Automated verification of potential GPS signal-in-space anomalies using ground observation data

For the Global Positioning System (GPS), signal-inspace (SIS) user range error (URE), the pseudorange inaccuracy attributable to the ground control and the space vehicles, is one of the major error sources affecting positioning accuracy and integrity. As SIS anomalies occur occasionally and UREs of tens of meters or even more have been observed, knowledge of the SIS anomalies in history has a great importance for not only assessing the general GPS SIS performance but also developing next generation GNSS integrity monitoring systems.