A calculation method for GNSS positioning precision based on the posteriori unit weight variance

Abstract The precision index is the primary basis for judging the GNSS positioning result, and the positioning mean error is usually used as the precision index in practical applications. In order to solve the problem of mismatch between positioning deviation and mean error in the priori situation, this paper proposed a positioning precision calculation method based on the posteriori unit weight variance and deduced the formulas combining sequential adjustment or Kalman filter, respectively. This method uses the characteristic that there are system errors in error corrections to calculate and screen the posterior unit weight variance. This method introduces the system error’s influence into the mean error, which can improve positioning precision. The application of static difference and RTK proved that this method has remarkable effects, which can significantly alleviate the problem of false high precision and improve the reliability of positioning mean errors.