A Global Positioning System (GPS) commercial receiver includes programmable logic that utilizes P-code modulated L1 and L2 GPS signals to derive estimates of in-phase and quadrature-phase components of both L1 and L2 signals, a programmable processor that calculates pseudoranges and pseudo-Doppler phases, and derives navigation solutions. A resulting complex accumulated L2 signal comprises near-ML estimates of desired L2 amplitude and pseudo-Doppler phase.