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CONTOUR MAPPING accurate highway maps from way speeds; GPS receivers digitized data. acquire satellite signals, The "GPS" stands for which are computer Global Positioning System, a processed on board the van, constellation of satellites for a continuous record of n 1989-90, the Ohio State operated by the Department the vehicle's location. University Center for of Defense to provide highly The van also has two Mapping (CFM), one of precise position information video cameras, which scan NASA's Centers for the Com- for aircraft, surface vessels the local terrain and produce mercial Development of and ground vehicles. The images whose location is Space, developed a vehicle GPSVan is a mobile data col- coordinated with the van's known as the GPSVan System lection system for mapping position at the time of imag- to meet a need for a cost- roads and their surroundings ing. Features such as street effective way of creating while driving at regular high- lights, utility poles, manholes and roadside structures can thus be positioned on the base maps. All this data is fed into a computerized Geo- graphic Information System (CIS). The expense of switch- ing map data to electronic databases is eliminated because the digitizing has already been done aboard the van. The GPSVan has been used in commercial mapping oper- ations but CFM continues to advance the technology. A novel and commercially promising advancement is the use of satellite positioning technology to determine the contours of a construction site. That was accomplished in a three-year project jointly conducted by CFM and George J. Igel & Company, Inc., Columbus, Ohio. In 1994, Igel was able to use the GPS survey system to determine the contours of a construction site by driving ENVIRONMENT over it in regular patterns. AND RESOURCES Using GPS receivers and MANAGEMENT software produced by CFM, lgel employed an antenna- equipped pickup truck to collect data on ground elevations, which were recorded and registered as contours. The IgelICFM team was able to cover about six acres per hour with complete contours -1 plotted "on the fly." The data proved accurate to within one-tenth of a foot in all dimensions. At left is a view of a vehicle based system at a construction site. A closeup of the base station receiver and antenna is shown at right. Below is a view of the vehicle- mounted antenna that backpack instead of the mined and communicated via receives the satellite signals, truck. The GPS survey sys- the computer screen to the which are used to calculate tem will be used to reduce operator. By comparing the the coordinates of points on the time required for map- machine's position to the the ground. ping and staking, and to mon- final design, the operator AMT Systems Engineering, itor the amount of soil moved determines how much cut- one of CFM's industrial part- on a given day. ting and filling is required. A ners, designed the enclosure Igel and CFM have contin- graphical user interface is for the survey system; a ued development work on being designed to assist the more advanced final product the construction application operator in evaluating the has been configured for a toward an eventual capabili- site and to support on-thefly ty to obtain elevations while decision making. Igel and using earth-moving equip CFM envision a future system ment. The team has conduct- capable of feeding GPS sig- ed experiments in which GPS nals and design information positioning is used to control directly to the vehicle's a cutting blade on earth mov- hydraulic controls to auto- ing equipment for total site mate the earth cutting and grading by means of digitized filling function. design information. In these experiments, a computer and TV-like moni- 97 tor display the digitized site design to the machine opera- ENVIRONMENT tor. Using CPS, the machine's position on the site is deter- AND RESOURCES MANAGEMENT