Performance Testing of a Real-Time Software-Based GPS Receiver for x86 Processors

摘要

Given the demanding computational requirements of software-based GPS receivers, high data processing efficiency is required to obtain real-time performance. There are two basic approaches to accomplish this: reducing the number of computations required, or improving the efficiency with which the computations are carried out. This paper takes the latter approach, primarily by using the MMX technology available on x86-compatible processors. The interface between hardware and software, fast acquisition through FFT methods, Doppler removal and code correlation are the focus of this paper. The real-time performance of the receiver in static mode is also reviewed in this paper.. It is demonstrated that FFT acquisition can deliver a fast acquisition method suitable for software receivers. Initial results indicate a reasonable tracking performance of the receiver while tracking up to eight channels in real-time. The single-point position and velocity accuracies are at the meter and decimeter per second level, respectively when using a 1 ms coherent integration time.