Development of Data Transfer and Communications for Underwater Wireless Sensor Networks, 20-R8071Printer Friendly Version
Inclusive Dates: 05/19/09 09/30/09
Background - The purpose of this project was to develop sonar communication and data transfer technologies for underwater wireless sensing networks (UWSNs). Many environmental applications require high-resolution, high-frequency monitoring of underwater events or processes. Low-cost, self-configurable, and scalable UWSNs can help capture and understand aquatic dynamics in high spatiotemporal resolution, providing a much-needed capability in environmental research and regulatory monitoring at a reasonable budget. In contrast to radio channels for land-based wireless communications, in situ underwater wireless devices can only effectively transmit signals via acoustic channels. Design of sonar communication protocols incurs additional complexity and technical challenges. This project sought to significantly expand SwRI's expertise in the field of underwater communication and support SwRI staff to actively compete for external funding.
Approach - A sonar communication protocol was developed to enable underwater signal transmission. Messages are encoded using a variation of the pulse position modulation scheme to achieve low-bit error rate and ensure proper synchronization between the transmitter and receiver. A prototype UWSN was developed to collect temperature data from multiple underwater locations and transmit the measurements, via sonar communication, to a wireless-internet-enabled laptop that periodically emails the complete data file to a remote workstation for analysis.
Accomplishments - All major technical tasks have been completed according to the original project scope. A sonar communication protocol was successfully developed and tested for transmitting messages through acoustic channels. The prototype UWSN system was deployed and tested for temperature sensing in different laboratory and field settings, including a swimming pool and a large-diameter well. Field demonstrations showed that the transmitter and receiver successfully communicated to each other over the acoustic channel and the data were successfully sent to a remote workstation.
The developed UWSN filled a previous gap in SwRI technology offerings. The project staff submitted a National Science Foundation grant proposal to use the UWSN technology developed in this project to characterize contaminant transport in a polluted Rio Grande tributary. The project staff is actively developing business and collaboration opportunities to use the UWSN technology resulting from this work.