Research On The Method Of Base-band Signal Processing In The Single Channel Monopulse Angle Autotracking Receiver

Because of the advantages of good real-time performance, low dynamic hysteresis, low equipment complexity on the satellite, the single channel monopulse autotracking systems have been widely applying in the inter-satellite autotracking system. Thereinto, the angle autotracking receiver is extremely significant. The inter-satellite beacon signal with wide Doppler frequency shift range and low signal-to-noise ratio (SNR) induces the angle autotracking receiver achievement especially the base-band signal processing method to be important to the system.The theory of single channel monopulse autotracking system and the autotracking receiver was described on this thesis at first, through analysing and calculating the characteristic of the beacon signal of the data relay satellite systems which the Low Earth Orbit (LEO) spacecrafts track, the signal model was established; the performance of different base-band signal processing methods was compared, the synchronous demodulation method to demodulate the error signal with low SNR was selected; the signal processing algorithms referring to the synchronous demodulation, such as the IF sampling, the carrier acquisition, the carrier tracking, the best matched filter and so on, was theoretically analysed, and the key parameters were simulated on the thesis; the error signal offset (ultimately affect the autotracking accuracy) caused by the random noise was also simulated. Finally, the engineering implementation of the base-band signal processing of the channel monopulse autotracking system, including the hardware design and the FPGA algorithm were described, through doing detailed testing to obtain the specific experimental data, the experimental results demonstrates the feasibility of proposed engineering implementation of the base-band signal processing, and also demonstrates the accuracy of simulations.