COMBINED DETERMINATION OF THE EARTH'SDISTURBING POTENTIAL
The refinement of the earth's gravity field is one of the important tasks in phy-sical geodesy. The development of science and technology has provided a lot of infor-mation on the earth's gravity field. It is possible to determine the parameters of this field by combining various types of data. In the process of combination, it is necessary to assign appropriat weights to various types of data according to their spectrum and ac-curacy(Wenzel 1982). Following Meissl's Work (1971)- this paper starts with a description of the spectrum property of various types of data related to the earth's gravity field, such as potential, geoidal undulation, gravity anomaly, gravity disturbance, coat density, deflection of the vertical, and vertical gradient of the gravity anomaly. It then presents the accuracy in the harmonic coefficients computed from various types of data and estimates the attainable maximum degree according to Rapp(1971).