Chicago Transit Authority deploys GPS devices on bus fleet

GPS World, Feb, 2005

The Chicago Transit Authority (CTA), which provides nearly 1 million bus rides on an average weekday using a bus fleet that numbers about 2,000, is outfitting buses with a GPS-gyro-odometer tracking system to provide automated voice announcements that make its bus routes easier to navigate for customers who are hearing or visually impaired.

The system, developed and supported by Clever Devices Ltd. of Syosset, New York, is used by nearly 6,000 buses in Chicago, Washington D.C., Baltimore, Dallas, Boston, Long Island, Pittsburgh, Santa Monica, Sacramento and elsewhere.

Clever Devices' system integrates a proprietary GPS receiver and antenna to provide solutions for ADA compliance, automatic vehicle location, maintenance monitoring, automatic passenger counting, computer-aided dispatch, wireless real-time and local area networks, and data collection and bus-stop inventory.

Inputs such as real-time position, heading, speed and other information obtained by the GPS receiver, rate of turn from an integrated on-board gyro, and distance traveled from an odometer signal, are collected and processed using Clever Devices' PerfectNav software algorithms--allowing transit agencies using the technology to take advantage of continuous tracking in challenging urban environments.

Stephen Bennett, proposal manager for Clever Devices, described a recent test of GPS alone in New York City that resulted in GPS scattering (multipath) and data up to seven blocks off the actual vehicle location, as well as complete loss of signal while the bus traveled through a major New York City tunnel. However, Clever Devices' Intelligent Vehicle Network system with PerfectNav GPS-gyro-odometer fleet-tracking technology was always correctly located on the street of travel, according to Bennett.