ESTIMATION OF ZENITH TROPOSPHERIC DELAY USING COMBINED GPS/GLONASS PPP METHOD
1) Department of Surveying and Geoinformatics, Central South University, Changsha 410083
2) Department of Geomatics Engineering, University of Calgary, Calgary T2N1N4, Canada
Abstract:A combined GPS/GLONASS precise point positioning (PPP) approach is proposed to estimate zenith tropospheric delay (ZTD),and the results are compared with those from GPSonly PPP. The
new ZTD products of IGS are used as references to assess the estimated ZTD. The numerical computations are conducted using IGS data collected at three Chinese stations within one GPS week. The results show that the different settings of elevation angle cutoff and spectral density value of tropospheric delay parameter have a large impact on the ZTD estimates. Compared with GPS-only PPP, the ZTD estimates obtained from the combined GPS/GLONASS PPP are more consistent with IGS products.