[Ovmsdev] Locations and scripts
Stephen Casner
casner at acm.org
Thu May 30 08:08:40 HKT 2019
I caught one! (An instance of a "vehicle on flatbed" alert while
recording a CAN log of the GPS data.)
What I see is a sharp deviation in the GPS position at the time of the
alert. So it may just be that I should set the alert threshold to a
larger value, or perhaps that the default value should be increased.
We might also make the trigger more robust by considering the rate of
change to be consistent with moving the car rather than a shift in GPS
position calculation.
The deviation that triggered the alarm was followed by a deviation of
larger magnitude about an hour later, but repeat alarms are disabled
until the car is turned on and then parked again. The duration of my
recording was approximately one day; I should probably gather more
data to see if I get any deviations that are even larger.
I've attached the data and my analysis for others to view. It is a
zip file containing four files:
location.crtd is the recording of CAN bus 1 with a filter for ID
0x100 and a hack to keep only records with data.u8[0] = 83, 84 or
85.
location.graf is the output of an awk script I wrote to graph the
deviations in the GPS latitude, longitude and altitude values.
These are output as a sequence of three X,Y timeseries with the X
values being GMT timestamps and the Y values being the difference
in the GPS coordinate values relative to the first sample in the
recording. The latitude and longitude values are in degrees; the
altitude values are in megameters to make them similar in scale to
the lat/lon. A fourth timeseries shows the calculated distance
relative to the first sample, again in megameters. A fifth
timeseries shows artificial values to mark GPS lock transitions;
there was no transition near the time of the alert. I translated
the CRTD timestamps to absolute time by equating the last log
timestamp with the log file write time, so there may be some
inaccuracy. The notification I received on my phone was at 21:30
GMT and in the data the spike begins at 1559079188.763 = 21:33:08.
wander.png is a large screenshot of the graph presented by a
little graphing tool named graf that runs under X on *nix and is
good for data exploration. If you are interested you can find the
source at https://github.com/kernelsid/graf
zoomed.png is a screenshot of the same graf session zoomed in on
the spike that triggered the warning.
The distance that triggered the warning was 640 meters, greater than
the 500 meter default threshold. The larger distance that occurred
about an hour later was 753 meters.
-- Steve
On Thu, 23 May 2019, Stephen Casner wrote:
> Finally, after some travel and other delays, getting back to this
> question of the false flatbed alarms. I've started logging with:
>
> OVMS# can log crtd /sd/location.crtd 1:100
>
> Plus I've hacked the filter function in canlog to save only those
> frames with data.u8[0] = 83, 84 or 85, so the total is about 5MB per
> day. I can leave that running for a while.
>
> -- Steve
>
> On Tue, 2 Apr 2019, Mark Webb-Johnson wrote:
>
> > The 'can log crtd ...' would be fine. That logs directly to disk, and would be the easiest for a replay (to try to recreate the problem).
> >
> > I don't think there is any easy way to pre-filter for B1, so the whole of ID 0x100 would be fine.
> >
> > If we can get a full crtd trace around the time of the problem, then get told 'I got a text notification of vehicle on flatbed at 7:50pm on 4th', we can narrow it down and replay just that part.
> >
> > Regards, Mark.
> >
> > > On 2 Apr 2019, at 2:53 PM, Stephen Casner <casner at acm.org> wrote:
> > >
> > > I think Mark is requesting "can log trace" rather than "can log
> > > crtd". For the former you have already implemented rotation of
> > > the log files based on max size as configurable in the web UI, right?
> > >
> > > -- Steve
> > >
> > > On Tue, 2 Apr 2019, Michael Balzer wrote:
> > >
> > >> I've used the trace command to log high volume CAN traffic, that's no problem (at least with a recent module having the SD speed fix).
> > >>
> > >> The tracing just lacks a file rotation, but that shouldn't be hard to add.
> > >>
> > >> Regards,
> > >> Michael
> > >>
> > >>
> > >> Am 02.04.19 um 04:58 schrieb Mark Webb-Johnson:
> > >>> I am not sure if the SD is fast enough to store can log files. It would not be too hard to start/stop logging in javascript (without code changes).
> > >>>
> > >>> Regards, Mark.
