02718nam a2200253 a 450000500170000000800410001703500150005810000370007324501000011026000570021030000510026749000270031850001010034550200570044652015760050365000300207965000270210970000330213670000460216970000470221571000770226281000590233985600660239820260818134633.0140618s2012    th ad  |||   |000 0 eng d  a.b121331521 aWickramasinghe, Chathura Hasanka10aImproving  real-time PPP positioning by combining QZSS-LEX message and IGS ultra-rapid products  aPathum Thani :bAsian Institute of Technology,c2012  a65 leaves :bill., charts +e1 online resource1 aThesis ;vno. RS-12-16  aA thesis submitted in partial fulfillment of the requirement for the degree of Master of Science  aThesis (M.Sc.) - Asian Institute of Technology, 2012  aGlobal Positioning  System  (GPS)  has  become  a  day  to  day  tool  with  multiple applications.  Errors associated  with  GPS observations  makeit  impossible  to  use a single receiver  for  geodetic,  geodynamic  and  vehicle  automation  applications  requiring  centimeter or  millimeter  level  accuracy.  Real  Time  Precise  Point  Positioning  (RT  PPP)  has  become  a powerful tool that can provide positioning accuracy comparable to the network solution(Ge et al.  2007)without  the  need  of  GPS  base  station  network.  International  GNSS  service  (IGS) has  been  providing  data  necessary  for  PPP  via  internet  in  real  time.  Quasi-Zenith Satellite System  (QZSS)  is  a  Japanese  GPS  augmentation  system  that  provides  real  time  PPP correction  through  an  experimental  signal  (LEX)  from  June  2011.  LEX  signal  provides  real time  GPS  satellite  ephemeris  and  clock  correction.  The  accuracy  of  these  corrections  will directly affect the positioning accuracy(Zumberge et al. 1997). This paper compared the LEX PPP  data  with  the  IGS  Ultra  rapid  data products to  analyze  the  accuracy  of  LEX  data. The analysis showed LEX data has systematic errors that can be corrected. A new algorithm was developed to  correct  clock  error  and  ephemeris  errors  using a liner  model  and  wavelet transformation. This  method improved  LEX  ephemeris  accuracy  to  decimeter  level  and  the clock correction accuracy to 0.01 microseconds. As a result LEX based real time positioning accuracy was improved by 37%. 0aGlobal Positioning System 0aGeographical positions0 aLal Samarakoon,eChairperson0 aTaravudh Tipdecho,eExamination committee0 aManukid Parnichkun,eExamination Committee2 aGeoinformatics Center, Asian Institute of Technology,eScholarship donor2 aAsian Institute of Technology.tThesis ;vno. RS-12-16  3Full-Textuhttp://203.159.5.9/ait-thesis/detail.php?q=B03879