Introduction to GNSS - GNSS Remote Sensing: Theory, Methods and Applications - page 16

1.4 GNSS Observations and Applications

The applications of GNSS technology are dependent on human imaginations, which
are limitless. GNSS only provides the real time position, velocity and time (PVT)
but the gurus of this gigantic field envisage the next millennium as the time for
Positioning and Timing. The paradigm shift from the military usage to the civil
applications has changed the whole scenario. At present, each new car has the
built in Navigator to guide the commuter to his destination with digital maps.
The talking pedestrian navigator can guide the virtually impaired people to their
destination. The hikers and the mountaineers can never be lost due to their personal
navigators. New cell phones are equipped with the GPS receiver and the integration
between communication and navigation will produce miracles in the near future.
The location-based services will enhance the mobile market with the choice of
real time gamming and emergency call identification facilities. The aviation and
aerospace industry is using GNSS for guidance and control. The spacecrafts get their
orbit and attitude determined by the virtue of GNSS. The UAV/UMV are controlled
and guided by the same technology and the guided missiles get their way by the
application of this advancement. The maritime sector was the first user of GNSS.
At present, GNSS is contributing in Navigation safety, Collision prevention, Vessel
traceability to automate maneuvers in narrow spaces, Automatic Identification
Systems (AIS), and vessel traffic management system and Search & Rescue (SAR)
services. In addition to that, it has wide applications in the fields of Oceanography
and Marine Engineering. In Public Transport system, GNSS is providing great
features for electronic toll system, automated trains and subways, fleet management,
route guidance, passenger information system, traffic management and security
services like trackers. GNSS is playing a pivotal role in the fields of environment
monitoring and control, agriculture and fishing, civil engineering, disaster and relief
operations, Telecommunications and energy sectors. The Time information obtained
by the GNSS is playing a great role in electronic banking, finance and insurance.
The universal time is also maintained by the GNSS signal in space.

1.4.1 GNSS Observation Network

The International GNSS (Global Navigation Satellite Systems) Service (IGS) was
formally established in 1993 by the International Association of Geodesy (IAG),
and began routine operations on 1 January 1994 (Beutler et al. 1999 ). The IGS
coordinates a worldwide network of permanent tracking stations with about 350
GPS stations (Fig. 1.2 ), which are financed and operated by numerous organizations,
providing the high quality data products for use in GNSS related Earth science
research, navigation application and educational outreach.