Performance Analysis of Satellite Navigation based on the Least-Squares Method

Abstract

Generally, the accuracy of satellite navigation is strongly affected by the deployment of the satellites relative to the user's equipment and also affected by the type of navigation methods to be applied. In the first part of this paper, four types of navigation methods are considered, each of which uses real-ranges, pseudo-ranges or altitude data to determine the position of user's equipments, and then the least-squares method is applied to utilize all measured range data. Next, the expressions for covariance matrices are given in generalized form by which dilutions of precision (DOPs) such as GDOP, VDOP, HDOP and TDOP are derived, and then simplified equations of DOPs are found on condition that the deployment of satellites is in typical geometry. Also, the characteristics of each type of navigation methods is discussed referring to the equations of DOPs derived in this paper, and computer simulation results are added to show the effect of applying the least-squares method and switching the type of navigation method in case that range measurements are not good.