Numerical techniques for designing frozen repeat orbits as reference trajectories have been extensively studied for polar orbit missions. For near-equatorial orbits, larger perturbing forces are experienced at lower inclinations. The greater perturbations make such near-equatorial orbits’ long-periodic behavior much more sensitive to changes in initial conditions. Thus, a more careful selection of optimization parameters and a longer convergence time is often required. This makes the numerical optimization stage for a near-equatorial orbit more delicate. Past proven techniques involved a preliminary estimate, a first optimization for the initial osculating elements, and a second optimization to ensure end-cycle continuity. This paper first reviews these techniques specific to near-equatorial frozen repeat orbit design and evaluates them in comparison with polar orbit designs. Then, this paper counterproposes a more efficient orbit design scheme that reduces the design process from two optimizations to only one optimization with a filtering stage. As a result, the orbit design process is much more efficient and less prone to convergence issues, especially when addressing orbit end-cycle discontinuity.

用于将冻结重复轨道设计为参考轨迹的数值技术已被广泛研究用于极轨任务。对于近赤道轨道，在较低的倾角下会受到较大的扰动力。更大的扰动使得这种近赤道轨道的长周期行为对初始条件的变化更加敏感。因此，通常需要更仔细地选择优化参数和更长的收敛时间。这使得近赤道轨道的数值优化阶段更加精细。过去经过验证的技术涉及初步估计、初始密切元素的第一次优化以及确保结束周期连续性的第二次优化。本文首先回顾了这些专用于近赤道冻结重复轨道设计的技术，并与极地轨道设计进行了比较评估。然后，本文反提出了一种更有效的轨道设计方案，将设计过程从两个优化减少到只有一个优化和过滤阶段。因此，轨道设计过程更加高效且不易出现收敛问题，尤其是在解决轨道结束周期不连续性问题时。