GNSS Markets and Applications - Understanding GPS: Principles and Applications - page 641

Like any venture, there are always risks to success. The GNSS market looks
extremely promising, but there are concerns that any prudent entrepreneur should
be aware of. As GPS receivers embed themselves in our cars, cell phones, PDAs,
laptops, watches, and cameras, and they become wedded to wireless communica-
tions links therein, a potential backlash from consumers could limit market growth.
More and more we are becoming a society where privacy rights are being eroded by
fear of crime and terrorism abetted by technology that fosters the erosion.
Telematics, or the provision of services to mobile users, is one area where the line
between location awareness by the service provider can easily become location
awareness by unwelcome surveillers.
Governments have made use of covert tracking techniques for many years. GPS
with communications just makes it easier. As small, inexpensive wearable
GPS/communications devices become more prevalent, the opportunity to impinge
on privacy grows and, if abused, could lead to a backlash that could prompt legisla-
tion limiting the market [10].

12.2 Civil Navigation Applications of GNSS

Commercial use of GPS has its roots in the predecessor program, the Transit Satel-
lite Navigation System. It was fielded by the U.S. Navy in the early 1960s and used
by nuclear submarines to fix their positions in the open ocean. A satellite came into
view only every 90 minutes (approximately), so the system was not very useful to
aircraft. Just as Navy ships were the primary users, large commercial vessels also
became users as receiver prices dropped. This drop was spurred by new emerging
technology and by the oil crisis of 1973. By then, equipment prices were in the
$100,000 range and could actually be justified by large oil tankers as a cost offset to
wasted bunker fuel caused by inaccurate navigation. Then prices dropped even fur-
ther, and large fishing vessels became the growing market. This was accompanied
by markets in land and ocean survey.
When GPS concepts were being explored in the 1965-1973 time frame as a
solution for aircraft navigation, Congress demanded that in exchange for funding it,
there would be two conditions: the GPS had to be a joint service program, and it had
to have a civil signal. These roots of commercial GPS are shown in Figure 12.1.
As soon as there were GPS satellites in the sky, there was a commercial market.
The first satellites were launched in the late 1970s, and it became possible to find
one's time very accurately knowing one's location whenever a satellite was visible.
With three satellites in view, periods of two-dimensional positioning and velocity
determination were possible. With four satellites, this increased to three dimen-
sions. As more satellites were added, the daily periods of good navigation (i.e., low
GDOP) grew longer until full 24-hour coverage was achieved in the early 1990s. As
GPS use increased and technology marched forward, the prices of user equipment
came down, fueling even greater usage. The primary technological advances that
spurred this were large-scale integrated circuits, monolithic microwave integrated
circuits, dense memory chips, and microprocessors [2].
The first companies to offer commercial GPS products were the same ones
developing military equipment (e.g., Magnavox and Rockwell Collins). Magnavox