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- 某航空弹药伪码激光引信信号处理技术研究
- 作者： 李钰 来源： 北京理工大学 年份： 2016 文献类型 ： 学位论文 关键词： 伪随机码 相关检测 蒙特卡罗方法 激光引信 信号处理 FPGA应用
- 描述： 激光引信是近炸引信的主流体制之一。由于其在精确定距、抗电磁干扰及目标方位识别等方面具有独特优势，因此在国内外得到广泛研究。由于伪随机码有良好的随机特性，其相关函数接近白噪声的相关函数，且具有可预先确定性和可重复性，因此，与等间距脉冲体制的激光引信相比，伪随机码激光引信在保密性、抗有源电磁干扰和不受静电感应影响等方面有明显优势。 本文以某航空弹药配用的激光引信为应用对象，在分析激光探测和伪随机码测距原理的基础上，对探测到的激光回波信号进行处理，利用伪随机码的自相关特性来实现测距和抗干扰功能。在对目标和背景回波信号特性分析的基础上，用蒙特卡罗方法对脉冲激光探测和伪随机码激光探测的虚警概率、探测概率、信噪比和探测阈值的统计分布规律进行了分析，为选用伪码测距体制，合理选择伪随机码激光引信探测器的信噪比和探测阈值提供了依据。为提高测距精度，改善信号性能，用相干平均算法对信号进行处理，以提高信噪比。根据战技指标的要求选取合适的伪随机码参数，设计了基于FPGA的5级伪随机序列产生器。为了对回波信号进行相干平均处理，得到信号的具体信息特征，用FPGA完成对信号的A/D采样及存储的控制。本文设计了相关检测的软件模块，包括伪码延时模块、相关运算模块、峰值搜索模块和距离计算模块，用FPGA实现并用Modelsim进行仿真，最后完成了信号处理系统的硬件设计。仿真结果表明本文提出的测距方法及电路设计有效可行。 关键词：伪随机码；激光引信；相关检测；信号处理；FPGA应用；蒙特卡罗方法AbstractLaser is one of the three major systems of proximity fuse.Owing to the upstanding random characteristic of pseudorandom code and the sharp auto correlation characteristic similar to white noise, moreover, it possesses ascertainable and repeatable characteristics. For this reason, pseudorandom code laser fuse has been improved essentially in the secrecy characteristic, the anti-active anti-jamming, non-influence from static inductance, and etc aspects. The dissertation regard the laser fuse applied to aeronalitic shot aimed at oil storehouse as application object, the oil storehouse as the detection object, on the basis of the principle of distance detection by laser fuse and pseudorandom code, process the echo signal. Realize the distance detection and anti-jamming function, based on the correlation theory. After analyze echo character of target and typical background, analyze the probability of pulse laster and preudorandom code detecting, the false alarm probability and the SNR by Monte-Carlo method,. In order to advance the precision of the detection and improve the signal status, used the coherent average method to process the signal and advance the SNR. Select appropriate parameter of pseudorandom code to satisfy the fighting request, design a 5 pseudorandom code genarating circuit based on FPGA. In order to process the signal by coherent average method and get the particular information of the signal, control the sampling and storing of signal by FPGA. Design the correlation detecting system software which includes preudorandom code delay module, correlation module, peak value search module and distance calculating module, these modules are realized by FPGA. Finally, the hardware circuits of signal processing design are finished.Keywords: Pseudorandom code; laser fuse; correlation detecting; signal processing; FPGA application; Monte-Calo method