Satellite methods of gravity field study. Status and future prospects

A definition of a Global geodetic observing space system design and space geodetic techniques are described. It is proposed that the Global geodetic observing space system shall consist of 1-2 MEO (Medium Earth Orbit) spacecraft(s), a LEO (Low Earth Orbit) spacecraft featuring on-board gravity gradiometer and/or 2 LEO spacecrafts featuring high-precision satellite-to-satellite tracking (SST) instruments, GNSS (GLONASS, GPS and Galileo) navigation spacecrafts (if needed), a passive satellite of Blitz-M type, launcher and launch facilities, ground control segment, a timing system, ground processing facilities. Geodetic technique includes a conventional dynamic method together with gravimetry and altimetry methods, a satellite gravity gradiometer and/or satellite-to-satellite tracking to measure relative position between two LEO spacecrafts.