| 摘要: |
| S模式的广播式自动相关监视技术（Automatic Dependent Surveillance-Broadcast,ADS-B）是目前空中交通管制大力推广的技术，但ADS-B信号在远距离传输过程中，由于传输信道的影响，会出现幅度减小和能量衰减等问题，从而导致接收到的微弱ADS-B信号不能正确译码。针对这种情况，提出用小波变换对信号做增强处理的方法，首先改进小波系数，接着确定分解层数，再利用重构指数来选取最优小波基，最后对阈值进行改进，考虑在不同的小波分解尺度上选取不同的阈值。对实际数据进行测试的结果表明，该算法能有效地对ADS-B信号进行增强，对信号强度为-94 dBm的微弱信号也能正确译码，译码准确率明显提高，对空中管理、空间安全等实际应用有一定意义。 |
| 关键词: 空中交通管理；ADS-B；信号增强 小波变换；重构指数 |
| DOI： |
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| 基金项目:四川大学科研项目资助（0020505501663） |
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| An ADS-B Signal Enhancement Algorithm Based on Wavelet Transform |
| LI Jiaxin,WANG Wei,GAO Yong |
| (1.School of Electronics and Information Engineering,Sichuan University,Chengdu 610065,China;2.The Second Research Institute of Civil Aviation Administration of China,Chengdu 610041,China) |
| Abstract: |
| The S-mode automatic dependent surveillance-broadcast(ADS-B) is a technology popularized by air traffic control(ATC).However,in the long-distance transmission,ADS-B signals will have amplitude reduction and energy attenuation due to the influence of the transmission channel,so the problem is that the weak ADS-B signals received cannot be decoded correctly.In this paper,a method based on wavelet transform for signal enhancement is proposed.Firstly,the wavelet coefficients are improved.Then,the number of decomposition layers is determined.Then the reconstruction index is used to select the optimal wavelet base.Finally,the threshold is improved,and different thresholds are selected on different wavelet decomposition scales.The test results of the actual data show that the algorithm can effectively enhance the ADS-B signal,and also correctly decode the weak signal with signal strength of -94 dBm.The decoding accuracy is obviously improved,which has great significance for practical applications of ATC and space security. |
| Key words: air traffic control(ATC) ADS-B signal enhancement wavelet transform reconstruction index |
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