Research - Satellite constellations - rosettes with intersatellite links and double surface coverage

two separate moving planes of satellites A rosette satellite constellation with intersatellite links has two locally-separate surfaces of interconnected satellites over ground terminals - one mesh of interconnected satellites ascending, i.e. moving northward from south to north, the other mesh descending from north to south.

This layering of redundant meshes affects satellite coverage, the network design for that constellation, and routing of traffic across that constellation. The redundancy of two overlapping mesh fabrics arguably makes the second layer of intersatellite links unnecessary, which is why most low-orbit constellations with intersatellite links use polar Walker star geometries with a single mesh layer (a cut torus), and not inclined Ballard rosettes or Walker delta constellations (spindle tori). Connecting the meshes locally is considered difficult, as the ascending and descending satellites move past each other rapidly, requiring very fast tracking and frequent intersatellite link handovers.

The deployed Iridium and Iridium NEXT are polar Walker stars with intersatellite links. Teledesic, most famously, and LeoSat, most recently, proposed the same. Still, there have been proposals for rosette constellations using intersatellite links that must take account of this coverage property: in the 1990s, Motorola's M-Star and then Celestri, and now most of Telesat and SpaceX's Starlink.

Work related to double surface coverage includes:


Lloyd Wood (lloydwood@users.sourceforge.net)