Sarawut Ninsawat
Dr. Sarawut Ninsawat is Associate Professor at Asian Institute of Technology. He is a Thai representative charter member of OSGeo foundation. His research interests are application of Remote Sensing and GIS for natural resource management, developing Web Mapping Application especially focus on the implementation of standard OGC Web services. Additionally, the various Location-Based Service applications were developed to utilize the location information for agriculture, environment and logistic purpose.
Sessions
The tropospheric delay is a source error for positioning using the Global Navigation Satellite System (GNSS). The signals of GNSS transmit the troposphere to the receiver, which are usually represented by zenith tropospheric delay (ZTD). ZTD can be estimated by using the Precise Point Positioning (PPP) method. Currently, there several positioning software packages to calculated PPP and estimated ZTD values by using GNSS data. This study aims to estimate ZTD value using PPP technique and analyze different results. Bernese, goGPS, and Net_Diff GNSS processing software are used to process GNSS data. To analyze the positioning PPP values, we compare between N/E/U components of coordinate estimated and referent values. Different ZTD values are investigated by using statistical basic and Pearson correlation analysis. The positioning result show PPP values calculated by Bernese software is very stability with standard deviation about < 1 cm. The Net_Diff packages can estimate PPP coordinate of N/E/U components are least error values which RMSE are <13 cm, < 4 cm, and <9 cm respectively. The different ZTD values from three software packages at DSNI and LSN2 stations show very high relationship in near perfective value that is (R > 0.90).