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Center for Transportation Studies


Seminar Series – 2003

September 9

"Evaluating GPS for Assessing Road User Charges"

Pi-Ming Cheng
Mechanical Engineering

Seminar Article

This research was part of the ongoing ITS Institute research project to develop a GPS-based in-vehicle system for assessing road user charges. Our goal was to evaluate the GPS subsystem in the most difficult environments—areas where roads of different jurisdictions and possibly different fee structures are located in close proximity to each other.

September 23

"ITS and Industry Clusters"

Lee Munnich
Humphrey Institute of Public Affairs

Seminar Article

What is the role of ITS technologies in rural development? This study examines the recreational transportation manufacturing and wood products industry clusters in northwestern Minnesota and explores future roles for ITS in rural economic development.

October 7

"The Origins, Status, and Future of GPS"

Bradford Parkinson
Professor Emeritus—Department of Aeronautics and Astronautics, Stanford University

Special Twin Cities Campus Location: Room 3-180 Electrical Engineering & Computer Science Building [map]

Sponsored in conjunction with Honeywell and the U of M Department of Aerospace Engineering and Mechanics.

Seminar Article

From precision-guided munitions to in-vehicle navigation assistance, Global Positioning System technology has become the cornerstone of many navigation and guidance applications. Bradford Parkinson led the team that synthesized the Global Positioning System concept and engineered it to completion. Today, the GPS system provides locational information to military and civilian users worldwide. But technological improvements and competing signal issues continue to affect GPS and its more than 20 million users. Parkinson reviews the development of today's GPS, and looks ahead to the future of this vital technology.

October 21

"Inductive Loop Detector Signal Analysis"

Stan Burns
UMD Electrical and Computer Engineering

Seminar Article

Inductive loop detectors (ILDs) embedded in pavements are the predominant vehicle sensing system used in traffic management today. Typically, ILDs detect the presence of a vehicle by exceeding an eddy current induced inductance change threshold for a given ILD location. However, if one examines experimentally the time-dependent inductance change profile rather than the threshold switching for establishing an occupancy number, it appears that there are unique signatures associated with different vehicle types. This presentation will provide an overview of the theoretical basis for the ILD and illustrate how the time dependent inductance change can be used for vehicle type identification. Future plans call for continuing and expanding the effort using custom hardware and software to improve measurement resolution, response time, and field utility.

November 4

"Integrated Multi-Sensor Navigation Systems"

Demoz Gebre-Egziabher
Aerospace Engineering and Mechanics

Seminar Article

The recent availability of inexpensive microprocessors and solid-state sensors has made it possible to construct cheap, integrated multi-sensor navigation systems for cost-sensitive applications such as Unmanned Aerial Vehicles or automotive navigation. This presentation discusses the hardware design and algorithmic details of an integrated navigation system that fuses the information from an Inertial Measurement Unit, a magnetometer triad and a Global Positioning System receiver. Methods for modeling sensor and system errors for are presented. Performance and observability analysis shows that the observability of such systems is conditional when only GPS position fixes are used to aid the inertial sensors. With the addition of a magnetometer triad, it is shown that the system becomes unconditionally observable.

November 18

"Adaptive Modulation for Bandwidth- and Power-Efficient Transmission Over Wireless Links"

Mohamed-Slim Alouini
Electrical Engineering and Computer Science

Wireless communication systems need to operate over a wide variety of complex and harsh time-varying channels, whose quality is often insufficient to support the quality of service required by telecommunication applications. Due to this major impairment, efficient fade-mitigation techniques are required to improve radio link performance. As an alternative to classical fade-mitigation techniques (which are designed relative to the worst-case channel conditions), this presentation focuses on some new developments in adaptive transmission techniques. These schemes take advantage of a feedback loop between receiver and transmitter to vary the transmitted power and rate in order to provide either high power or high spectral efficiency. This concept is the basis for a new adaptive modulation scheme for simultaneous multimedia transmission over wireless links, and a new adaptive scheme that increases the coverage for a fixed transmitted power.

December 2

"The Effectiveness and Safety of Traffic- and Non-Traffic-Related Messages Presented on Changeable Message Signs"

Kathleen Harder
College of Architecture and Landscape Architecture

How effective are Changeable Message Signs (CMS) at communicating different types of messages to drivers? What impact does the use of CMS displays have on traffic flow? Are CMS messages responsible for traffic slowdowns? This research tested CMS messages, including both conventional traffic-related messages and AMBER alert (abducted child) messages. Participants in the study included 120 licensed drivers from different age groups, with experiments carried out in a fully interactive PC-based STISIM driving simulator.