【作者】 聂俊伟；

【导师】 王飞雪；

【作者基本信息】 国防科学技术大学 ， 信息与通信工程， 2012， 博士

【摘要】 以GPS为代表的GNSS(Global Navigation Satellite System，全球导航卫星系统)在取得广泛而成功应用的同时，也暴露出了严重的问题：导航系统的抗干扰能力差。如何提升卫星导航系统的抗干扰能力，以满足强对抗条件下导航战的需求，是GNSS领域的一大研究热点。导航战体制的最新发展对接收机抗干扰算法及性能评估技术提出了新的挑战。论文以卫星导航系统抗干扰天线阵的应用为背景，以准确、全面、高效为目标，研究了卫星导航接收机天线阵抗干扰性能评估与测试技术；以强对抗下的实用化为目标，研究了新型信号体制的抗干扰算法。具体从如下四个方面开展了研究工作：(1)针对传统天线阵抗干扰性能评估方法下评估结果准确度低的问题，建立了天线阵抗干扰处理传输函数的精确模型，深入研究了传统方法以阵列输出端为评估点以及采用窄带假设这两方面的不足。在此基础上提出了宽带模型下基于解扩输出端性能的新评估方法。新方法以等效阵列增益为指标，将传统评估方法最大可达10dB以上的偏差降低到了1dB左右。(2)针对现有统计性能评估方法中信号是否可用的判断依据不准确、单信号平均可用率难以描述导航接收机的定位需求两方面的问题展开研究。将前文提出的等效阵列增益引入接收机可用函数，将单信号的平均可用率指标扩展到接收机可定位概率、服务可用性等指标，完善了统计性能评估指标体系。进一步，针对工程测试中所需信号干扰场景数量大的问题，基于干扰子空间与信号子空间的夹角对称性，提出了一种平均可用率指标的高效测试方法。理论计算结果表明，新方法较蒙特卡洛法减少了80%以上的测试场景数。(3)给定信号干扰布局下的性能提升是统计性能进一步提高的基础。本文以特定场景下等效阵列增益为优化目标，针对空时最大信干噪比算法应用于BOC(Binary Offset Carrier，二进制偏置载波调制)类信号时存在的问题，提出了一种结合BOC信号频谱特性的基于双子带平均导向矢量的改进算法。对4元阵空时15阶处理而言，新算法等效阵列增益提升2.5dB左右，平均可用率提升约20%，且降低了阵列处理对相关峰畸变的多路径效应。在此基础上抽象出了子带加权最大信干噪比准则。(4)频域抗干扰是天线阵空频抗干扰的基础。传统频域抗干扰基于门限判决的思想进行干扰抑制，在大信号动态范围下存在难以克服的强信号与干扰错误判决的矛盾。针对这一问题，本文提出了一种全新的无门限的干扰判决算法。新算法以解扩输出端等效载噪比最大化为判决准则，根据谱线对等效载噪比的贡献大小来进行干扰判决，彻底摆脱了设置判决门限的困扰。在强信号、弱信号、干扰的各种组合情况下，新算法都能准确判决，性能损耗与理论最优值相差0.5dB以内。最后，对论文的研究成果及其工程应用情况进行了总结，并对下一步将要开展的工作进行了展望。论文的研究成果已经应用于我国自主卫星导航系统的导航战指标论证、抗干扰接收设备研制与测试方案设计等相关项目中。更多还原

【Abstract】 GNSS, represented by GPS, has been extensively and successfully applied to manyfields, while it has exposed serious difficulty of poor antijamming performance. How toimprove the system antijamming performance to meet the the requirements ofNAVWAR under the live-fire circumstance is a research focus in GNSS field. Latestdevelopments of NAVWAR bring forwad a new challege on the antijammingalgorithms and performance evaluation. On the background of GNSS antijam antennaarray, this dissertation has researched the performance evaluation and test techniques interms of accuracy, comprehensiveness, efficiency. And with the goal of practicability ofantijamming receivers, the dissertation has researched the antijamming algorithims ofnew signal modulation such as BOC signals. Four aspects will be carried out as follows:(1) Aiming at the problem of inaccuracy of result of performance evaluation bytraditional method, the dissertation constructed the accurate model of array processingtransfer function, analyzed the deficiency of narrowband hypothesis and array gainindex, put forwad an innovative performance evaluation based on the despread spectrumperformance with accurate wideband model. The new method used equivalent arraygain as index, reduced the evaluation errors from up to10dB to about1dB.(2) Aiming at the problem of inaccuracy of performance evaluation by traditionalmethod, the dissertation inverstigated the two aspects of statistic performanceevaluation: the judge criterion of single signal availability and overall signal availabilitywith respect to navigation requirements. The dissertation introduced the equivalentarray gain as the judge criterion of receiver availability, and extended the averageavailability of single signal to average solution probability and navigation serviceavailability. Additionally, the dissertation improved the test method of averageavailability; the new method decreased the amount of signal&interference scenariosgreatly utilizing the symmetry of angle between signal subspace and jammer subspace.Numrical calculation results indicated that the new method decreased the scenariosabout80%.(3) The performance improvement of given signal&interference scenarios is thefoundation of statistical performance enhancement. Aiming at increasing the equivalentarray gain, the thesis studied the problem of MSINR applied to BOC signal; proposed anovel method based on the average of the two subbands according to the BOC signal’sspectrum. The new algorithm with4antennas and15taps increased the equivalent arraygain about2.5dB and average availability about20%, decerased the ACF distortion ofarray processing. Furthermore, the weighted subbands MSINR criterion is introduced.(4) Aiming at fixing the problem of inaccurate judgement of strong signals andjammers with traditional frequency domain jammer suppression method, the dissertation put forward a novel jammer judgement method without judge threshold. To maximizethe despread spectrum performance, the new method judge the jammer spectrumaccording to the contribution on the equivalent carrier to noise ratio of received signalspectrum at different frequencies. In the multiple scenes combined with the weak signal,strong signal and jammer, the new method could make the accurate judgement, with theloss lower than0.5dB compared to the theoretic limit performance.At last, the research work of this dissertation and its application were summarizedand reviewd; and the future research to be carried out was also presented. The resultshave been used to index demonstration of NAVWAR, developing antijamming receiverand anti-jam performance measure scheme design of Chinese satellite navigationsystem.更多还原