Open CPN, NMEA 2000 and sending waypoints/routes

[weaver_fish]

When I've planned and activated a route on the laptop in OpenCPN, is it possible to send it out onto the NMEA 2000 bus so that the plotter, MFD and autopilot pick it up?

I've played with an Actisense NGT gateway but I can't see that it converts route data

 

[lpdsn]

When I've planned and activated a route on the laptop in OpenCPN, is it possible to send it out onto the NMEA 2000 bus so that the plotter, MFD and autopilot pick it up?

I've played with an Actisense NGT gateway but I can't see that it converts route data

I've not played around with sending route data from OpenCPN yet, but it's something I'm interested in so I'll have a look and come back to compare notes. Generally, the only way to have confidence it will work is to trace the NMEA0183 sentences and NMEA2K PGNs to check what your plotter, MFD and Autopilot use.

I guess you've got the Actisense data sheet from their website to see what it converts.

Alternative convertors are the AMEC one or one of the ShipModul multiplexers.

 

[PaulRainbow]

I don't have a complete answer, but i do know that OpenCPN doesn't do N2K (you most likely know that yourself). Once a route is activated OpenCPN will output the following four sentences (if you have the port set to output) :

$ECRMB
$ECRMC
$ECAPB
$ECXTE

That's obviously in NMEA 0183 format, so if you need to feed that to N2K you'll need to convert it somehow. I'm using a vYacht router to get my N2K data to the laptop via wifi but it does not output N2K.

The Actisense NGW-1 documentation lists those four sentences as being converted from 0183 to N2K http://www.actisense.com/products/nmea-2000/ngw-1/downloads-ngw1

So it looks as though it should work, have a word with Actisense before spending your money though. Be interested to hear the outcome as i'm thinking of buying one myself to get the route info to my cockpit displays.

 

[lpdsn]

Just skimmed the OpenCPN manual.

http://opencpn.org/ocpn/Adv_route-to-autopilot

Looks like it sends RMB, RMC and APB to the autopilot.

You can get the conversions here.

http://www.actisense.com/products/nmea-2000/ngw-1/downloads-ngw1

You can find the documentation on the N2K PGNs here.

http://www.nmea.org/Assets/20151026 nmea 2000 pgn_website_description_list.pdf

That's the best I can find with a free download.

You'd need to look for the mauals of the kit you're sending the messages to, but most stuff can be found online.

Hope this helps.

 

[PaulRainbow]

Just skimmed the OpenCPN manual.

http://opencpn.org/ocpn/Adv_route-to-autopilot

Looks like it sends RMB, RMC and APB to the autopilot.

It sends XTE too. Activate a route and turn the NMEA debug window on, outputs show in blue.

 

[lpdsn]

It sends XTE too. Activate a route and turn the NMEA debug window on, outputs show in blue.

Thanks. It'll probably be a few months before I get a chance to play with sending routes from OpenCPN myself.

 

[PaulRainbow]

Thanks. It'll probably be a few months before I get a chance to play with sending routes from OpenCPN myself.

After getting the vYacht stuff working it'll be a while before i can face another round

Finally ended up with the N2K network feeding the router, along with NMEA AIS data from the Garmin black box, because the vYacht will not correctly translate N2K AIS. That all works OK on the laptop and tablet. I then had to send NMEA 0183 GPS to the Garmin unit, as it will only work on N2K or NMEA 0183, not both. So, everything works, but i have a Garmin GMI 10 in the cockpit and it would be nice to get the route data on that.

 

[weaver_fish]

That's really helpful. I hadn't realised that rmb and the others contained the actual info I need to convert, I just thought they were simple GPS data.

 

[PaulRainbow]

That's really helpful. I hadn't realised that rmb and the others contained the actual info I need to convert, I just thought they were simple GPS data.

They contain this lot :

$ECRMB

RMB Recommended Minimum Navigation Information
14
1 2 3 4 5 6 7 8 9 10 11 12 13|
| | | | | | | | | | | | | |
$--RMB,A,x.x,a,c--c,c--c,llll.ll,a,yyyyy.yy,a,x.x,x.x,x.x,A*hh
1) Status, V = Navigation receiver warning
2) Cross Track error - nautical miles
3) Direction to Steer, Left or Right
4) TO Waypoint ID
5) FROM Waypoint ID
6) Destination Waypoint Latitude
7) N or S
8) Destination Waypoint Longitude
9) E or W
10) Range to destination in nautical miles
11) Bearing to destination in degrees True
12) Destination closing velocity in knots
13) Arrival Status, A = Arrival Circle Entered
14) Checksum


