Global Positioning System Reference
In-Depth Information
GPS
We encountered GPS in chapter 3 and saw how the system worked. Here,
we look at it from the other end—from the user's perspective—and then
consider where it will lead us in future.
Hand-held GPS devices (fig. 8.12), or dashboard-mounted instruments
with their route calculators and soothing voices, are commonplace and
even passé. The latest word in personal positioning and navigation systems
—but certainly not the last, as I will argue in this section—is the cell-phone
app. For example, a free Google application, beta-released at the time
of writing, provides Google Map pictures of your immediate location on
your phone, instead of crude line drawings we see on a dedicated GPS
receiver; this app guides you to your destination while performing Internet
searches to provide the latest information, such as tra≈c jams and road-
work updates.
Even more sophisticated is a new GPS navigation application for up-
scale automobiles, called Virtual Cable, already field-tested by a San Fran-
cisco company. It projects a head-up display onto your windshield, much as
a fighter pilot is presented with a HUD of vital information that allows him
to keep his eyes on the skies. The di√erence is that Virtual Cable shows, not
incoming missiles, but a 3-D image of a red cable suspended above the road
you are driving along, receding into the distance in true perspective and
turning left or right where you are to turn left or right. This form of route
guidance is very intuitive and presents the navigation directions in a man-
ner that is readily taken in by the driver. It's also undeniably very cool.
21
The applications of GPS are spreading across our lives like ink on a
blotting paper as we begin to absorb the full potential of this satellite
technology. Of course, in the future we will continue to use GPS to deter-
mine our location, whether we are hiking in the hills far away from civiliza-
tion or searching for a suburban restaurant. We will continue to seek
directions while in our car. Ambulance drivers, taxi drivers, and express
mail delivery companies will continue to use GPS to quicken their jour-
neys. Air tra≈c controllers will depend upon GPS to maintain safe dis-
tances between airplanes at busy airports. Tomahawk missiles will make
small harbor lighthouse (an irony), which then collapsed onto the boat. The pilot then had
to su√er the indignity of manually guiding his vessel into port with the wreckage of a
lighthouse strewn across the deck.
21. Details of this instrument, and videos of a field trial, can be seen at the website
