Tactics Plugin

[DavidBurch]

First, thanks for this fantastic plugin. Just learning how to use it, which brings up this question. I seem to be missing the current computations in some cases. Here is a specific one:

Key data in:
$GPRMC,000508.962,A,2528.5985,N,7422.1523,W,6.20,2 1.3,260717,,,D*42
$GPVHW,40.0,T,,M,5.7,N,,K*74
$WIVWR,29.9,R,14.1,N,7.2,M,26,K*7E

I get the right TWA, TWS, but current boxes are empty. The right value is 2.0 kts toward 315.

I have seen the current work fine in other cases, but not this one. I started and restarted several times. Any suggestions on what I might be doing wrong or need to do would be much appreciated. Thanks.

[rgleason]

Key data in:
$GPRMC,000508.962,A,2528.5985,N,7422.1523,W,6.20,2 1.3,260717,,,D*42
$GPVHW,40.0,T,,M,5.7,N,,K*74
$WIVWR,29.9,R,14.1,N,7.2,M,26,K*7E

I get the right TWA, TWS, but current boxes are empty. The right value is 2.0 kts toward 315.

The answer is probably in the Nmea 0183 sentence structure and what is required.
RMC - Recommended Minimum Navigation Information
VHW - Water speed and heading
VWR - Relative Wind Speed and Angle

1 2 3 4 5 6 7 8 9 | | | | | | | | | $--VHW,x.x,T,x.x,M,x.x,N,x.x,K*hh<CR><LF>

Field Number:

1. Degress True
2. T = True
3. Degrees Magnetic
4. M = Magnetic
5. Knots (speed of vessel relative to the water)
6. N = Knots
7. Kilometers (speed of vessel relative to the water)
8. K = Kilometers
9. Checksum

-- I don't see Degrees Magnetic or checksum.

======

1 2 3 4 5 6 7 8 9 | | | | | | | | | $--VWR,x.x,a,x.x,N,x.x,M,x.x,K*hh<CR><LF>

Field Number:

1. Wind direction magnitude in degrees
2. Wind direction Left/Right of bow
3. Speed
4. N = Knots
5. Speed
6. M = Meters Per Second
7. Speed
8. K = Kilometers Per Hour
9. Checksum

Looks ok.

Perhaps you can figure it out from this?

[DavidBurch]

Originally Posted by rgleason

The answer is probably in the Nmea 0183 sentence structure and what is required.
RMC - Recommended Minimum Navigation Information
VHW - Water speed and heading
VWR - Relative Wind Speed and Angle

1 2 3 4 5 6 7 8 9 | | | | | | | | | $--VHW,x.x,T,x.x,M,x.x,N,x.x,K*hh<CR><LF>

Field Number:

1. Degress True
2. T = True
3. Degrees Magnetic
4. M = Magnetic
5. Knots (speed of vessel relative to the water)
6. N = Knots
7. Kilometers (speed of vessel relative to the water)
8. K = Kilometers
9. Checksum

-- I don't see Degrees Magnetic or checksum.

======

1 2 3 4 5 6 7 8 9 | | | | | | | | | $--VWR,x.x,a,x.x,N,x.x,M,x.x,K*hh<CR><LF>

Field Number:

1. Wind direction magnitude in degrees
2. Wind direction Left/Right of bow
3. Speed
4. N = Knots
5. Speed
6. M = Meters Per Second
7. Speed
8. K = Kilometers Per Hour
9. Checksum

Looks ok.

Perhaps you can figure it out from this?

Thanks very much. I will try to see if not sending Magnetic is an issue, however, we have never run across that before. Also i note that this seems to be intermittent. In other geometries current shows up nicely. In the main configurations we care about, current shows up with these same sentence structures.

I mainly brought it up to see anyone else had seen this, and it seems the answer is probably no. The display issue noted could be related to the way I am simulating the sentences. This is not real data. If I can detect any unique vector geometry that might cause this, i will report back.

Thanks again.

[rgleason]

This plugin is new enough, so it may not have been picked up, however something has changed because set and drift does work in some configurations!

Tom may respond with better help.

[DavidBurch]

i have a configuration i can mock up and not get it, so we can vary from that for tests. For now we are studying the TWA computations with and without leeway correction, with and without current. Again, this is a tremendous asset (amongst so many in opencpn). I hope to be back shortly with our report.

[bcn]

It will be helpful to get the NMEA stream recorded. Or some essential parts. The VDR plug-in serves for this purpose.

[rgleason]

David, thankyou. I had an idea last night. If you can use vdr_pi to record the data atream and then post it, or upload it to the opencpn beta file thingie upload directory, if it is too big. Then others can see & test.

Let me know if you want to use the file thingie upload dir.

[rgleason]

Also these online Nmea 0183 decoding tools might help.
https://opencpn.org/wiki/dokuwiki/do...l:online_tools

[rgleason]

bcn, why the devil do your messages always sneak in ahead of mine? When I write my messages, your's are not posted, then after I write and post, your's sneak's ahead! This is really quite remarkable and I think it is just plain unfair!

[bcn]

5 hours earlier - the advantage being at UTC+

Perhaps you should reload threads before starting to read....

[rgleason]

I'm not so sure reloading is the problem.

[tom_BigSpeedy]

DavidBurch,

can you please record a sample of your NMEA data and upload here?
It would be to good to be able to reproduce the effect, i.e. show the current and then the dropout ...
I'm happy to assist finding the reason.
Simply use vdr_pi ...

Without your data stream its difficult to say ...
It could be some missing or invalid/rejected NMEA sentences during the failure ...

BR,

Tom

[CapnRon47]

All,
I am new to this forum, although I have been using OpenCPN on both a laptop and now on an Android tablet. As I mentioned elsewhere, I have a Kbox (https://hackaday.io/project/11055-kbox) which takes all my B&G NMEA data, adds a magnetic compass, gyroscopes for heel and pitch (XDR sentences), temp and barometer data and sends it out over a wifi link. Oh, and AIS data from my radio as well. I am running Android OpenCPN on a $49 tablet (running Kitkat) and I can display all the NMEA0183 data and charts, again over a wifi connection from the Kbox. I am interested in how to implement the tactics plug-in, but I assume that it only works with OpenCPN running on an Rpi. No problem, I have several Rpi's; one that I use with my telescope to control the mount and cameras and another that I plan to use on the boat as music server (Mopidy). But I am more interested in setting up OpenCPN and this tactics plugin. I will read thru the supplied pdf for this plugin. But since I already have most of the sensors required and the data is being sent out in NMEA0183 sentences over wifi, can someone help me short circuit my way thru the setup.

thanks,
Ron

[rgleason]

Ron I told you to read the manual in another thread and gave links. Good luck.

[Canne]

tactics is a great plugin for O and it gets even better when you have a heel sensor. I thought you might be interested to learn how I added a heel sensor for it - and a couple of bonus sensors - using an Arduino/Genuino 101 board. I wrote the necessary software which is, of course, free to use. It sends NMEA to USB serial line and is dead easy to use - plug it in!



From the GitHub link you can also have a Bluetooth Low Energy intelligent sensor version for those who are interested in IoT and concepts for sensors such as Signal-K presents.

Oh, how much it cost? Less than 30 units of currency for me (check the official link above; I bought mine from an electronics component supplier and grabbed the USB cable of a dead printer)!