本文主要研究内容
作者刘飞（2019）在《直升机时间域电磁探测系统动态噪声产生机理及抑制方法研究》一文中研究指出：直升机时间域电磁探测方法（Time-domain electromagnetic method,TEM）具有快速高效、机动灵活、适应地形能力强、探测深度大、分辨率高等优点,非常适于我国复杂地形条件下资源快速勘查应用。然而,在实际探测过程中,直升机TEM获得的二次场目标响应信号微弱,低至10-6V量级,极易受噪声干扰;最主要的是,由于采用直升机移动式平台作为载体,在飞行运动过程中接收传感器存在机械振动,在外界磁场环境中便会产生动态噪声,严重干扰TEM目标信号。经过均匀半空间下层状异常体正演模型分析,当探测系统动态噪声水平从56.7nV/m2降低到10.4 nV/m2时,探测深度可增加80 m。由此可见,动态噪声水平是直升机TEM探测系统的决定性指标之一,开展动态噪声抑制方法研究具有重要意义和实用价值。目前,国外已经研发了多套商用直升机TEM系统,分为硬支架类型和软支架类型,相应的动态噪声抑制技术基本发展成熟并处于核心保密状态。而我国研究起步较晚,自主研发的硬支架系统动态噪声水平大致在±15 nV/m2±35nV/m2,尽管达到国外同类型系统水平,但仍然存在很大的优化改进空间;对于软支架系统的研究处于起步阶段,缺乏相应的动态噪声抑制技术研究。因此,为克服直升机TEM系统的动态噪声问题,打破国外技术垄断,本文提出了基于机械共振方式的动态噪声抑制方法,并分别研制了与硬支架系统和软支架系统匹配的动态噪声抑制装置,实现了动态噪声的有效抑制。论文主要研究内容如下:（1）静态噪声决定直升机TEM系统的本底噪声,是实现探测系统低噪声水平的前提,因此,本文提出了基于噪声优化传感技术的直升机TEM系统静态噪声抑制方法。本文研究了差分方式的低噪声传感技术,通过最佳噪声匹配方法,优化设计了接收传感器的接收线圈及放大电路。经理论分析,接收传感器的噪声水平可达1.83 nV/Hz1/2@1kHz。经屏蔽室环境实验测试,研制的接收传感器输入端等效电压噪声达到1.83 nV/Hz1/2@1kHz,3 dB带宽可达71 kHz。经过探测系统野外地面测试,在4.5 h时间内,直升机TEM探测系统的静态噪声水平达到±1 nV/m2,漂移量为1 nV/m2;作为对比,国外同类型AeroTEM系统的静态噪声水平为±1 nV/m2,漂移量为3 nV/m2。（2）分析了直升机TEM系统的动态噪声产生机理和特性,提出了基于机械共振方式的直升机TEM系统动态噪声抑制方法。基于课题组前期研究基础,以硬支架直升机TEM系统为例,详细分析了动态噪声特性,得到以下结论。第一,动态噪声与TEM目标信号都由接收传感器产生,两者具有同源性;第二,接收传感器的运动形式包括大幅度低频率的摆动和小幅度高频率的机械振动两种,动态噪声主要由后者产生,并且动态噪声频率特性由接收传感器的机械特性决定。第三,直升机TEM系统接收传感器的机械特性受瞬变大电流情况下的一次场补偿限制,因此动态噪声是一个机电一体化的矛盾性问题。根据上述分析,提出了基于机械共振方式的直升机TEM系统动态噪声抑制方法。该方法的实现方案为,在瞬变大电流下一次场补偿的限定条件下,通过研制动态噪声抑制装置调节接收线圈的固有频率,使接收传感器工作于机械共振模式,从而改变动态噪声的频率分布,规避发射基频,最终实现动态噪声的抑制。（3）基于有限元的思想,将大尺寸的发射线圈和补偿线圈进行微元化处理与精细化计算,剖分了瞬变大电流情况下的一次场分布。然后基于精确求解的结果,限定了接收传感器的空间结构。针对硬支架直升机TEM系统,根据一次场计算结果,结合瞬变大电流特性,在发射线圈直径为12 m,补偿线圈直径为1.2m的条件下,接收线圈直径限定为为0.2 m,水平方向位移量为0.05 m;针对软支架直升机TEM系统,根据一次场计算结果,确定了发射线圈直径为25 m,补偿线圈直径为6 m的条件下,接收线圈直径限定为1.2 m。（4）基于一次场计算后确定的有限空间位移量,研制了与硬支架系统匹配的单自由度机械共振方式动态噪声抑制装置。经过地面测试,瞬变发射电流下降沿阶段,接收传感器的感应电压最大值为2.5 V,满足一次场补偿要求;此外,利用冲击法进行机械性能测试,接收线圈的固有振动频率被调节为8.6 Hz,规避了25 Hz发射基频。根据野外飞行试验结果,探测系统的动态噪声频率由传统方式的10-40 Hz调节为8.6 Hz,与接收传感器的固有振动频率吻合;此外,优化后的系统动态噪声水平达到±5 nV/m2,作为对比,传统方式下的系统的动态噪声水平为±15 nV/m2±35 nV/m2,国外同类型系统的动态噪声水平为±20nV/m2。基于本文建立的均匀半空间下层状异常体正演模型,优化改进系统动态噪声水平的降低范围,可增加探测深度超过50 m,探测分辨力也大幅度提升。（5）研制了六自由度机械共振方式软支架系统动态噪声抑制装置。基于软支架直升机TEM系统接收传感器的机械独立性,以及同心方式下接收区域内一次场强度小且分布均匀的电磁场环境,研制了六自由度机械共振方式的动态噪声抑制装置。经过运动学和动力学分析,并通过仿真模型计算得到接收传感器的6阶固有振动分别为1.89、1.89、1.96、3.48、3.67以及3.67 Hz,远低于25 Hz发射基频;此外,经过振动模态分析,接收传感器对引入动态噪声的振动模式不敏感。利用冲击法以及模拟飞行方法进行机械性能测试,得到接收传感器的固有振动频率为3 Hz,符合理论设计值,远低于25 Hz发射基频。经过实际飞行试验,得到动态噪声频率约为3 Hz,实现了动态噪声与TEM信号的频谱分离;此外,系统动态噪声水平降低为±0.5 nV/m2,远低于硬支架直升机TEM系统动态噪声水平,可以获得更优的探测深度和探测分辨力。综上,基于本文提出的机械共振方式动态噪声抑制方法,同时解决了硬支架和软支架直升机TEM系统的动态噪声问题,性能指标达到甚至超过国际先进水平,提高了探测系统的探测深度和探测分辨力。本文的研究可促进我国直升机TEM探测技术的发展,为我国复杂地形环境的地球物理勘查提供了支撑。
Abstract
