jgg     2012 32 (2):  55-59    ISSN: 0412-1961  CN: 21-1139/TG INTERNATIONAL REFERENCE IONOSPHERE AND ITS APPLICATIONIN FEATURES ANALYSIS OF IONOSPHERE ELECTRON DENSITY Wang Cheng ;and Wang Jiexian Department of Surveying and Geo-informatics, Tongji University, Shanghai 200092 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null