Shanghai Astronomical Observatory achieves high precision laser ranging before re-entry into the atmosphere of Tiangong-1

[China Instrument Network Instrument R&D] Recently, the re-entry of Tiangong-1 has become the focus of global attention. Prior to the release of information by China’s Manned Space Engineering Office, Beijing’s time was expected to reenter the atmosphere on April 1st ±1st. The prediction of the Tiangong-1 crash site needs to measure the current position and status of the Tiangong-1. The International Laser Ranging Fragmentation Group and relevant Chinese agencies are all organizing competent laser stations to carry out high-precision measurements.

According to the Tiangong-1 orbit forecast data provided by domestic professional forecasting agencies, the orbital altitude is currently less than 200 kilometers. The Shanghai Astronomical Observatory of the Chinese Academy of Sciences overcomes the problems of invisible optics and fast operation speeds. It successfully used the Laoshan 60 cm aperture satellite laser range finder at 0353 a.m. Beijing time to achieve Tiangong No. 1 laser ranging. The observation period was approximately 1.6. In minutes, a total of more than 12,000 valid observations were obtained, with a range accuracy of about 1 cm. This may be the last high-precision laser ranging before Tianmu No. 1 re-entry into the atmosphere. This successful survey provides valuable observational data for determining the Tiangong 1’s on-orbit position determination, on-track status, and drop point prediction.

The realization of centimeter-class laser ranging is due to the cooperation of laser radar developed by the Shanghai Observatory. This is an important load for the implementation of laser radar rendezvous and docking on the Tiangong 1 and has played an important role in the Tiangong 1’s multiple space rendezvous and docking mission. .

(Original title: High-precision laser ranging at the Shanghai Astronomical Observatory before achieving Tiangong-1's reentry into the atmosphere)