Satellite Based Positioning

Satellites have allowed us to realize geocentric reference systems, and increase the level of spatial accuracy substantially. They are critical tools in geodetic engineering for the maintenance of the ITRF. They also play a key role in mapping, surveying, and in a growing number of applications requiring positioning techniques.

The requirements for the development of the positioning system were:

• Suitability for all kinds of military use: ground troops and vehicles, aircraft and missiles, ships; Requiring only low-cost equipment with low energy consumption at the receiver end;
• Provision of results in real time for an unlimited number of users concurrently support for different levels of accuracy (military versus civilian);
• Around-the-clock and weather-proof availability;
• Use of a single geodetic data.

  A satellite-based positioning system set-up involves implementation of three hardware segments :

  • The space segment, i.e. the satellites that orbit the Earth, and the radio signals that they emit
  • The control segment, i.e. the ground stations that monitor and maintain the space segment components, and the user segment, i.e. the users with their hard- and software to conduct positioning.
  • In satellite positioning, the central problem is to determine values (X, Y, Z) of a receiver that receives satellite signals, i.e. to determine the position of the receiver with a stated accuracy and precision.