zhi sheng ji shi jian yu dian ci tan ce fang fa （Time-domain electromagnetic method,TEM）ju you kuai su gao xiao 、ji dong ling huo 、kuo ying de xing neng li jiang 、tan ce shen du da 、fen bian lv gao deng you dian ,fei chang kuo yu wo guo fu za de xing tiao jian xia zi yuan kuai su kan cha ying yong 。ran er ,zai shi ji tan ce guo cheng zhong ,zhi sheng ji TEMhuo de de er ci chang mu biao xiang ying xin hao wei ruo ,di zhi 10-6Vliang ji ,ji yi shou zao sheng gan rao ;zui zhu yao de shi ,you yu cai yong zhi sheng ji yi dong shi ping tai zuo wei zai ti ,zai fei hang yun dong guo cheng zhong jie shou chuan gan qi cun zai ji xie zhen dong ,zai wai jie ci chang huan jing zhong bian hui chan sheng dong tai zao sheng ,yan chong gan rao TEMmu biao xin hao 。jing guo jun yun ban kong jian xia ceng zhuang yi chang ti zheng yan mo xing fen xi ,dang tan ce ji tong dong tai zao sheng shui ping cong 56.7nV/m2jiang di dao 10.4 nV/m2shi ,tan ce shen du ke zeng jia 80 m。you ci ke jian ,dong tai zao sheng shui ping shi zhi sheng ji TEMtan ce ji tong de jue ding xing zhi biao zhi yi ,kai zhan dong tai zao sheng yi zhi fang fa yan jiu ju you chong yao yi yi he shi yong jia zhi 。mu qian ,guo wai yi jing yan fa le duo tao shang yong zhi sheng ji TEMji tong ,fen wei ying zhi jia lei xing he ruan zhi jia lei xing ,xiang ying de dong tai zao sheng yi zhi ji shu ji ben fa zhan cheng shou bing chu yu he xin bao mi zhuang tai 。er wo guo yan jiu qi bu jiao wan ,zi zhu yan fa de ying zhi jia ji tong dong tai zao sheng shui ping da zhi zai ±15 nV/m2±35nV/m2,jin guan da dao guo wai tong lei xing ji tong shui ping ,dan reng ran cun zai hen da de you hua gai jin kong jian ;dui yu ruan zhi jia ji tong de yan jiu chu yu qi bu jie duan ,que fa xiang ying de dong tai zao sheng yi zhi ji shu yan jiu 。yin ci ,wei ke fu zhi sheng ji TEMji tong de dong tai zao sheng wen ti ,da po guo wai ji shu long duan ,ben wen di chu le ji yu ji xie gong zhen fang shi de dong tai zao sheng yi zhi fang fa ,bing fen bie yan zhi le yu ying zhi jia ji tong he ruan zhi jia ji tong pi pei de dong tai zao sheng yi zhi zhuang zhi ,shi xian le dong tai zao sheng de you xiao yi zhi 。lun wen zhu yao yan jiu nei rong ru xia :（1）jing tai zao sheng jue ding zhi sheng ji TEMji tong de ben de zao sheng ,shi shi xian tan ce ji tong di zao sheng shui ping de qian di ,yin ci ,ben wen di chu le ji yu zao sheng you hua chuan gan ji shu de zhi sheng ji TEMji tong jing tai zao sheng yi zhi fang fa 。ben wen yan jiu le cha fen fang shi de di zao sheng chuan gan ji shu ,tong guo zui jia zao sheng pi pei fang fa ,you hua she ji le jie shou chuan gan qi de jie shou xian juan ji fang da dian lu 。jing li lun fen xi ,jie shou chuan gan qi de zao sheng shui ping ke da 1.83 nV/Hz1/2@1kHz。jing bing bi shi huan jing shi yan ce shi ,yan zhi de jie shou chuan gan qi shu ru duan deng xiao dian ya zao sheng da dao 1.83 nV/Hz1/2@1kHz,3 dBdai kuan ke da 71 kHz。jing guo tan ce ji tong ye wai de mian ce shi ,zai 4.5 hshi jian nei ,zhi sheng ji TEMtan ce ji tong de jing tai zao sheng shui ping da dao ±1 nV/m2,piao yi liang wei 1 nV/m2;zuo wei dui bi ,guo wai tong lei xing AeroTEMji tong de jing tai zao sheng shui ping wei ±1 nV/m2,piao yi liang wei 3 nV/m2。