Ship-borne dynamic absolute gravity measurement based on cold atom gravimeter

Abstract

Cold atom gravimeter is gradually developing towards miniaturization, dynamics and practicality. It is of great significance to apply it to deep and far sea absolute gravity measurement and underwater long navigation time and high-precision navigation. At present, most cold atom gravimeters are still in the state of laboratory static base or quasi-static base measurement, which is difficult to meet the gravity measurement needs in dynamic application scenarios. Therefore, the research on "static to dynamic" of cold atom interferometric gravity measurement is very urgent and key. In this paper, the basic principle of dynamic measurement is analyzed, the basic method of combined measurement of cold atom gravimeter and accelerometer is given, a set of absolute dynamic gravity measurement system based on cold atom gravimeter and inertial stabilization platform is built, and the ship-borne dynamic measurement experiment is carried out by using the combined measurement method of cold atom gravimeter and traditional accelerometer. Firstly, the continuous absolute gravity measurement for about 40 h is carried out in the laboratory static environment to preliminarily evaluate the performance of the cold atom gravimeter. The sensitivity is 447 µGal/<inline-formula><tex-math id="M2">\begin{document}$\sqrt {{\text{Hz}}} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20220113_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20220113_M2.png"/></alternatives></inline-formula>, and the long-term stability can reach 2.7 µgal. On this basis, the ship-borne experiment is conducted, the survey ship sails on the lake at a speed of about 4.6 kn, and the ship-borne absolute dynamic gravity measurement is carried out by means of repeated survey lines. After evaluation, the internal coincidence accuracy of the four repeated survey lines is 2.272 mGal, and the external coincidence accuracy values of the four voyages are 2.331, 1.837, 3.988 and 2.589 mGal respectively. Finally, according to the experimental results, the possible problems are further analyzed and summarized. This experimental study provides preliminary verification and technical scheme reference for marine absolute dynamic gravity measurement.