Comparative Study of different methods used for GPS GDOP Approximation

Abstract

The global positioning system(GPS), is a satellite based navigation system. Which is used in many applications such as communications, navigation, military, earth observation ,civil, and commercial user. So for correct position measurement, need to select best subset of satellites out of all combinations, which are used for finding user position. For this, the factor which helps in finding best subset of satellites from all the combinations is geometric dilution of precision(GDOP). It is a dimension less factor, which indicates the quality of the solution. the low GDOP value indicates the accurate solution. There are different methods for GDOP approximation, they are matrix inversion, closed loop algorithm, artificial neural networks. This paper compares GDOP approximation using these methods. The simulation results show that artificial neural networks have better accuracy than other methods.