Moon’s Positioning System. A comparative approach.
- Paper number
IAC-05-D1.1.05
- Author
Mr. Ignacio Javier Clérigo Vecino, University of Valladolid, Spain
- Year
2005
- Abstract
ESA’s Aurora Plan and George W. Bush’s 43rd Vision of Space Exploration predict a prosperous future for human space exploration. There is no doubt about Moon playing a key role in our preparation for Mars human journey. The use of Moon as an intermediate platform in complex missions has been discussed for decades and many future visions present a stable Moon base as a stepping stone in human space exploration. This scenario forecasts an increasing human and robotic activity on Lunar surface that will raise the need of an accurate way of navigation across the Moon. With a weak and irregular magnetic field (compasses are useless) and an homogeneous landscape, orientation on the Moon is not an easy question. This is even more problematic in robotic exploration. As robots evolve from command based to fully autonomous systems a precise navigation system becomes critical. The goal of this paper is to summarize and study the viability of three alternatives to implement a Lunar surface navigation system: a novel method that uses radio signals from Earth, a navigation satellite constellation and a classical approach based on star trackers. The proposed system relays on radio signals from the Earth and it works exactly in the same way as satellite navigation systems, but instead of satellites there are fixed Earth stations equipped with a high gain antennas and atomic clocks. Receivers at the Moon will use the signals from stations to resolve the trilateration problem and to estimate the position on the Moon near side surface. A more standard alternative based on Lunar MEO satellite constellation, like GPS or Galileo is also presented. It will provide global coverage and high accuracy real time position measurements. This options is suitable for any application but the deployment and operation costs are huge. Last approach discussed takes advantage of the fact that stars are always visible from the Moon’s surface. Star tracker compasses have been successfully employed in spacecraft attitude estimation but they can also be employed to estimate the local coordinates on the Moon. This is a cheap and medium-precise solution that can be recommendable when real time positioning is not a requirement. This paper compares accuracy, limitations and deployment costs for all these alternatives. A final recommendation for different scenarios and applications is proposed pointing up the possibilities to apply this technologies in navigation on space and on other planets.
- Abstract document