Method to predict and fit antenna phase center of LEO satellite considering attitude information

A method to predict and fit an antenna phase center (APC) of a low Earth orbit (LEO) satellite considering attitude information, comprising:

• transforming a spacecraft body-fixed coordinate system to obtain a transformed spacecraft body-fixed coordinate system, and obtaining a transformation matrix from an orbital coordinate system to the transformed spacecraft body-fixed coordinate system;
• obtaining, according to the transformation matrix from the orbital coordinate system to the transformed spacecraft body-fixed coordinate system, corresponding rotation angles during a transformation process;
• wherein the transformation process is to make the orbital coordinate system rotate around an X-axis, a Y-axis and a Z-axis of the orbital coordinate system in turn;
• obtaining rotation angles of an orbit determination time period to predict rotation angles of an orbit prediction time period;
• obtaining, according to the rotation angles of the orbit prediction time period, a transformation matrix from the spacecraft body-fixed coordinate system to an Earth-fixed coordinate system corresponding to each prediction moment in the orbit prediction time period;
• obtaining, according to the transformation matrix from the spacecraft body-fixed coordinate system to the Earth-fixed coordinate system corresponding to each prediction moment in the orbit prediction time period, a correction vector from a center of mass (COM) to a phase center of a downlink signal antenna of a LEO satellite in the Earth-fixed coordinate system at each prediction moment in the orbit prediction time period;
• obtaining, according to the correction vector, an orbit coordinate of the phase center of the downlink signal antenna of the LEO satellite at each prediction moment in the orbit prediction time period to obtain an orbit of the phase center of the downlink signal antenna of the LEO satellite;
• and
• performing an ephemeris parameter fitting on the orbit of the phase center of the downlink signal antenna of the LEO satellite in a fitting time period.