Design and Implementation of a Real-Time Three-Frequency COMPASS Software Receiver

GNSS software-defined receiver is of importance in satellite navigation system, especially in the fields of receiver design and satellite navigation system scheme validating. The general scheme of COMPASS software receiver has been proposed, and the main software functional modules were designed using XML language. A real-time software receiver with 12 channels on PC platform has been implemented, which can process COMPASS B1/B2/B3 C (civil) code signal. The receiver can be capable of post-processing datasets from collection hardware or real-time processing data stream through PCI bus interface. A lot of performance improvement approaches have been proposed to enhance the speed of the software receiver, which include computational platform choosing, acquisition and correlator arithmetic optimization, program code optimization with SIMD instructions on CPU and CUDA instructions on GPU. Using this methods, the software receiver can reach real-time processing capacity under 80 MHz sampling rate and 2 bit quantization conditions. The positioning results show that the software receiver's three-dimensional positioning accuracy is superior to 10 m under 95 % confidences.