Harvey Mudd College
Gold Codes are XORed combinations of taps from Linear Feedback Shift Registers (LFSRs). This is used in spread-spectrum communications, including the Code-division multiple access (CDMA) that GPS satellites use.
The GPS reference used to find the taps for the C/A code is [http://www.naic.edu/~phil/rfi/gps/AFD-070803-059-1.pdf].
See also:
All GNURadio flowgraphs are at https://github.com/gallicchio/learnSDR