作者: Shen, ZY (Shen, Ziyu); Shen, WB (Shen, Wen-Bin); Zhang, SX (Zhang, Shuangxi)
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摘要: In this study, we propose an approach for determining the geopotential difference using high-frequency-stability microwave links between satellite and ground station based on Doppler cancellation system. Suppose a satellite and a ground station are equipped with precise optical-atomic clocks (OACs) and oscillators. The ground oscillator emits a signal with frequency f(a) towards the satellite and the satellite receiver (connected with the satellite oscillator) receives this signal with frequency f(b) which contains the gravitational frequency shift effect and other signals and noises. After receiving this signal, the satellite oscillator transmits and emits, respectively, two signals with frequencies f(b) and f(c) towards the ground station. Via Doppler cancellation technique, the geopotential difference between the satellite and the ground station can be determined based on gravitational frequency shift equation by a combination of these three frequencies. For arbitrary two stations on ground, based on similar procedures as described above, we may determine the geopotential difference between these two stations via a satellite. Our analysis shows that the accuracy can reach 1 m(2) s(- 2) based on the clocks' inaccuracy of about 10(-17) (s s(-1)) level. Since OACs with instability around 10(-18) in several hours and inaccuracy around 10(-18) level have been generated in laboratory, the proposed approach may have prospective applications in geoscience, and especially, based on this approach a unified world height system could be realized with one-centimetre level accuracy in the near future.
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