Tuesday, May 20, 2014

Galileo RTK with NV08C-CSM hw 4.1

Being European I am often subject to skepticism about Galileo and compelled to justify its delays and usefulness. Explaining why Galileo is better and needed is beyond the scope of my blog but IMHO there is one key selling point that not many people stress.

Galileo was designed from the ground up in close collaboration with the USA: GPS and Galileo share L1 (1575.42 MHz) and L5/E5a (1176.45 MHz). In the future, a dual frequency GPS+Galileo L1/L5 receiver will deliver products with an incredible ratio between (performance+availability)/silicon.
According to scheduled launches there could be 12+ satellites supporting open L1+L5 by the end of this year already.
In the meantime, NVS touches base first in the mass-market receiver domain by delivering consistent carrier-phase measurements for GPS+Glonass+Galileo.

I have recently run zero-baseline double-differences in static, perfect visibility conditions using a high-end survey antenna:
Figure 1: Galileo double differences in static zero-baseline (NV08C-CSM hw4.1)
Using E11 as reference, the carrier phase noise is well contained within 0.01 circles (2mm).
With RTKLIB I run a Galileo-only static IAR and the result is as expected:

Figure 2: Static IAR with Galileo only (4 IOVs)
The combined GPS+Galileo static IAR looks like this:

Figure 3: Static IAR with GPS+Galileo
Note the 12 satellites above the 10° elevation mask used in the computation of carrier ambiguities :)

Understandably, Skytraq is working on GPS+Beidou carrier phase and I may publish some results on that too although visibility of Beidou MEOs is not great from here.

In the meantime, for people who wonder where uBlox NEO6T stands in terms of GPS carrier phase noise in similar conditions to the above here it is my result:
Figure 4: GPS double differences in static zero-baseline (uBlox NEO6T)
Which shows similar noise levels to NV08C-CSM.

3 comments:

Đình Tú Vũ said...
This comment has been removed by the author.
Paweł Wysocki said...

Hi!

How did you enable Galileo signal reception on NV08C? I have two receivers, one with 4.08 firmware, second with 4.09 but none of them see Galileo sats. Only GPS, Glonass and SBAS (EGNOS).

Best Regards

Michele Bavaro said...

Hello, I think Galileo is still not enabled by default in stock FW. NVS has a Galileo enabled FW though and I used that, please try contacting them.