Orbit determination of spacecraft in orbit has been mostly dependent on either GNSS satellite signals or ground station telemetry. Both methods present their limitations, however: GNSS signals can only be used effectively in earth orbit, and ground-based orbit determination presents an inherent latency that increases with the Earth-spacecraft distance. For spacecraft flying formations, an alternative method of orbit determination, independent of external signals, consists in the observation of the spacecraft’s position with respect to the central body through the relative positioning history of the spacecraft within the formation. In this paper, the potential of the relative positioning method is demonstrated in the context of the SunRISE mission, and compared with the mission’s previously proposed orbit determination methods. An optimization study is then made to find the optimal placement of a new spacecraft in the formation so as to maximize the positioning accuracy of the system. Finally, the possibility of removing part of the system’s relative bearing measurements while maintaing its observability is also studied. The resulting system is found to be observable, but ill-conditioned.

在轨航天器的轨道确定主要依赖于 GNSS 卫星信号或地面站遥测。然而，这两种方法都存在局限性：GNSS 信号只能在地球轨道上有效使用，而基于地面的轨道确定存在固有的延迟，该延迟会随着地球与航天器距离的增加而增加。对于航天器飞行编队，另一种独立于外部信号的轨道确定方法包括通过航天器在编队内的相对定位历史来观察航天器相对于中心体的位置。本文在 SunRISE 任务的背景下展示了相对定位方法的潜力，并与该任务先前提出的轨道确定方法进行了比较。然后进行优化研究，以找到新航天器在编队中的最佳位置，从而最大限度地提高系统的定位精度。最后，还研究了在保持其可观测性的同时去除部分系统的相对方位测量值的可能性。由此产生的系统被发现是可观察的，但病态的。