（2）fen xi le zhi sheng ji TEMji tong de dong tai zao sheng chan sheng ji li he te xing ,di chu le ji yu ji xie gong zhen fang shi de zhi sheng ji TEMji tong dong tai zao sheng yi zhi fang fa 。ji yu ke ti zu qian ji yan jiu ji chu ,yi ying zhi jia zhi sheng ji TEMji tong wei li ,xiang xi fen xi le dong tai zao sheng te xing ,de dao yi xia jie lun 。di yi ,dong tai zao sheng yu TEMmu biao xin hao dou you jie shou chuan gan qi chan sheng ,liang zhe ju you tong yuan xing ;di er ,jie shou chuan gan qi de yun dong xing shi bao gua da fu du di pin lv de bai dong he xiao fu du gao pin lv de ji xie zhen dong liang chong ,dong tai zao sheng zhu yao you hou zhe chan sheng ,bing ju dong tai zao sheng pin lv te xing you jie shou chuan gan qi de ji xie te xing jue ding 。di san ,zhi sheng ji TEMji tong jie shou chuan gan qi de ji xie te xing shou shun bian da dian liu qing kuang xia de yi ci chang bu chang xian zhi ,yin ci dong tai zao sheng shi yi ge ji dian yi ti hua de mao dun xing wen ti 。gen ju shang shu fen xi ,di chu le ji yu ji xie gong zhen fang shi de zhi sheng ji TEMji tong dong tai zao sheng yi zhi fang fa 。gai fang fa de shi xian fang an wei ,zai shun bian da dian liu xia yi ci chang bu chang de xian ding tiao jian xia ,tong guo yan zhi dong tai zao sheng yi zhi zhuang zhi diao jie jie shou xian juan de gu you pin lv ,shi jie shou chuan gan qi gong zuo yu ji xie gong zhen mo shi ,cong er gai bian dong tai zao sheng de pin lv fen bu ,gui bi fa she ji pin ,zui zhong shi xian dong tai zao sheng de yi zhi 。（3）ji yu you xian yuan de sai xiang ,jiang da che cun de fa she xian juan he bu chang xian juan jin hang wei yuan hua chu li yu jing xi hua ji suan ,pou fen le shun bian da dian liu qing kuang xia de yi ci chang fen bu 。ran hou ji yu jing que qiu jie de jie guo ,xian ding le jie shou chuan gan qi de kong jian jie gou 。zhen dui ying zhi jia zhi sheng ji TEMji tong ,gen ju yi ci chang ji suan jie guo ,jie ge shun bian da dian liu te xing ,zai fa she xian juan zhi jing wei 12 m,bu chang xian juan zhi jing wei 1.2mde tiao jian xia ,jie shou xian juan zhi jing xian ding wei wei 0.2 m,shui ping fang xiang wei yi liang wei 0.05 m;zhen dui ruan zhi jia zhi sheng ji TEMji tong ,gen ju yi ci chang ji suan jie guo ,que ding le fa she xian juan zhi jing wei 25 m,bu chang xian juan zhi jing wei 6 mde tiao jian xia ,jie shou xian juan zhi jing xian ding wei 1.2 m。（4）ji yu yi ci chang ji suan hou que ding de you xian kong jian wei yi liang ,yan zhi le yu ying zhi jia ji tong pi pei de chan zi you du ji xie gong zhen fang shi dong tai zao sheng yi zhi zhuang zhi 。