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Independent Test Capability (ITC)ITC Synchronous Bus (ITCSB)
1553 and SpaceWire Interception
Justin MorrisSteven SeegerBrandon BaileyScott ZemerickMark Pitts
Jeff JoltesJustin McCartyDan NawrockiGary CarvellPeter Medley
ITC Team Members
Contact Us: [email protected] Website: http://itc.ivv.nasa.gov
External Website: http://www.nasa.gov/centers/ivv/JSTAR/ITC.html
Agenda
• ITCSB Description• ITCSB Features• ITCSB Interception• Current Use– Demonstrations
• Conclusion
NASA IV&V Facility Independent Test Capability 2
ITCSB Description
• Re-usable communication mechanism– Ensures consistent and correct data passing
among distributed simulation components
• Provides synchronization between distributed applications
• Flexible and extensible design– Can be extended to incorporate any
communication protocol
NASA IV&V Facility Independent Test Capability 3
ITCSB Features
• Transport agnostic• Cross platform C++ implementation• Robust User API• Specialized Layers:– MIL-STD-1553B– ESA SpaceWire– Time Sync
• Dynamic interception allows data manipulation – Without modification to software
NASA IV&V Facility Independent Test Capability 4
ITCSB Interception
• Dynamically added and removed• Priority-based• Block, pass, and modify data– Fault injection– Bus monitoring
• Available utilities– 1553 Interceptor GUI– SpaceWire Interceptor GUI– Various command line utilities
NASA IV&V Facility Independent Test Capability 5
Development & Interception
• ITCSB used to create simulation components– Useful for easy integration into simulation environment– Common libraries guarantee communication correctness
• Interception can come later– Development can occur without any consideration of interception– Dynamic nature of interception means it can be used later without
modification to simulation component
• Interception is future-proofing– Any work can be done later without modification to code– Code can be augmented by insertion of interceptions on the
network
• Development of interceptors separate from components
NASA IV&V Facility Independent Test Capability 6
Data Flow With Interceptor
Interceptor Modifying Data
Interceptor Blocking Data
ITCSB Interception
NASA IV&V Facility Independent Test Capability 7
Node A Node BITCSB
Interceptor
Normal Data Flow
ModifyBlock
Current Use
• GPM Operational Simulator (GO-SIM)• JWST IV&V Simulation and Test (JIST)
Environment
NASA IV&V Facility Independent Test Capability 8
ITCSB is the Main Communication Hub within GO-SIM and JIST
NASA IV&V Facility Independent Test Capability 9
NASA IV&V Facility Independent Test Capability 10
NASA IV&V Facility Independent Test Capability 11
Conclusion
NASA IV&V Facility Independent Test Capability 12
• ITCSB provides– Communications backbone for future simulation development– Synchronization for distributed simulation components
• Mitigates timing concerns
– Interceptors that allow the changing of data without modification to software under test
• ITCSB interception is the most beneficial feature for the IV&V analysts– Provides mechanism for fault injection– Allows for testing scenarios that are often impossible with
hardware