SOG 0.3kts but I am not moving!

[Tehani]

Originally Posted by rgleason

Please see Dave's Post
https://www.cruisersforum.com/forums...ml#post3591306

If RMC/VTG show stable SOG values at 0 knots (that is best seen on a 1-2 minute VDR capture), I don't see any other possibility either.

This does not contradict the other posts, since it is also normal to see SOG of up to 0.5 knots in AIS messages from moored ships.

A simple calculation: 0.5m error between position calculations with 1s intervals means a speed calculation of almost 1 knot.
(0.5 * 3600) / (1 * 1851.8)

[bcn]

Originally Posted by Tehani

A simple calculation: 0.5m error between position calculations with 1s intervals means a speed calculation of almost 1 knot.
(0.5 * 3600) / (1 * 1851.8)

1m/s = aprox. 2knots..

[LifePart2]

This is getting so frustrating.

Yesterday, coming in to an anchorage in the Bahamas for about 5 minutes I was apparently travelling at about 2000 kts. It was not a static number, it varied, but it was between 1000 and 2700 kts. For about 5 minutes. Then it reverted to a more normal number.

Unfortunately I do not know if the same thing was happening on the laptop as:
a) we were coming in to a tricky anchorage, so trying to pay attention to that and
b) OpenCPN on the laptop had shut itself down (again) so was not running.

I made two changes at the beginning of this sailing season and since then I have been having all these problems.

One was the installation of the Quark mulitplexer as my ShipModul had died. I tried to get another ShipModul but for some reason at that time I could not get one, so had to go with the Quark. One issue I can see with the Quark is that it is limited to an output speed of 38400 The RPI is connected to the Quark by usb. The laptop connects by wifi.

The second was the upgrade of the software to the latest OpenPlotter (RPI) and OpenCPN (laptop and RPI). That immediately kicked off the wxWidgets problems, so then I downgraded to the older OpenPlotter and incrementally updated. It seems that when I upgraded the SignalK the wxWidgets problem resurfaced. So I degraded the signalK again. But I still seem to have more problem with signalK than without, so at the moment I have turned off the signalK input in OpenCPN and am using the basic USB connection. Maybe I should just remove OpenPlotter completely as I don't use any of the other signalK or node red features. I got it as it seemed the easiest way to install OpenCPN at the time.

So, to summarize, here are all the current problems I am having:

1) OpenCPN randomly shuts down (laptop and RPI). I walk away from the monitor, come back and find the OCN has gone. Yesterday both the laptop and RPI shut down at exactly the same time. Coincidence? Or is there something in the NMEA stream that could have triggered that? The two machines share no connection apart from the NMEA input by wifi and usb.

2) OpenCPN freezes (RPI only). This seems to happen when zooming in or out a long way on the Explorer charts. Happened twice in quick succession yesterday. When that happens I have to turn off power to RPI and reboot it as it is completely unresponsive to all inputs.

3) Satellite input is momentarily lost (RPI only). The satellite indicator turns to red blob instead of green bars. Then it comes back again. Does not seem to happen on the laptop. The RPI is connected by usb, the laptop by wifi. I tried connecting the RPI by wifi but it has happened then also.

4) (RPI and Laptop) Occasionally my position jumps to either latitude 0, or longitude 0, or both. My recorded track then shows a long line to and from that position. Actually this has been randomly but rarely happening for several years, so is not related to recent upgrades.

5) (RPI) Speed showing as not zero when we are not moving at all. When this happens the speed is always in the same direction, not random directions. Yesterday our speed, at anchor, was consistently 0.4kts forwards (never any other direction) as indicated by the COG predictor line.

6) (RPI only) Heading (as shown by the heading predictor line and orientation of the own ship icon) gets stuck for minutes at a time pointing in the wrong direction. When this happens it is stuck in the direction. The direction is not consistent (ie not any particular direction such as North) but will stay stuck in that direction for minutes at a time, and then will resume normal operation

7) (RPI only) when I open the NMEA Debug Window I am unable to pause, copy or interact with the window in any way. I can't even minimize, resize or close it by using the window controls. The only way I can close it is to click behind it on the Connections page and de-select the checkbox.

