X波段雷达模拟器多模信号产生模块的研制

【作者】 马敏；

【导师】 蔡竟业；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2011， 硕士

【摘要】 随着雷达技术的迅速发展,对雷达信号的要求也越来越高,雷达引信呈现出多样性,而雷达回波信号也具有宽频带、多模式、捷变频、高分辨频率等特点。但雷达场外测试成本高、周期长、回波参数难以控制,故雷达模拟器应运而生。本文首先对频率合成技术、雷达引信和雷达模拟器的发展状况做了概述。在理论分析部分,对雷达回波信号模型和频综的性能和指标做了简要介绍;对DDS(Direct Digital Synthesis)技术的原理和性能进行了较为详尽的分析,并对基于DDS的几种频率合成技术做了分析和对比。结合线性调频雷达的工作原理,对DDS线性扫频对雷达点目标的测距精度和距离分辨率的影响做了理论分析和仿真。设计首先基于FPGA(Field-Programmable Gate Array)和DDS技术提出了产生VHF(Very High Frequency )复合雷达信号的方案并实现,充分利用DDS的高分辨率、捷变频、可调频等特点,产生精度高且带宽和重复周期可调,工作模式灵活可控的多模式调制信号(线性调频、三角调频和正弦调频)。结合倍频、混频实现上变频以及频带展宽,从而研制出一种X波段雷达模拟器硬件电路,中心频率为8~12 GHz,频带宽度为0~600 MHz,步进为1 MHz,扫频重复周期0~256 us,步进为50 ns。FPGA设计在实现灵活控制的同时,充分展现模块化和面积优化的思想,便于移植和技术升级;VHF模块电路杂散小于-75dBc,相噪在频偏1kHz处优于-110dBc/Hz。同时,利用FPGA产生多种类型可变速率调相码序列,包括巴克码、L序列、M序列以及四相码。本文较为全面的阐述了复合雷达信号模拟器的方案设计和软硬件实现过程,对同类设计有一定的借鉴价值。更多还原

【Abstract】 With the rapid development of radar technology, the demand of radar signals is getting much higher. Radar fuze is diversified and radar echo signals have broadband, multi-mode, fast frequency hopping, high-resolution frequency characteristics. However, the high cost of testing the radar outside, long cycle, radar echo signals’parameters are difficult to control, so the radar simulator came into being.Firstly, the frequency synthesis technology, radar fuze and radar simulator development were outlined. In the theoretical analysis part, the radar echo signal model and frequency synthesizer performance indicators are briefly introduced, and the principle of DDS technology and performance of a more detailed analysis. Combining the working principle of linear frequency modulation (LFM) radar, the impact of DDS linear sweep signal on the radar point target range accuracy and range resolution has been theoretically analyzed and simulated.The VHF module which is based on FPGA and DDS technology achieves compound radar signals. It has high precision and adjustable bandwidth and period and flexible modes. Combination of frequency multiplying and mixing, the system achieves the frequency up-conversion and spectrum spreading, which developed an X-band radar simulator hardware. The center frequency is 8~12 GHz, bandwidth 0~600 MHz with step 1 MHz and the sweep repetition period is 0~256 us with step 50 ns .FPGA design achieves flexible control and is full of ideas modular and area optimization for easy migration and technology upgrades. The spur of VHF module circuit is less than-75dBc, phase noise at 1kHz offset better than -110dBc/Hz.At the same time, it can produce multiple types of phase-modulated code sequence with variable code speed. This paper proposed complete scheme of software design and implementation process of achieving comprehensive exposition of the complex radar signals, and provides an effective method of similar design.更多还原