Abstract
The global coverage of a Sun-synchronous orbit is investigated in this paper to provide reasonable references for the orbit design of remote-sensing satellites. Firstly, the connection between revisiting and repeat ground-tracking is bridged applying the concept of Q value. Starting from the Q-value-determined base interval, a mathematical expression is derived for the accessing sequence of the nodes. Then, the coverage percentage is acquired by mixing the accessing sequence and coverage area, which depends on the orbital altitude and observation angle. Finally, the coverage of a satellite in a Sun-synchronous orbit is illustrated from three aspects: time-varying coverage percentage, minimal coverage time and minimal observation angle required by global coverage. Validation of the existing satellites' parameters shows that the method proposed in this paper is simple but effective, and these coverage analyses will contribute to shortening the time to design an optimal Sun-synchronous orbit for remote-sensing satellites.
