, Fmr Director, Intelligent Veh. Lab, Mechanical Engineering
In 2002, the Intelligent Vehicles Lab (IV-Lab) introduced lane-guidance assistance technology to Metro Transit. The system is designed to assist bus drivers with maintaining proper lane position while using bus-only shoulders during periods of high congestion. In 2002, under sponsorship of the Federal Transit Administration, this system was pilot-tested by sixteen drivers from Metro Transit. Through the pilot study, the system was shown to significantly improve the lane-keeping performance of transit drivers. The goal of this project is to equip 10 Minnesota Valley Transit Authority buses with the lane-guidance technology. These buses will operate on Cedar Avenue, the Crosstown, and I-35, both to and from downtown. To support a new non-contact sensor installed on a test bus, an improved means to estimate vehicle heading is required. Previous embodiments of the IV-Lab system found that heading estimates with one-degree accuracy were sufficient to properly guide the bus, maintaining an error of approximately 10 centimeters in a narrow lane. However, when GPS is lost, the sensitivity of the non-contact guidance of the bus is extremely sensitive to heading initial-conditions errors. A new system to maintain navigation when GPS signals are unavailable has been developed and tested.
The 2-D velocity sensor has been integrated with the other sensors on the bus, and the augmentation system has been run in real time. The results are promising and could offer decimeter accuracy for outages of up to 10 seconds.
Researchers are preparing a report to document the design and performance of the position estimator. Performance was documented by artificially blocking the guidance GPS receiver while maintaining a high accurate "fix" solution on the reference DGPS receivers.