Zhu Xiangwei

One-state and twice Kalman filter timescale algorithms

We first propose a one-state Kalman filter time scale algorithm, nand derive the analytical expressions of the weights and the predictions. nBased on the analytical expressions, we introduce the virtual Kalman nsampling time. The theoretical analyses and the simulations both validate nthat we can optimize the frequency stability on any one of the certain nobservation intervals of the time scale by means of choosing a certain nvirtual Kalman sampling time. Then, based on this algorithm, we propose na twice Kalman filter time scale algorithm, and describe the principle nof the algorithm. The forming time scale only involves walk random nfrequency modulation noise (RWFM), and does not involve white frequency nmodulation noise (WFM). The weights are in inverse proportion to the nintense of RWFM. The short-term and middle-term frequency stability nof the time scale is higher.

Analysis of Phase Noise Effect on Receiver-Transmitter Homologous System

Transmitter and receiver homologous system, which contains down-conversion, A/D sampling, digital signal management, D/A recovering and up-conversion, effect the signal passing through the system. This paper presents the corresponding signal transmission model of the system, analysis the influence of phase noise on the signal, and deduces the formula for the first time that describing signal changes caused by phase noise of standard frequency based on the suppose that time of receiving-ransmitting changed already. The conclusion shows that: the factor which is associated with the change rate of standard frequency is introduced to both the carrier frequency and code rate, this factor can be equivalent to a Doppler frequency offset, and the formula of the Doppler offset is deduced, Finally, the experimental results are consistent with the theoretical analysis conclusion.