This is a summarized paper．Two topics are discussed：Firstly．the concept development and application of four kinds of satellite gravity surveying technology are introduced； Secondly，some problems of theory and method， which must be considered in study of Earth’s gravity field based satellite gravity data，are expounded．

The propagating path of satellite signals through the atmosphere is a curve which is difficult to precisely plot．In order to precisely calculate the correction to its curvature we take a fold line as the ap proximation of]st degree to the refractive curve，then divide the fold line into several sections．Thus the re—
fractive curve can be approximated by circular arc．According to the above consideration， a series of strict formulae to calculate the curvature correction under the condition of different zenith distances are derived. At last，a model which is convenient and precise for calculating the curvature correction has been established．

On the basis of analyzing ordinary ridgc estimator's and Stein estimator's properties，a new based estimator of unknown parameters，which is called combined ridge with shrunken(CRS)estimator， is generated for Gauss— Markov model by combining the ordinary ridge estimator and Stein shrunken estimator．The CRS estimator can overcome the detects of the ordinarv ridge estimator and the Stein shrunken estimator．Its properties in the mean squared error and under the Pitman's measure o c closeness are ivestigated. In the sense of the mean squared error comparisons between these biased estimators cqre explored． The determination of biased parameter of the CRS eslimator is discussed and some important conelusions are drawn．The thoretical and computational results demonstrate that the CRS estimator is a potentail estimtor in surveying adjuslment．