OpenCPN 4.8.0 - No heading line shown on ship icon

[Bamba]

I am using OpenCPN 4.8.0 on my new computer. In NMEA Debug window I can read the heading (GPHDT,259.3,T<0x0D><0x0A>) but on my ship icon it shown only the COG but the heading line is not showing. I need your assistance please. Thanks in advance.

[cagney]

What value is your Options->Ships->Heading Predictor Length...set to?

[Bamba]

Hi,
It is set to 3 NMi

[cagney]

If you play this gpx file in the vdr plugin .....do you see the "own Ship's" heading line?
PacCupStart.gpx.pdf
Save the file and delete ".pdf" in the filename before trying.

[Dsanduril]

The sample sentence you posted (GPHDT,259.3,T<0x0D><0x0A>) does not have a checksum (it should appear as "*XX" after the "T" and before the CRLF). Do you have the checksum box ticked (it is by default) in the connection setup?

[Bamba]

Dear Cagney, I am trying to activate the VDR two buttons in my toolbar but I cannot succeed. If I go to ToolBar>Options>Plugins I cannot see VDR to activate these two buttons in my toolbar. See attached screenshot of my plugin window.

Dear Dsanduril, Yes in the connection setup I do have the "Control checksum" box ticked. See attached screenshot of this window. Also see attached my NMEA Debug window.

[bcn]

Bamba...


you ned to install the VDR plug-in first:
at Options|plug-ins scroll down until you find the VDR packet, install it and check if it is enabled.
If the two VDR icons (one is for recording, the other for playing files) do not show up at the tool bar, restart OpenCPN.


Hubert


Sorry, but you are using an outdated version of OpenCPN - managed plug-ins are in the latest 5.2 series. In your case you will need to go to opencpn.org/downloads and download and install the VDR plug-in.

[Bamba]

Dear bcn,
Thank you! I've installed VDR plugin and upgraded my opencpn to 5.2.4; No both buttons are visible in my toolbar.

Dear cagney,
I played gpx file in the vdr plugin and I can see "own Ship's" heading line. See attached screenshot from my computer.

[Dsanduril]

Well, your debug window is quite interesting. All on the same Com port, but your RMC sentence has a checksum and your GGA and HDT sentences do not have a checksum (the checksum is "*" followed by two hexadecimal characters at the end of the sentence just before "<0x0D><0x0A>".

I would try un-ticking the "Control Checksum" box and re-starting OpenCPN. I don't have your version installed any more, so I can't test it. My recollection is that in some of the older versions that check box didn't work as designed, but I don't recall specifics.

If that doesn't work then the option is to install the NMEA Converter plugin. That can take all the sentences without checksum as input and "fix" them, then pass them along to OpenCPN.

Option B, go back the vendor of the device sending the data and ask why some sentences have a checksum and some don't.

[Edit] the screen shot you posted isn't for the current Com1 connection, that is at 38400 baud, it is the default settings box. You would have select the Com1 configuration in the box that lists the current connections, then it will populate the information below and you'll know if the checksum box is ticked for that connection (each connection setting is independent).

[Bamba]

Dear Dsanduril,

Thanks a lot for your message.
- First step: I un-tick the "Control Checksum" box with OpenCPN 5.2.4. The heading shows immediately but while I am presently at anchor the vessel's speed was jumping from 0 to over 10kts. Then I restarted OpenCPN as you advised and the heading disappeared. I repeated the process many times but still the same.

Second step: I re-installed OpenCPN 4.8.0 then I un-tick the "Control Checksum" box with OpenCPN 4.8.0. Nothing happened immediately. Then I restarted OpenCPN as you advised and now the heading is showing with normal variation of vessel's speed (0 to 0.4kt) while at anchor. But with this second configuration, I found three things you can see in attached screenshots:

1- Ship's position shown in left down corner looks not changing every 0.0001NMi as usual. Minutes for latitude and longitude are showing 49.5000 and 57.3000

2- GPS signal shown in right top corner is not round to confirm safe for navigation.

3- In option menu, if I click on "Plugins" it is empty.

These are presently the three things I need to be assisted.
Thanks so very much for all your supports

Bamba


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[Dsanduril]

For #3, Plugins empty I have no idea.

For the 5.2.4 issue, it sounds as if OpenCPN is not exiting cleanly, and so it not saving the connection setting with the box unticked. If you want to go down the path of editing the configuration file manually let me know, I can show you how to edit the file outside OpenCPN (but that is a workaround, we should fix why it is not saving when you exit).

With the control checksum unticked you are now getting position in two sentences: GGA and RMC, where before it was presumably only coming from RMC. So, I suspect the jumpy speed and other observations are from having two sources of data. The two sentences provide some different information so you probably want them both, but for a test, in the Connections setup, I would set RMC to ignore (check "ignore sentences" and then select the RMC sentence from the dropdown using the ellipsis (...) on the right. Then also try again with GGA on ignore and see the differences.

For the GPS icon not round, this is because you now have the GGA sentence being accepted. And so the GPS icon changes to bars (like a cell phone) that show the number of active satellites. This is acceptable for navigation, we may need to update the manual to make that clear. The round icon was there previously because only the RMC sentence was being accepted (only that one had a checksum) and it does not contain information on the number of satellites.

For the precision display of the position, in the sample you posted previously the position was 0351.70S, 01058.16E (RMC) and 0351.700S, 01058.165E(GGA). This is 03°51.7'S and 10°58.16(5)E. I would check the debug window when you see what appears to be low precision and confirm what is being sent in the sentence. In this case there is only one decimal in latitude, while there are two or three in longitude.

I don't think that was entirely a helpful response, but do try ignoring the different sentences and do look at the debug window to see how many decimal places are coming from the GPS and then we can work from there.

[Bamba]

Hi Dsanduril,

1- Ignor RMC sentence test: when I did it the following happened: heading line on vessel icon disappeared but heading info was showing on dashboard; ship's position was showing with 3 digits after the decimal on dashboard; SOG and COG disappeared from dashboard. See two attached screenshots of map and NMEA Debug for this first test.



2- Ignor GGA sentence test: when I did it the following happened: heading line and heading info were both showing; ship's latitude was showing with 1 digit after the decimal on dashboard and longitude was showing with 3 digits after the decimal on dashboard; SOC and COG were both showing. See two attached screenshots of map and NMEA Debug for this first test.
Also find attached NMEA Debug when all sentences are accepted. Then if I compare the three mentioned NMEA Debug ship's position are looks not different. The positions for these tests are different only on the dashboard.

[Bamba]

Hi,
I also noticed that in addition to the position rounded up and updated per 0.01NMi, the ship icon on the map is jumping every 0.01NMi as well. See attached screenshot.

Bamba