Relay repeater system for unmanned helicopter

The invention discloses a relay transmitting system used for an unmanned helicopter, which rises the height of the unmanned helicopter to promote the transmission quality of signals in a spatial channel, and can transmit the relay with a weak signal even in the distance, thus increasing the communication distance; the invention is characterized by high sensitivity, wide dynamic range, broad transmitting band and good anti-interference performance. The invention comprises two main parts of an airborne part and a ground part, wherein, the airborne part is carried with a relay transmitting subsystem and consists of four modules of an airborne receiving antenna, an airborne relay transmitting module, a broad band filter and an airborne transmitting antenna; and the ground part comprises a ground receiving subsystem including three modules of a ground receiving antenna, a vehicle low noise amplifier and a ground receiving module. The system of the invention is simple, high-efficient and reliable and has low cost.