$ECRMC

RMC Recommended Minimum Navigation Information
12
1 2 3 4 5 6 7 8 9 10 11|
| | | | | | | | | | | |
$--RMC,hhmmss.ss,A,llll.ll,a,yyyyy.yy,a,x.x,x.x,xxxx,x.x,a*hh
1) Time (UTC)
2) Status, V = Navigation receiver warning
3) Latitude
4) N or S
5) Longitude
6) E or W
7) Speed over ground, knots
8) Track made good, degrees true
9) Date, ddmmyy
10) Magnetic Variation, degrees
11) E or W
12) Checksum


$ECAPB

APB Autopilot Sentence "B"
13 15
1 2 3 4 5 6 7 8 9 10 11 12| 14|
| | | | | | | | | | | | | | |
$--APB,A,A,x.x,a,N,A,A,x.x,a,c--c,x.x,a,x.x,a*hh
1) Status
V = LORAN-C Blink or SNR warning
A = general warning flag or other navigation systems when a reliable
fix is not available
2) Status
V = Loran-C Cycle Lock warning flag
A = OK or not used
3) Cross Track Error Magnitude
4) Direction to steer, L or R
5) Cross Track Units, N = Nautical Miles
6) Status
A = Arrival Circle Entered
7) Status
A = Perpendicular passed at waypoint
8) Bearing origin to destination
9) M = Magnetic, T = True
10) Destination Waypoint ID
11) Bearing, present position to Destination
12) M = Magnetic, T = True
13) Heading to steer to destination waypoint
14) M = Magnetic, T = True
15) Checksum


$ECXTE

XTE Cross-Track Error – Measured
1 2 3 4 5 6
| | | | | |
$--XTE,A,A,x.x,a,N,*hh
1) Status
V = LORAN-C blink or SNR warning
A = general warning flag or other navigation systems when a reliable
fix is not available
2) Status
V = Loran-C cycle lock warning flag
A = OK or not used
3) Cross track error magnitude
4) Direction to steer, L or R
5) Cross track units. N = Nautical Miles
6) Checksum

 

[bitbaltic]

That's really helpful. I hadn't realised that rmb and the others contained the actual info I need to convert, I just thought they were simple GPS data.

Just for the sake of form, none of them do contain route data, they contain information for steering to an activated waypoint. It wasn't clear from your first post that this was what you wanted (though I realise from subsequent posts this is the case). At first I thought you were asking about how to send a complete route to your MFD using the RTE sentence. This is the only actual 'route' sentence and it sends a list of waypoint names to allow the receiving device to construct the route.

What you are looking at here is sentences (commands) for steering to a waypoint, and the info in the sentence changes in real time as you move from waypoint to waypoint along your route. It is different to transmitting the data for a route in a single or short succession of 0183 sentences.

 

[pvb]

Just for the sake of form, none of them do contain route data, they contain information for steering to an activated waypoint. It wasn't clear from your first post that this was what you wanted (though I realise from subsequent posts this is the case). At first I thought you were asking about how to send a complete route to your MFD using the RTE sentence. This is the only actual 'route' sentence and it sends a list of waypoint names to allow the receiving device to construct the route.

What you are looking at here is sentences (commands) for steering to a waypoint, and the info in the sentence changes in real time as you move from waypoint to waypoint along your route. It is different to transmitting the data for a route in a single or short succession of 0183 sentences.

Must admit I thought the OP was looking to export a route. As you say, just sending odd waypoint data doesn't do the same thing.

 

[Hoolie]

The OP is using an Actisense NGC device not an NGW-1. I believe it is only the NGW that does conversions between NMEA2000 and NMEA 0183. It can't be done with a NGC.

 

[adwuk]

Yes, it is possible. You need to translate from 0183 to 2000 formats for the waypoints. NMEA 2000 does have a packet format for routes, but the B&G stuff doesn't seem to support it. I made a device that does this, and in the end decided to let it do the navigation as well. Chart plotter doesn't get used very much anymore now.

 

[weaver_fish]

The OP is using an Actisense NGC device not an NGW-1. I believe it is only the NGW that does conversions between NMEA2000 and NMEA 0183. It can't be done with a NGC.

My typo - is a NGW1! Think we have a workable solution, problem was my misunderstanding of NMEA 0183 nav data

 

[Dockhead]

You can send waypoints over 0183, but you can't send routes to any plotter I know. Certainly it doesn't work on my Zeus plotters.

If you want to try to send it over N2K, you will need, as others have mentioned, a converter, since OpenCPN doesn't speak N2K. I doubt, however, that most plotters will accept a a route over the network, whether it comes by 0183 or N2K.

Or you can do what I do -- just export them to a thumb drive, and import them from there. Takes a few seconds on my system.

I do this ALL THE TIME, because I do all my route planning in OpenCPN. In very complicated waters like the Baltic, a route for a day's passage may have 100 waypoints, and it is just not feasible to do it directly on the plotter.

 

[Hoolie]

Odd really. Our now ancient Garmin GPS152 readily accepts routes and waypoint data from Ocpn. Why a regression?