It says so...

Today I convolutional decoded the messages sent by PRN127.
Then I used the SBAS teacher to interprete the result and, well, you can see the message 9 yourself.

Fig. 1: "SBAS teacher" (contribute of ESA) to interpret MSG9.

X: 18521754.08 Y: 37836816.64 Z:1649068.8
that is
Lat: 2.24398167 Lon: 63.9174794 Alt: 35781111.72

See the snapshot of the view of the earth from the satellite!

Fig. 2: How actually the PRN127 bird sees the earth.

If my calculations are not wrong, from Nottingham is
Elev: 7.959023 Azim: 108.99077 Distance: 40797572.51

I leave comments to the readers :)

P.S.: Thanks to Massimo and Simone for your precious contributes!

Weird results (PRN127 is really GAGAN?)

Nothing special,
just posting some strange acquisition results I've been achieving in Nottingham (UK). How can it be that GAGAN signal (PRN127) was stronger than EGNOS?

Figure 1: INMARSAT 4-F1 (PRN127) orbit data. Courtesy of heavens-above.com

Fig. 2: The code search space, definitely an acquisition...

Fig. 3: The SBAS PRNs correlation result hystogram. PRN127 is stronger than PRN120, PRN124, and PRN126?


Fig 4: As a comparison, the GPS PRNs correlation result hystogram...


Fig. 5: And finally, ESA's creature (should I say Surrey's creature maybe?) is still happily transmitting its data... Go Galileo, go!


P.S.: The front-end is this time a Rakon GRM6800 (nice piece of hw believe me).

Giove-A acquisition with SiGe GN3S

The filter inside the GN3S is quite narrow, but in clear sky conditions, Giove-A E1C channel is easily detectable (thanks to my friend Luca for the images).
The frequency search space is ±5 kHz, the code is 8 ms long, thus about 130941 samples.
Fig. 1: The search space of Giove-A E1C

The typical BOC(1,1) correlation function shape is zoomed below:
Fig. 2: The correlation function zoomed around the peak

A certain smoothing of the peaks can be noted, certainly due to the filter characteristics mentioned above.

The SiGe GN3S signal spectrum (bought @ sparkfun.com)

Fig 1: The SiGe GN3S sampler signal spectrum