Ground support of satellite systems

The application of the GPS system in surveying jobs done for engineering purposes is inhibited by unsatisfactory precision of position defining, uneven precision of coordinates, and precision fluctuations over time. This situation is made even more difficult by the limited access to signal and by terrain obstacles which are often found at sites where engineers are working. This paper presents various aspects of strengthening the GPS system with overground support which depends on access to the constellation of GPS satellites and on the conditions the environment offers to observation. The paper also describes the results of preliminary precision analysis obtained at various configurations of the support, which significantly improve the geometry of positioning, whenever appropriate conditions are secured.