OMNISTAR, INC.'s DGPS Used to Map a Hopi Indian Reservation

© Presented with permission from GPS World magazine

The Hopi Indian people have lived in northeastern Arizona for a millennium. The Hopi Reservation, which covers an area of more than 1.5 million acres, contains 14 communities and is home to approximately 10,000 Native Americans. A public land survey of the Hopi Reservation does not exist. So, to help the Hopi manage their cultural and natural resources, they had to start a comprehensive program of GPS mapping. They used real-time GPS to map their wetlands from horseback. To do this they used an eight-channel GPS unit with datalogger, coupled to an Omnistar differential satellite communications unit that receives corrections from a geostationary communications satellite. This setup provided the Hopi with a real-time accuracy of plus or minus 1 meter and eliminated the need for a costly base station. They used this system aboard their off-road trucks to map roads and trails in the reservationπs rugged and isolated back country. They also relied on GPS to perform geodetic control surveys, using nine-channel GPS survey units with real-time kinematic radio communications. To support their geodetic application, they had a network of 22 first-order triangulation stations (including two first-order GPS horizontal control stations) scattered across the reservation. This allows them to use short baselines for maximum accuracy. The Hopi routinely performed a variety of boundary surveys to map clan lands, archaeological sites, and village infrastructure. They are currently using GPS to create maps of eagle and hawk nest areas as part of their cultural preservation program. They will soon be able to position inaccessible nest sites using a system that consists of a laser rangefinder, compass, and inclinometer unit coupled with the eight-channel GPS unit with datalogger and differential corrections service system. Tribe members perform all of the GPS fieldwork. To help analyze and display their results, they used two workstations running geographic information system software.

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