NMEA0183 Library Extension for encoding AIS

[ronzeiller]

Do not know if this is the right place for this:
Is it somewhere already, or are there any plans, or is there somebody working on NMEA2000 AIS PGNs converting to "NMEA" !AIVDM sentences yet?

[ronzeiller]

Hi Timo,

So I have started an Addendum to NMEA0183 library for AIS encoding from parsed N2k values from ParseN2kPGN129038, which is Type 1: Position Report Class A to start with:

https://github.com/ronzeiller/NMEA0183/tree/ais-development
Edit: AIS is now made as separated Add On and not within the NMEA0183 Library
https://github.com/ronzeiller/NMEA0183-AIS

Even if it is far from a Pull Request, it is working code.
I will try to code an example for Arduino, which is extra work, because I am using Atom/PlatformIO.

Before I continue with encoding other sentences, would you like to have a look and comment on the code?

[ronzeiller]

Example: https://github.com/ronzeiller/NMEA0183/tree/ais-development/Examples/NMEA2000ToNMEA0183AIS
added.

One Issue I found: the COG is not correct.
Have to figure out what the ParseN2kPGN129038 is delivering, degrees or radiant?

Because I now for sure, that this ferry boat was sailing COG around 260°... :-)

I got from N2kParser:

Name Value --> AIS Value
REPEAT = 0 --> 0
UserID = 238991940 --> 238991940
NavStatus = 0 --> 0
ROT = 0.00 --> 0
SOG = 5.81 --> 58
Accuracy = 0 --> 0
Longitude = 15.23 --> 9136800 --> 0000100010110110101010100000
Latitude = 44.08 --> 26449399 --> 001100100111001010111110111
COG = 4.75 --> 47
Heading = 1.45 --> 1
RAIM = 0
!AIVDM,1,1,,A,13SrrA000r15eE0I>Euh;h3h0000*5B

[ttlappalainen]

4.75 rad = 272 deg.

I checked and it should be right on ParseN2kPGN129038 and returns radians.

I tried to keep all units in SI, but unfortunately originally did not fix that to lat/lon, which are in degrees. There are also some other inconsistense. All angles except lat/lon should be in radians.

[ronzeiller]

Type 1 Class A Position Report should work now with all units corrected.

[ronzeiller]

Working NMEA0183 Library Add On for converting:
NMEA2000 PGN 129038 => AIS CLASS A Position Report, Message Type 1
NMEA2000 PGN 129039 => AIS Class B Position Report, Message Type 18
NMEA2000 PGN 129794 => AIS Class A Ship Static and Voyage related data, Message Type 5
NMEA2000 PGN 129809 => AIS Class B "CS" Static Data Report, making a list of UserID (MMSI) and Ship Names used for Message 24 Part A
NMEA2000 PGN 129810 => AIS Class B "CS" Static Data Report, Message 24 Part A+B

can be found here:
https://github.com/ronzeiller/NMEA0183-AIS

There is lot's to might be improved....
So any suggestions and/or Pull Requests are welcome.