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The topology of an onboard computer network is determined by the physical location of nodes (sensors, computer modules, databases, etc). Data flows in network are determined by a sender and receiver pair (or set of receivers in case of multicasting). A packet flow could be organized through a number of intermediate switches. Time division multiple...
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Citations
... It can be implemented in SpaceWire/GigaSpaceWire networks, (Raszhivin, 2013). Terminal nodes are responsible for data transmission only in allowable for them timeslots (Figure 14). ...
Quality of service (QoS) requirements such as priorities, packet delivery and packet delivery time are important and critical for embedded networks and networkson-chip (NoC) [1]. We consider mechanisms for QoS support in the SpaceFibre, SpaceWire and GigaSpaceWire protocols, possibility of using them in embedded networks and NoC. In the article we analyze approaches for QoS provision, their feasibility and value of QoS in SpaceWire/GigaSpaceWire and in SpaceFibre networks. Networks with different topologies and traffic pattern are used to study and to evaluate the performance. Various traffic types such as the data packets, streaming data, commands will be transmitted in networks. Data delivery characteristics for SpaceFibre and SpaceWire/GigaSpaceWire networks are analyzed and compared. Also we compare characteristics that are achievable in NoC, which are based on QoS mechanisms of SpaceFibre, SpaceWire and GigaSpaceWire. Hardware costs are one of the main constraints for embedded networks and NoC. Therefore we compare hardware costs of basic SpaceFibre, SpaceWire and GigaSpaceWire routers.
... It can be implemented in SpaceWire/GigaSpaceWire networks, (Raszhivin, 2013). Terminal nodes are responsible for data transmission only in allowable for them timeslots (Fig.14). ...
Embedded systems are widely used in many fields, from space industry to medicine. In this paper we consider Quality of Service (QoS) in embedded networks. Different QoS are analyzed. The authors consider three structures and implementations of the network layer for providing QoS, compare their implementation characteristics and evaluate hardware costs. They consider QoS mechanisms support in modern space network protocols, possibility of using them in embedded networks. Hardware costs are one of the main constraints for embedded networks. Therefore hardware costs of basic routers with these QoS mechanisms are compared.
... Research into the configuration of schedules for SpaceWire-D networks is ongoing at the University of Dundee and elsewhere [5] [6]. Figure 2 shows an example schedule for a single initiator with 64 time-slots and a combination of different virtual bus types [3]. ...
SpaceWire-D is a deterministic extension to the SpaceWire protocol designed to satisfy hard real-time constraints on a SpaceWire network. This allows a single SpaceWire network to be used for both control applications and payload data-handling. The Atmel AT6981 Castor device is a LEON2-FT based system-on-chip with multiple integrated peripherals including an eight-port SpaceWire router and three internal SpaceWire engines each containing three DMA channels, an RMAP initiator, and an RMAP target. This paper describes the SpaceWire-D protocol; the design of RTEMS networking software to test the protocol using the AT6981 system-on-chip; and the results of those tests.
Arase is a small scientific satellite program conducted by the Institute of Space and Astronautical Science/Japan Aerospace Exploration Agency, which is dedicated to the detailed study of the radiation belts around Earth through in situ observations. In particular, the goal is to directly observe the interaction between plasma waves and particles, which cause the generation of high-energy electrons. To observe the waves and particles in detail, we must record large volumes of burst data with high transmission rates through onboard mission network systems. For this purpose, we developed a high-speed and highly reliable mission network based on SpaceWire, as well as a new and large memory data recorder equipped with a data search function based on observation time (the time index, TI, is the satellite time starting from when the spacecraft is powered on.) with respect to the orbital data generated in large quantities. By adopting a new transaction concept of a ring topology network with SpaceWire, we could secure a redundant mission network system without using large routers and having to suppress the increase in cable weight. We confirmed that their orbit performs as designed.[Figure not available: see fulltext.].
