[Ovmsdev] Strange issues with Car GPS accuracy.

[Michael Geddes]

*sigh* I'm now at the point where my OVMS is next to unusable because of
the GPS interference issue.  I switched back to my old ovms unit (no GSM
daughter board and the external power doesn't work)... And the problem went
away. Even with the faster polling. So it seems something is possibly wrong
with the OVMS hardware itself.. Maybe some noise on the can bus is playing
havock? It's most peculiar.

It might also make sense of something I'm seeing on the HUD which is that
it periodically stalls and resets.
I guess I should move the daughter board across to check out that.

Michael


On Mon, 29 May 2023, 4:06 pm Michael Balzer, <dexter at expeedo.de> wrote:

> Michael,
>
> if the module affects your car's builtin navigation system, I think that
> points to some EM interference. While the module has passed the EM tests
> for certification, it still emits some EM noise, and some devices are more
> sensitive to this than others. There also may be a satellite outage
> affecting Australia currently, that adds to the sensitivity.
>
> You could try to selectively switch off Wifi and the modem when the issue
> occurs, to see if one of these cause it.
>
> If not, you could try reorienting and replacing the module in the car,
> especially if it's very close to the nav system's GPS antenna.
>
> Regards,
> Michael
>
>
> Am 27.05.23 um 10:07 schrieb Michael Geddes:
>
> Latest: I changed the startup vehicle to None and turned off the mobile.
> Still getting drifting vehicle GPS until I unplug the OVMS.  Hardware
> issue? Does anybody have any clues?
>
> Michael
>
> On Sun, 21 May 2023, 11:41 am Michael Geddes, <frog at bunyip.wheelycreek.net>
> wrote:
>
>> Hi all,
>> I'm having a bunch of weird things going on which seem correlated to
>> having the OVMS running.  I'm not convinced of causation yet.
>>
>> My car's Nav system is drifting out majorly (like by >100m) and then
>> seems to stay out.  This causes major distractions as the nav system keeps
>> giving me warnings about going down one-way roads and it makes the
>> navigation 'interesting' to use.
>>
>> I also noticed that Android Auto location was frozen in one place, so I
>> assumed this was coming from the car - or meant to be anyway.  I reduced
>> the polling rate (new work I'm doing) slightly and this freezing no longer
>> happens. (To 3 speed queries per second).  But the drifting out on the
>> Navigation  still happens... but then not on AA!? Very very weird.
>>
>> If I unplug the OVMS from the OBD port (as I'm driving) it seems to (but
>> not immediately - after a minute or so) correct itself.  It's hard to
>> confirm this is directly resulting .. but it seems to be?
>>
>> I turned off my ECU2OBD which should mean that it is resorting to 1 per
>> second POLL with a low throttle value.  I'll run with some logs to make
>> sure this is what is happening.. but it still seems that this hasn't
>> stopped this issue from happening.
>>
>> I've tried turning the GSM power off. No result.
>>
>> Another note: I seem to have stopped getting anything near regular
>> updates from the OVMS GPS. Every now and again it gets a successful change
>> come through.  Still working on diagnosing that.. maybe it's related?
>>
>>
>> Any thoughts / help would be useful.
>>
>> //.ichael
>>
>>
>>
>>
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