High-speed and low-speed collaborative low-orbit satellite communication system and method

The invention relates to a high-speed and low-speed collaborative low-orbit satellite communication system and method. The system comprises a Ka phased-array antenna, an L receiving antenna, an L transmitting antenna and a transceiver, the Ka phased-array antenna, the L receiving antenna and the L transmitting antenna are respectively in communication connection with the transceiver; the transceiver is in communication connection with the satellite service assembly and the data transmission assembly. The L receiving antenna is used for receiving an L-band uplink instruction sent by the ground terminal; the ground terminal comprises a ground L station and a ground K station; the L transmitting antenna is used for transmitting L-band downlink low-speed data to a specified ground terminal and broadcasting navigation data to a ground terminal in a service area; the Ka phased-array antenna is used for sending Ka-band downlink high-speed data to a specified ground terminal; and the transceiver is used for sending t