DSP method to receive spread spectrum signals

A DSP (digital signal processing) method designed to process band-spread signals transmitted by Navstar GPS (Global Positioning System) navigation satellites is described. It can in general be applied to signals spread by binary codes. The signal is quantized by means of a hard limiter. This corresponds to a 1-bit A/D (analog/digital) conversion. The sine/cosine frequency conversion function is reduced to a square wave function. Mixers and low-pass filters are implemented by digital counters. A DSP reads the counters and performs the control loop functions. This hardware-optimized solution is presented and compared to a common analog realization. It is shown that the dynamic behavior of the hardware-optimized method is equal to that of the analog decoding method