Determination of geopotential difference by hydrogen masers based on precise point positioning time-frequency transfer

TL;DR

This paper demonstrates a method to determine geopotential differences between remote sites using hydrogen masers and precise point positioning time-frequency transfer, aligning experimental results closely with model predictions.

Contribution

It introduces a novel approach combining hydrogen masers and precise point positioning for geopotential difference measurement, validated through experiments.

Findings

Experimental geopotential difference closely matches model calculations.

The method is feasible and effective for remote geopotential measurements.

Results support potential applications in geodesy and Earth sciences.

Abstract

According to the general relativity theory, the geopotential difference can be determined by gravity frequency shift between two clocks. Here we report on the experiments to determine the geopotential difference between two remote sites by hydrogen masers based on precise point positioning time-frequency transfer technique. The experiments include the remote clock comparison and the local clock comparison using two CH1-95 active hydrogen masers linked with global navigation satellite system time-frequency receivers. The frequency difference between two hydrogen masers at two sites is derived from the time difference series resolved by the above-mentioned technique. Considering the local clock comparison as calibration, the determined geopotential difference by our experiments is 12,142.3 (112.4) m^2/s^2, quite close to the value 12,153.3 (2.3) m^2/s^2 computed by the EIGEN-6C4 model. Results show that the proposed approach here for determining geopotential difference is feasible, operable, and promising for applications in various fields.