Research And Implementation Of Angular Error Signal Demodulation Technology

Demodulation Technology of Angle Error Signal is one of the core technologies in the satellite communication field,especially in the relay satellite system,which has the advantages of better real-time tracking and smaller dynamic hysteresis.With the development of satellite communication technology,demodulation of angular error signal by digital method becomes the difficulty and focus of angle tracking receiver under the condition of low signal-to-noise ratio,large Doppler range and high Doppler shift rate.In this paper,the basic principle of Demodulation Technology of Angle Error Signal is analyzed,and the basic structure of single channel mono-pulse angle tracking receiver is introduced.The FFT frequency estimation algorithm for carrier acquisition and The phase-locked loop technique for carrier tracking during the synchronous detection are simulated.The simulation results show that the FFT frequency estimation algorithm is suitable for the follow-up phase-locked loop carrier tracking,and Third-order phase-locked loop can quickly and accurately track the carrier frequency.The principle of four-phase modulation angle tracking receiver is introduced.Emphasis on the four-phase modulation single-carrier signal and four-phase modulation wideband signal,under different conditions of signal to noise ratio angular error signal demodulation simulation.The results show that the demodulation performance of single-carrier IF signal and wideband IF signal is better than that of envelope detection under low SNR condition.Also as can be seen from the analysis,the demodulation accuracy of the synchronous detection increases with the increase of the average accumulation time.Finally,the hardware design of the demodulation digital processing module of angular error signal is given,including system architecture design,hardware circuit function design,device selection and configuration circuit design.Build test platform to test the angular error signal demodulation digital processing module,and analyze the test results.The results show that the overall performance of the angular error signal demodulation digital processing module designed in this paper can meet the engineering technical requirements.The digital realization method of angle error signal demodulation proposed in this paper is feasible.