An NRZ and biphase-L formatted, three code hexaphase modulated GPS signal transmission communication method provides for the simultaneous modulation of the C/A code, the P(Y) code and a NEW code all modulating a single carrier for GPS use in one or both L1 and L2 bands. The use of the C/A code and the P(Y) code which are NRZ formatted with a NEW code biphase-L formatted and using hexaphase modulation on the three signals provides for spectral separation between the C/A code signal and the NEW code signal, all three modulated on a single carrier frequency.