Since I now am using Explorer o-charts I can't just revert to a backup SD card image as I would lose the license. So somehow I have to figure out how to fix all these issues but, frankly, I have no idea where to start. Is this a problem with my GPS antenna (Standard Horizon smart antenna from when I still had the Standard Horizon chart plotter that then died), or is it a Quark issue, or is it an RPI issue, or is it an OpenCPN ior OpenPlotter ssue?

I do have another GPS antenna connected to the AIS. Normally I only turn on the AIS when making night passages. With the speed restriction on the Quark I wonder if the AIS would overwhelm it. Certainly I have noticed (even before all these changes) that with AIS running I would lose my ownship data (speed, direction etc) briefly, especially when first turning on the AIS.

As you can see, there is a lot going on here. I really, really would appreciate some help in figuring out just what is happening and how to fix it, bearing in mind also that I need a working system (with the Explorer charts) to navigate through the Bahama shallows.

I should mention also that I am NOT getting any icons on-screen indicating either a voltage or overheating issue with the RPI.

I am able to put the RPI online by wifi to my phone's hotspot so I can upload stuff from that if needed. Also I can install and run the VDR but I don't know how much space on my SD card that might take up?

So frustrated with it. So is my wife who tells me we should just use Navionics like everyone else.

Please help.

Noel

[nohal]

Noel...

Simplify your config to the bare minimum, make sure it works, then keep adding back complexity until it starts causing problems. The last thing added is likely the cause.
It is really hard if not impossible to troubleshoot a complex system like yours without having access to it.

[LifePart2]

Totally makes sense. But how do I simplify it? What do I take out? Apart from the OpenPlotter which, I agree, I don't need, it seems to me I need everything else:

GPS antenna
NMEA inputs
multiplexer to combine them
OpenCPN to navigate.

What do I remove and how do I do that?

Noel

[Tehani]

Originally Posted by LifePart2

Totally makes sense. But how do I simplify it? What do I take out? Apart from the OpenPlotter which, I agree, I don't need, it seems to me I need everything else:

GPS antenna
NMEA inputs
multiplexer to combine them
OpenCPN to navigate.

What do I remove and how do I do that?

Noel

Noel,

To analyze your case, we need a detailed list of connected devices (GPS brand and model, sensors/instruments, AIS, autopilot, etc.), and above all, where they are connected (NMEA2000, NMEA0183 cable, WiFi, etc.).

At the moment, the problems you describe suggest that you have a data loop, or that there is saturation of the USB channel at 38400.
See if the GPS is connected on the NMEA2000 side, because it's possible (I don't know) that Quark is translating absolutely everything, and with NMEA2000 throughput. (Rapid updates of COG/SOG and Position).

Normally, in these cases, to isolate the source of the problem, you start by disconnecting a few things: AIS, sensors, etc., and then connecting them again one by one, in various sequences. Opps, now I read that Nohal has said something similar to him.
Remove entries from the multiplexer, one at a time.

And you also have to decide if the use of SignalK is necessary. From what I've read, SignalK is useful for sending collected data to specific dashboards with json, especially engine data (you might be interested in that), but it adds CPU load and is not optimal between NMEA0183, Seatalk and NMEA2000.

J.L.

[Tehani]

Copy the OpenCPN I/O Channels Settings screen and display it. You may very well need to set filters.

[CarCode]

To find out not OpenCPN is the culprit simply use another software for testing. qtVlm is for free as well and available also for Raspberry:
https://www.meltemus.com/index.php/en/

[verkerkbr]

I' have never had this kind of problems. Here is what I have running on my RPI 4 with 2 GB.

RaspiOs64 based on Debian Bullseye for Arm64.

Then OpenCPN in the flatpak version with all the plugins available.

First install the flatpak enviromentL: sudo apt install flatpak.

Then go the to flatpak.hub and searcch for OpenCPN. There you ffind the instruction and the for the setup op OpenCPN 5.6. After that you get an Icon. The OpenCPN version is uniform and works on all Linux systems.

The signalK server kan you install with:

first NPM install: sudo apt install npm.

Then the installation of SignalK:
sudo npm install -g ---unsafe-perm signalk-server

To start the signalk server at startup:

sudo signalk-server setup (Everything to no)

signalK dasboard is: localhost:3000 in any browser.

