Automatic modulation recognition of radio fuzes using a DR2D-based adaptive denoising method and textural feature extraction

The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference systems.However,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio fuzes.To solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is proposed.First,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)signal.Then,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for classification.The DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical algorithms.The trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.

Pulse Compression Technique of Radio Fuze

The advantages of using phase-coded pulse compression technique for radio fuze systems are evaluated. With building mathematical models a matched filter has been implemented successfully. Various simulations for pulse compression waveform coding were done to evaluate the performance of fuze system under noisy environment. The results of the simulation and the data analysis show that the phase-coded pulse compression gets a good result in the signal identification of the radio fuze with matched filter. Simultaneously, a suitable sidelobe suppression filter is established by simulation, the suppressed sidelobe level is acceptable to radio fuze application.

Small MEMS smart antenna for software radio fuze

The signal transceiver of the software radio fuze depends on the front-end radio frequency（ RF） antenna. RF micro-electro-mechanical-system（ MEMS） smart antennas have the capability of flexible beam rapid scanning,multi-beam forming and so on,which can improve the ability of detecting,sensing and tracking multiple targets of the fuze. The small RF MEMS smart antenna consists of a 2 × 2 aperture coupled antenna array and six 1-bit MEMS phase shifters. Simulated results demonstrate that the antenna can complete beam steering angles of ± 30° in both X and Y plane at 17. 3 GHz. All components can be fabricated and monolithically integrated with MEMS technology which causes the system low cost and small volume. The RF MEMS smart antenna presents a good and important prospect for the development of the software radio fuze antenna.

Scattering Center Extraction of UWB Radio Fuze's Target Based on Polar Hough Transform

In order to extract the feature information of ultra wide-band (UWB) radio fuze target and give full play to the warhead's strike ability, a method based on polar Hough transform for scattering centers extraction of the target was proposed in this paper. It firstly utilized the fuze scanning to obtain the distance and azimuth information of the target's main scattering centers at different times, i.e. the track information of scattering centers under the polar coordinates, then used the polar Hough transform to transform the track into the parameter space in order to accumulate the dots and drew 3-D parameter space diagram, in which the peak points corresponded to the target's scattering centers. The simulation results indicate that the method can not only extract scattering centers efficiently and accurately, but also has strong anti-noise performance, and the algorithm is simple and easy to be implemented in engineering.

Method for Improving the Ranging Accuracy of Radio Fuze

Stepped frequency radar waveform is put forward for improving the accuracy of radio fuze ranging. IFFT is adopted to synthesize one dimension high resolution range profile. Furthermore, the same range reject method and selection maximum method are made use of removing target redundancy and the simulation results are given. Characters of the two methods are analyzed, and under the proposal of Weibull distribution clutter envelope, the CFAR same range selection maximum method is adopted and realizes the accurate profile and ranging.

Cognitive interference decision method for air defense missile fuze based on reinforcement learning

To solve the problem of the low interference success rate of air defense missile radio fuzes due to the unified interference form of the traditional fuze interference system,an interference decision method based Q-learning algorithm is proposed.First,dividing the distance between the missile and the target into multiple states to increase the quantity of state spaces.Second,a multidimensional motion space is utilized,and the search range of which changes with the distance of the projectile,to select parameters and minimize the amount of ineffective interference parameters.The interference effect is determined by detecting whether the fuze signal disappears.Finally,a weighted reward function is used to determine the reward value based on the range state,output power,and parameter quantity information of the interference form.The effectiveness of the proposed method in selecting the range of motion space parameters and designing the discrimination degree of the reward function has been verified through offline experiments involving full-range missile rendezvous.The optimal interference form for each distance state has been obtained.Compared with the single-interference decision method,the proposed decision method can effectively improve the success rate of interference.

Design of Fuze Antenna Beamformer Based on DSP

According to the algorithm of the fuze antenna beamforming and the requirement for the realtime performenee, a fuze antenna beamformer based on digital signal processor （DSP） was designed. The program was written in C, and in order to reduce the operation time of DSP, the key part of the matrix operation was written in simple algorithm. The precise and speediness of DSP calculation results were analyzed through Matlab and the Profiling tools in Code Composer Studio （CCS）. The results show that the precise and the speediness both can satisfy the requirement for the fuze antennh beamforming.

