According to the differential technology of carrier phase smoothed pseudo-range in the application of high-precision measurements, the principle of single-frequency and dual-frequency carrier phase smoothed pseudo-range are derived in this article, and then the model of those are given. The precision of single-frequency and dual-frequency differential navigation positioning are compared and the advantages of dual-frequency carrier phase smoothed pseudo-range positioning are analyzed. The experiment shows that the differential position precision can obtain the level of sub-meter.