Abstract:

In the unified S-band （USB） tracking telemetering and control （TT&C） system，the ground station extracts the range information through the phase delay of the ranging tone transmitted by the satellite TT&C transponder. Considering the influence of the ranging tone extraction filter and channel noise on the downlink modulation system， the modulation index of the downlink ranging tone will fluctuate unexpectedly. So the system efficiency and communication distance of the whole TT&C system are affected. This paper introduces a ranging sound power decoupling method for a miniaturized USB TT&C transponder， which simplifies the design of the uplink receiver while eliminating the adverse effect of the uplink received signal strength on the modulation system through the normalisation of the received power， so as to guarantee the power efficiency of the modulation signal of the measurement and control transponders. The feasibility and effect of the method are verified by product measurement.

Key words: unified S-band（USB）, tracking telemetering and control（TT&C） transponder, modulation, phase modulation index, decoupling method

摘要：

在航天统一S波段（unified S-band，USB）测控系统中，地面测控站通过星上的USB测控应答机转发的测距音相位延迟提取距离信息，考虑到测距音提取滤波器以及信道噪声对下行调制度的影响，下行测距音的调制度会发生非预期的起伏，从而影响整个测控系统的功率效率与通信距离。提到了一种微小型USB测控应答机测距音功率解耦方法，在简化上行接收机设计的同时，通过进行接收功率归一化，消除上行接收信号强度对调制度的不利影响，保障了测控应答机调制信号的功率效率，并通过产品实测对方法的可行性与效果进行了验证。

关键词: 统一S波段, 测控应答机, 相位调制, 调制度, 解耦方法