独立测距通道超低空无线电引信

针对多通道功能复用脉冲或脉冲多普勒(PD)引信测距误差较大,严重制约引信超低空性能的问题,提出基于独立测距通道的超低空无线电引信。该超低空无线电引信由目标探测通道和独立测距通道组成,其中目标探测通道采用PD体制,独立测距通道采用线性调频连续波(LFMCW)体制。仿真分析结果表明,基于独立测距通道的超低空无线电引信安全距离仅需0.7 m,在目标探测通道距离波门调整过程中引信目标探测区得到最大程度的保留,同时具备3 m高度飞行目标的近距探测能力。

SAR无线电引信目标定向探测模型及仿真

为了提高打击地面目标无线电引信定向起爆控制能力,提出一种基于合成孔径雷达(SAR)的对地无线电引信目标定向算法。通过构建弹目交会场景,采用SAR原理合成得到窄波束,对两波束的回波信号进行和差计算得到目标与弹轴的夹角。仿真结果表明,该算法对弹目交会角在39°~64°的方向,目标定向识别误差不大于1.2°,表明了SAR技术能够大幅提高无线电引信对目标的定向精度和算法的泛用性,能够为无线电引信目标定向起爆技术提供技术支持。

引信对稀疏丛林多普勒波束锐化成像与仿真方法

为了克服对地打击无线电引信对稀疏丛林地形地貌成像能力不足问题,将雷达成像技术应用于对地打击无线电引信,提出引信对稀疏丛林的多普勒波束锐化成像与仿真方法。首先,分析无线电引信俯冲姿态成像几何关系;其次,对树木建立计算机仿真模型,进而得到仿真的回波数据;最后,对回波数据实施距离向压缩、多普勒中心估计、距离走动校正、俯仰向快速傅里叶变换等算法操作,得到无线电引信对稀疏丛林的多普勒波束锐化成像仿真结果。通过在计算机中构造多个稀疏丛林起伏地貌场景,对所提成像方法进行仿真验证。实验结果表明,该方法对稀疏丛林成像效果良好,成像结果可以为引信用地形地貌智能识别算法的开发提供数据支撑,促进对地打击无线电引信识别与毁伤技术的发展。

基于功率谱熵的无线电引信目标与干扰信号分类方法

无线电调频引信在战场环境容易受到干扰信号的干扰导致早炸,丧失打击能力。为提升无线电调频引信抗干扰能力,准确识别引信目标与干扰信号,提出一种基于功率谱熵特征的无线电调频引信目标与干扰信号分类识别方法。利用实测采集的无线电引信检波端输出信号,通过提取目标和干扰信号的功率谱指数熵和Renyi熵特征构成特征向量,作为K邻近(KNN)分类器的输入进行目标和干扰信号分类识别,并利用5-折交叉检验方法对其进行验证。结果表明:目标和干扰信号的功率指数熵和Renyi熵具有显著差异性,使用KNN分类器对其进行分类识别时,最高的识别准确率可达99.47%。

毫米波调频无线电引信干扰技术研究

针对毫米波调频引信的数字射频存储转发、正弦调幅扫频、噪声调幅和噪声调频,提出了干扰方法。采用滤波分离差频信号,并从差频信号中提取多普勒信号参数的方法,将毫米波调频引信信号的差频测距结果以及多普勒信号作为引信启动的联合判决条件。仿真结果表明,对该体制引信施加正弦调幅扫频干扰和间隔转发干扰的欺骗效果明显,覆盖接收机的大功率噪声信号均能有效压制回波信号。

超宽谱对无线电引信的作用效应实验研究

为了检测某型无线电引信的抗电磁脉冲能力并确定其能量耦合机理,利用超宽谱高功率微波(UWS-HPM)发生器,实验研究了该型引信的电磁脉冲辐照效应。实验表明:电点火头本身以及勤务处理状态下的无线电引信在超宽谱高功率微波辐照下是安全的;超宽谱高功率微波场强峰峰值达到106 kV/m时,解除引信保险可使实验引信的电点火头全部引爆。电点火头被引爆的能量耦合机理是:超宽谱高功率微波辐照能量耦合进入引信执行级电路,使其晶闸管误导通。

无线电引信的超宽谱辐照效应及其防护

探讨了超宽谱高功率微波对无线电引信的辐照效应、耦合机理和防护方法。利用超宽谱高功率微波辐照源对多姿态的无线电引信进行了辐照实验并对结果进行了分析,实验表明当引信和弹体的轴向与超宽谱高功率微波的电场极化方向一致时,引信最容易被引爆,辐照效应最明显。通过理论分析和辐照实验找出超宽谱高功率微波能量耦合机理为:引信和弹体上感应的瞬变电压通过引信电源电路传递到执行电路,瞬变电压上升率超过了电路中晶闸管的断态电压临界上升率,使晶闸管意外导通,导致引信误动作。在不影响引信工作特性前提下,采取增加防护器件和替换敏感器件的加固方法,可以提高引信抗干扰能力。采用综合防护加固方法可使引信在超宽谱高功率微波辐照下不再产生误动作,达到了防护加固的目的。

