jgg     2009 29 (5):  129-131    ISSN: 0412-1961  CN: 21-1139/TG APPLICATION OF IGU EPHEMERIS TO MOUNTAIN-BASED GPS OBSCURATION PREDICTION Feng Wei1）;Jin Huihua1，2）;Shao Jiani1）; and Lin Xuefeng1） 1）61081 Troops，Beijing 100094 2）61892 Troops，Beijing 100094 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null