Abstract：The relation between the accuracies of ionofree combination pseudorange observation and P code pseudorange observation is analyzed. The experiment results show that when the qualities of P1 and P2 code pseudorange are very different, the accuracy of the ionofree combination pseudorange declines, as a result, the accuracy of point positioning using ionofree combination pseudorange is worse than that of point positioning using P1 code pseudorange . In order to solve the problem, a new point positioning method is proposed. The key of this new method is to determine the observation which should be used at every epoch. If the accuracy of P1 and P2 code pseudorange are similar, the ionokfree combination pseudorange should be used. Otherwise, the P1 code pseudorange. The experiment results show the new method can improve the point positioning accuracy effectively.
