Wang: Sounds good! Thanks! Did you try it? Jean: many many thanks for sharing all the scripts! Your paper has caught my attention. I will print it and read it.
Marcus: I was not expecting to "see" the signal because I already knew it was under noise floor. My conclusion of "signal absence" was after my GPS receiver was not able to decode it when I replayed it with an USRP. However, due to my little knowledge of GPS, it did not occur to me any other way of searching, so I thank you for your suggestion. I nearly killed my pc with a naive approach. :P I need a wiser one. Sylvain: interesting. I will try that too. Thanks! 2015-08-21 9:07 GMT-03:00 Sylvain Munaut <246...@gmail.com>: > Hi, > > > are you sure you did not see GPS? The problem is that GPS is often below > the > > thermal noise floor and only detectable by the virtue of processing gain. > > I'd try and take a whole lot of samples (like: 2s worth of samples), and > > calculate the autocorrelation[1]. You should see peaks at multiples of 1 > ms, > > because that's the spreading code's period. > > You can also square the signal, then decimate it a bit and FFT it and > you'll see peaks at whatever doppler the sat currently has. (so you'll > see different peaks for different sats). > > > Cheers, > > Sylvain > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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