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

[Carsten Andrich]

On 06.08.22 00:50, Hal Murray wrote:
> All of the timing receivers that I'm familiar with assume a fixed location.
>
> Are you sure the F9T will work while moving?
> If so, does it maintain the same accuracy?

The F9T datasheet [1] specifies the "operational limits" as ≤ 4 g 
dynamics, 80 km altitude, and 500 m/s velocity. The time pulse accuracy 
(5 ns absolute, 2.5 ns differential) is specified only for "fixed 
position mode", so it may degrade when used on the move.

The F9P RTK positioning accuracy does not degrade substantially for 
non-stationary use, as far as I can tell without a 20k€ INS groundtruth. 
I hope the same applies to the F9T's timing performance. Verifying that 
is one of the reasons behind building the prototype.

[1] 
https://content.u-blox.com/sites/default/files/ZED-F9T-00B_DataSheet_UBX-18053713.pdf#page=4