3609.094,N,00520.376,W,1,,,09,F,,,,*04
altitude = 2
$GPRMC,122231,A,3609.094,N,00520.376,W,003.0,267.5,1706114,0.000,E*50
$GPGGA,122231,3609.094,N,00520.376,W,1,,,09,F,,,,*04
altitude = 2
$GPRMC,122232,A,3609.094,N,00520.376,W,003.0,267.5,1706114,0.000,E*53
lat = 36.1515666667
lon = -5.3396
sog = 3
cog = 267.5
a_cog = 2680
!AIVDM,1,1,,A,91b9Ilh0P3wWSbPDcr?:N3P20000,0*65

Since in my setup I receive 5 GPRMC statements per second, I skip some of these, producing an AIVDM only every so many seconds (here: 2, set by option)

Works fine for me on Windows, Python 3.3.

Good luck, and please check the options for correct address/port number etc.

There is also an option "-serial" to direct the output to a COM rather than UDP.

PS: Please download and use the "fg2vdm.zip" toolkit. It includes the latest version of RMC to VDM converter, called at2vdm.py. It is an enhanced version of rmc2vdm.py mentioned in the first post of the thread. It also includes a tool to produce static Type 5 sentences, which one might need to properly identify the vessels by name/callsign etc.