【作者】 刘鹏；

【导师】 刘楠； 范振林；

【作者基本信息】 西安电子科技大学 ， 工程硕士（专业学位）， 2018， 硕士

【摘要】 雷达导引头凭借作用距离远和能够全天候工作的优点在导弹制导领域获得广泛应用,然而,雷达导引头面临日益复杂多变的电磁干扰环境,使得抗电子干扰和低截获概率等性能成为其重要技术指标。由于MIMO雷达在抗目标“闪烁”、抗干扰、降低雷达截获概率和提高对微弱目标的检测能力等方面具有明显的优势,因此成为现代雷达发展的一个方向,如果把MIMO雷达技术应用于雷达导引头中,会进一步提高雷达导引头的整体性能。MIMO雷达的波形正交性直接影响系统性能,本文首先设计了MIMO雷达导引头的发射信号波形。分时正交频率编码信号的特点是各阵元发射具有相同频带的线性调频信号,这样既能满足相参处理的要求,又具有较高的多普勒容忍性,而且由于采用分时频率分集的正交方式,使其正交性优于传统的MIMO正交波形。接着设计了MIMO雷达导引头的信号处理流程。MIMO雷达信号处理的关键在于恢复各阵元发射信号的回波,因此根据设计的发射信号波形特点和导引雷达阵列结构设计了一套通道分离方法,首先通过不同的带通滤波器将各个阵元的回波信号与其它阵元的回波信号分离开,然后再经过延时、频谱拼接将得到一个频谱连续的合成线性调频信号,这样使用常规的线性调频信号的脉冲压缩处理便可完成对合成信号的脉压。最后对MIMO导引头的抗干扰方法进行了研究,主要针对三种干扰进行识别或抑制,包括有源压制性干扰、延迟转发式欺骗性干扰以及部分采样直接转发式欺骗性干扰。其中,当存在旁瓣有源压制性干扰时,采用自适应波束形成方法对其进行抑制;当存在延迟转发式欺骗性干扰时,由于输出信号中干扰成分的导向矢量会随着延迟转发时延的不同而发生变化,因此采用不同的导向矢量权做波束形成,比较输出信号中目标幅值的变化便可判别真假目标;当存在部分采样直接转发式欺骗性干扰时,由于干扰机采样截取的脉冲宽带较小,干扰信号占据很小的频带宽度,因此可通过带通滤波器将回波信号分成两个频带,然后分别对这两部分作脉压处理后,计算其同一位置目标峰值的比值,并根据判别准则便可识别真假目标。通过仿真实验验证,设计的分时正交频率编码信号不仅可通过频域滤波分离不同阵元发射信号的回波,而且保证了各阵元发射信号间的隔离度可达到50dB以上;设计的信号处理流程可成功分离出各阵元发射信号的回波,并能解算出导弹与目标之间的距离和角度信息;设计的抗干扰方法能有效的对相应的干扰进行识别或抑制。为MIMO雷达导引头的工程实现打下来良好的理论基础。更多还原

【Abstract】 The radar seeker has been widely used in missile guidance field because of the range coverage of it is far and can work around the clock.However,the radar seeker faces a electromagnetic jamming environment which is complex and changing,making the anti-electronic jamming ability and low probability of interception become the important indicators.Because MIMO radar has obvious advantages in anti-target "flickering",anti-jamming,reducing the probability of radar interception,and improving the ability to detect weak targets,it becoming the development direction in modern radar.By applying the MIMO radar into the radar seeker,can further improve the overall performance of the radar seeker.The waveform orthogonality of MIMO radar affects the system performance directly.In this thesis,We design the waveform of the transmitted signal of the MIMO radar seeker.The character of Time-sharing orthogonal frequency-coding waveform is each array element emits a chirp signal with the same frequency band,which can satisfy the requirements of phase-parameter processing and the Doppler tolerance is high,by using orthogonality in Time-sharing frequency diversity,make it better than traditional MIMO quadrature waveforms.Then the signal processing of the MIMO radar seeker is designed.The key of MIMO radar signal processing is to recover the echoes of the transmitted signals of each array element.Therefore,a set of channel separation methods is designed according to the characteristics of the transmitted signal waveform and the structure of the guided radar array.First,Separate the echo signal of each element and the echo signal of other elements through different band-pass filters.Then,a spectrally continuous synthetic chirp signal is obtained after delay and spectrum splicing,so that the pulse compression processing of the conventional LFM can be used to complete the the pulse pressure of the synthesized signal.Finally,analyze the anti-jamming method of the MIMO seeker,mainly for the identification or suppression of three types of jamming,including active masking jamming,delayed repeater deceptive jamming,and partial sampling direct repeater deceptive jamming.Among them,when there is a side lobe active suppressive jamming,we adapt beamforming method to suppress it;when there is delayed relay deceptive jamming,the steering vector of the jamming component in output signal will change with delay different delays,different emission-oriented vector rights are used to make beam forming,and the true and false targets can be discriminated by comparing the changes in the target amplitude in the output signal;when there is a partial-sample direct-directive deceptive jamming,the jamming is caused by the jammer.The pulse width of sampling and interception is small,and the jamming signal occupies a very small frequency bandwidth.Therefore,the echo signal can be divided into two frequency bands by a band-pass filter,and then the two pulse voltages are processed respectively to calculate the same position target.The ratio of the peak,and according to the criterion can be identified true and false goals.Through simulation experiments,it is verified that the Time-sharing orthogonal frequency-coding waveform not only can separate the echoes about transmitted signals of different array elements through frequency domain filtering,but also ensure that isolation between the transmitted signals of each array element can reach more than 50 d B;the signal processing can successfully separate the echoes about transmitted signals of each array element and can solve the distance and angle information between the missile and the target.The anti-jamming method can effectively identify or suppress the corresponding jamming.It is a good theoretical basis for engineering implementation of MIMO radar seeker.更多还原