[time-nuts] Re: Ublox F9T tick to phase

[stefan.hegnauer at gmx.ch]

To the best of my knowledge there is no PID in ublox GNSS receivers for the state prediction, including the Z9T. There is a Kalman filter, though. It generates the (x,y,z,t) prediction and thus the time pulse, plus a number for the expected quantization error in the UBX-TIM-TP message due to the fixed frequency of operation (TCXO). I.e. every single hardware timepulse is off by the calculated respective quantization error. For best performance the timepulse quantization error **must** be taken into account.

The main influence you have on Kalman filter parameters is selecting the correct ‘dynamic platform model’ for your application, see the (F9T) integration manual for details. Yes, this may seem a bit corse.

\-Stefan