Design and Verification of TT&C System for Queqiao-2 Relay Satellite

Abstract

Based on the situations where ground stations can’t directly measure hunar far-side or polar regions， and where current tracking and control systems face limitations in improving telemetry rates and measurement accuracy dueto the Earth-Moon distance，the Queqiao-2 relay satellite’s TT&C system is designed to achieve a four-way measurement chain-Earth-satellite-probe-satellite-Earth-enabling real-time tracking and measurement of lunar spacecraft that are not directly visible from Earth. Additionally this system serves to validate a GMSK+PN-based tracking and control communication scheme. Since the in-orbit launch of the Queqiao-2 relay satellite，the TT&C syatem has consistently and stably perfomed TT&C tasks. Simulation results of the four-way meaurement demonstrate that it can achieve meter-level positioning accuracy for the lander. Calculation of the new TT&C scheme indicates that it can achieve centineter-level ranging accuracy at the Earth-Moon distance. The actual operational perfomance and simulation verification results demonstrate that the Queqiao-2 relay satellite’s TT&C system design meets the mission requirements and can provide reference for the design of TT&C systems for future deep space exploration and lunar exploration missions.

Keywords

Queqiao-2 / TT&C system / unified carrier system / four-way measurement / GMSK + PN