Preliminary results of postprocessing G12 raw data

I prepared a couple of RINEX files (using programs that you can download here) generated from a GPS12 and a GPS12XL placed about 15 mts. apart and put them into a GeoGenius project along with some Broadcast Ephemeris obtained from the net.

These were the results for the baseline (DX,DY,DZ):

LogTime DX(mt) DY(mt) DZ(mt) SigmaDX(mm) SigmaDY(mm) SigmaDZ(mm) SigmaN(mm) SigmaE(mm) SigmaH(mm)

5 min 10.8655 5.3768 -11.4147 25.1 45.9 29.5 25.4 46.1 29.0

10 min 11.0570 5.5441 -11.2064 8.3 15.7 9.9 8.4 15.7 9.7

Then, I downloaded some EUREF data from a reference station (MAD2) about 30 Km from my position (I think it is the NASA satellite tracking facility in Robledo de Chavela, for those who know). The results, using also 10 minute data were:

LogTime DX(mt) DY(mt) DZ(mt) SigmaDX(mm) SigmaDY(mm) SigmaDZ(mm) SigmaN(mm) SigmaE(mm) SigmaH(mm)

10 min 4086.8462 34848.2643 -2007.3460 43.9 43.6 26.7 25.3 44.4 43.9

The complete reports for the three processed baselines as generated directly by the postprocessing package can also be checked here (report1,report2, report3).

Some remarks:

• The postprocessing was done as static. Larger errors are expected without the avantage of knowing that we are not moving.
• I have had the postprocessing software for one day, and didn't look at the manuals, so I might be doing some major blunder. For instance, I don't know what is the meaning (level of confidence) of their sigmas.
• These results are way too good to be true (that is, I doubt that they can be consistently reproduced). I'll have to go two or three times more to the very same spot and record more data.
• The given solution corresponds to a float double difference solution. The demo version of the software doesn't allow integer ambiguity resolution. However, given the comments from Sam Storm van Leeuwen in a recent post about the half-cycle ambiguity of the GPS12, it is quite likely that any algorithm trying to finding integer ambiguities won't work.

In conclusion, despite the low figures obtained, I wouldn't expect much more than a around-the-meter accuracy. Let's see.