An STD Reliability Test for Kinematic GPS processing: A Case Study Based on KARS and Applanix POSGPS Software

摘要

Practical experiences have shown that the standard deviations (STD) obtained from kinematic GPS processing software may not always reflect the actual error due to the lack of information about functional correlation. Neglecting the physical correlation between epochs, systematic errors and improperly modeled parameters may cause incorrect estimation of the standard deviation. A number of the GPS processing software consider the variance-covariance matrix of the observations without correlation or simply deal with the diagonal components only,. As a consequence, the a posteriori standard deviations of the estimated coordinates could be too optimistic and may not represent the actual quality of the estimated coordinates. This is particularly important when the improperly estimated STDs are used as a priori values for GPS/IMU (Global Positioning Systern/Inertial measurement unit) Kalman filtering, and consequently defining the georeferencing error budget of imaging sensors, such as airborne digital camera, LiDAR (Light Detection and Ranging) and IfSAR (Interferometric synthetic aperture radar).