After many moons, I finally have something that may be of interest to
people.
kkGPS (for lack of a better name) is the beginning of a software GPS
receiver with software correlators. Right now it uses a 5MS/s simulated
noise free signal from six "satellites" with IFs of ~1.25MHz. The
software decodes subframes 1, 2, and 3 and uses ephemeris data to
calculate the user position.
Currently the correlators run about 4x slower then needed for a realtime
12 channel receiver on my P3 550Mhz with PC100 ram. A P4-HT 3.2Ghz with
PC3200 ram that I have access too seems to be able to run a ~30 channel
receiver in realtime. The SSE correlator is a work in progress.
This is prototype code, so excuse the mess.
THERE WILL BE MAJOR CHANGES MADE TO THE CODE.
http://www.kamieniecki.com/krys/gps/README.txt
http://www.kamieniecki.com/krys/gps/kkGPS-0.0.zip