Research And Implementation Of Single-pulse Single-channel Angular Tracking Algorithm

Auto-tracking system is an important part of tracking and data relaying satellite system.Its reliable tracking ability is the foundation of inter-satellite communication and data transmission.At present,there are several tracking methods which are commonly used:step tracking,conical scan tracking and mono-pulse tracking.The mono-pulse tracking has many advantages,such as good real-time tracking,simple on-board device and small dynamic lag.It is a practical way for the auto-tracking system whether in domestic or in foreign countries.Within the inter-satellite link,the signal-to-noise ratio is low while the Doppler dynamic range is large,which makes the baseband signal processing technology becoming the focus of the whole system.In this paper,the basic principle of the mono-pulse single channel auto-tracking system is duly analyzed,and the formula derivation is carried out as well.On this basis,carrier acquisition and tracking techniques,detection techniques and accumulation techniques used in the baseband signal processing of the auto-tracking receiver are fully studied.The results show that the high-frequency estimation method based on multiple FFT combination can fast and accurately lock the target frequency.The third-order phase-locked loop can track the inter-satellite link signal carrier without error.The synchronous detection has better demodulation performance under low SNR conditions.Besides,the scheme of auto-tracking using partial bandwidth of broadband data transmission signal is studied and the scheme is simulated.The simulation results verify the feasibility of this scheme.Meanwhile,the different demodulation algorithms are simulated under different signal-to-noise ratios,and the simulation results are compared with each other and analyzed in details.The results show that:Although the two-phase modulation method can only track the single-frequency signal,the demodulation performance is the best one without any doubt.The baseband hardware circuit of the mono-pulse single channel auto-tracking receiver is well designed.The baseband signal processing scheme based on FPGA is designed and implemented in VHDL language.A mono-pulse single channel auto-tracking receiver test system is built and the designed baseband signal processing algorithm is tested and verified by several experiments and calculations.As a conclusion,the final testing results verify the feasibility of the baseband signal processing scheme and the correctness of the simulation analysis.