[time-nuts] New (old) receiver

Jason Rabel jason at extremeoverclocking.com
Wed Mar 5 11:15:49 EST 2008


> Hi everybody;
>  I just got a Motorola Oncore+ GPS receiver for use with a disciplined
> Frequency standard I'm building and was wondering if anyone could tell me
> if it will be useful for this purpose.
>  The part number is R5122U1154. I know it's a bit late to ask this
> question after the purchase but I didn't find out till now that there are
> many receiver models for different uses. A learning moment for my
> education.
>  Regards, Bob K7hbg

I have a couple with the same firmware (3.1). Really the only difference
between that and the newest is the 100PPS fix as detailed below. But if you
aren't going to use the 100PPS then I wouldn't bother upgrading. I believe
Synergy GPS will upgrade the firmware for $25 per receiver (the firmwares
are not public domain).


Version 3.1 Released 4/99 Models: R5xxxUxxx4
. First position fix on power-up is now forced to 3D only. Subsequent fixes
may be 2D or 3D. Resulting new times to first fix are:
Hot Start (position, date, time, almanac and ephemeris): 20 s
Warm Start (position, date, time, olt and almanac): 50 s
Cold Start (no stored information): 450 s
. Date command (@@Ac) defect corrected when setting the base year
. Infrequent UTC navigation data decoding error corrected
. Message synchronization improvements to reject unhealthy satellite data

Version 3.2 Released 8/00 Models: R5xxxUxxx5
. Filtered and Unfiltered positions are now initialized to the same location
(0,0,0)
. Default date changed to 1/1/2000
. The 100PPS output has been corrected to prevent occasional pulse
misplacement







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