非相干散射雷达波形设计与处理软件

发布时间：2018-04-09 21:41

本文选题：非相干散射雷达　切入点：波形设计　出处：《西安电子科技大学》2014年硕士论文

【摘要】：作为地球大气层和外部空间之间的接口,电离层对人类各项活动的影响不容小觑。无论是广播、无线通信、测量、导航,还是空间探测,都受到电离层的重要影响。非相干散射雷达以其独特的非相干散射探测方式,使得从地面远程探测电离层成为可能。由于探测目标的特殊性,非相干散射雷达通常采用复杂的发射波形来进行电离层探测。同时,通过计算机软件进行雷达信号处理可以大大提高整个系统的灵活性。本文结合我国首部非相干散射雷达的建设与应用,深入研究了非相干散射雷达波形设计,同时设计实现了一套信号处理软件。首先,研究了非相干散射雷达探测原理及探测技术。分析了电离层散射谱的形成过程以及散射信号信噪比极低的特点,给出了噪声校准的方法。重点研究了模糊函数理论,推导出回波信号自相关函数与电离层散射信号自相关函数及模糊函数之间的关系,给出了信号处理过程中关键的时延剖面矩阵的概念,以及电离层回波信号自相关函数和功率谱的计算方法。其次,研究了非相干散射雷达波形设计及相应的信号处理方法。对长脉冲、巴克码和二相交替码三种信号编码方式进行了研究,仿真分析了各自的模糊函数。引入多相交替码这种新的非相干散射雷达信号编码方式,极大地扩充了交替码可用的编码集合,提高了波形设计的灵活性。同时,多相交替码具有和二相交替码类似的模糊函数和相同的距离分辨率。提出了使用跳频编码调制多相交替码各组编码的改进方式,以减少发射脉冲组数,提高探测效率和探测精度,并给出了详细的信号编码及信号处理流程。最后,针对现有非相干散射雷达系统设计实现了一套信号处理软件,进一步提高了系统处理方式的灵活性和可靠性。分析了软件功能需求,根据需求将软件划分为网络数据接收存储、文件管理、信号处理、用户界面四个功能模块。对各个模块分别进行了设计,详细阐述了每个模块的设计思路及数据高速采集、高效信号处理、多功能绘图等关键技术,并通过软件实现了雷达信号处理算法。最后,对整个软件进行了功能测试,验证了各个模块功能的完整性和正确性,并验证了信号处理算法的正确性。
[Abstract]:As an interface between the Earth's atmosphere and outer space, the ionosphere has a significant impact on human activities.Whether broadcast, wireless communication, measurement, navigation, or space exploration, are significantly affected by the ionosphere.Incoherent scattering radar makes it possible to remotely detect the ionosphere from the ground because of its unique incoherent scattering detection method.Because of the particularity of target detection, incoherent scattering radar usually uses complex emission waveform to detect ionosphere.At the same time, radar signal processing by computer software can greatly improve the flexibility of the whole system.Combined with the construction and application of the first incoherent scattering radar in China, the waveform design of the incoherent scattering radar is studied in depth, and a set of signal processing software is designed and implemented.Firstly, the detection principle and detection technology of incoherent scattering radar are studied.The formation process of ionospheric scattering spectrum and the characteristic of extremely low signal-to-noise ratio of scattering signal are analyzed, and the method of noise calibration is given.The fuzzy function theory is studied emphatically, the relation between the echo signal autocorrelation function and the ionospheric scattering signal autocorrelation function and the ambiguity function is deduced, and the concept of the key time-delay profile matrix in the signal processing is given.And the calculation method of autocorrelation function and power spectrum of ionospheric echo signal.Secondly, the design of incoherent scattering radar waveform and the corresponding signal processing methods are studied.Three signal coding methods, long pulse, Barker code and two-phase alternating code, are studied, and their fuzzy functions are simulated and analyzed.Polyphase alternating code is introduced as a new coding method for incoherent scattering radar signals, which greatly expands the coding set available for alternating codes and improves the flexibility of waveform design.At the same time, the polyphase alternating code has the same ambiguity function and the same distance resolution as the two-phase alternating code.In order to reduce the number of transmitted pulses and improve the detection efficiency and precision, an improved method of modulation multiphase alternating code with frequency-hopping coding is proposed. The detailed signal coding and signal processing flow are also given.Finally, a set of signal processing software is designed and implemented for the existing incoherent scattering radar system, which further improves the flexibility and reliability of the system processing mode.The software function requirement is analyzed, and the software is divided into four functional modules: network data receiving and storage, file management, signal processing and user interface.Each module is designed, the design idea of each module and the key technologies of high speed data acquisition, high efficiency signal processing and multifunction drawing are described in detail, and the radar signal processing algorithm is realized by software.Finally, the function of the whole software is tested to verify the integrity and correctness of each module and the correctness of the signal processing algorithm.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.51

【共引文献】