National University of Defense Technology

Guangfu Sun

Feixue Wang

Lei Chen

Wenxiang Liu

Xinming Huang

Zengjun Liu

Ke Zhang

Rong Zhou

Sixin Wang

Zukun Lu

Jingyuan Li

Pengcheng Ma

Honglei Lin

Muzi Yuan

Xiaozhou Ye

Gang Ou

Pengcheng Zhang

Wei Xiao

Zongnan Li

Xiaomei Tang

A design method for a satellite navigation signal system with mixed modulation of direct spread spectrum and frequency hopping includes: modulating the spread spectrum code sequence of multipath signal components; mixing and multiplexing with the signal components corresponding to the same frequency point; forming a baseband code sequence; separating signal components corresponding to the baseband code sequence to obtain separated radio frequency signals; recombining and modulating separated radio frequency signals; controlling the frequency hopping pattern by the frequency hopping code sequence if the separated radio frequency signals are authorized signals, and performing mixed frequency synthesis modulation; performing direct combined radio frequency modulation if the separated radio frequency signals are unauthorized signals, and obtaining the recombined signal component; amplifying the signal power to obtain the direct spread spectrum navigation signal.

Designed method for satellite navigation signal system with mixed modulation of direct spread spectrum and frequency hopping

A Beidou short message communication method and a system for a low-power user terminal are provided. The method includes following steps: by a user terminal, receiving outbound signals broadcast by a central station and forwarded by a satellite transponder, and constructing a short message access frame with a fixed length for transmission; by the central station, receiving and parsing the short message access frame, so as to realize the allocation of time-frequency resource blocks and transmit the time-frequency resource blocks to the user terminal; by the user terminal, transmitting a short message communication frame with a fixed format to the central station; by a communication receiving device of the central station, receiving and sequentially carrying out sampling preprocessing, anti-interference processing, rapid capture and tracking demodulation on the short message communication frame to obtain communication service information, and pushing receipt information to the user terminal to complete an information push.

Beidou short message communication method and system for low-power user terminal

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Changsha, China

Guangfu Sun