GNSS is a global navigation satellite system comprising of network of satellites that transmit ranging signals used for positioning and navigation anywhere around the globe; on land, in the air or at sea. The US Global Positioning System (GPS/Navstar GPS), the Russian Global Navigation Satellite System (GLONASS) and the upcoming European GALILEO system, Data communications satellites with navigation payloads and Augmentation systems are all part of GNSS.

The 746th Test Squadron (746 TS) has conducted complex GPS jamming experiments since the early 1990s and played a key role “behind the scenes” creating multiple high-profile jamming environments for programs such as the Joint GPS Combat Effectiveness (JGPSCE) exercises and Quick Reaction Tests. These programs, conducted to support real-world operations, enhanced the 746th TS’s ability to recreate realistic jamming environments and resulted in the 746 TS earning the reputation as the recognized experts for open-air GPS vulnerability testing.

As the designers and builders of infrastructure; surveyors, engineers and construction contractors know well the benefits gained from a strong infrastructure. Whether transportation, utilities or communication systems, infrastructure constitutes a society’s basic structure, the foundation upon which the growth of a community, state or entire nation depends.

In order to provide seamless navigation to the world aviation community by airport service providers, the International Civil Aviation Organization (ICAO) has adopted a new strategy on the implementation of Future Air Navigation System (FANS) and use of non-visual aids for approach, and landing. The solution for the above requirements is Global Navigation Satellite System (GNSS). A stand alone GPS fails to provide the required navigation accuracy for all phases of the flight. Therefore, to achieve the required navigation accuracy, the core constellation i.e. GPS, GLONASS, and Galileo (under planning stage) needs augmentations to fulfill the GNSS, particularly in satellite-based augmentations such as WAAS (USA), EGNOS (Europe), MSAS (Japan), GRAS (Australia) and GAGAN (India). It also includes ICAO’s acceptance of an offer to make the Global Orbiting Navigation Satellites System (GLONASS) available for use by civil aviation. The ICAO Council had earlier accepted a similar offer concerning the GPS. These three satellite constellations (GPS / GLONASS / Galileo) are the key components of the GNSS. This article describes briefly, the different systems including GAGAN (India) and the status of GNSS.

Since Japan is an earthquake prone country with a lot of volcanoes and active faults, Geographic Survey Institute (GSI), the Government of Japan has constructed about 1,200 GPS Fixed Stations called “electronic control points” all over Japan. Since 2003, GSI released GPS data to public through web site. The authors have already checked and confirmed the evidence of early warning for the past big earthquakes such as Tokachi Earthquake (M8.0: 2003.9.26) and Nigata Chu-etsu Earthquake (M6.8: 2004.10.23) which occurred in Hokkaido, north of Japan and middle of Japan respectively. International GPS Service (IGS) provides world wide GPS data at GPS stations located at 10 stations near Indonesia and other Asian regions.