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<div class="moz-cite-prefix">Although filtering now I just got
another false alert while parking with perfect GPS situation:<br>
<br>
<span><tt>Currently at 51.322430;7.344803 (GPS lock; 10
satellites)</tt><br>
<br>
Alert: <br>
</span>
<div class="moz-text-plain" wrap="true" style="font-family:
-moz-fixed; font-size: 12px;" lang="x-western">
<pre class="moz-quote-pre" wrap="">Vehicle is being transported while parked - possible theft/flatbed (@51.322502;1.166667)</pre>
</div>
<br>
So it's not a small jitter, it's complete nonsense. That's with
GPS from the modem, may be different for car GPS.<br>
<br>
We'll need a different approach. Maybe ignore/drop GPS coordinates
too far from the last known position?<br>
<br>
Regards,<br>
Michael<br>
<br>
<br>
Am 26.11.19 um 21:31 schrieb Michael Balzer:<br>
</div>
<blockquote type="cite"
cite="mid:4ad12c2c-4b27-7dbd-7e5b-1b4824e78574@expeedo.de">
<pre class="moz-quote-pre" wrap="">Depends on the GPS source. On the modem it's 5 seconds.
If you're using GPS from the car, it depends on the sample frequency when parked / off.
But the low pass filter will pass a large step in distance also if it's a single one, so on an actual movement it will trigger before 5 samples have passed.
Regards,
Michael
Am 26.11.19 um 21:24 schrieb Stephen Casner:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Michael,
Good idea. How much time does 5 samples represent?
-- Steve
On Tue, 26 Nov 2019, Michael Balzer wrote:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">I've had my first false alert last night, from the log it seems caused by a single false GPS reading.
I've added smoothing over 5 samples to the distance check, that should eliminate the false alerts unless the GPS errors are huge or persistent.
I've also added the coordinates to the notification so we can see how large the error can become if it still occurs.
Regards,
Michael
Am 21.08.19 um 23:43 schrieb Greg D.:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Hmmpf.
Precession of the GPS constellation, perhaps? Folks in northern Nevada
or Idaho should be next...
Greg
Stephen Casner wrote:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Greg,
Mine has been quiet for the past couple of months without increasing
the alarm distance beyond the default 500 meters.
-- Steve
On Wed, 21 Aug 2019, Greg D. wrote:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">A quick follow-up to this thread...
I've noticed that since this past spring that the number of false alerts regarding the
flatbedding of my Roadster have taken a sharp spike upward. Neither my car's normal
parking spot in the garage, nor the location of my house / garage have changed. The
difference in frequency did not appear to coincide with a firmware update, so I'm at a
bit of a loss to explain it.
Has anyone else noticed this?
Did the Government make a change to the GPS satellite fleet?
Not an issue, really, but definitely something odd going on.
Greg
Stephen Casner wrote:
Greg,
Attached are graphs of your data. gregd.all.png shows all of the
data, and gregd.peak.png is the highest distance deviation of 369
meters, which is less than the default 500 meter threshold.
It looks like there is a diurnal pattern to the data with increased
deviations around midnight local time (the X axis times are UTC).
It also looks like your home elevation must be about 380 meters since
the altitude variable drops down to negative that amount frequently,
which would occur when that value is taken as zero (there is a special
case in the code to treat some values as zero).
I tried overlaying my data and yours, but there seems to be no
correlation between the peaks in my data and the peaks in yours.
Interestingly, my data does not show a similar diurnal pattern.
-- Steve
On Tue, 4 Jun 2019, Greg D. wrote:
200mb of logs sent to Steve for analysis....
Greg
Stephen Casner wrote:
Thanks. For me, today's log was much quieter. The maximum excursion
was 115 meters and it was roughly coincident with loss of lock.
-- Steve
On Fri, 31 May 2019, Greg D wrote:
Ok. I'll let it run for a few days and see what happens. Not planning to drive the ca
r until next week.
Greg
On May 31, 2019 2:11:31 PM PDT, Stephen Casner <a class="moz-txt-link-rfc2396E" href="mailto:casner@acm.org"><casner@acm.org></a> wrote:
On Fri, 31 May 2019, Greg D. wrote:
Tried this, and am not getting anything written to the file system
(vfs
ls /sd shows zero bytes in gps.crtd). Did I miss some sort of setup
step?
Nothing gets written (or at least the file size as reported is not
updated) until the recording is stopped with "can log off".
-- Steve
</pre>
</blockquote>
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<pre class="moz-quote-pre" wrap="">--
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
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<pre class="moz-quote-pre" wrap="">
</pre>
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<br>
<br>
<pre class="moz-signature" cols="144">--
Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
Fon 02333 / 833 5735 * Handy 0176 / 206 989 26
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