It is very hard to find raw RF data for analysis. The only source I was able to find on the internet was http://www.jks.com/gps/gps.html
It contains a 59 MB file, that has the following properties:
- Sample rate - 5.456 MHz
- Sample size - 1 bit per sample
- Sample order - within a byte bit 0 is the earliest sample, and bit 7 is the latest sample
- Intermediate frequency (IF) - 4.092 MHz.
It is important to note that the intermediate frequency is above half the sample rate - this will cause signals to be aliased down to 4.092 - (5.456/2) = 1.364 MHz, and the spectrum to be inverted.
If you download this file, and combine it with the project's C source, you will be able to experiment with this project and obtain a valid position fix. To do this, use the following command line
fsgps -s 5456000 -i 4092000 gps.samples.1bit.I.fs5456.if4092.bin