Processing Galileo

The first prototype of SdrNav20 is working these days to receive the Galileo signal in space.

Figure 1: First SdrNav20 assembled prototype.

Using a simple patch antenna, the first acquisition done using a 8MHz bandwidth reports the expected spectrum purity and signal properties.

Figure 2: Power spectrum of signal acquired on SdrNav20 channel 1. A bandwidth of 8MHz is wide enough for BOC(1,1), but not CBOC(6,1,1/11). A bandwidth limitation is anyway introduced by the antenna SAW filter as well.

Figure 3: Time series and histogram of the acquired signal. The gain of the satellite tuner was set to 60dB (RF) and 8dB (IF), which could not excite the second MSB of the MAX19505 ADC.

The acquisition of Galileo PFM shows the typical BOC(1,1) correlation shape.:

Figure 4: BOC(1,1) correlation shape, averaged on 100 codes (400ms).

A short file (for anybody to try his/her own acquisition) can be found here.

EDIT 27/12/2012: Acquiring with SdrNav20 Galileo-FM2 (Galileo-PFM seemed momentarily disabled)

Figure 5: Galileo-FM2 E1 correlation shape, averaged on 100 codes (400ms).

The messages on E1B looked good, but still dummy:

a98e40000000002aaaaa4f4f2ffb8000
00955555555555555555555544790000
a98ec0000000002aaaaa5063173b8000
3f4a63d11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f83b4db6d54000
3f4a63f11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f803cb10954000
3f4a64111ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f8225d9ad54000
00955555555555555555555544790000
a990c0000000002aaaaa4823ab3b8000
00955555555555555555555544790000
a99140000000002aaaaa6957e27b8000
3f4a64711ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f80a454ed54000
3f4a64911ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f803617e554000
3f4a64b11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f83be7d8154000
3f4a64d11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f813ff0c154000
3f4a64f11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f82b79aa554000
00955555555555555555555544790000
a99440000000002aaaaa6d48287b8000
00955555555555555555555544790000
a994c0000000002aaaaa726410bb8000
00955555555555555555555544790000
a99540000000002aaaaa531059fb8000
d3978d7c6c2e85281e379780ce9f8000

A sample file is here.

Adding to the above, SdrNav20 demonstrates acquisition of L2C and L5 (or Galileo E5a):

Figure 6: Power spectrum of L2C signal captured with SdrNav20

Figure 7: Signal acquisition of GPS L2C signal (only of enabled PRNs)

Figure 8: Power spectrum of L5 signal captured with SdrNav20

Figure 9: Signal acquisition of GPS L5 signal (only of enabled PRNs) 

Figure 10: Signal acquisition of Galileo-PFM on E5a

A couple of files for L2C and L5 are stored respectively here and here. Please mind that L2C acquisition (without assistance) can be a long process given the length of the codes :)

Cheers!

Michele

P.S.: The file name is self-explicative: fs is sampling frequency, fif is intermediate frequency, bw is bandwidth, interleaved I&Q has 'int8_t' type samples (pretty much as the GN3Sv2 used to output).