Martin Siderius, Ph.D., Associate Professor, Electrical and Computer Engineering
Since electromagnetic signals do not travel very far in the ocean, acoustics are the best substitute for exploring the underwater environment. Depending on water clarity objects might be able to be seen for tens of meters but not much beyond. Exploring the depths of the ocean may require probing over thousands of meters. Using systems similar to terrestrial technologies such as cellular phones, GPS and WiFi networks underwater requires using acoustics and can be extremely challenging. Remote sensing above ground uses electromagnetic signals for applications like Google Earth and weather forecasting images. Similar sensing systems for mapping the ocean floor or predicting ocean currents requires acoustic remote sensing. One very important difference between electromagnetic and acoustic signals is the speed of propagation. The speed of light is 3x108 m/s while sound travels at 330 m/s in air and 1500 m/s in water. Delays between acoustic transmission and reception can be problematic; particularly for two-way communications. For example, cell phone conversations over 15 km or 150 km are as natural as sitting in the same room; however, using a 15 km acoustic link underwater introduces a 10 second delay.
There is currently great concern about the impact of sonar systems on marine life. A variety of marine mammals use sound for navigation and communication. Some sonar systems may cause interference or even physiological damage. Siderius has been researching how marine life use acoustics and the ability of traditional sonar systems to be modified to minimize or eliminate impact. One component of his research is developing techniques to use naturally occurring sounds such as those from breaking waves as a surrogate sound source for ocean exploration. These sounds are proving to be highly useful for remote sensing when special processing techniques are applied.
Siderius’ teaching and research focuses on topics related to acoustics and electromagnetics. Prior to his faculty appointment at the Maseeh College, he was Vice-President and Principal Scientist at HLS Research Inc., a startup company he co-founded in 2004. HLS Research is dedicated to applied and basic research on wave propagation phenomena. Siderius spent three years as a Senior Scientist at the Science Applications International Corporation. From 1996-2001 he was on the scientific staff of the NATO Undersea Research Centre in La Spezia, Italy. Siderius has a B.S. degree in physics from Western Washington University and M.S.E.E. and Ph.D. degrees in electrical engineering from the University of Washington.
For more information, please contact the Department of Electrical and Computer Engineering at the Maseeh College:
Phone: (503) 725-3806
Web site: www.ece.pdx.edu