[time-nuts] Re: Please help. Motorola Oncore

[Marcelo Dantas]

Hi Everyone,

Good news.
I was able to resolve the issue by doing this:

Plugged the GT+ GPS, which goes onto the previous "can't find anything"
bad-almanac mode.
Open WinOncore and set the device to factory defaults.
Then set-up the device by passing my location, local time, setting timezone
to GMT-4 and setting it to GPS time, not UTC time.
After that the device starts sending out a message every second as
expected, then satellite signal bars magically start to appear.
In a minute or so the bad-almanac message disappears. Everything seems to
be ok.
I send the @@Bb 01 command to have it send out satellite location messages,
which populates the sky map.
If I do any other combination it will stay in the "can't find anything"
mode.

Once the GT+ was running for a while I sent the following commands in order:
record alm
@@Be 00
record alm c
This generated an almanac file on the WinOncore folder, which is completely
different from the .alm or .al3 ones we get online.

I then plugged in the UT+ (which at this point has no battery installed
anymore, therefore won't store any configuration/almanac).
Repeated the process plus loading the previously saved almanac.
It immediately "sees" the satellites and starts working normally (gotta get
a new battery for this one).

This is it.
I thank everyone for your guidance as it assisted me do further research
and dig deeper into the commands necessary to make it work.
Hopefully this info will help someone in the future.

Thanks!
Marcelo.



On Tue, Sep 20, 2022 at 5:15 PM Hal Murray <halmurray at sonic.net> wrote:

>
> > I am in NY, N 41.10.0481, W 074.11.2900, 408ft. So I enter this data
> into the
> > initial reference position. Telling the software to set it into the
> position
> > hold position. For the initial reference time I tried entering UTC time
> and
> > leaving the GMT offset +0, or my local time and setting the GMT offset
> to -4,
> > also some
>
> I would power cycle and try again without telling it the time or location.
>
> Getting started is tricky for a GPS receiver.  You might have nudged it
> into a
> stuck/buggy state.
>
> Doppler shift is significant and the signal is very low bandwidth.  Thus
> the
> receiver has to be listening on the right frequency in order to hear the
> signal from a satellite.
>
> If it has an up to date almanac and the clock is accurate and the position
> is
> known, it can figure out which satellites should be visible and calculate
> the
> frequency to listen on.
>
> If the clock or location is off a bit, it has to search near the predicted
> frequencies.  Warm start.
>
> If it doesn't have an almanac, it has to do a random search of all
> possible
> frequency buckets to find a satellite, then download the almanac.  Cold
> start.
>  It's roughly 15 minutes to get the whole almanac.  The satellite may go
> out
> of view while that is happening.  It may find another satellite...
>
>
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
>