Research And Implementation Of Fast Frequency Guidance Technology And Digital Receiver Technology In Electronic Countermeasure Systems

Broadband digital channelized receiver technology is one of the important technologies in the field of electronic countermeasures.Due to the complexity of the electromagnetic environment and the variability of signal forms in modern battlefields,the performance and stability requirements of receiver systems are higher.The receiver system needs to achieve the functions of intercepting,measuring,sorting and identifying radar signals,and guiding the emission of jamming signals.The signal processed by channelization directly affects the performance of the entire receiver system.Therefore,researching and implementing the entire receiver system is of great significance.In this thesis,based on the overall design requirements of two electronic countermeasures systems,the theoretical research and engineering implementation of two subsystems have been completed.The specific research contents are as follows:1)In response to the high noise threshold requirements of the Kay algorithm,an improved Kay algorithm has been proposed based on the ideas of windowing and filtering,which reduces the signal-to-noise ratio threshold requirements of the original Kay algorithm and improves its frequency estimation performance under low noise thresholds.2)Sub-system 1 is designed to implement the fast frequency guidance technology of the analog electronic countermeasure system.It requires completing channelization and fast frequency measurement tasks for input signals,and quickly guiding the input signals to the corresponding radio frequency bands based on the measurement results.To address the issues of high DSP resource consumption,large frequency measurement errors,and long measurement and guidance time of the existing digital channelization processing system,the system analyzed each link of the entire system framework.With the goal of reducing DSP resource consumption and minimizing system time delay while ensuring a high-speed clock frequency of 312.5MHz,a digital channelization framework with fast frequency measurement and guidance functions was designed.This framework mainly includes the selection and implementation of the channelization receiver framework and frequency measurement algorithm,as well as the optimization design of the prototype filter for the channelization receiver,which further reduces resource consumption and system time delay.The system was first analyzed theoretically and digitally simulated.Then,based on this,the on-site programmable gate array code design,module debugging,and system debugging of each sub-module were completed.Finally,the digital channelization fast frequency measurement and guidance sub-system were implemented on the hardware platform based on the XC7K410 T chip,and the correctness and effectiveness of the system were verified through board-level testing.3)Sub-system 2 is responsible for the design and implementation of the digital receiver,including the channelized receiver and signal detection,as well as the accurate measurement of the four major parameters of pulse arrival time,pulse width,radio frequency,and pulse amplitude.According to the requirements of Sub-system 2,research was conducted on the extraction of pulse parameters from radar signals.In response to the disadvantage that the existing pulse extraction algorithm is difficult to implement at high speed due to frequent changes in detection thresholds,an adaptive energy detection pulse extraction algorithm was proposed.This algorithm provides a method for estimating the average power value of noise and calculates the threshold value based on this,updating the threshold value within one detection cycle,thereby improving the real-time signal pulse extraction capability of the digital receiver system.The FPGA code design,simulation,and verification of the high-efficiency digital receiver sub-system based on the RFSo C platform were then carried out.