The invention provides a tangential low-thrust in-
orbit circular orbit calibration method based on (Global Navigation
Satellite System) GNSS precise
orbit determination. The calibrated tangential thrust F is used for controlling a
spacecraft orbit, and the tangential low-thrust in-orbit
circular orbit calibration method is characterized by comprising the following steps: measuring by utilizing a GNSS to obtain the
spacecraft position information, and performing a
Unscented Kalman filtering method to obtain estimated values of
spacecraft position and velocity information under a J2000 coordinate
system; calculating an instantaneous orbit semi-major axis of a spacecraft according to the estimated values of the spacecraft position and the velocity information; averaging the instantaneous orbit semi-major axis in the orbital
nodal period before each measurement moment to obtain the average orbit semi-major axis at the moment; and subtracting the average orbit semi-major axes before and after the action of the tangential thrust of a
circular orbit to obtain orbit semi-major axis variation
delta a, and calculating the tangential thrust calibration value of the circular orbit according to the
delta a. In the calculation process, the GNSS is completely used to obtain the real-time orbital data without data support of a
ground station, and the calibration method has accurate and reliable result and simplicity in calculation and is easy to realize.