Avionics Architectures for Explorations
(AAE) Disruption Tolerant Networking (DTN)
FY13 Summary
Adam Schlesinger
NASA - JSC
October 30, 2013
1
Introduction and Purpose - DTN
•
NASA is developing the Disruption Tolerant Networking (DTN)
protocol suite that extends the terrestrial Internet capabilities into
highly stressed data communication environments where the
conventional Internet protocols do not work well. The DTN project is
a separate AES project.
•
The DTN protocol suite is being standardized by the Consultative
Committee for Space Data Systems (CCSDS) and all of the DTN
protocols will be international standards, supported by open-source
software that can help users implement the new capabilities.
•
The AAE project is performing trade studies to determine the best
location for DTN within the spacecraft architecture, including key
considerations such as size, weight and power, processor utilization,
storage capacity, device real estate, and required data rates.
•
The AAE project is also studying the impact of having DTN nodes at
other locations within the end-to-end communication architecture,
including key considerations such as network reliability,
implementation costs, and the need for international interoperability.
2
Accomplishments in FY13
• Development of baseband processor software
application including integration of DTN
• Development of SDR transceiver system using GNU
Radio and the USRP
3
Baseband Processor Software Application
• Developed a generic baseband processor software
application that can be used with multiple SDR platforms
and has many features:
– Framing of CCSDS space packets into CADUs
– Data randomization and Reed-Solomon error correction
– Support for multiple data streams (Telemetry, Commands,
Voice, Video, etc.)
– Support for CCSDS formatted packets or generic UDP
– DTN gateway for native or non-native DTN users with
integration of ION 3.1.3
– Web interface that automatically updates with useful statistics
– XML-based configuration files for easy setup and deployment
– Fill data generation to keep radio link active
– CCSDS packet generation for testing/debugging
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Baseband Processor Software Web Interface
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Baseband Processor Configuration File
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Using DTN with other CCSDS Protocols
7
SDR Transceiver System with USRP
• Developed a radio transceiver system using the
GNU Radio open-source SDR development
architecture targeted for the Universal Software
Radio Peripheral (USRP).
8
SDR Transceiver System with USRP
• Demonstrated multiple modulation schemes: BPSK, QPSK,
GMSK
– Currently use BPSK on the forward link and QPSK on the return link
for the demo
• Demonstrated using a wide range of frequencies on a single
platform
– Currently use S-Band for the demo but can operate anywhere from
400 MHz to 4.4 GHz
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Plans for FY14 – Funding Dependent
• Integrate DTN with CFS in collaboration with both
the DTN and CFS AES projects
• Conduct trade studies to determine
benefits/weaknesses of where DTN resides on a
spacecraft (flight computer, radio or external router)
• Demonstrate DTN network management and
security features in iPAS
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