Coverage Analysis of Lunar Communication/Navigation Constellations Based on Halo Orbits and Distant Retrograde Orbits

Abstract

With more and more missions around the Moon, a communication/navigation constellation around the Moon is necessary. Halo orbits, due to their unique geometry, are extensively studied by researchers for this purpose. A dedicated survey is carried out in this work to analyse the coverage ability of halo orbits. It is found that a two-satellite constellation is enough for continuous one-fold coverage of the north or the south polar regions but never both. A three-satellite constellation is enough for continuous one-fold coverage of both north and south polar regions. A four-satellite constellation can cover nearly 100% of the whole lunar surface. In addition, the coverage ability of another special orbit – distant retrograde orbit (DRO) – is analysed for the first time in this study. It is found that three satellites on DROs can cover 99·8% of the lunar surface, with coverage gaps at polar caps. A four-satellite constellation moving on spatial DROs can cover nearly the whole lunar surface. By combining halo orbits and DROs, we design a five-satellite constellation composed of three halo orbit satellites and two DRO satellites. This constellation can provide 100% continuous one-fold coverage of the whole lunar surface.

Multi-orbit Lunar GNSS Constellation Design with Distant Retrograde Orbit and Halo Orbit Combination

“…Analysis of the SVOP Values. Referring to the literature 9 , it is known that the period of the L1-point Halo orbit is about 8 to 12 days, the period of the L2-point Halo orbit is between 4 and 15 days, and the period of the DRO is concentrated between 6 and 28 days. To ensure the stability of the multi-orbital constellation, the period of the Where T stands for the orbital period, and the orbital period interval between each picture in the order is about 1.465 days; the colour value stands for the SVOP value; the horizontal coordinate stands for the lunar longitude and the vertical coordinate stands for the lunar latitude.…”

“…Weiren (2018) analyzed and designed the overall design of the point relay satellite communication mission based on the characteristics and technical difficulties of the L2-point relay satellite mission 8 . Gao (2020) proposed a lunar communication constellation design using a combination of Halo orbit and DRO, which is a five-satellite constellation consisting of three Halo orbit satellites and two DRO satellites that provides 100% continuous coverage of the entire moon's surface 9 . However, the communication constellation only has a one-fold coverage of the Moon, so it can only be used for real-time communication and not for navigation and positioning.…”

Comparison of Autonomous Orbit Determination for Satellite Pairs in Lunar Halo and Distant Retrograde Orbits

“…This suggests that we could use this combination if we were to deploy the satellite pair on such a configuration. The instability of halo orbits reduces with the increasing amplitude (Gao & Hou, 2020), which is also a property favoring this choice.…”

“…This problem can be solved by adding a certain out-of-plane amplitudes to generate spatial DROs. Quasi-periodic orbits are usually generated in this way (Gao & Hou, 2020;.…”

“…The second sub-problem will be the focus of our forthcoming paper. We remark that other factors that are required to be considered when designing lunar navigation constellations include coverage ability (Gao & Hou, 2020) and maintenance (Guzzetti et al, 2017), which are beyond the scope of the current study.…”