Abstract-Distributed satellite systems are large research topics, spanning many fields such as communications, networking schemes, high performance computing, and distributed operations.
12DARPA's F6 fractionated spacecraft mission is a prime example, culminating in the launch of technology demonstration satellites for autonomous and rapidly configurable satellite architectures. Recent developments at Surrey Space Centre have included the development of a Java enabled system-on-a-chip solution towards running homogenous agents and middleware software configurations.Modern commercial agent middleware solutions are typically written in Java which is unsuited to real-time mission critical embedded systems due to problems with large standard libraries, a slow and undeterminable execution model, and dynamic class loading times; to name a few reasons. To overcome these issues, an investigation into real-time Java processing & execution technologies has explored methods of implementing hardware-based Java runtime environment (JRE) or Java virtual machine (JVM) for embedded systems. This paper discusses the key experimental parameters, such the agent application footprint and performance as well as the stack call depth and memory profiling of these threaded behaviours on differing Java execution platforms. A standard agent middleware application which implements IP-based networking was used for experiments towards delay tolerant operations. Additional benchmark applications on many Java-based platforms were also ran to estimate the stabilities and real-time capabilities on emulated and real embedded hardware. ...............................................................8 REFERENCES ........................................................................9 ACKNOWLEDGEMENTS ...................................................... 10 BIOGRAPHY ...................................................................
BACKGROUNDIn terrestrial systems, more recent key technologies include distributed computing used in intranets to distribute computationally intensive tasks and wireless network technologies such as those found in laptops for the Internet. Distributed computing is typically enabled by middleware, a software layer offering services to connect software components across a network for integration or sharing computing resources. Java based technologies have been key in enabling many distributed applications using the internet protocol suite (IP) and existing application programming interfaces (APIs). In space systems, like other terrestrial systems, the use of IP has become prevalent and has been used on numerous missions Terrestrial distributed computing is applied to two very different areas. One area aims at highly networked, high performance computing (HPC) for virtual organizations with extremely large pools of resources. The other targets embedded environments, such as wireless sensor networks (WSN), where computing ability, memory, power and communications are extremely limited compared to high performance co...