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.