Objectives Haiyang-2 B(HY2B), launched on 24 October 2018, is the first satellite of Chinese marine dynamic environment monitoring mission. It is mainly used to detect various marine dynamic environmental parameters such as sea surface height, sea surface wind field, and gravity field.

Methods Precise orbit tracking and determination is very key for the mission. The reduced-dynamic precise orbit determination for HY2B was carried out utilizing the spaceborne GPS observation in January 2021 and the orbit accuracy was evaluated by means of four methods.

Results The results show that: (1) The average value of the carrier phase fitting residual is about 7.2 mm, and the three-dimensional position difference between adjacent arcs of 28 h orbit determination overlapping for 4 h is less than 1.5 cm. (2) Compared with the precision orbit ephemerides (POE) issued by Centre National d'Etudes Spatiales (CNES), the root mean square (RMS) average values of the difference in direction radial, along-track, cross-track and three-dimensional(3D) position are 1.5 cm, 2.0 cm, 1.4 cm and 2.9 cm, respectively. (3)The satellite laser ranging validation statistics RMS is about 2 cm. (4) By applying phase center variation model constructed by residual method, the 3D RMS difference with CNES POE product is reduced from 3 cm to 2.5 cm.

Conclusions In conclusion, high-precision HY2B satellite orbit products can be obtained basing on space-borne GPS observation of the HY2B satellite.