Often my students ask about a clear definition of Global Navigation Satellite System (GNSS); since in many instances the definitions of GNSS are application specific and not lucid.
As it is known to us that GNSS is a satellite based navigation and positioning system. This system provides autonomous spatial positioning with global coverage. A GNSS allows small electronic receiver to determine its location using signals transmitted from navigation satellites. For anyone with a GNSS receiver, the system can provide location (and time) information in all weather conditions, day and night, anywhere in the world.
GNSS is made up of three segments: (1) satellites orbiting the earth; (2) control and monitoring stations on the earth; and (3) the GNSS receivers owned by users. GNSS satellites broadcast signals from space that are picked up and identified by GNSS receivers. Each GNSS receiver then provides three-dimensional location (latitude, longitude, and altitude), precise time information, and other information for calibration purposes.
Individuals may purchase GNSS receivers that are readily available through commercial retailers. Equipped with these receivers, users can accurately locate where they are and can easily navigate to where they want to go, whether walking, driving, flying, or sailing. GNSS has become a mainstay of transportation systems worldwide, providing navigation for aviation, ground, and maritime operations. Disaster relief and emergency services depend upon GNSS for location and timing capabilities in their life-saving missions. Activities such as banking, mobile phone operations, and even the control of power grids, are facilitated everyday by the accurate timing provided by GNSS. Engineers, surveyors, geologists, geographers, and countless others can perform their work more efficiently, safely, economically, and accurately using the GNSS technology.
There are currently two GNSSs in operation: the United States’ NAVigation Satellite Timing And Ranging Global Positioning System (NAVSTAR GPS, commonly known as GPS) and the Russian GLObal'naya NAvigatsionnaya Sputnikovaya Sistema (GLONASS). A third system, Galileo, is currently being developed in Europe; and a fourth, Compass Navigation Satellite System (or Beidou II; commonly referred as Compass) has been initiated by China. Other than these global systems there are some regional or local systems as well.
With the advent of GPS and GLONASS, and soon with the addition of Galileo and Compass, the application by civil users of global positioning, navigation, and timing services has mushroomed around the world and has popularized the concept of GNSS. Unfortunately we have yet to come up with a commonly accepted and actionable definition of GNSS (Swider 2005). Swider (2005) has defined GNSS as:
GNSS collectively refers to the worldwide civil positioning, navigation, and timing determination capabilities available from one or more satellite constellations.
A definition of GNSS given by International Civil Aviation Organization is (ICAO 2005):
GNSS is a world-wide position and time determination system that includes one or more satellite constellations, aircraft receivers, system integrity monitoring augmented as necessary to support the required navigation performance for the intended operation.
Another simple definition is:
GNSS is a satellite-based system that is used to pinpoint the geographic location of a user’s receiver anywhere in the world.
The above definition is short, simple, and memorable; however, it is technologically not sound enough. A better definition of GNSS is (Bhatta 2008):
GNSS is a network of satellites that continuously transmits coded information, which makes it possible to precisely identify locations on the earth by measuring distances from the satellites.
Whatever the earlier definitions we may find in the literature, a good definition of GNSS can be given as (Bhatta 2010):
GNSS is a system consisting network of navigation satellites monitored and controlled by ground stations on the earth, which continuously transmit radio signals that are captured by the receivers to process, and thus to make it possible to precisely geolocation of the receiver by measuring distances from the satellites and to provide precise time information any were in the world at any time.
'Geolocation' refers to identifying the real-world geographic location of a GNSS receiver.
References
Swider, R.J. 2005, Can GNSS Become a Reality?, GPS World, 16(12): 20–20.
ICAO 2005, Draft Galileo SARPS – Part A, Working Paper, International Civil Aviation Organization NSP/WG1: WP35, 12 pp.
Bhatta, B. 2008, Remote Sensing and GIS, Oxford University Press, New York, 872 pp.
Bhatta, B. 2010, Global Navigation Satellite Systems : Insights into GPS, GLONASS, Galileo, Compass, and Others, BS Publications, Hyderabad, 438 pp.
