jgg     2011 31 (3):  134-137    ISSN: 0412-1961  CN: 21-1139/TG STUDY ON PREDICTION OF ZENITH TROPOSPHERIC DELAY BY USE OF BP NEURAL NETWORK Wang Yong 1, 2) ; Zhang Lihui 3) ;and Yang Jing 3) 1)School of Surveying & Land Information Engineering, Henan Polytechnic University, Jiaozuo 4540002)Earthquake Engineering Research Center, Hebei United University,Tangshan 0630093)College of Mining Engineering, Hebei United University, Tangshan 063009 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null