GNSS Markets and Applications - Understanding GPS: Principles and Applications - page 652

geodetic organizations are using GPS to form active control networks that rely on
GPS to tie together positions rather than referencing them back to fixed monuments
by conventional surveying means. California has established an earthquake

monitoring system along these lines.

12.6.3 Attitude Determination Systems
While a limited market segment, GPS receivers have been proven to be useful in
determining the attitude of host vehicles. Examples include pointing a long artillery
gun barrel, finding an aircraft's attitude, outputting ship's heading, pitch, and roll,
and particularly determining spacecraft attitude. These applications go back to the
1980s with the military funding the research and development. In the mid-1990s, a
unit was introduced called the Trimble Advanced Navigation System Vector Atti-
tude Determination System, which many researchers applied to various attitude
determination problems, including NASA/Stanford's Gravity Probe-B spacecraft.
All of these systems make use of either multiple antennas for three-dimensional solu-
tions or at least a linear array to determine a pointing vector. Honeywell obtained
one of the earliest patents (6088653) for a vehicle application, where a three-
antenna GPS receiver is integrated with a vehicle inertial sensor. Today, integrations
between GPS receivers and inertial sensors are a very high-tech market area requir-
ing software development that uses sophisticated Kalman filtering algorithms. In
2002, a similar integration was used for a typical space application of GPS attitude
determination aboard NASA's Thermosphere, Ionosphere, Mesosphere Energetics
and Dynamics (TIMED) spacecraft by Johns Hopkins University Applied Physics
Laboratory. The TIMED mission studied the influences of the Sun and humans on
the least explored and understood portion of Earth's atmosphere—the mesosphere
and lower thermosphere/ionosphere.

12.7 GNSS and Telematics and LBS

A truly exciting and major growth area for GNSS equipment and services is in what
is euphemistically called transport telematics , or vehicle location-awareness ser-
vices. Driven mainly by service providers looking for steady income streams, these
services rely heavily on knowing where a user is located and being able to communi-
cate with that user. Estimates of this market segment range between $1 billion and
$11 billion by 2008. The uncertainty is due to the difficulty allocating the revenue to
the telecommunications companies and to the actual location awareness service pro-
vider. Nonetheless, as the world's cell phone population approaches the half billion
mark and GPS chips proliferate, the technology is available to satisfy the basic ele-
ments of a telematics service. In its infancy now, there are the standard vehicle track-
ing services, most notably QUALCOMM's OmniTRACS for commercial vehicles
and GM's OnStar for consumers. They make use of OnStar's primary service, which
is safety and stolen vehicle recovery. Typical OnStar services include contacting the
dispatcher of emergency vehicles in an accident and remotely unlocking the car of a
user who has lost his keys. This is besides the normal route guidance functions used
regularly by most customers.