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Acoustic Telemetry for UUVs using Walsh/m-sequence Waveforms

ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Underwater acoustic (UWA) telemetry requires wideband waveforms for anti-multipath which are simultaneously easy to equalize and demodulate. The Walsh/m-sequence waveforms proposed here are robust to multipath and with appropriate time-guard bands do not require equalization. For example, in the UCSB prototype acoustic modem, a data rate of 133 bps is achieved using 8-ary Walsh signaling with an 11.2 msec. symbol duration. Demodulation is performed using noncoherent detection, and hence accurate phase tracking, which is difficult to achieve in the UWA channel, is not required. However, telemetry from unmanned underwater vehicles (UUVs) is more problematic due to large Doppler shifts resulting from platform motion. A new receiver algorithm based on Matching Pursuits is proposed which combines channel and Doppler shift estimation. Symbol-error rate (SER) simulation results are presented for the UWA modem under realistic Doppler/multipath conditions.

Identiferoai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/605039
Date10 1900
CreatorsIltis, Ronald A.
ContributorsUniversity of California, Santa Barbara
PublisherInternational Foundation for Telemetering
Source SetsUniversity of Arizona
Languageen_US
Detected LanguageEnglish
Typetext, Proceedings
RightsCopyright © International Foundation for Telemetering
Relationhttp://www.telemetry.org/

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