Satellite communication simulator for Cubsats
Sammanfattning: The Miniature Student Satellite (MIST) is a project at the Royal Institute of Technology in Stockholm, Sweden. The goal of the project is to launch a satellite designed and constructed by different student teams. The satellite carries seven scientific experiments that continuously collects experiment data as the satellite orbits the Earth. When the satellite is launched, the communication link between the satellite and the ground station is an essential part. This communication consists of a radio link between the on-board computer through a radio module and the ground station on Earth. Satellite communication is not a new field and there exist predefined communication standards and protocols. These standards and protocols are quite extensive and need to be tailored for the specific mission. Once a satellite is launched, it is out of reach for further development. This makes it crucial that the software running on the on-board computer are well tested and correctly integrated with the mission control system (MCS) that are used the send commands to control the satellite from Earth. Since satellite radio equipment is expensive, this bachelor thesis describes how to set up, implement and test an end-to-end communication chain between the satellite on-board computer and the MCS using a hardware simulator. The simulator both mimics the functionality of an on-board radio and replaces the ground station and radio link. Communication standards and protocols are studied and investigated, alongside with on-board pre-implemented subsystem libraries and an MCS named Elveit from Solenix. As the simulator also replaces the radio link, data transfer errors such as data loss, data corruption and, connection time windows can be simulated and tested. The simulator development results in a feasible end-to-end communication chain between the on-board computer and the MCS. This includes mimicking and acting as a radio module against the on-board computer, simulation of the radio link with the possibility to add transmission errors and, acting as a ground station against the MCS. To ensure that the simulator performs as the on-board radio module, the simulator performance is tested against the on-board computer. These results can be compared with on-board radio module performance to make sure that the behavior is similar.
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