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Decentralized and Pulse-based Clock Synchronization in SpaceWire Networks for Time-triggered Data Transfers

Borchers, Kai (2020) Decentralized and Pulse-based Clock Synchronization in SpaceWire Networks for Time-triggered Data Transfers. Dissertation, Universität Würzburg.

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Official URL: https://opus.bibliothek.uni-wuerzburg.de/frontdoor/index/index/year/2020/docId/21560


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.

Item URL in elib:https://elib.dlr.de/140212/
Document Type:Thesis (Dissertation)
Title:Decentralized and Pulse-based Clock Synchronization in SpaceWire Networks for Time-triggered Data Transfers
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Refereed publication:Yes
Open Access:Yes
Number of Pages:173
Keywords:Communication; FPGA; Formal verification; SpaceWire
Institution:Universität Würzburg
Department:Fakultät für Mathematik und Informatik
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space System Technology
DLR - Research area:Raumfahrt
DLR - Program:R SY - Space System Technology
DLR - Research theme (Project):R - Scosa Onboard Computing (old)
Location: Bremen
Institutes and Institutions:Institute of Space Systems > Avionics Systems
Deposited By: Borchers, Kai
Deposited On:11 Jan 2021 08:41
Last Modified:11 Jan 2021 09:46

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