jgg     2014 34 (5):  70-74    ISSN: 0412-1961  CN: 21-1139/TG ANALYSIS OF GLOBAL IONOSPHERIC GRID MODEL INTEGRATED  GPS/GLONASS 1）College of Geomatics，Xi’an University of Science and Technology，Xi’an 710054 2）State Key Laboratory of Geodesy and Earth’s Dynamics，Wuhan 430077 3）School of Geodesy and Geomatics，Wuhan University，Wuhan 430079 Received: 2013-09-23  Revised: null  Online: 2014-09-26 Supporting info