SBAS PRNs in GSV messages while generating GPS signal, USRP B210

[ArinaVetrova]

Hello, I'm trying to imitate GPS signal with gps_sdr_sim + USRP B210 USRP is conected via cable and attenuator to GNSS recevier GEOS 5

Generated signal wih command: ./gps-sdr-sim -e brdc1730.24n -l 60.000000,120.000000,100 -b 16 -d 500 -v

In generated signal I see only GPS PRNS:

02   89.4  63.5  21074375.2   4.9
03  142.9  17.6  23841091.6  11.4
08   96.5  12.2  24655937.5  12.8
10   18.6   9.6  24857832.7  10.4
14  217.3  65.9  20586596.1   4.7
17  261.7  51.2  21553103.5   5.3
19  264.1  22.3  23587355.2   8.2
21   70.9  47.9  21907183.5   5.8
22  272.6  60.7  21195404.2   4.8
24  330.9  15.5  23792933.6   8.5
30  215.3  10.3  24499806.0  11.9
32   41.0   7.6  25190432.7  11.7
Time into run = 500.0

Running signal with cmd ./tx_samples_from_file --args="master_clock_rate=52e6" --file gpssim.bin --type short --rate 2600000 --freq 1575420000 --gain 50 --repeat

I've tried different levels of gain + attenuators, couple of times I saw recevier fixed on translated coordinates, but al other time in NMEA messages I see untracked SBAS PRNs and sometimes PRNs of GPS satellites, like this:

What am I doing wrong? Thanks for help!

[Sselion]

I would like to say that I am not an expert on SBAS, so please check my claims.

SBAS (WAAS, Egnos, ...) using same base frequency as L1 GPS and E1 Galileo and its signal is modulated by own PRN. The receiver is trying to decode all satelite signal it can receive and sometimes it can evaluate a part of the signal that looks like it is from a satellite that is not simulated.

That's why you can see sometimes blinking satellite like Galileo or SBAS in received signal and I think, this is normal behaviour of receiver. As long as you don't get the data from these ghost satellites, I'd be fine.