As it is known to us that GNSS is a satellite based navigation and positioning system. This system provides autonomous spatial positioning with global coverage. A GNSS allows small electronic receiver to determine its location using signals transmitted from navigation satellites. For anyone with a GNSS receiver, the system can provide location (and time) information in all weather conditions, day and night, anywhere in the world.
GNSS is made up of three segments: (1) satellites orbiting the earth; (2) control and monitoring stations on the earth; and (3) the GNSS receivers owned by users. GNSS satellites broadcast signals from space that are picked up and identified by GNSS receivers. Each GNSS receiver then provides three-dimensional location (latitude, longitude, and altitude), precise time information, and other information for calibration purposes.
Individuals may purchase GNSS receivers that are readily available through commercial retailers. Equipped with these receivers, users can accurately locate where they are and can easily navigate to where they want to go, whether walking, driving, flying, or sailing. GNSS has become a mainstay of transportation systems worldwide, providing navigation for aviation, ground, and maritime operations. Disaster relief and emergency services depend upon GNSS for location and timing capabilities in their life-saving missions. Activities such as banking, mobile phone operations, and even the control of power grids, are facilitated everyday by the accurate timing provided by GNSS. Engineers, surveyors, geologists, geographers, and countless others can perform their work more efficiently, safely, economically, and accurately using the GNSS technology.
There are currently two GNSSs in operation: the United States’ NAVigation Satellite Timing And Ranging Global Positioning System (NAVSTAR GPS, commonly known as GPS) and the Russian GLObal'naya NAvigatsionnaya Sputnikovaya Sistema (GLONASS). A third system, Galileo, is currently being developed in Europe; and a fourth, Compass Navigation Satellite System (or Beidou II; commonly referred as Compass) has been initiated by China. Other than these global systems there are some regional or local systems as well.
With the advent of GPS and GLONASS, and soon with the addition of Galileo and Compass, the application by civil users of global positioning, navigation, and timing services has mushroomed around the world and has popularized the concept of GNSS. Unfortunately we have yet to come up with a commonly accepted and actionable definition of GNSS (Swider 2005). Swider (2005) has defined GNSS as:
GNSS collectively refers to the worldwide civil positioning, navigation, and timing determination capabilities available from one or more satellite constellations.
A definition of GNSS given by International Civil Aviation Organization is (ICAO 2005):
GNSS is a world-wide position and time determination system that includes one or more satellite constellations, aircraft receivers, system integrity monitoring augmented as necessary to support the required navigation performance for the intended operation.
Another simple definition is:
GNSS is a satellite-based system that is used to pinpoint the geographic location of a user’s receiver anywhere in the world.
The above definition is short, simple, and memorable; however, it is technologically not sound enough. A better definition of GNSS is (Bhatta 2008):
GNSS is a network of satellites that continuously transmits coded information, which makes it possible to precisely identify locations on the earth by measuring distances from the satellites.
Whatever the earlier definitions we may find in the literature, a good definition of GNSS can be given as (Bhatta 2010):
GNSS is a system consisting network of navigation satellites monitored and controlled by ground stations on the earth, which continuously transmit radio signals that are captured by the receivers to process, and thus to make it possible to precisely geolocation of the receiver by measuring distances from the satellites and to provide precise time information any were in the world at any time.
'Geolocation' refers to identifying the real-world geographic location of a GNSS receiver.
References
Swider, R.J. 2005, Can GNSS Become a Reality?, GPS World, 16(12): 20–20.
ICAO 2005, Draft Galileo SARPS – Part A, Working Paper, International Civil Aviation Organization NSP/WG1: WP35, 12 pp.
Bhatta, B. 2008, Remote Sensing and GIS, Oxford University Press, New York, 872 pp.
Bhatta, B. 2010, Global Navigation Satellite Systems : Insights into GPS, GLONASS, Galileo, Compass, and Others, BS Publications, Hyderabad, 438 pp.
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