The invention discloses a three-axis sun-oriented control method of a
satellite for a guaranteeing
satellite-earth link. The three-axis sun-oriented control method comprises the following steps: solving a projection of a sun vector under a
satellite orbit coordinate
system according to the sun vector calculated according to a
satellite orbit; establishing a sun-oriented reference coordinate
system according to the
satellite orbit and the definition of the satellite polarity, and calculating an attitude
quaternion of the sun-oriented reference coordinate
system relative to the
satellite orbit coordinate system; calculating an error
quaternion between an attitude
quaternion of a star relative to the satellite
orbit coordinate system and the attitude quaternion of the sun-oriented reference coordinate system relative to the satellite
orbit coordinate system; carrying out attitude
reference tracking according to a symbol of the error quaternion; and when continuously meeting that the error quaternion is smaller than a preset threshold value, establishing a
star sensor sun-oriented sign, carrying out three-axis stabilization sun-oriented control by virtue of a
star sensor, and otherwise, continuing to carry out two-axis sun-oriented control based on
sun sensor. By virtue of the three-axis sun-oriented control method, the smoothness of the satellite-earth link after the sun orientation of a sailboard can be guaranteed, and a near-optimal maneuvering path is guaranteed when a sun-oriented maneuvering manner is changed into a ground-oriented maneuvering manner.