A Heads Up Display based on a DGPS and Real Time Accessible Geo-Spatial Database for Low Visibility Driving

Heon-Min Lim, Bryan Newstrom, Craig Shankwitz and Max Donath

Abstract:	Poor visibility conditions are a causal factor in many crashes each year. The inability to see road boundaries, obstacles, and other vehicles on the road is especially of concern during the winter. Snowplow drivers, in particular, are affected because they must often drive when visibility is poor, when roads are snow covered and lanes are hard to discern. There are serious safety and economic repercussions if snowplows cannot perform their function. We are investigating how to effectively use the vehicle’s sensed location in the lane (using high accuracy RTK DGPS) to provide feedback to the driver based on a conformal heads-up display (HUD). When visibility is poor, this latter technology provides the driver with lane boundary information, corrected for eye perspective, projected onto the windshield. A prototype HUD has been experimentally verified and demonstrated on a truck. We have also developed an in-vehicle geo-spatial database query processor that allows us to extract the needed data in real time. As the vehicle moves along the road, the vehicle's DGPS derived position is used to pull the data from this "digital map" and provide it to the HUD's graphics processor. The system allows the driver of the vehicle to see the 'computed' road boundaries projected directly over the 'actual' road boundaries even if they are obscured by snow, rain, or darkness. We have documented and quantified the latency and accuracy errors associated with projecting geographic information onto the HUD. Image frame rates exceeding 10 Hz have been demonstrated. Typical latency for computation and display are less than 20 ms and display projection error is equivalent to 0.5 meters at 120 meters (as viewed by the driver). This is equivalent to about a 0.25 degree sighting angle. Database access times are 20- 40 ms with 5-10 ms UDP packet transfer times; a typical query using existing databases is 1-3 packets long.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	469 - 478
Cite this article:	Lim, Heon-Min, Newstrom, Bryan, Shankwitz, Craig, Donath, Max, "A Heads Up Display based on a DGPS and Real Time Accessible Geo-Spatial Database for Low Visibility Driving," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 469-478.
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