Localization of Rovers on the Lunar Surface using the Monopulse Technique

Kurzfassung

The interest in the Moon has significantly increased in the recent years due to the fact that the International Space Station will retire in the near future and because of the increased space activity of private companies. However,one major challenge of currently planned Lunar missions is the provision of cheap and reliable energy, restricting most missions to short durations and reducing mobility. In order to overcome this problem, the LunarSpark company envisions launch-ing a space-based power plant to orbit the Moon. This system can pro-vide energy via laser to customers on the Lunar surface and thus eliminates the problem of cheap and reliable energy. Further, the system shall au-tonomously detect the coarse relative position between the satellite and the customer. This is needed in order to trigger a laser-based localization of the exact customer position, as it is already commonly performed in laser-based communication systems. LunarSpark decided to deploy a Radio-Frequency (RF) beacon on the cus-tomer system. This beacon is used to retrieve a coarsely estimated customer position via microwaves and is investigated in this thesis. The monopulse technique is used for this purpose because unlike a radar measuring Doppler and distances, which is sensitive to topography and spatial position uncer-tainties when converting to the relative angular position, the monopulse technique allows to directly measure the angular direction. Thus, this work analyzes the requirements that such an RF beacon needs to fulfill for the monopulse technique, as well as how its operation fits into the overall opera-tional timeline of the LunarSpark system. In addition, it also establishes the design parameters of this beacon. The work is supported with theoretical and simulated performance analyses to derive the final design parameters.