Are you interested to use several OpenPlotter items ?

First you have to install the dependentsies:

sudo apt install python3-wxgtk4.0 python3-ujson python3-pyudev whois vlc

And then download the advanced openplotter file and install it.
dpkg -i (name of the openplotter deb)

That is all.

Gps at home is an usb gps with 3 sat systeems: Glonass, GPS and Galilea.

On the boat is a AIS transponder connected to the RPI SignalK server via serial/usb adapter or with NMEA2000 input with a Actisens NGT-1 or with a small and cheap Canable canbus adapter.


Bram

[bdbcat]

Noel...
Please see https://www.cruisersforum.com/forums...ml#post3591306


Please verify this now. If this setting is correct (NOT checked), then we may investigate your configuration further. Otherwise, wasting time....


Dave

[LifePart2]

Dave, not sure which setting you mean? Do you mean the calculate SOG from position? That is unchecked, and has been all along.

I appreciate all your efforts on OpenCPN, it is a fantastic program that I have been using for years now. Just very frustrating this last few months.

I just unplugged the usb from the RPI and plugged it into my laptop. Turned off the wifi input.

Everything seemed to be happy.

On the RPI I turned on the wifi input.

All working fine except that it seems to keep losing the NMEA input (satellite icon goes to red blob) for a couple of seconds and then it finds it again. But the same thing happens on the laptop and android tablet. Maybe I cannot have them all connected to the wifi at the same time?

Then I unplugged from laptop and put it back into the RPI and turned off wifi on RPI. Now it seems happy. For the moment. I will leave it running for a while and see what happens, but at the moment it is all running correctly. So what changed???

The idea of some kind of data loop sounds intriguing. How would we identify or prevent that?

Here is what I have:

Standard Horizon smart GPS input into

Standard Horizon gx2000 VHF (otherwise when I leave the radio on all day the radio beeps every 10 minutes that it has lost GPS signal.)

The VHF inputs into input 4 on the Quark-Elect A031 multiplex at 38400 baud.

Also coming into that is the SeaTalk (depth, wind, autopilot, water temp, STW) 4800 baud.

The Quark-Elec outputs by USB and wifi both at 38400 baud.

RPI receives USB direct from Quark. I no longer am using the Signal K at all. I would like to remove that but don't know how.

There is NO NMEA2000 nor NextGen Sea Talk

So the Quark has just two inputs - NMEA from radio and SeaTalk - and two outputs - USB and wifi.

Ok, just went back to look at the RPI and found that OpenCPN had shut down. So I guess it wasn't happy after all. I have restarted OpenCPN (not the whole RPI) and it seems happy so far.

Maybe I need to install that qtVlm and see what happens with that?

I am suspicious of the Quark

What is my next step?

[bcn]

Originally Posted by LifePart2

Dave, not sure which setting you mean? Do you mean the calculate SOG from position? That is unchecked, and has been all along.

Just to make sure - that one:

[LifePart2]

yep, that one. Unchecked

Noel

[LifePart2]

More info:

After yesterdays crash I started it up without any plugins (Dashboard and o-charts). I then left it running overnight, connected by wifi to the NMEA.

This morning it is still running.

BUT, the status bar shows (non fluctuating) SOG 6.40kts COG --- and the heading line points to 100 deg Mag which is correct.

So, the SOG is still incorrect. But it didn't crash.

NMEA: $GPRMC,114143,A,2343.0814,N,07601.1851,W,000.0,291 .8,21O322,,,A*64<0X0D><0X0A>

Now, after closing the NMEA debug window, the SOG shows ---

I have noticed and commented before that the SOG sometimes gets stuck on a number instead of being constantly updated. That seems to be what happened overnight. The tide changed at some point and moved the boat around, so we might have briefly hit 6kts for a second, and then the display got stuck at that until I changed the display by opening and closing the debug window.

Next step?

Thanks

Noel

[bdbcat]

Noel...
The way I would tackle this is to use NMEA filters. Start by removing all NMEA sentences except RMC. Test for a while. I'd be very surprised if your speed wanders with only RMC messages coming in.
Then add NMEA message types, one by one, testing for some minutes between changes. Sooner or later you will find the offender/conflict.


Good Luck
Dave