Research On Receiving Algorithms Of Data Transmission And TT&C Integrated Service Signals With Large Bandwidth And High Efficiency Modulation

In recent years,there is a growing demand for an integrated communication link that possesses both high-precision measurement and control functions and high-bandwidth data transmission function in near-Earth scenarios.Based on this fact,the binary offset carrier(BOC)modulation method is employed in the near-Earth scenarios,and this paper proposes a data transmission and TT&C integrated service signals system based on BOC(15,2.5)cos + 16APSK(5)by leveraging the splitting spectrum characteristics of BOC modulation.On the one hand,BOC(15,2.5)cos modulation signal is used for TT&C service,which transmits remote control/telemetry information,measures the target spatial motion parameters and provides guidance parameters for the data transmission service signals.On the other hand,16APSK(5)modulation signal is used for data transmission service,which can transmit uplink and downlink communication data such as text,sound,image,etc.In addition,TT&C service signals and data transmission service signals share the same communication link and transmit at the same frequency point.The paper mainly investigates the receiving algorithms of this kind of integrated service signals in the near-Earth scenarios.On the premise of meeting the performance metrics,the receiving algorithms are designed with simple structure,low computational complexity,and convenient engineering implementation.Finally,this paper accomplishes the analysis of Matlab simulation results and the design of FPGA hardware simulation platform in terms of receiving algorithms.The main contents of this paper are summarized as follows:(1)The acquisition algorithm for integrated service signals is studied.First,the TT&C service signals are filtered out by utilizing the filter,and then this paper achieves the traversal search of the Doppler frequency shift in the frequency domain by combining with FFT fast acquisition algorithm,which realizes the fast acquisition of TT&C service signals.In order to effectively reduce the probability of false acquisition,the method of Tong detector and acquisition verification are designed in the paper.Moreover,Matlab is used to verify the acquisition algorithm.It is proved that the acquisition algorithm realizes the fast acquisition without ambiguity and the acquisition time is less than 5s in the environment of ±11.34 kHz Doppler frequency domain,100 km communication distance and carrier to noise ratio(CNR)with 65 dB-Hz.(2)The tracking algorithm for integrated service signals is explored.In the paper,the carrier tracking loop based on the second-order frequency locked loop and the third-order Costas phase locked loop structure is adopted to obtain the precise tracking of both carrier frequency and phase,and the pseudo-noise(PN)code tracking loop based on the second-order delay locked loop structure is used for precise tracking of PN code.Furthermore,Matlab is employed to verify the tracking algorithm.It is demonstrated that the tracking algorithm can achieve stable signal tracking in the environment of carrier velocity 3 Mach,the existence acceleration and jerk,and CNR greater than 65dB-Hz.(3)The FPGA simulation platform of receiving algorithms for integrated service signals is designed.In Vivado simulation tool,comprehensive Verilog HDL is utilized to design and simulate each module of proposed algorithms.The simulation results show that the receiving algorithms achieving the signal acquisition time with less than 5s,are capable of realizing stable signal tracking and occupy less hardware resources under the conditions of the dynamic environment of sinusoidal Doppler and the CNR with 65 dB-Hz,which validates the feasibility of the engineering implementation for the signal receiving algorithms in this paper.