Development and Application of A GNSS Signal Record／Playback Equipment

In this paper, a GNSS signal record and playback equipment is designed and implemented. This device takes advantage of the fact that the frequency converter(mixer) produces difference frequency and sum frequency. In the recording and playback stage, different frequency conversion methods are used, and the sum frequency and the difference frequency in the frequency conversion result are respectively used, so that the unwanted band among multiple GNSS signals with a farther frequency center is removed, only leaving a useful signal.The cost and complexity of the equipment have been reduced so that the acquisition and playback can be done using the inexpensive SDR platform. The device has been proved to be able to record and play back signals such as GPS L1／L2 and BDS B1, and can be widely used in teaching experiments, research and development of GNSS receivers, and scientific research fields.