The Design And Implementation Of An IF Analog System With A Scalable Digital Array

With the development of radar technology,the digital array radar with larger array scale has been continuously applied.The function and performance of radar system are greatly improved.The ideal simulation method of point target echo can not meet the test requirements of radar system.It is necessary to consider the dynamic simulation of multi-scattering point target echo.In addition,how to evaluate the whole digital array radar system in the laboratory without constructing expensive hardware-in-the-loop simulation system is also a practical problem to be considered.In this dissertation,based on the development of multi-channel IF simulation system for multi-functional integrated digital array radar system,the modeling of multi-scattering point target echo in both time and space domains is carried out.A digital intermediate frequency(IF)simulation system is developed which can simulate the dynamic echo characteristics of arbitrary waveforms of multiple scattering point targets.Based on the preset multi-scattering point target model,the system is composed of a host computer control software,a high-performance signal processing circuit and four multi-channel analog signal generation circuits.The IF echo signals with up to 128 channels is generated to simulate the dynamic characteristics of the multi-scattering point target echo in velocity,distance,angle and power.The high-performance signal processing circuit is responsible for generating the radar baseband signal,while the multi-channel analog signal circuit generates the target,interference baseband signal and noise according to the related characteristics provided by the host computer.Combining the three signals,the intermediate frequency signal with 150 MHz central frequency is generated by digital up-conversion,interpolation and digital-to-analog conversion.In order to improve the reliability and versatility of the system,the system is designed in accordance with VITA46.0 and VITA48.1/VITA48.2 specifications.The modular and integrated design idea is adopted.VPX 6U is used to reinforce the structure,while taking into account the reliable heat dissipation of air cooling and conducting cooling.The main functions and performance of the system have been tested and verified.The results show that the system can realize flexible setting and loading of target multi-scattering model,target motion characteristics and environmental characteristics under the control of host computer control software.According to the set model and parameters,the IF analog signals of multi-channel complex signals can be generated dynamically and in real time.The successful development of this system effectively supports the comprehensive test and verification of the related functions and performance of the multifunctional integrated digital array radar system except antenna and RF circuit.