In nano-satellite missions, Software Defined Radios (SDR) have been widely used in the implementation of communication subsystems in order to increase the flexibilization both in the space segment and on the ground stations. Also, Commercial Off-The-Shelf components (COTS) are widely used to develop subsystems for nano-satellite missions in order to reduce development costs and because those are relatively easy to purchase especially for developing countries. However, COTS components are not space-certified and it becomes a problem when satellites are wanted to be used in high reliability missions. An example of that is Ten-Koh, a Low Earth Orbit (LEO) environment observation satellite developed in the Kyushu Institute of Technology in Japan, in which one of the top-level mission requirements was to re-use as much as possible the components utilized on a previous successful mission (Shinen-2) in order to mitigate the failure risks by using non-certified/non-space heritage components and to decrease the development time following the lean satellite design methodology. In this research, an SDR implementation for the space segment is proposed in order to optimize the communication system designed for Ten-Koh satellite. The proposed implementation consists of the integration of two COTS modules (a single-board computer with a radio frequency module) using embedded Linux, Python and GNU radio developing tools. The purpose is to demonstrate that the proposed system can be used safely in future satellite missions overcoming the design constraints, limitations and issues experimented during the Ten-Koh design and operation phases showing the improvements in terms of performance, flexibility, cost and development time. In addition to above, this research shows the on-orbit issues presented in the Ten-Koh mission due to the radiation effects and describes the facilities, equipment, methodology and results of a radiation test performed for the main processor used in the Ten-Koh mission and for the single-board computer used in the proposed SDR system in order to find the possible causes of the failures presented on-orbit and to compare the results for verifying if the proposed system can be used safely in the radiation environment on LEO orbit.九州工業大学博士学位論文 学位記番号：工博甲第498号 学位授与年月日：令和2年3月25日1 - INTRODUCTION|2 - TEN-KOH MISSION OVERVIEW|3 - TEN-KOH COMMUNICATION SYSTEM ARCHITECTURE|4 - PROPOSED SDR IMPLEMENTATION|5 - RESULTS AND DISCUSSION|6 - RADIATION TEST|7 - CONCLUSION九州工業大学令和元年
