Precise position estimation is of great importance for many applications. Unfortunately it is still an extreme technical challenge. Due to non idealities measurements are influenced by stochastic as well as deterministic errors. In this contribution a derivation on the error propagation for additive white Gaussian noise, for inaccurate coordinates for satellites and base stations respectively as well as for an improper velocity of propagation of the electromagnetic wave for both the GPS system and the local position measurement system LPM is given