超宽谱电磁脉冲对无线电引信的耦合及防护加固

通过利用超宽谱电磁脉冲(UWS-EMP)源对5种无线电引信进行了辐照,分析了超宽谱电磁脉冲与无线电引信的耦合模式和作用机理。分析得出:超宽谱电磁脉冲主要是通过后门耦合到引信电源模块,引起电源波动,使晶闸管意外导通,导致引信意外发火。根据耦合模式和作用机理对引信进行了防护加固,并对防护加固后的引信进行了辐照和仿真。辐照实验和仿真结果证明:防护加固措施大大提高了引信抗超宽谱电磁脉冲的能力,加固后的引信执行电路抗UWS-EMP干扰的场强从58 kV.m-1提高到130 kV.m-1,而引信的防护加固措施对引信的效能没有影响。

无线电引信信号去噪的最优小波基选择

为解决小波技术在无线电引信应用中最优小波基的选择问题,在对小波基基本参数及性质进行分析的基础上,根据无线电引信信号的特点,归纳出适用于无线电引信信号去噪的小波基特点.引入参数重构因子对小波基去噪效果进行评判,进一步得出db12,db13和db17小波基适用于无线电引信信号去噪的结论.仿真实验结果的对比验证了所得结论的正确性.

超宽带电磁脉冲对典型引信的耦合效应研究

为明晰超宽带电磁脉冲对典型无线电引信的干扰和损伤影响,应用时域有限积分法对典型无线电引信腔体耦合效应进行了数值模拟研究。以典型无线电引信腔体及其低频电路板实际结构为对象进行建模,仿真研究了超宽带电磁脉冲对该引信腔体的耦合特性,分析了引信高低频电路间连线过孔参数和脉冲参数对耦合效应的影响规律,研究了加装印刷电路板对耦合效应的影响。结果表明:与圆形和正方形孔缝相比,矩形孔缝的耦合系数受极化方向的影响显著;脉冲上升时间越小,耦合系数越大;加装印刷电路板后,腔体相同位置处耦合系数下降,谐振频率改变。

窄带电磁辐射对无线电引信的作用规律

针对无线电引信电磁防护性能试验评估的技术需求,提出了连续波电磁辐射效应试验方法和操作程序.试验研究了某型分米波无线电引信的单频、扫频和调幅电磁辐射效应,确定了不同调制方式下的临界起爆场强变化规律.结果发现:单频电磁辐射导致无线电引信起爆的场强存在上限值;单频、扫频、调幅电磁辐射导致无线电引信意外起爆的能力依次增强,最小临界起爆场强仅为0.38V/m,以此为基础,分析了连续波电磁辐射对无线电引信的干扰机理,提出了无线电引信电磁防护加固方法和高效干扰方法.

无线电引信执行电路抗超宽谱电磁脉冲研究

为了研究强无线电引信对电磁脉冲辐照效应的防护加固措施,对某型引信执行电路进行超宽谱辐电磁脉冲(UWS-EMP)辐照实验,分析了超宽谱电磁脉冲干扰引信执行电路的原因是它能够使引信执行电路中的晶闸管意外导通,使引信发火。对防护加固改造前后的引信执行电路用UWS-EMP进行了对比辐照实验,用PspiceA/D仿真软件进行了仿真实验,结果证明防护加固措施大大提高了无线电引信执行电路抗UWS-EMP的能力,而且对引信的性能没有影响。

无线电引信双源辐照效应研究

为了探索复杂电磁环境对无线电引信的作用规律,提出双辐射源电磁环境构建方法和试验方法,试验研究了无线电引信的双辐射源电磁环境效应,找到了使无线电引信意外起爆的双辐射源辐照频率组合方式和敏感阈值。发现双辐射源使无线电引信意外起爆的作用机理:引信天线及弹体接收到差频为多普勒频率的复合连续波信号,经自差机振荡器混频、检波管检波并滤波后,输出信号幅度较大的正弦波信号,经低频电路放大、信号整流积分及抗干扰惯性支路的共同作用,通过增幅速率选择电路,触发执行级电路误动作导致引信意外起爆。