Research On Communication Ranging Waveform Design And Signal Processing Technology Of Millimeter Wave Inter-Satellite Link

In recent years,small satellite formation flight and inter satellite link technology are widely used in communication,navigation and other fields,so it has become a research hotspot in the aerospace field.Under this trend,it is necessary to ensure the relative stability of formation configuration and realize inter satellite cooperation through inter satellite communication and relative position measurement.Focusing on the inter satellite link,aiming at the integration of inter satellite communication and ranging,this paper carries out system scheme design and simulation research from two aspects:inter satellite communication ranging waveform design and signal processing technology research.The main work of this paper is as follows:(1)In view of the relatively independent status of satellite communication and ranging system,based on the millimeter wave band single carrier transmission system,this paper adopts the scheme of waveform sharing,and designs a communication ranging waveform.The waveform uses gray complementary sequence to form the ranging waveform,and takes the head of the ranging waveform as the preamble sequence of the shared waveform,which effectively realizes the integration of inter satellite communication and ranging,ensures the system performance and saves the resource consumption of the satellite.(2)Aiming at the problem of time and frequency synchronization in inter satellite link,this paper studies the signal processing technology and proposes a time-frequency synchronization algorithm based on preamble sequence.The time synchronization algorithm based on preamble sequence uses the sharp autocorrelation property of gray sequence to find the best sampling time through correlation peak search,and has low synchronization error under low SNR.The frequency offset estimation algorithm based on preamble sequence refers to the decimal frequency offset estimation method.By designing the length of preamble sequence,it can effectively resist random noise and improve the stability of estimation algorithm.(3)Aiming at the problem that the nonlinearity of power amplifier leads to the deterioration of system demodulation performance,a signal detection algorithm based on deep learning is proposed.By feeding data to the deep neural network,a model mapping from complex symbols to bit data is established.The simulation results show that considering the nonlinearity of power amplifier,the signal detection algorithm based on deep learning can improve the system performance by about 3dB and effectively improve system performance.(4)Based on the proposed communication ranging waveform and signal processing algorithm,this paper uses USRP equipment to build a software defined radio platform to realize the complete processes of signal transmission,acquisition and communication ranging waveform processing,which further verifies the feasibility of the research content and lays a foundation for the future practical application.