水下弹载超声波探测发射信号的直接数字频率合成与实现

【作者】 解立洋；

【导师】 陈荷娟；

【作者基本信息】 南京理工大学 ， 机械电子工程， 2011， 硕士

【摘要】 面对未来战场态势,浅海近距反潜作战武器中机载航弹和舰载火箭弹仍担负着重要使命,对于配用于这些武器系统的现代引信来说,其智能化的弹载(on-board)目标探测器,若能够自动搜索、定位、跟踪目标,为引信发火控制系统提供更多信息,则将对提高弹药或战斗部的毁伤能力起很大作用。超声探测技术已经普遍应用于现代引信的水下弹载目标探测器中,但因搜索“视场”窄,使用传统技术仅能完成“发现”目标功能,欲从感知物体的回波中快速获取目标信息,并实现“发现、定向、定位”,必须赋予其智能化的功能。国内正研制的水下弹载超声波探测系统,模仿蝙蝠发声与听觉功能,能够快速、准确地定向捕获、跟踪、定位目标。其中,受系统中枢控制的数字式发射信号的发生是研究的关键问题之一,尤其是发射信号的调制方法直接影响探测器的分辨率。根据数字信号传输、处理误差小,易于提取波形信息、特征以及信号重构等优点,本文根据引信探测器的on-board特点,为了减小探测的信号失真、提高探测分辨率,设计了弹载探测器对称三角线性调频脉冲信号发生器,采用直接数字频率合成技术DDS(Direct Digital Synthesizer)实现发射信号的产生。讨论了几种常用发射信号(单频、线性调频、双曲调频、伪随机信号),并在距离、速度分辨力等方面作了细致的比较；分析了产生线性调频信号的几种技术方案以及DDS技术的波形产生及数字调制原理：选用单片机和AD9852芯片设计了信号发生器的硬件系统,并搭建了硬件测试平台进行了实验验证。实验结果表明,本文设计的对称三角线性调频信号发生器满足设计要求。更多还原

【Abstract】 Facing the future battlefield situation, the airborne depth bomb and the ship-based rocket bomb still play an important role in the short-range antisubmarine weapons which are used in the epeiric seas. For the modern fuzes of the weapons, it will improve the damage ability of ammunition or warhead effectively if their intelligentized on-board object detecting sets can search for, locate and track the objects automatically so as to provide more information for the firing system of the fuzes.The supersonic sounding technology is widely used in underwater on-board object detecting sets of the modern fuzes. But because of the narrow search range, they can only find the object with the traditional technology. They must be intelligentized so as to obtain the information of objects rapidly from the target echo and accomplish the mission of searching for, orientating and locating the object. Our county was developing the underwater on-board supersonic detecting set. By simulating the cry and audition function of bats, it could orientate, track and locate the objects rapidly and precisely. The generation of digital transmitting signal which is controlled by the system processing center is one of the key researching questions, especially the modulation method of transmitting signal which directly influences the resolution of detectors.Because the digital signal has the following advantages:less error of transmitting and processing, easily extracting the waveform information and characteristic, easily reconstruct-ing signal. By the on-board characteristic of the fuze detector, the thesis designs the signal generator using the DDS technology which generates symmetric triangular linear frequency modulated pulse signal so as to reduce the signal distortion and improve the resolution of the detecting system.The thesis analyzes the frequently-used transmitting signals(CW, LFM, HFM and PR) and compares the resolution of distance and velocity with each other detailedly; The thesis analyzes several kinds of methods which generate LFM signal and the theory of signal generation with DDS technology; The thesis uses the microcontroller and AD9852 chip to design the hardware system of the signal generator and makes the experimental verification.The experiment results show that the signal generator meets the design requirements.更多还原