OpenCPN - incorrect bearings from ship

[rgleason]

I mean to say your GPS!

Sent from my SCH-I545 using Cruisers Sailing Forum mobile app

[rschaedel]

All:
I am finally able to receive internet access now that we are anchored in Linekin Bay. Thanks for your suggestions.

Hubert: When I click on the red dot for VDR/ Record, I get a window that lists 3 files - Dashboard, Grig and VDR. If I click on VDRpii, I can select Save. This yields only the choice to replay when I click Play. It does not show anything because I have not recorded anything.
What is the mistake that I am making?

rgleason: Are you saying that under Options, Display,units you have nothing (0) entered under assumed variation? If so that suggests that it is made to adjust for magnetic variation internally and that something has gone wrong with my device.

[nohal]

rschaedel...
When you click on the Record icon, it simply asks you to specify some name for a NEW file to save the recording to. Fill in something like "mynmeastream.txt" to the only field where you can write and click the Save button. The plugin will start recording the nmea stream on the background, until you click the same icon again.
Then give us the created file.

Pavel

[rgleason]

Yes (0). Yes perhaps somethong is wrong with your device. Do as pavel suggests. He needs your VDR file to help.

Sent from my SCH-I545 using Cruisers Sailing Forum mobile app

[rschaedel]

Pavel;
Thanks for the advice but where do I save the .txt file? When I click on Save, a message comes up - "you cannot save to this location, do you want to save to your documents?"
Bob

[bcn]

Select for instance the desktop folder or "your documents"

[rschaedel]

Thanks, I am making progress (slowly). I have now downloaded the file and have it on my desktop. When I tried to upload it as an attachment for you to read, I got the message that it exceeds the maximum number of bytes permitted.
Bob

[bcn]

Perfect - now change the file type to .doc and you will be able to upload it...

[rschaedel]

I am not sure whether this .doc file has been properly attached. Let me know.
Bob
[ATTACH]106222[/ATTAC

[bcn]

The first part of the stream

$GPRMC,113609.000,A,4350.6461,N,06936.8935,W,0.00,183.26,280715,,,A*7D
$GPGGA,113610.000,4350.6461,N,06936.8936,W,1,10,0.8,11.5,M,-32.0,M,,0000*53
$GPGSA,M,3,26,16,31,23,03,29,32,27,09,14,,,1.4,0.8,1.1*33
$GPRMC,113610.000,A,4350.6461,N,06936.8936,W,0.00,183.26,280715,,,A*76
$GPGGA,113611.000,4350.6461,N,06936.8936,W,1,09,0.9,11.5,M,-32.0,M,,0000*5B
$GPGSA,M,3,26,16,31,23,03,29,27,09,14,,,,1.4,0.9,1.1*33
$GPGSV,3,1,12,26,83,050,36,16,63,228,31,31,48,080,37,23,45,303,36*78
$GPGSV,3,2,12,03,23,253,29,29,21,045,25,27,14,175,26,09,12,316,24*77
$GPGSV,3,3,12,14,01,143,23,08,09,179,24,32,15,213,10,40,00,000,*71
$GPRMC,113611.000,A,4350.6461,N,06936.8936,W,0.00,183.26,280715,,,A*77
$GPGGA,113612.000,4350.6461,N,06936.8936,W,1,09,0.9,11.5,M,-32.0,M,,0000*58
$GPGSA,M,3,26,16,31,23,03,29,27,09,14,,,,1.4,0.9,1.1*33
$GPRMC,113612.000,A,4350.6461,N,06936.8936,W,0.00,183.26,280715,,,A*74
!AIVDM,1,1,,B,152Kcf@P00K1AhDI5bHGjOvJ00Rd,0*64
$GPGGA,113613.000,4350.6461,N,06936.8936,W,1,09,0.9,11.5,M,-32.0,M,,0000*59
$GPGSA,M,3,26,16,31,23,03,29,27,09,14,,,,1.4,0.9,1.1*33
$GPRMC,113613.000,A,4350.6461,N,06936.8936,W,0.00,183.26,280715,,,A*75
$GPGGA,113614.000,4350.6461,N,06936.8936,W,1,09,0.9,11.5,M,-32.0,M,,0000*5E
$GPGSA,M,3,26,16,31,23,03,29,27,09,14,,,,1.4,0.9,1.1*33
$GPRMC,113614.000,A,4350.6461,N,06936.8936,W,0.00,183.26,280715,,,A*72
$GPGGA,113615.000,4350.6461,N,06936.8936,W,1,09,0.9,11.5,M,-32.0,M,,0000*5F
$GPGSA,M,3,26,16,31,23,03,29,27,09,14,,,,1.4,0.9,1.1*33

The RMC sentence has a field for variation but this is empty in your case:
$GPRMC,113614.000,A,4350.6461,N,06936.8936,W,0.00, 183.26,280715,,,A*7

So this doesn't help, I fear.
The VDR streaming file has a lot of blank lines - something I have not seen before.

The other option is to use the NMEA debug window taking a screen shot.
Gets enabled at Options|Connections

It would be interesting to see your settings for the serial port(s) as well.

Another idea: Please check under Options|Display|units your settings for bearings. (First thing to do perhaps)

Hubert

[bdbcat]

Folks...

I think I see what's going on here.

1. There is a bug in OCPN v4.0 in the caption for the settings entry relating to user variation.

In O4 it reads: "deg (+W, -E)"

Corrected, it should read: "deg (-W, +E)"

This error was corrected in Feb, 2015, for the OCPN 4.1 Beta series.
"Change label for setting variation from (+W, -E) to (-W, +E). FS#1694"


So, this explains why manually entering the "wrong" value seems to work properly, and entering the "right" value" doubles the correction in the wrong direction.

2. The BU353 trace attached above shows that there is no variation data coming form the receiver. So we will need to manually enter a value (reversing the polarity for the bug in O4), or....

3. I highly recommend that you install the WMM PlugIn, activate it, and allow the system to calculate the theoretical variation at your position.

Good Luck
Dave

[rschaedel]

Dave and Hubert:
I am sorry not to have replied sooner but am now in Rockland where we once again have internet service.

I have downloaded the WMM plugin to my desk top. How do I get it to function with OpenCPN?
Bob

[rgleason]

I don't mean to be a pain, but shouldn't this be fixed in Version 4.0? with a small letter update or something? It is sort of important and that is the most recent "Stable" version. Or should people be using v4.1?


I guess the reason I have not noticed this is we have (0) and the wmm_pi installed.

[bdbcat]

Rick...

There are lots of things fixed in 4.1 that have not been backported into 4.0.

This one is small potatoes, since there is a workaround. Use Wmm, or simply reverse the sign of user-entered variation in the settings dialog.

There are worse troubles, like the Mac keyboard character bug in Waypoint properties that Gerhard mentions regularly.....

We could do a Service Release of 4.0. But we probably won't. It is just a matter of managing limited Dev resources. I would not oppose a Service Release if some new developer comes along with the time and energy....

Thanks
Dave

[rschaedel]

Dave and Rick:
One thing I do not understand with my problem is why does OpenCPN show the correct magnetic bearings when it receives GPS input from my Raymarine chartplotter? When using the Raymarine input I never had any need to enter a number for assumed variation. It was presumably 0 since I never had even looked at Options, Display, Units.
Are we sure that my problem does not originate in my BU353-S4?

Or could it be that the Raymarine chartplotter calculates the correct variation and it overwrites any errors generated by OpenCPN?

Am I the first person who has posted this problem?
Bob