GNSS Markets and Applications - Understanding GPS: Principles and Applications - page 645

waterway maintenance, coupled with strong economic activity, will allow steady
growth to a level of nearly $200 million annually by 2008. This segment, however,
has a fairly low growth rate due to the maturity of the market [11].

12.2.2 Air Navigation
There are essentially two kinds of markets and two regimes of operation to consider
in the airborne area. There are 224,000 GA aircraft registered in the United States
and Canada. The U.S.-based Aircraft Owners and Pilots Association asserts that
this represents 77% of the world GA aircraft population, so there would be an addi-
tional 67,000 in the rest of the world. These aircraft are privately owned by individ-
uals or companies for personal or corporate transportation, or recreational flying.
The second category is the air carrier industry, which employs just over 5,000 air-
craft in North America and a similar number worldwide. Both of these markets will
have a high demand for GPS as a long-range area navigation system, since phaseout
of current VOR and NDB navigation aids is slated to begin in 2010 [12].
Loran-C provides effective coverage over most of North America, and coverage
is growing in Northern Europe, the Middle East, and parts of Asia. Of course, none
of these land-based systems can provide contiguous coverage over uninhabited or
oceanic areas, as does GPS. For this regime of navigation, most transoceanic airlin-
ers currently rely on INS and GPS. GPS capability is routinely installed in all new
Boeing and Airbus aircraft.
In the GA aircraft market, Loran-C navigators used to dominate, but penetra-
tion by GPS into this market is phenomenal, especially as GPS-aided approach
capabilities become standard at most airfields. Figure 12.3 is representative of this
equipment.
GPS now provides commercial and GA airborne systems with sufficient integ-
rity to perform NPA. NPA is the most common type of instrument approach per-
formed by GA pilots. The FAA has instituted a program to implement NPA. This
so-called overlay program allows the use of a specially certified GPS navigator in
place of a VOR or NDB receiver to fly the conventional VOR or NDB approach.
New NPA overlays that define waypoints independent of ground-based facilities
and that simplify the procedures required to be flown are being put into service at
the rate of about 500 to 1,000 approaches per year and are almost complete at the

Figure 12.3 Typical general aviation GPS navigator. (Courtesy of GARMIN.)