On-orbit regression frozen orbit semi-major axis attenuation rate estimation method and estimation system thereof

The invention belongs to the field of spacecraft attitude determination and control, and particularly relates to an on-orbit regression frozen orbit semi-major axis attenuation rate estimation method and an estimation system thereof. Marking a descending node longitude of a nominal regression orbit and a nominal orbit period; carrying out validity judgment on the GNSS data, if the GNSS data are valid, putting the calculated data into the marked data, and if the GNSS data are invalid, returning; calculating an intersection period of a corresponding number of turns and a nominal orbital period; the intersection point period of the corresponding number of turns obtained through calculation is subtracted from the nominal orbit period, and the period change rate is calculated through least square according to the period difference; performing weighted filtering on the periodic change rate for calculation; calculating a semi-major axis attenuation change rate through the periodic change rate; and performing thresho