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Joseph A. Rice SPAWAR Systems Center, San Diego Naval Postgraduate School, Monterey

DARPA ATO Disruption Tolerant Networking Program August 2, 2005 Seaweb acoustic com/nav networks. Joseph A. Rice SPAWAR Systems Center, San Diego Naval Postgraduate School, Monterey +1 831 402 5666 rice@nps.edu. Seaweb is a US Navy experimental technology.

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Joseph A. Rice SPAWAR Systems Center, San Diego Naval Postgraduate School, Monterey

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  1. DARPA ATO Disruption Tolerant Networking Program August 2, 2005 Seaweb acoustic com/nav networks Joseph A. Rice SPAWAR Systems Center, San Diego Naval Postgraduate School, Monterey +1 831 402 5666 rice@nps.edu Seaweb is a US Navy experimental technology. SPAWAR Systems Center, San Diego

  2. US Navy Seaweb InitiativeEnabling Undersea FORCEnet for cross-system, cross-platform, cross-mission, cross-nation interoperability • Integrated undersea applications • Littoral ASW sensor telemetry • METOC sensor telemetry • Sensor-to-sensor cueing • Submarines • Submersibles • UUVs • Collaborative operations • Command & control • Deployable ranges • Harbor defense • Through-water digital com/nav networks • Scaleable wide-area wireless grid • Composeable architectural flexibility • Fixed and mobile autonomous nodes • Gateways to command centers • Persistent and pervasive • Low source level, wide band, high freq J. Rice, “Enabling Undersea FORCEnet with Seaweb Acoustic Networks,”Biennial Review 2003, SSC San Diego TD 3155, pp. 174-180, December 2003 SPAWAR Systems Center, San Diego

  3. Demonstrated capabilities:FBE-India June 2001 Racom buoy • SSN with BSY-1 sonar Seaweb TEMPALT • Ashore ASW command center • Seaweb server at SSN and ASWCC • Acoustic chat and GCCS-M links to fleet • SSN/MPA cooperative ASW against XSSK • Flawless ops for 4 continuous test days Experimental DADS sensor node J. Rice, et al, “Networked Undersea Acoustic Communications Involving a Submerged Submarine, Deployable Autonomous Distributed Sensors, and a Radio Gateway Buoy Linked to an Ashore Command Center,”Proc. UDT Hawaii, October 2001 SPAWAR Systems Center, San Diego

  4. CTS RTS RTS CTS DATA RTS DATA CTS RTS CTS DATA DATA Seaweb message example:Multi-Access Collision Avoidance (MACA)Internet Protocol (IP) G. Hartfield, Performance of an Undersea Acoustic Network during Fleet Battle Experiment India, MS Thesis, Naval Postgraduate School, Monterey, CA, June, 2003 SPAWAR Systems Center, San Diego

  5. US Navy SPAWAR SBIR topic N93-170 advanced and commercialized DSP-based acoustic comms SBIR contractor: Benthos, Inc. (formerly Datasonics, Inc.) ATM-885 telesonar modem 3rd generation telesonar modem, Benthos ATM-885 • Introduced in 2000 • TMS320C5410 DSP • 5-kHz bandwidth • 2400 bit/s, uncoded • 15 kbit/s with optional daughter board • Various forward-error-correction options 4th generation telesonar in development, SBIR N03-224 Standard firmware for non-networked applications • UUV command & control • Oceanographic telemetry • Tsunami warning systems • Oil industry US Navy firmware for Seaweb applications K. Scussel, “Acoustic Modems for Underwater Communications,”Wiley Encyclopedia of Telecommunications, Vol. 1, pp. 15-22, Wiley-Interscience, 2003 SPAWAR Systems Center, San Diego

  6. Node A Node B Planned approach:Adaptive modulation Demodulate RTS transmission Reconstruct transmitted waveform RTS Estimate channel scattering function CTS Specify Data-packet comms parameters Determine h(τ, t ) / Doppler / SNR S. Dessalermos, Undersea Acoustic Propagation Channel Estimation, MS Thesis, Naval Postgraduate School, Monterey, CA, June 2005 Data Map channel characteristics against available repertoires and signal techniques Final decision SPAWAR Systems Center, San Diego

  7. RTS 9 bytes CTS 9 bytes DATA up to 2 kbytes SRQ 9 bytes up to 2 kbytes DATA Demonstrated capability:MACA (multi-access collision-avoidance) protocol enables undersea networks with security, reliability, efficiency, and low cost A B Seaweb channel-tolerant utility packets resolve the compound constraints of: • Variable QoS, link outages • Channel multipath, Doppler, dynamic SNR • Limited spectral bandwidth • Asymmetric, half-duplex channel • Slow propagation, long latencies • Multi-access interference • Battery-limited operations J. Rice, et al, “Adaptive Modulation for Undersea Acoustic Telemetry,”Sea Technology, May 1999 SPAWAR Systems Center, San Diego

  8. Seaweb 2005 NSW ExperimentFebruary 2005, Panama City, FL SRQ link-layer mechanism NSMA (Neighbor Sense Multiple Access, a cross-layer variation on CSMA) Ranging and node localization New repeater mooring design Iridium-equipped Racom buoy SDV Periscope Controller Compressed image telemetry NPS, SSCSD, CSS, Benthos DADS ASW Barrier Sea Eagle ACTD NSW Expeditionary Ops 2010 Mine RECO SPAWAR Systems Center, San Diego

