[time-nuts] Ublox F9P multi-band GPS receiver

[Bob kb8tq]

Hi

In every other generation of uBlox parts, the “high end” modules (in this case the P and the T) pretty much did the same 
thing with only minor differences. You do need precise position to get precise time. You also need precise time to get precise
position. That’s just the way GPS works and always has worked. 

What gets us wrapped up are a bunch of specs that really are not very well qualified. Just what they mean be this or that
is rarely clear. Is a timing accuracy tracing it all the way back to BIH in Paris? Is a location accuracy doing the same sort 
of thing? Even when they try to quantify a spec, that footnote may or may not be completely correct. A lot of these docs 
still talk about the M8 parts when you drill down into them.

The only way to really know is to try some parts and see. That’s the way it’s always been with these modules from pretty
much all the vendors. 

Bob

> On Jan 25, 2019, at 6:07 AM, Mike Cook <michael.cook at sfr.fr> wrote:
> 
> So the ultimate question is: Do you need a F9P  in order to find the precise position of your F9T Antenna so that you can set up the F9T or is the F9T’s survey mode as accurate ( I doubt it as the doc gives position accuracy 2m ). Come to think of it, do you need three positioning receivers to be sure of your position? and three P9Ts so that you can use differential mode for best timing accuracy. I see no on board quantization error correction mentioned, nor quantization error reporting though I expect that is there, so for best accurracy that has to be added.  This looks as though it could get expensive.
> 
> 
>> Le 24 janv. 2019 à 07:30, Dustin Marquess <dmarquess at gmail.com> a écrit :
>> 
>> This looks ideal to me:
>> 
>> https://www.u-blox.com/sites/default/files/RCB-F9T_ProductSummary_%28UBX-18069985%29.pdf
>> 
>> -Dustin
>> 
>> On Wed, Jan 23, 2019 at 8:01 PM Angus via time-nuts
>> <time-nuts at lists.febo.com> wrote:
>>> 
>>> Hi,
>>> 
>>> It doesn't look like the F9P does anything special for timing - the
>>> timing specs given in the F9T spec sheet are 5 ns (1-sigma, clear sky,
>>> absolute mode) and +/- 4ns jitter, but for the F9P are 30ns RMS and
>>> 60ns for 99%.
>>> 
>>> I think I want an F9T :)
>>> 
> 
> In the year 1000 CE, the Persian Muslim scholar al-Biruni first used the term second in Arabic and defined it as 1⁄86,400 (that is, 1/(24 × 60 × 60)) of a mean solar day.
> 
> 
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