Two-Way Time Transfer With Dual Pseudo-Random Noise Codes

We have developed a new Two-Way Satellite Time and Frequency Transfer modem in order to improve measurement precision and reduce operational costs. The new modem is based on software-defined radio technology. Transmission and reception of signals between distinct ground stations are based on a pseudo-random noise code similar to the one used for GALILEO or GPS's modernized ranging signal. Our developed signal is introduced by a pair of pseudo-random noise codes that are separated in the frequency domain. The advantage of this signal is that the operational costs are below those of conventional signals, but yield better precision. We have recently carried out Two-Way Time Transfer experiment using the new signal. For evaluation of time transfer precision, GPS observations have been taken at the same time. Results show that the measurement precision of the new signal is better than 100 ps, and clock behavior of two stations was found to be consistent compared with GPS carrier-phase time transfer.
See also ADM002186. Presented at the Precise Time and Time Interval Systems and Applications Meeting (40th Annual) held in Reston, VA on 1-4 December 2008. Published in the Proceedings of the Precise Time and Time Interval Systems and Applications Meeting (40th Annual), p459-466, 2008. The original document contains color images.