Tianwen-1 Radio Occultation Observation Experiment and Feature Analysis

Abstract

China’s Tianwen-1 probe orbiting Mars provides necessary conditions for Mars-to-Earth Mars radio occultation observation, and can effectively support the exploration of Mars atmosphere and ionosphere retrieval. In this paper, the first domestic Mars radio occultation observation experiment based on Tianwen-1 was introduced. Firstly, Tianwen-1 was used to forecast the orbit and the occultation observation arc of the ground deep space station. Then, deep space stations were organized to observe the entire process of Tianwen-1 Mars occultation, and the original downlink signals of the probe were sampled and recorded. Finally, the self-developed deep space open-loop measurement software was used to process and analyze the downlink signals of Tianwen-1, to extract the radio occultation features of Mars. The results show that the amplitude diffraction speckles and frequency warping features in the signal were successfully extracted, which confirms that the Mars-to-Earth Mars radio occultation event has been effectively observed, and important technical experience and measurement data have been accumulated for subsequent scientific research on Mars atmospheric exploration based on Tianwen-1.

Keywords

Tianwen-1 / radio occultation / Mars atmosphere / atmosphere retrieval / feature analysis