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【范围】
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Application perspective
The bandwidth and resolution of aerospace remote-sensing payloads continue to advance, placing ever increasing
demands on onboard data-handling networks. At the same time, economics and rapid development requirements are
driving onboard data-handling networks toward flexible, nonproprietary architectures and interface standardization. These
characteristics are extensively addressed in existing ground-based net- works. However, unlike most ground-based
networks designed primarily to support the transfer of non-real- time data between computers, an onboard data-handling
network must support the real time needs of the aerospace remote-sensing environment.
Network perspective
Aerospace remote-sensing data is characterized by synchronous components, common to continuous mode sensors,
and asynchronous components, common to event driven sensors. Both sensor types have real time data-handling
requirements, and sensor performance is driving data bandwidth requirements into multiple gigabit per second range.
Even at these higher data rates, aerospace systems will continue to be constrained by size, weight, and power limitations.
In order to achieve high data-rate performance while maintaining low size, weight, and power, onboard data-handling
subsystems must employ highly integrated components and must avoid the higher layer protocol features commonly
found in ground-based networks. Furthermore, space-based data-handling networks must be fault tolerant and able to
withstand the rigors of launch and the harsh space environment.
Adaptation of existing ground-based network standards is not practical because of insufficient bandwidth and high power
dissipation. Also, conversion of current implementations to space qualifiable processes is not feasible. Therefore, a new
onboard data-handling network standard for aerospace remote-sensing applications is necessary.
Technology perspective
Fiber Optic and ASIC technologies have matured to the point that multiple gigabit data-handling networks for aerospace
applications are practical. Fiber Optic technology is especially appealing because of its extremely high bandwidth
capacity. Multimode fibers have been demonstrated to be radiation hard with negligible increase in signal loss over a ten
year life in space radiation environments. Space qualifiable connectors have been designed and built specifically for fiber
cable. Techniques for low loss termination and coupling of fibers have been perfected. High power laser diodes capable
of operation over a wide temperature range and low noise optical receivers are now available. State-of-the-art
semiconductor materials and processes, as well as packaging techniques, are leading towards smaller, faster, and lower
power devices that will enable high-speed data-handling systems for space applications.
This standard establishes the design requirements for a fiber optic serial interconnect protocol, topology, and media. The
application target for this standard is the interconnection of multiple aerospace sensors, processing resources, bulk
storage resources and communications resources onboard aerospace platforms. The standard is for subsystem
interconnection, as opposed to intra-backplane connection.
1.1 Purpose
The purpose of this standard is the specification of a highly reliable and fault tolerant fiber optic network that is compatible
with the harsh thermal, mechanical, and radiation environments of aerospace applications requiring small size and low
power dissipation. This standard will specify a node-to-node operating data rate range of 100 Mbps through 2.5 Gbps.
The standard will define physical and logical protocol, and sub-network management functions which allow mixing high-
speed synchronous and asynchronous distributed access for deterministic communications.strRefField
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