About GPS
Understanding how GPS works and its capabilities
What is GPS?
GPS stands for Global Positioning System. It consists of a worldwide radio-navigation system made up of 24 satellites and ground-based receivers used to “locate” objects on earth.
How does GPS determine the location of an object on earth?
GPS determines location by triangulation. Triangulation is a method of calculating an object’s location by measuring the distance between it and other reference points, such as satellites, which locations are known. Triangulation requires a minimum of three known reference points.
Distance = Speed x Time
Calculating the distance between the radio and three separate satellites allows triangulation of the radio’s location on earth. Zeon Digital radios are located by multiplying the time it takes for the radio signal to travel between a satellite and the radio’s GPS receiver, with the speed of the radio signal (near the speed of light).
How do GPS satellites and receivers accurately measure time?
GPS satellites use highly accurate atomic clocks to set their time which is synchronised with ground-based satellite monitoring bases around the world. This time is then synchronised with the radio’s GPS receivers in order to accurately determine the amount of time it takes for the signal to travel to and from the satellite.
How are satellite locations accurately known?
The high altitude orbits of a satellite, around 17,000+ kilometres above the earth, guarantee there will be very little disturbance to the location of the satellite. While satellite orbits are exact, the movement of GPS satellites around these orbits is also constantly monitored to ensure accuracy by the US Department of Defence using very precise radar to check each satellite’s exact altitude, position and speed.
The location of all visible satellites is written to an almanac, typically hourly.
What objects can be located by GPS?
Modern GPS receivers have been miniaturised and can be easily integrated into cars, trucks, boats, planes and radios – just about everything!
How can GPS location errors occur?
Factors such as moisture in the atmosphere, nearby buildings and frequency interference (such as radio, television) can affect the amount of time it takes for a signal to reach the GPS receiver, resulting in an inaccurate location calculation.
Understanding how GPS works and its capabilities
What is GPS?
GPS stands for Global Positioning System. It consists of a worldwide radio-navigation system made up of 24 satellites and ground-based receivers used to “locate” objects on earth.
How does GPS determine the location of an object on earth?
GPS determines location by triangulation. Triangulation is a method of calculating an object’s location by measuring the distance between it and other reference points, such as satellites, which locations are known. Triangulation requires a minimum of three known reference points.
Distance = Speed x Time
Calculating the distance between the radio and three separate satellites allows triangulation of the radio’s location on earth. Zeon Digital radios are located by multiplying the time it takes for the radio signal to travel between a satellite and the radio’s GPS receiver, with the speed of the radio signal (near the speed of light).
How do GPS satellites and receivers accurately measure time?
GPS satellites use highly accurate atomic clocks to set their time which is synchronised with ground-based satellite monitoring bases around the world. This time is then synchronised with the radio’s GPS receivers in order to accurately determine the amount of time it takes for the signal to travel to and from the satellite.
How are satellite locations accurately known?
The high altitude orbits of a satellite, around 17,000+ kilometres above the earth, guarantee there will be very little disturbance to the location of the satellite. While satellite orbits are exact, the movement of GPS satellites around these orbits is also constantly monitored to ensure accuracy by the US Department of Defence using very precise radar to check each satellite’s exact altitude, position and speed.
The location of all visible satellites is written to an almanac, typically hourly.
What objects can be located by GPS?
Modern GPS receivers have been miniaturised and can be easily integrated into cars, trucks, boats, planes and radios – just about everything!
How can GPS location errors occur?
Factors such as moisture in the atmosphere, nearby buildings and frequency interference (such as radio, television) can affect the amount of time it takes for a signal to reach the GPS receiver, resulting in an inaccurate location calculation.
