Evaluation of International Terrestrial Reference Frame Colocated Ties through Compatibility Testing

Abstract

Evaluation on the agreement between colocated ties and ties estimated from space geodesy techniques before the intertechnique combination is essential to an accurate combination solution realization. Previous studies evaluate their agreement based on the magnitude of postfit residuals with normalized residuals during the intertechnique combination and magnitude of their differences through intratechnique combination from space geodetic measurement. This study formulates an alternative criterion based on the critical value of the chi-square test statistic through compatibility testing for the evaluation of both ties agreement. Individual terrestrial reference frame solution and corresponding colocated ties data within 14 colocated sites used in ITRF2000 realization were selected for the study. It was found that the devised criterion flagged and retained the same set of colocated ties in common with previous contribution results, which makes itself another alternative for further validation. Given the demand of the fusion of several groups of data for better derived information in geosciences and remote sensing, this criterion could also be applied to outlier detection for each group of data during the fusion process.