LAUSR

It is important for China's Land Observing Satellite-1 to run in a repeat ground-track orbit with almost constant altitude over the same geographical area, so the satellite can have a high-precision deformation monitoring capability. The strong continuity of reference trajectory and high computational efficiency of the algorithm are required in the satellite orbit design stage. To fulfill those requirements, we first propose a fast orbit design method based on objective dimensionality reduction and decoupling optimization, which makes the satellites drift naturally without additional propellant consumption. Besides, a completely different convergence standard for the orbit design is introduced, which greatly reduces the complexity of the optimization process by decreasing the optimization objective dimension. Meanwhile, an optimal strategy keeping the argument of latitude constant is proposed, which reduces the coupling characteristics among optimization objectives. In addition, the optimization model of the repeat ground-track orbit is established. Then, the steepest descent method is introduced to solve this optimization problem. Simulation results in the high-order gravity force reveal that the position accuracy and velocity accuracy of the reference trajectory are up to millimeters and centimeters per second respectively. The calculation efficiency of our method is about 56 times faster than that of the NSGA-II method.