[time-nuts] LEA-M8T

[Tom Van Baak]

> The runs I did used a number of modules, not just uBlox products. Some modules
> did worse than others on position. I dropped them out of the group before I moved
> on to timing. 

Hi Bob,

I had access to a pre-release ublox combined GNSS receiver a few years ago and found the same thing. My conclusion was that for GPSDO timing use, a plain GPS-only receiver was superior.

Like I said yesterday, at some point in the evolution of GNSS integration and cooperation, the situation will improve. AFAIK there's no intrinsic, technical reason that multiple proprietary PNT systems can't perform better as a whole than one alone. But for a GPSDO it seems we're not there yet. Who knows how much receiver firmware or OOB internet access it will take to solve this. But it can be solved.

Note that these multi-GNSS problems are likely much less if you post-process or use common-view. But a cheap GNSS receiver in a GPSDO is in the awkward position that it only works with live signals.

Again if someone has links to technical papers on this topic, that would be welcome. 

/tvb