卫星通信中的一种应答机空间操控方法

A Space Operation Way of Transponder in Satellite Communication

针对运行超过10年的某太阳同步轨道卫星通信应答机的载波捕获性能下降问题,提出了一种新的“载波+遥控副载波”上行信号空间操控方法。首先根据所测量的应答机温度、自动增益控制电压及载波锁定参数,分析空间环境对卫星应答机的影响;接着调整上行信号结构,即通过移除测距副载波与减小遥控副载波调制度来增加载波功率。空间操控结果表明:应答机在单粒子效应下损伤,其倍频器二极管受温度调制影响;应答机温度越高载波捕获就越困难,高于26.2℃时载波无法实现捕获与锁定;新方法下的上行载波增益提高了约3.1 dB且交叉调制减少,载噪比提升优于3.1 dB;在25.9℃时,载波锁定时长超过120 s,约4倍于同温下的原有情形;拓展了上行注入窗口时长,遥控发令成功率为100%。新方法已应用于在轨卫星长期管理,为载荷延寿工作提供空间操控支持,可有效降低上行链路增益预算需求并施行于相应场合。

A new space operation way to signal modulation mode containing only carrier plus telecontrol subcarrier is proposed to deal with the transponder carrier acquisition degradation in satellite communication of a low earth orbit(LEO)satellite running on sun synchronous orbit for over 10 years.The space environment effects on the transponder are firstly analyzed based on the telemetry parameters including temperature,auto gain control(AGC)voltage and carrier lock from the satellite.Then the uplink signal is adjusted to increase the carrier power by demodulating the range subcarrier and lowering the telecontrol subcarrier modulation index.The results in space operation show that the transponder is damaged by the single event burnout(SEB),and the diode of the frequency multiplier is affected by temperature modulation of the transponder.The higher the transponder temperature,the more difficult the capture of carrier,and when the temperature is higher than 26.2℃,the carrier cannot be captured and locked.When the new method is applied,the carrier gain increment is about 3.1 dB,the intermodulation decreases,and the carrier-to-noise ratio improvement is more than 3.1 dB.When the transponder temperature reaches 25.9℃,the carrier locking time exceeds 120 s,which is 4 times the oringnal one at the same temperature.The length of the uplink injection window is extended,and telecontrol command execution is 100%.The new approach can be applied to the long-term management of satellites in-orbit effectively,and can extend payload service life and reduce the gain budgets in the uplink.