Research On Effect Of High Speed Micro-Vibration On Ka-Band Measurement And Control System

In recent years, the development of near-space communication technology is rapid. Near-space communication can provide a series of communication business services between ground and vehicles with communication facilities, the study of near-space tracking and communication system has become one of the important research fields. The near-space communication environment is different from others because of the high dynamic vehicles. It is found in the engineering measurement that the communication will be knocked out within a short period of time, even though there is no black-out area, and this phenomenon appears in each segment. After preliminary analysis, it's known that the rain fade is not the result of communication breakdown, there is the mechanical rotation, the controlled job of aircraft and the aerodynamic which will induce a kind of vibration, and the amplitude of that vibration is centimeter which is near to Ka-band wavelength. The vibration will lead to a certain degree of Doppler frequency offset. The purpose of this paper is to study the synchronization performance and error performance of Ka-band tracking and communication systems, reveal its influence on synchronization capture and tracking loop mechanism. The main work is as follows:1. Introduce the Ka-band spread spectrum measurement and control system structure and relevant technology; Introduce the generation of Doppler frequency offset principle, near-space communication characteristics and classification of the measurement and control communication system.2. Respectively in two aspects of capturing and tracking phase, discuss spread spectrum synchronization technology in the system. First, introduce several kinds of synchronization capture technology, and focus on a method based on Fast Fourier Transforms(FFT) algorithm with the simulation analysis. Secondly, introduce the structure of phase-locked loop and frequency-locked loop in the tracking synchronization technology with performance simulation.3. Introduction to the concept of micro-motion, from the general micro-motion modeling to micro-vibration modeling, complete the micro-vibration-Doppler modeling. Based on the micro-vibration-Doppler modeling, analyze the characteristics of Doppler induced by vibration motion in detail.4. On the basis of micro-vibration-Doppler modeling, set up two kinds of high dynamic Doppler Effect modeling: high speed micro-vibration-Doppler and accelerated motion micro-vibration-Doppler according to the characteristics of aircraft. Through the simulation experiment about Ka-band spread spectrum measurement and control system under the condition of the two kinds of physical modeling communication, analyze the synchronization performance and error performance of spread spectrum system. The simulation results show that the performance of spread spectrum synchronization tracking influenced by the Doppler effect induced by the high frequency vibration.