A Feasibility Study on Ground-based Localization for Mars Exploration
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
The goal of this work is to assert the feasibility of the use of a ground-based network, consist-ing of beacons, to aid in the provision of localization for mobile stations on Mars. The daysideionosphere can be utilized to refract and reflect radio signals to some receiver beyond the hori-zon. The propagation of radio signals is studied with the use of a simulation, which makes useof a ray-tracing method to track radio signals in the ionosphere.Several scenarios are defined to classify the state of the ionosphere. A nominal scenario isprovided, with ionospheric properties prevalent at Mars. Furthermore, scenarios are definedto include both a minimum and maximum solar activity, as well as dust storms and SEP events.The determination of the position of a mobile station can be done by exploiting the proper-ties of the received signal. Three localization technologies are studied in detail in this work,being the time of arrival ( TOA ), received signal strength ( RSS ) and angle of arrival ( AoA ). TheCramer-Rao lower bound ( CRLB ) is used to determine the lower bound of the precision of aposition estimate, produced by any of these technologies. A comparison of the obtained pre-cisions shows that it is possible to obtain a precision of less than 13m for any scenario whenusing TOA technology, and 6m when using AoA technology. Furthermore, a coverage of atleast 92 % is achieved in all but the most extreme scenarios. The coverage increases with de-creasing frequency. The best results are obtained with a frequency of 2.5M Hz. Moreover, itis shown that the best precision is obtained by placing beacons either in a rectangular or tri-angular grid on Mars, with beacons spaced 10 ◦ apart. By doing so, a 4m precision can evenbe obtained under the nominal scenario for a frequency of 2.5M Hz and 4.5M Hz with anytechnology. Ultimately, a ground-based beacon system has proven to be a sound solution toproviding positioning estimates on the Martian surface.
Place, publisher, year, edition, pages
2015. , 112 p.
Technology, Mars, Ionosphere, Localization
IdentifiersURN: urn:nbn:se:ltu:diva-45742Local ID: 36a8d96f-1f52-44d8-833d-041a5bbaf274OAI: oai:DiVA.org:ltu-45742DiVA: diva2:1019039
Subject / course
Student thesis, at least 30 credits
Space Engineering, master's level
Validerat; 20150824 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved