Abstract: Objective In the first part of the paper we discuss the challenges of huge networks and multi-GNSS da-ta processing for the zero-difference(ZD)strategy.Using 4weeks’of data from global IGS GPS/GLONASS stations,we performed daily data processing with data sampling ranging from 5-15min.Acomparison of the processing time and product precision under different sampling data shows:①Computation efficiency is greatly improved by increasing data sampling;our results show the improve-ment of maximum 52%;② Difference of product precision was marginally observed,and product pre-cision is almost the same when the sampling rate was changed from 5-10min.To analyze the impact ofdifferent products on positioning applications,we performed PPP for 22globally distributed IGS sta-tions and kinematic precise orbit determination for GRACE satellites using products generated fromdifferent data sampling procedures.Results show:①Ｓｔａｔｉｃ　ＰＰＰ　ｐｒｅｃｉｓｉｏｎ　ｄｉｆｆｅｒｓ　ｂｙ　ｌｅｓｓ　ｔｈａｎ　２ｍｍand 6mm for the horizontal and height components,respectively;②ｋｉｎｅｍａｔｉｃ　ＰＰＰ　ｐｒｅｃｉｓｉｏｎ　ｄｉｆｆｅｒｓby less than 1.5cm for each coordinate component and less than 2cm in three-dimensions.