Satellite selection algorithm to improve precision and real-time performance of GPS positioning

Based on an analysis of the influence of both the number of satellites and one satellite to GDOP, it is concluded that GDOP progressive decreases dully with the increase of the number of satellites, but the decreasing amplitude reduces. With consideration of both GPS positioning precision and real-time performance, a combination of 6 satellites is selected to calculate position. Based on the definition of the contribution to GDOP, two satellite selection algorithms are proposed, whose performance is compared with the best GDOP algorithm. Simulation results indicate that there is little difference between the GDOP of 6 satellites and that of all observed satellites, and the two algorithms proposed by this paper have almost the same selected satellites with that of best GDOP algorithm, but with much less computations.