> > >>>
> > >>>> On 2 Apr 2019, at 10:28 AM, Stephen Casner <casner at acm.org> wrote:
> > >>>>
> > >>>> Well, for my car this event has occurred twice in a few months, so the
> > >>>> idea of running a CAN bus dump in a wifi session all the time is not
> > >>>> practical. What we would need would be a CAN bus dump to rotating
> > >>>> files, like the error message logging can do.
> > >>>>
> > >>>> -- Steve
> > >>>>
> > >>>> On Tue, 2 Apr 2019, Mark Webb-Johnson wrote:
> > >>>>
> > >>>>> Steve,
> > >>>>>
> > >>>>>> What should I look for when this false alarm occurs? Is it likely
> > >>>>>> that the alarm is issued when stable GPS operation is restored, so
> > >>>>>> what I really would need to see is a log of conditions before the
> > >>>>>> alarm?
> > >>>>> What we would ideally need would be at the time of the issue:
> > >>>>>
> > >>>>> metric list v.p
> > >>>>> CAN bus dump (can1) ID #100, B1=0x83,0x84,0x85
> > >>>>>
> > >>>>> I appreciate that is hard. Perhaps just leave a CAN bus dump running
> > >>>>> over wifi throughout the event? You could leave that running for
> > >>>>> hours. We could then replay that back through a box to recreate the
> > >>>>> issue.
> > >>>>>
> > >>>>>> And now that I have issued some messages in the app, how do I switch
> > >>>>>> back to other functions? Is there a way to make the keyboard drop and
> > >>>>>> then find the buttons at the bottom of the screen? (I realize that
> > >>>>>> restarting the app would be a solution.)
> > >>>>> Just click on the screen, away from the keyboard.
> > >>>>>
> > >>>>> Regards, Mark.
> > >>>>>
> > >>>>>> On 2 Apr 2019, at 5:47 AM, Stephen Casner <casner at acm.org> wrote:
> > >>>>>>
> > >>>>>> Mark,
> > >>>>>>
> > >>>>>> The false alarm occured again a few minutes ago. I wanted to use the
> > >>>>>> web shell UI to check some status, but using the new messages feature
> > >>>>>> of the iPhone app I found the wifi was wedged again. After I turned
> > >>>>>> wifi off and then back to client mode I would log in from the web
> > >>>>>> again. I issued a location status command that indicated good lock.
> > >>>>>>
> > >>>>>> What should I look for when this false alarm occurs? Is it likely
> > >>>>>> that the alarm is issued when stable GPS operation is restored, so
> > >>>>>> what I really would need to see is a log of conditions before the
> > >>>>>> alarm?
> > >>>>>>
> > >>>>>> And now that I have issued some messages in the app, how do I switch
> > >>>>>> back to other functions? Is there a way to make the keyboard drop and
> > >>>>>> then find the buttons at the bottom of the screen? (I realize that
> > >>>>>> restarting the app would be a solution.)
> > >>>>>>
> > >>>>>> -- Steve
> > >>>>>>
> > >>>>>> On Mon, 1 Apr 2019, Mark Webb-Johnson wrote:
> > >>>>>>
> > >>>>>>> I don't see this on the Model S vehicle.
> > >>>>>>>
> > >>>>>>> I suspect the issue is not handling GPS lock indicator correctly
> > >>>>>>> in the vehicle modules. For the roadster, we use ID#100, B1=0x85
> > >>>>>>> (GPS direction and altitude), B2==1 to control this, but that was
> > >>>>>>> always a 'best guess' without much data to back it up.
> > >>>>>>>
> > >>>>>>> Regards, Mark.
> > >>>>>>>
> > >>>>>>>> On 31 Mar 2019, at 11:12 PM, Stephen Casner <casner at acm.org> wrote:
> > >>>>>>>>
> > >>>>>>>> Mark,
> > >>>>>>>>
> > >>>>>>>> This message reminds me to mention that both Timothy Rodgers and I
> > >>>>>>>> have received false alarm car-theft notifications from OVMS. Have
> > >>>>>>>> you? I presume these are caused by temporary inaccuracy in the GPS
> > >>>>>>>> signal.
> > >>>>>>>>
> > >>>>>>>> -- Steve
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