[time-nuts] Re: GPSDO/GNSSDO project: STM32G4 + u-blox ZED-F9T + TDC7200

[John Ackermann N8UR]

On 8/6/22 23:47, dk4ww at gmx.net wrote:

> RTK corrections works only from F9T to F9T.
> you need RTCM 7 ( MSM 7) messages. (RTCM 1077 and more)

Thanks for that, Uwe!  I looked at the ZED-F9T Integration Manual 
(section 3.1.5).  The info seems to me a bit incomplete, but it says:
"Time mode is a special receiver mode where the position of the receiver 
is known and fixed and only
  the time and frequency is calculated using all available satellites."

That doesn't reference whether the unit is the master or the slave, so 
the assumption is that it applies to both, I guess.  The manual gives 
the setup required to set timing mode and enter fixed position, and how 
to configure the master to output the necessary messages, but doesn't 
provide configuration for the slave.  Presumably it needs to be in (a) 
fixed position mode, and (b) have differential corrections turned on 
with the correct messages enabled.

There's a proprietary message, RTCM 4072.1, that must be received before 
the slave will sync.  I suppose that's u-blox's vendor lock-in.

John