Event
Lab for Telecom Sciences Lecture: Mark Shayman, "MIMO Transmitters"
Thursday, July 12, 2012
2:00 p.m.
Lab for Telecommunications Sciences Auditorium
Laboratory for Telecommunications Sciences Lecture Series
Geolocation of MIMO Transmitters using Time Difference of Arrival
Professor Mark Shayman
Department of Electrical and Computer Engineering
University of Maryland
LTS Auditorium
Laboratory for Telecommunications Sciences
8080 Greenmead Drive
College Park
Abstract
By measuring time of arrival (TOA) of the signal from a target transmitter to several sensors, the target can be localized as the intersection of circles. However, if the target is non-cooperative, TOA cannot be measured and only the time difference of arrival (TDOA) can be obtained for each pair of sensors.
TDOA for a pair of sensors localizes the target to a hyperbola with the sensors as foci and the TDOA multiplied by the speed of light as the distance between the vertices.
Given sufficient sensors, the target can be localized as the intersection of the corresponding hyperbolas.
The traditional cross-correlation method for determining TDOA assumes that the target has a single transmit antenna. However, there is growing interest in geolocating transmitters that have multiple antennas. We investigate methods of computing the TDOA when the transmitter has multiple antennas, and looking to the future, possibly a large number of antennas.
The effect of multiple antennas on the cross correlation method is described geometrically. We also propose an alternative method for determining TDOA. When used in concert with the cross-correlation method, the combined method eliminates nearly all incorrect results; it will label a result that would have been incorrect as "inconclusive." By using a sufficient number of sensors and discarding TDOAs that are inconclusive, correct geolocation is possible in a high proportion of cases.
Biorgraphy
Mark Shayman is a professor in the Department of Electrical and Computer Engineering and an affiliate faculty member of the Institute for Systems Research. He has been Associate Dean for Faculty Affairs and Graduate Programs in the A. James Clark School of Engineering. Recently he was appointed Associate Dean for Student Success in the Graduate School. His research interests are in networking and wireless communication systems. He is a Fellow of IEEE.
