A tracker architecture for Global Positioning System (GPS) receivers is disclosed. A typical tracker comprises an RF front end and GPS architecture. The architecture comprises a bus structure, a Central Processing Unit (CPU) core, cache, RAM, and ROM memories, and a GPS engine that comprises a receiving, tracking, and demodulating engine for GPS and Wide Area Augmentation Service (WAAS) signals. The GPS architecture can couple to at least two different protocol interfaces via the bus structure, where the protocol interfaces are commonly used in different applications.