  9. 8. Node A retransmits the 1 subpacket specified by the SRQ. Demonstrated capability:Selective Automatic Repeat Request (SRQ) is a link-layer mechanism for reliable transport of large datafiles even when the physical layer suffers high BERs Node A Node B RTS 2. Node B is prepared to receive a large Data packet as a result of Seaweb RTS/CTS handshaking. 1. Node A initiates a link-layer dialog with Node B. CTS HDR 4. Node B receives 12 subpackets successfully; 4 subpackets contained uncorrectable bit errors. 3. Node A transmits a 4000-byte Data packet using 16 256-byte subpackets, each with an independent CRC. 5. Node B issues an SRQ utility packet, including a 16-bit mask specifying the 4 subpackets to be retransmitted. 6. Node A retransmits the 4 subpackets specified by the SRQ mask. 7. Node B receives 3 of the 4 packets successfully (future implementation of cross-layer time-diversity processing will recover 4 of 4). B issues an SRQ for the remaining subpacket. SRQ HDR 9. Node B successfully receives and processes Data packet. SRQ HDR J. Kalscheuer, A Selective Automatic Repeat Request Protocol for Undersea Acoustic Links, MS Thesis, Naval Postgraduate School, June 2004 SPAWAR Systems Center, San Diego

  10. Demonstrated capabilities:Seaweb 2004 UV racom buoy 6-8 min deployment time Deck Staging SPAWAR Systems Center, San Diego

  11. Seaweb 2004 Undersea Vehicle Experiment cellular grid deployment Average speed 6.5 knots Average 1 repeater every 20 min SPAWAR Systems Center, San Diego

  12. SPAWAR Systems Center, San Diego

  13. COMEX Seaweb 2004 grid post mortem Impacted by trawling along the 300-m isobath3 nodes removed, 6 nodes displaced or damaged FINEX SPAWAR Systems Center, San Diego

  14. Ship Ship Seaweb 2004 ExperimentUndersea Vehicle initiates the Seaweb sessions Seaweb network-layer statistics show excellent performance with dropped messages attributable to UV limited aspect, UV fix-expansion uncertainty, and interference from other UV active sonar Seaweb network-layer success Return receipt Initiating message Response message Undersea Vehicle Undersea Vehicle SPAWAR Systems Center, San Diego

  15. NPS The Seaweb Initiative is performing Seaweb navigation experiments this year as risk mitigation for CNAVSeaweb 2005 UUV ExperimentsMonterey Bay, May 9-11, July 20-22St. Andrews Bay, December 5-9 GPS satellite constellation Iridium satellite constellation Racom buoy gateway node Shipboard command center ARIES UUV SLOCUM UUV constellation of 6 Seaweb repeater nodes fixed on seabed SPAWAR Systems Center, San Diego

  16. DARPA CNAV architectures include situation adaptive, energy conserving, and transitional topologies • Mobile formations • Swarms • Mobile node as gateway • Zebranet flooding • Assimilation following ad hoc deployment • Fixed grids • Self-healing • Seamule SPAWAR Systems Center, San Diego

  17. What can DTN do for Seaweb? • Network layer is fragile – needs dynamic routing for healing during/after disruption • No reliable packet transport need mechanism for recovering lost packets at the network layer • No support for data mules • Infrastructure support needs work • currently no packet counter (move to 8b) • rough time synchronization: ~0.1s resolution, 16b timer, ~12 hour rollover • Seaweb expertise is UW acoustics & systems, not in networking • Simulation support lacking (OPNET radio modeler has been adapted for the telesonar channel) • Development funding & assistance from network experts SPAWAR Systems Center, San Diego

  18. What does Seaweb do for D-DTN?(why get involved?) • General: • Closely related to tactical radio MANET problem • Naval warfare applications/transition • Specific: • Reality check for DTN in harsh environments • “brutal constraints” comparable to MANPACK constraints • DTN isn’t a bolt-on – need a stripped-down bundle protocol issues with time stamps, header efficiency, time sync • DTN must be integrated into system with routing etc DTN gets a hard problem with a likely transition on success Can DTN be made to work in such constrained environments? • Testbed system to sea roughly 4 times a year SPAWAR Systems Center, San Diego

  19. Seaweb advanced concepts Saturating the undersea battlespace Backward compatible with Seaweb Seastar tier Sensor grids and UUV swarms against SSK, UUV, and sea-mine threats Networked weaponry Fully mobile networks (e.g., CNAV) Seaweb wide-area network Seastar local-area network Conclusion: Seaweb is an enabling technology for Undersea FORCEnet and Sea Shield Seaweb spiral development Fulfilling the Seaweb blueprint Directional transmit & receive Four bands Full physical-layer repertoire, from low-rate/clandestine to high-rate/overt signaling Adaptive modulation & power control Automatic cellular handoff for mobile nodes Ad hoc network initialization Integration with manned platforms ¼ A-size modem Asymmetric links Submarine Low-rate C2 High-rate data telemetry Autonomous node Seamules SPAWAR Systems Center, San Diego

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