Spectral characteristics of generation after next satellite navigational sensors

Abstract

Upcoming space missions are expected to go farther from Earth and be more autonomous and self-sufficient. Most man-made satellites are controlled from Earth-based ground stations that also perform guidance and navigation functions. Onboard star trackers and GPS units are commonplace on satellites and part of the guidance, navigation and control systems, permitting in situ measurement and update to the guidance solution. However, without an extension of the network, GPS units are not expected to operate in deep space, making them suitable for spaceflight in the near-Earth orbits only. Star trackers, which use an optical payload, permit accurate pointing of the satellite via the methods of astrometry, but do not provide a full guidance and navigation solution. In this paper we explore characteristics of a generation-after-next satellite navigational sensor concept where, using optical or infrared spectral measurements in addition to the typical techniques of astrometry for locating stars, onboard autonomous computation of a navigational solution is possible. Spectral measurements allow estimation of stellar velocities, in addition to relative locations. We hypothesize that recent space missions have generated the star catalogs, with both position and velocity measurements, necessary to anchor measurements of the new conceptual sensor.