A crustal movement observation system using quasi-zenith satellites

The proposal for an observation system of crustal movement using two quasi-zenith satellites is presented. In the system, two quasi-zenith satellites have a retro-directive antenna on board and an earth station have two beam antenna in the direction to the two quasi-zenith satellites. The crustal movement at the area of the earth stations is obtained by interfering with two signals from the retro-directive antennas which transmit the receiving waves from the earth station antenna. The link budget for the system is carried out, and a spherical reflector antenna for two beam antenna is designed.