Research On Signal Detection Technique Of Single Channel Monopulse Spread Spectrum Angle Tracking System

Due to its advantage of soluing the issue of phase inconsistency and gain deviation in multichannel transmission systems as well as reducing plenty of equipment resources,Single Channel Monopulse technique has a high practical value in the antenna based angle tracking systems.In the single-channel single-pulse angle tracking system,when the antenna beam is narrow,in order to obtain better communication quality,the antenna beam of the receiver needs to be precisely aligned with the transmitting antenna beam and can track the target signal in real time.Therefore,it is of great significance to study the synchronization and detection of angular error signals in single-channel single-pulse angular tracking system.This thesis focuses on the capture and tracking techniques of the spread angle error signal in single-channel single-pulse tracking system,and detects the error signal of the spread angle under different signal modulation modes under different single channel synthesis modes.The main work of this thesis is as follows: 1.The acquisition technique of the spread angle error signal is studied.The basic principle of serial capture method,partial parallel capture method and FFT-based parallel code phase method are given,and their capture performance is compared and analyzed.At the same time,a parallel method with three-point difference algorithm is designed while the performance of the proposed acquisition scheme is simulated and analyzed in the singlechannel single-pulse system under 0/p modulation.The performance simulation shows that when the SNR is-18 dB,the scheme can obtain more than 90% signal acquisition probability.2.The carrier tracking and code tracking techniques of the spread angle error signal are studied.This thesis analyzes the characteristics of the spread angle error signal and demonstrates the feasibility of the kostas loop to track it.A phase tracking scheme based on the locked loop and the delay locked loop is given.Through the performance simulation analysis,the phase tracking scheme can obtain good tracking performance when the SNR is-18 dB under the condition that the residual frequency is 500 Hz.3.The detection technology of the spread angle error signal is studied.The detection method of the spread angle error signal under different single channel synthesis mode and different data modulation mode is given,and the simulation model of single channel single pulse system is established.In the 0 / p modulated single-pulse single-pulse system with UQPSK modulation,the high-order cumulant method is used to identify the data signal modulation method,and a detection scheme of the angular error signal is given.At the same time,the influence of the UQPSK signal's power factor on the extraction of the characteristic parameters and the recognition probability of the modulation scheme is simulated and analyzed while the power factor range which can accurately identify the UQPSK modulation signal is given.4.Aiming at the problem of detection of angular error signals in single-channel single-pulse system with four-phase modulation,a kind of displacement detection algorithm is proposed,and the envelope of diagonal error signal is estimated.In this method,the noise interference in the system is suppressed by the correlation between the data signal and the Gaussian noise.The performance simulation shows that the method can obtain better angular error signal detection performance.