Open CPM GPS instability

[john murfet]

Some time ago I upgraded to CPM v4 on a Windows 7 laptop. The GPS crashed repeatedly after 4 or 5 hours running and required removing and re inserting the GPS's USB to get it going again.
Recently I tried the 4.4 upgrade and found it has the same problem. I've tried 2 different GPSs with the same results. I've had to re install v3.22 which doesn't have the issue with either of them.

Does anyone know how to fix this?

[bdbcat]

John...

What GPS device are you using?

Dave

[john murfet]

I have a round magnetic base dongle with no brand that uses the Prolific USB to serial driver. I also have a ND 100S GPS stick that uses the same driver.
Both these produce the same problem.

[bdbcat]

John...

You report that the GPS "crashes" after 4 or five hours. By crashing, I suppose you mean that the GPS position is lost, the boat icon goes grey.

Does this happen repeatably on an otherwise quiet system? Or are you underway, and exercising the machine in other ways in addition to OCPN?

Have you upgraded the GPS drivers recently? Prolific drivers come in a lots of flavors....

Any possibility of mechanical instability? I have found that USB ports deteriorate over time, such that any slight mechanical shock or jolt will cause a temporary dropout.

Any other circumstances to note?

I note that this is not a common problem, in fact not ever reported in exactly these terms. So this suggests that there is something "unusual" going on with your environment.

Thanks
Dave

[john murfet]

Thanks for your help Dave. Yes when underway OCPM loses the GPS. The small LED is still flashing on the dongle but OCPM's boat icon has gone grey. This is when nothing but OCPM is running on the computer.
Also the anchor watch wakes me in the middle of the night when the GPS gets lost.
The way the GPS is monitored in 3.22 is obviously different to the later versions because if you remove the GPS in 3.22 it doesn't trigger the anchor alarm.
I'll try upgrading the drivers and maybe even a different computer.
It's a tricky one.

[rgleason]

John, small point but it is OpenCPN "OPENsource Chart Plotter Navigation" with an N

CPM (CP/M) was a very old operating system by Digital Research, competing with ms-dos which really came later.

[john murfet]

Bit of a typo there. Sorry about that.

[john murfet]

Finally solved the problem. Dave was right. the driver for the GPS was the culprit.
On upgrading the driver for this device Windows was reporting the most recent driver was already installed, but Windows is wrong.
I found and installed the original driver from 2008 and Open CPN v4.4 and the GPS have been happy for days on end ever since.
Thanks Dave.