Useful links

http://www.techlib.com/electronics/index.html

http://ludens.cl/Electron/Electron.html

http://www.katjaas.nl/complexintegrator/complexresonator.html

Good information on GPS NMEA strings and parsing http://www.gpsinformation.org/dale/nmea.htm

Spread Spectrum

http://www.holmea.demon.co.uk/Spread/Spread.htm

http://www.tapr.org/ss_g1pvz.html#part_two