Using Global Navigation Satellite System, (GNSS) e.g. GPS systems, for surveying or machine control comes with the consideration of the accuracy and precision of the GNSS receiver’s position.
The basic idea of GNSS systems is establishing a satellite network in which each satellite sends a signal at a defined time to receivers.
The distance from the satellite to the receiver can be calculated, by measuring the time difference from the transmitter to receiver.
Using at least 4 satellites simultaneous the 3D Position of the receiver (vertical and horizontal) can be calculated, if the position of each satellite is known.
The accuracy of GNSS Systems is influenced by the realization of the needed infrastructure causing the influences on the transmitted signals that make the position calculation possible.
Satellites used for GNSS Systems are moving at approx. 4 km per seconds (with respect to the earth) under varying conditions. Due to the movement of the receiver and the transmitter we need to take a look at the factors that determine the accuracy of GNSS Systems.