[Ovmsdev] Strange issues with Car GPS accuracy.

[Michael Geddes]

It's definitely something to do with the daughter board for GSM+GPS since
I've take it out and it all seems fine!!!  I have the OBD2ECU updating the
speed at an acceptable rate too.

//.ichael

On Mon, 19 June 2023, 10:02 pm Michael Geddes, <frog at bunyip.wheelycreek.net>
wrote:

> *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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>>
>> --
>> Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
>> Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
>>
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