用于北斗有源天线的自适应发射机电路的设计与实现

北斗卫星导航系统可提供(radio determination satellite service,RDSS)短报文通信服务是其独特之处。为适应北斗RDSS短报文通信收发机制，设计了一种可应用于北斗有源天线的自适应发射机电路。提出并验证了使用分段、低成本的线性放大器代替对数放大器，来实现环路控制电路(voltage control amplifier,VCA)；通过在传统北斗有源天线发射链路前端增加自动增益控制电路(automatic gain control,AGC)模组，实现了有源天线在0~30 m对不同射频线缆材质、长度造成损耗的自动适应，从而保证了北斗短报文通信设备在天线端的一致性、可靠性与易用性。

Adaptive transmitting module used in Beidou active antenna

The Beidou satellite navigation system is unique in its ability to provide RDSS short message communication services. In order to adapt to the Beidou RDSS short message communication mechanism, this paper designs an adaptive transmitter circuit that can be applied to the Beidou active antenna. A VCA loop control circuit is implemented by using a segmented, low cost linear amplifier instead of a log amp; the AGC module is added at the front end of the traditional Beidou active antenna transmit link, and the active antenna is implemented to automatically adapt to the loss of material and length of different RF cables within 30 meters, thus ensuring the consistency, reliability and ease of use of Beidou short message communication equipment at the antenna end.