jing guo de mian ce shi ,shun bian fa she dian liu xia jiang yan jie duan ,jie shou chuan gan qi de gan ying dian ya zui da zhi wei 2.5 V,man zu yi ci chang bu chang yao qiu ;ci wai ,li yong chong ji fa jin hang ji xie xing neng ce shi ,jie shou xian juan de gu you zhen dong pin lv bei diao jie wei 8.6 Hz,gui bi le 25 Hzfa she ji pin 。gen ju ye wai fei hang shi yan jie guo ,tan ce ji tong de dong tai zao sheng pin lv you chuan tong fang shi de 10-40 Hzdiao jie wei 8.6 Hz,yu jie shou chuan gan qi de gu you zhen dong pin lv wen ge ;ci wai ,you hua hou de ji tong dong tai zao sheng shui ping da dao ±5 nV/m2,zuo wei dui bi ,chuan tong fang shi xia de ji tong de dong tai zao sheng shui ping wei ±15 nV/m2±35 nV/m2,guo wai tong lei xing ji tong de dong tai zao sheng shui ping wei ±20nV/m2。ji yu ben wen jian li de jun yun ban kong jian xia ceng zhuang yi chang ti zheng yan mo xing ,you hua gai jin ji tong dong tai zao sheng shui ping de jiang di fan wei ,ke zeng jia tan ce shen du chao guo 50 m,tan ce fen bian li ye da fu du di sheng 。（5）yan zhi le liu zi you du ji xie gong zhen fang shi ruan zhi jia ji tong dong tai zao sheng yi zhi zhuang zhi 。ji yu ruan zhi jia zhi sheng ji TEMji tong jie shou chuan gan qi de ji xie du li xing ,yi ji tong xin fang shi xia jie shou ou yu nei yi ci chang jiang du xiao ju fen bu jun yun de dian ci chang huan jing ,yan zhi le liu zi you du ji xie gong zhen fang shi de dong tai zao sheng yi zhi zhuang zhi 。jing guo yun dong xue he dong li xue fen xi ,bing tong guo fang zhen mo xing ji suan de dao jie shou chuan gan qi de 6jie gu you zhen dong fen bie wei 1.89、1.89、1.96、3.48、3.67yi ji 3.67 Hz,yuan di yu 25 Hzfa she ji pin ;ci wai ,jing guo zhen dong mo tai fen xi ,jie shou chuan gan qi dui yin ru dong tai zao sheng de zhen dong mo shi bu min gan 。li yong chong ji fa yi ji mo ni fei hang fang fa jin hang ji xie xing neng ce shi ,de dao jie shou chuan gan qi de gu you zhen dong pin lv wei 3 Hz,fu ge li lun she ji zhi ,yuan di yu 25 Hzfa she ji pin 。jing guo shi ji fei hang shi yan ,de dao dong tai zao sheng pin lv yao wei 3 Hz,shi xian le dong tai zao sheng yu TEMxin hao de pin pu fen li ;ci wai ,ji tong dong tai zao sheng shui ping jiang di wei ±0.5 nV/m2,yuan di yu ying zhi jia zhi sheng ji TEMji tong dong tai zao sheng shui ping ,ke yi huo de geng you de tan ce shen du he tan ce fen bian li 。zeng shang ,ji yu ben wen di chu de ji xie gong zhen fang shi dong tai zao sheng yi zhi fang fa ,tong shi jie jue le ying zhi jia he ruan zhi jia zhi sheng ji TEMji tong de dong tai zao sheng wen ti ,xing neng zhi biao da dao shen zhi chao guo guo ji xian jin shui ping ,di gao le tan ce ji tong de tan ce shen du he tan ce fen bian li 。ben wen de yan jiu ke cu jin wo guo zhi sheng ji TEMtan ce ji shu de fa zhan ,wei wo guo fu za de xing huan jing de de qiu wu li kan cha di gong le zhi cheng 。
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标签：直升机探测论文; 硬支架系统论文; 软支架系统论文; 静态噪声论文; 动态噪声论文; 吉林大学2019-06-25论文;