Analysis of positioning errors in radionavigation systems

This paper presents the comparisons of error characteristics between time of arrival (TOA) and time difference of arrival (TDOA), especially the relationship between position estimates and their error covariance. The errors of pseudorange measurements are considered as weighted or correlated due to the constellations of satellite and environment of a user. It is analytically demonstrated that the error covariance matrix and position estimates for TDOA are the same as those for TOA.. It also shows that the error covariance for TDOA does not change regardless of any single difference operator.