A Practical Evaluation of Airborne Laser Mapping for Highway Engineering Surveys

Ron Berg and James Ferguson

Abstract:	Airborne laser mapping integrates three technologies into a single system to produce accurate digital terrain models (DTM) of the earth’s surface. The three technologies, Light Detection and Ranging (LIDAR) using laser, Global Positioning System (GPS) satellites, and Inertial Navigation Systems (INS), have all been available for several years. Developments in all three technologies have allowed the integrated system to be utilized in an airborne environment with increasing levels of accuracy. The Ministry of Transportation Ontario (MTO) decided to investigate the potential of airborne laser mapping for its highway engineering surveys. Traditionally, conventional or airborne GPS photogrammetric mapping is collected in a project area for preliminary highway design. This is followed by more accurate ground surveys in critical areas (ie. pavement surfaces) at the detail design stage. MTO wanted to determine whether airborne laser mapping could provide an alternative to its traditional process. A pilot project was conducted on a 23-kilometre stretch of 2-lane highway in Northern Ontario. A digital terrain model (DTM) was generated from the LIDAR point data. Simultaneously acquired digital imagery was individually rectified and mosaiced, then draped over the DTM to facilitate map compilation of existing ground features. The GPS and INS data were utilized in both processes to spatially reference the data. The resultant DTM and vector data were compared to ground audit surveys conducted by total station throughout the project area. Although the airborne laser mapping has proven to be less accurate than conventional photogrammetric mapping in some respects, it offers certain advantages that may be beneficial in the highway design process. This paper examines the achievable accuracy, benefits, and limitations of airborne laser mapping for highway engineering surveys.
Published in:	Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000) September 19 - 22, 2000 Salt Palace Convention Center Salt Lake City, UT
Pages:	1854 - 1864
Cite this article:	Berg, Ron, Ferguson, James, "A Practical Evaluation of Airborne Laser Mapping for Highway Engineering Surveys," Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000), Salt Lake City, UT, September 2000, pp. 1854-1864.
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