The GPSVan^TM is a mobile mapping and data collection system that can map rail, highway and the transportation infrastructure (e.g., roads, signs, and bridges) while traveling at normal traffic speed. A Mobile Mapping System (MMS) can be defined as a moving platform, upon which multiple sensor/measurement systems have been integrated, to provide three-dimensional near-continuous positioning of both the platform and simultaneously collected geo-spatial data. The Center for Mapping pioneered this technology, realizing very early that Geographic Information Systems (GIS) require up-to-date and high-quality spatial data to enhance the decision making process in transportation and urban planning. The GPSVan^TM positioning module integrates the Global Positioning System (GPS) in differential mode, and an independent Dead-Reckoning System (DRS) that records the vehicle's position during temporary GPS data outages (satellite signal blockage by trees or other obstructions). The positioning of the vehicle is good to 10 cm when GPS data is available at three-second intervals. GPS data outages of 30 s, 60 s and 120 s cause the positioning degradation to the level of 0.2 m, 0.4 m and 1.0 m, respectively. Additional attributes, i.e., road signs, bridges, etc., can be recorded by a system operator, using a PC keyboard, or the touch screen of the system's portable computer. Below is a sample pair of stereo images. Click To View full-size versions.

An imaging module of the GPSVan^TM consists of a stereo camera system that records stereo images of the roadway, as the van moves down the highway(700k mpeg) . The stereo system is supplemented by an analog camera system, that runs in continuous video mode, and captures a photographic log of the survey. Each video frame is time-tagged with the GPS signal, and geodetic coordinates (i.e., latitude, longitude and ellipsoidal height) are assigned to every image. Digital stereo pairs are processed in a post-mission mode, to determine geodetic coordinates of objects such as road edges and centerlines, curbs, street signs, mile markers, etc., with a relative accuracy of 5-10 centimeters within 10-40 meters from the vehicle. The analog imagery provides an information for urban planners and tax assessors, as well as the real estate and transportation industry. Data collected by the GPSVan^TM can be converted into a format compatible with a Geographic Information System (GIS), and used by the rail and transportation authorities to establish management priorities, and control safety features, such as speed limits and location of the warning signs.

This technology, which has been developed over the past five years at the Center for Mapping at The Ohio State University is being extensively exploited for surveying, mapping, and feature inventory applications. One of the most challenging and demanding tasks was the inventory survey of 7,000 miles of track for the Burlington Northern Santa Fe Corporation (BNSF), with submeter accuracy. The results of the BNSF survey represent an unprecedented accomplishment, both in accuracy and in the number of miles surveyed. For over 95 percent of the quality checkpoints, coordinates provided by the GPSVan^TM System were within 50 cm from ground truth. The GPSVan^TM System results are better, less expensive, and available much faster than data from any other mapping technology.

The prototype van is available for marketing demonstrations and actual surveys. Second generation vehicles that have the DRS replaced by an Inertial Navigation System (INS) are currently being built and sold for commercial purposes.