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An amateur MATLAB script for simple analyses of L1 C/A code.
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Homework.png
L1_generator.m
README.md

README.md

I had not enough time to adjust the code or develop it well. It was my homework and I needed to get it ready quickly before the deadline in spite of the lack of knowledge/experiences of signal applications :)

Here are a few notes for the script;

  1. PRN codes are verified
  2. The frequencies of NAV signal and PRN codes are downgraded by 10e3 coefficient to make the signal processing faster and make the signals on graphs more visible/analyzable.
  3. In BPSK Modulation function, the carrier signal has not the real frequency because of the reason above.
  4. I have a lot of lack of knowledge of signal analyses/applications for now, so I use a PSD function written by Daniel Pascual. It seems a general plotting, not special for my C/A codes.
  5. PRN generator functions are just for Space Vehicle 1 and 2, these functions and other functions can be generalized for all vehicles.
  6. For correlation graphs, the y axes limit of cross correlation plot should be set as [0 1] to get the same y axes with auto correlation plots, so the difference between auto-corr and cross-cor can be seen well.
  7. I plot the NAV+C/A graph during one period of NAV signal to show the signal behavior while NAV data is 1 and 0. Most probably, you need to zoom in to analyse the signals, because vertical lines are so close each other.

After I study on GPS/GNSS signals and general signal analysis topics well and feel ready to re-code this script or code a new script from the scratch, I will update this repo.

To-Do for Me;

  1. Draw the FFT graph of PRN correlations(raw and modulated)
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