They carry a hand-held receiver that calculates where they are and limns their movements on its tiny screen.
Discerning a fish around the village of Wallingford, they followed the route and used Mr. Wood's hand-held receiver to map the car journey.
The satellites emit signals that hand-held receivers translate into information for navigation purposes.
In amateur radio direction finding, the competitor uses a hand-held receiver to locate radio beacons at up to five control points that are not marked on the map.
Consider the constellation of global-positioning satellites that provide precise tracking information to hand-held receivers.
Dr. Norbert B. Hemesath, manager of advanced technology at Collins, said hand-held receivers will probably begin reaching American soldiers in 1992.
Even though consumer GNSS receivers have a minimal risk of interference, a few airlines disallow use of hand-held receivers during flight.
But by the time of the gulf war in 1991, consumer models of hand-held receivers cost $1,000 or less.
A second type of display, which the group calls a "haptic pointer interface", was inspired by the hand-held receiver used in the Talking Signs system of remote signage.
The hand-held receivers, employing parallel-processing computer technology, simultaneously track the four satellites to plot the user's geographic position on the basis of longitude, latitude and altitude.
