@phdthesis{Drobczyk2024,
  author    = {Drobczyk, Martin},
  title     = {Ultra-Wideband Wireless Network for Enhanced Intra-Spacecraft Communication},
  doi       = {10.25972/OPUS-35956},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-359564},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2024},
  abstract  = {Wireless communication networks already comprise an integral part of both the private and industrial sectors and are successfully replacing existing wired networks. They enable the development of novel applications and offer greater flexibility and efficiency. Although some efforts are already underway in the aerospace sector to deploy wireless communication networks on board spacecraft, none of these projects have yet succeeded in replacing the hard-wired state-of-the-art architecture for intra-spacecraft communication. The advantages are evident as the reduction of the wiring harness saves time, mass, and costs, and makes the whole integration process more flexible. It also allows for easier scaling when interconnecting different systems. This dissertation deals with the design and implementation of a wireless network architecture to enhance intra-spacecraft communications by breaking with the state-of-the-art standards that have existed in the space industry for decades. The potential and benefits of this novel wireless network architecture are evaluated, an innovative design using ultra-wideband technology is presented. It is combined with a Medium Access Control (MAC) layer tailored for low-latency and deterministic networks supporting even mission-critical applications. As demonstrated by the Wireless Compose experiment on the International Space Station (ISS), this technology is not limited to communications but also enables novel positioning applications. To adress the technological challenges, extensive studies have been carried out on electromagnetic compatibility, space radiation, and data robustness. The architecture was evaluated from various perspectives and successfully demonstrated in space. Overall, this research highlights how a wireless network can improve and potentially replace existing state-of-the-art communication systems on board spacecraft in future missions. And it will help to adapt and ultimately accelerate the implementation of wireless networks in space systems.},
  subject      = {Raumfahrttechnik},
  language  = {en}
}
@phdthesis{Borchers2020,
  author    = {Borchers, Kai},
  title     = {Decentralized and Pulse-based Clock Synchronization in SpaceWire Networks for Time-triggered Data Transfers},
  doi       = {10.25972/OPUS-21560},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-215606},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2020},
  abstract  = {Time-triggered communication is widely used throughout several industry do- mains, primarily for reliable and real-time capable data transfers. However, existing time-triggered technologies are designed for terrestrial usage and not directly applicable to space applications due to the harsh environment. In- stead, specific hardware must be developed to deal with thermal, mechanical, and especially radiation effects. SpaceWire, as an event-triggered communication technology, has been used for years in a large number of space missions. Its moderate complexity, her- itage, and transmission rates up to 400 MBits/s are one of the main ad- vantages and often without alternatives for on-board computing systems of spacecraft. At present, real-time data transfers are either achieved by prior- itization inside SpaceWire routers or by applying a simplified time-triggered approach. These solutions either imply problems if they are used inside dis- tributed on-board computing systems or in case of networks with more than a single router are required. This work provides a solution for the real-time problem by developing a novel clock synchronization approach. This approach is focused on being compatible with distributed system structures and allows time-triggered data transfers. A significant difference to existing technologies is the remote clock estimation by the use of pulses. They are transferred over the network and remove the need for latency accumulation, which allows the incorporation of standardized SpaceWire equipment. Additionally, local clocks are controlled decentralized and provide different correction capabilities in order to handle oscillator induced uncertainties. All these functionalities are provided by a developed Network Controller (NC), able to isolate the attached network and to control accesses.},
  subject      = {Daten{\"u}bertragung},
  language  = {en}
}