Evaluation of Dual-Frequency GBAS Performance using Data from Public Receiver Networks

This paper examines the effectiveness of two proposed methods for dual-frequency smoothing in Ground Based Augmentation Systems (GBAS) based on data collected in 2010 by clusters of nearby receivers whose measurements are publically available. After an extensive search turned up no ionospheric anomalies, data from several clusters of CORS and IGS stations under nominal conditions was examined, and results from three of these clusters are presented. Across these clusters, the variation with regard to receiver noise and multipath errors is very large. However, in all cases, dual-frequency smoothing performed well and generally agreed with theoretical predictions. These results confirm that future multiplefrequency GBAS systems using these methods are practical as long as receiver multipath is controlled to the level of the best CORS and IGS receivers.