Base Band Video Signal Decoding Algorithm Design And Simulation Study Of Second Surveillance Radar

Secondary radar is an important equipment in modern air traffic control system, it identify the target by interrogator sending a inquiry toward the aircraft and the aircraft responsing in the air. Since high reliability and stability is strongly demanded, secondary radar decoding processing system has been a hot issue in radar signal processing at home and abroadAt present, traditional Aero Traffic Control system of Europe is still used in China. Signal processing in software is mainly based on the"traditional sliding window method". Although the sliding window method can remove most of the fruit, the sliding window method using only the position information of pulse, so when overlapping of the reply signals are more than two, only two targets can be identified simultaneously, namely, in the case of high-density respondent, more garble and fruit, the detection probability is low, the error rate is high.From what has been concered, the traditional sliding window method has major shortcomings in picking up the imformation of target. in particularly,it is not suitable for high-density respondent processing. Therefore, in order to allow more serious overlapping of signals can be detected in high probabily and low false alarm probabily, even ensure the real framework and code can be extracted effectively , providing reliable information for the subsequent respondent-related and track processing. In this paper, a new algorithm is proposed based on the traditional sliding window method, mainly as follows:(1)In the pulse detection, Increased pulse width, amplitude processing;(2)In the framework detection, Increased the extraction of the code;(3)In the reference pulse selection, dealt with the reference impulse amplitude;(4)In the dephantom aspects, increased the amplitude relevant on the basis of distance relevant ;(5)In the code confidence analyzing, using the minimum error method ; (6)In defruit, based on the algorithm of 5 March 3 to remove the fruit and the rest of the phantom.In this paper, the reply signals are simulated in matlab simulation platform , to extract the target with the new algorithm and traditional algorithm independently, the simulation results demonstrate the effective of the new algorithm, it can extract reply signal correctly in the case of serious Interference environment, so further the decoding capabilities of secondary radar. Mainly as follows: when the ratio of signal to noise is more than 25 ,it can decode more than four overlapping signals and extract the real codes correctly, and ensure the correct ratio in high-density respondent. to a certain extent, improve the detection probability and lower the error ratio , so resolve the shortcomings of traditional sliding window method and meet the modern requirements of rapid development of air traffic control .This paper introduces the background of the paper; describes the course of development of secondary radar; briefes monopulse secondary radar system principles; introduces the major mode of radar and its corresponding response signal formats and the rules of determination; the main functions and software design and simulation of monopulse secondary radar decoding system; at the same time, compared the new algorithm results effect with the traditional decoding algorithm.This issue is according to the real facts of China's air traffic control, mainly on the multiple intertwined, overlapping of reply signals analysis, identification and processing of mode A / C. In this issue I am primarily responsible for the decoding algorithm studies. (pulse detection, dephantom, defruit, code extraction and confidence analysis).