Satellite roll angle calculation method and on-orbit task planning method

The invention provides a method for calculating a satellite side-sway angle, which comprises the following steps of: firstly, calculating a moment te corresponding to the maximum value of a satellite elevation angle, calculating a moment ts corresponding to the minimum value of the distance from a ground target point to a satellite, then judging whether the values of te and ts are equal or not, if so, calculating the side-sway angle, and if not, calculating the side-sway angle. Wherein the side-sway angle is equal to the included angle between the position vector of the satellite at the te moment and the position vector of the ground target point, and if not, recalculating the numerical values of te and ts. The satellite top crossing moment of the ground target point is calculated, and the satellite deflection angle at the moment is solved, so that the remote sensing satellite earth observation task planning is realized, and the flexibility of the observation target point can be improved by adjusting the side