People > Faculty
John Sahr
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John Sahr Professor Signal and Image Processing 426D Sieg Box 352500 University of Washington Seattle, WA 98195 |
| Phone: (206) 685-4816 E-mail: jdsahr@ee.washington.edu |
Cornell University, Electrical Engineering 1990 Ph.D.
California Institute of Technology, BSEE 1984
Biosketch
John Sahr was born in Seattle and grew up in Yakima and Selah, Washington. He became a radio amateur in the mid 1970s (WB7NWP) and continued his interest in radio wave propagation, communication, and radar in college. He attended Caltech 1980--1984, was president of his dorm (Fleming House), and was inspired by many marvelous faculty there. In 1984 John began graduate study at UCLA, working on a 380 GHz plasma imaging experiment.
In 1985 he went to Cornell University for the remainder of his graduate studies, operating and building a 50 MHz radar for studies of the high latitude ionosphere. The experimental campaigns were carried out in Sweden and Norway. As a postdoc John helped develop a new data acquisition system for the Jicamarca Radar Observatory, and processed incoherent scatter data from that radar.
In 1991 John joined the Electrical Engineering faculty at the University of Washington, shortly afterwards being appointed Adjunct to the UW Geophysics Program. John became an Associate Professor in 1997. In addition to the Geophysics Faculty, John also works with faculty and staff of the UW Astronomy Department, sharing some space at the Manastash Ridge Observatory near Ellensburg, WA.
Professor Sahr performs research primarily in VHF radar remote sensing of the Earth's upper atmosphere, but also collaborates in research projects in signal processing, image processing, and wireless communications.
Honors
Young Scientist Award, URSI General Assembly, Kyoto, Japan, 1993
National Young Investigator Award, National Science Foundation, 1993--1998
Young Scientist Award, URSI "Electromagnetic Scattering in Gases and Plasmas (ESGAP)" Conference, France 1994
Canadian Corporation for Space Science, Invited Speaker, Department of Physics and Astronomy, University of Western Ontario, May/June 1996
Young Scientist Award, URSI General Assembly, Lille, France, 1996
Henry Booker Fellowship, 1996. National Academy of Sciences and US National Committee of the International Union of Radio Science
Faculty Achievement Award, UW College of Engineering, 1996
"Best Professor" Award, IEEE Student Branch, UW EE Department, 1996.
Research Interests
Space plasma physics, ionospheric turbulence, radar remote sensing, interferometry, and inverse problems; collaboratory experience in MPEG4, VLSI testing and ASIC design, wireless communications.
Research Projects
We operate a completely passive 100 MHz radar which detects scatter from commercial FM broadcasts. We've detected scatter from over 1000 km, resolving the range and Doppler spectrum with unprecedented detail. See the Radar Remote Sensing Lab for more information, including live output from the Manastash Ridge Radar.
Radar Remote Sensing Lab: http://rrsl.ee.washington.edu/
Selected Publications
Zhou-C; Fremouw-EJ; Sahr-JD Optimal truncation criterion for application of singular value decomposition to ionospheric tomography Radio-Science.vol.34, no.1; Jan.-Feb. 1999; p.155-66.
Uppala-SV; Sahr-JD Recursive structures and finite impulse response implementations of linear multiuser detectors for an asynchronous CDMA system IEEE-Journal-on-Selected-Areas-in-Communications.vol.16, no.9; Dec. 1998; p.1736-46.
Sahr-JD; Lind-FD Passive radio remote sensing of the atmosphere using transmitters of opportunity Radio-Science-Bulletin.no.284; March 1998; p.4-7.
Sahr-JD; Lind-FD The Manastash Ridge radar: a passive bistatic radar for upper atmospheric radio science Radio-Science.vol.32, no.6; Nov.-Dec. 1997; p.2345-58.
Uppala-SV; Sahr-JD On the design of quadratic filters with application to image processing IEEE-Transactions-on-Image-Processing.vol.6, no.4; April 1997; p.608-14.
Sahr-JD; Fejer-BG Auroral electrojet plasma irregularity theory and experiment: a critical review of present understanding and future directions, Journal-of- Geophysical-Research.vol.101, no.A12; 1 Dec. 1996; p.26893-909.
Sahr-JD; Application of closure phase and self-calibration to radar interferometric imaging of atmospheric and ionospheric irregularities, Journal-of-Atmospheric- and-Terrestrial-Physics. vol. 58, no. 8-9; June-July 1996; p. 959-64.
Recent Conference Papers
Sahr, Lind, Zhou, Gidner: PIERS99, "Passive Bistatic VHF Radar Technique for Atmospheric and Ionospheric Radioscience" Taipei, Taiwan, March 1999.
Uppala-SV; Sahr-JD Performance analysis of the decorrelating detector in the presence of synchronization errors 1997 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing, PACRIM.10 Years Networking the Pacific Rim, 1987-1997 (Cat. No.97CH36060). IEEE, New York, NY, USA; 1997; 2 vol.
Uppala-SV; Sahr-JD Computing probability of errors of linear multiuser detectors in white Gaussian noise and Rayleigh fading channels ICC '98.1998 IEEE International Conference on Communications. Conference Record. Affiliated with SUPERCOMM'98 (Cat. No.98CH36220). IEEE, New York, NY, USA; 1998; 3 vol. xxxvii+1838 pp. p.360-4 vol.1.
Active Grants
NSF ionospheric physics, 1999-2002.
RRF systolic array, 1998-1999.
Recent Graduate Students
Sathyadev V. Uppala, multiuser receivers, summer 1998
Frank Lind, Geophysics, radar remote sensing of ionospheric turbulence, August 1999.
Chucai Zhou, Electrical Engineering, signal processing theory and practice for passive bistatic radar, summer 2001
Dawn Gidner, Electrical Engineering, VHF radar scatter from turbulent plasma structures in the ionosphere, summer 2002.
Todd Elson, Submillimeter Tunneling Amplifier, Summer 2000
Editorships
Geophysics Research Letters, Associate Editor
International Union of Radio Science (URSI), Commission G
