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111.
三轴平台快速自标定与自对准方法探讨 总被引:4,自引:2,他引:4
为了提高地地导弹的作战效能,探讨了适应机动发射导弹快速发射要求的三轴平台快速自标定与自对准技术。误差标定及补偿是提高惯性系统使用精度的重要手段,但标定的完善性与快速性之间存在矛盾。误差标定及方位对准采用导弹水平状态七位置一体化方案,在约13.6分钟内能自主对准并标定出平台二十一项系数。导弹水平状态标定与对准可以基本消除阵风干扰的影响,且陀螺仪标度因数与漂移的估计采用有参考力矩的零力矩法,保证了标定、对准的快速性与准确性。经仿真验证,测量时间为1分钟时,漂移率估计误差在0.003°/h以内,测量时间为2分钟时估计误差在0.001°/h以内。 相似文献
112.
针对再入过程中标准轨迹的实际长度需要通过多次更新或迭代求解的问题,提出了一种基于机动系数的通用再入轨迹设计方法。该方法将机动系数定义为真实轨迹长度与初始纵程之比,将再入过程中的机动性进行了量化,可以快速获得到达指定目标可行的轨迹长度;采用真实轨迹长度作为设计参考阻力加速度剖面的依据,避免了轨迹长度的迭代,简化了再入轨迹的生成流程;轨迹曲率问题采用动态航向偏差走廊的方法,控制终端航向偏差、剩余航程满足设计需求。设计轨迹跟踪控制器进行参考轨迹跟踪,完成再入制导。在机动系数区间内指定机动系数进行了数值仿真。仿真结果表明,所提出的标准轨迹制导方法能够快速生成满足路径及终端约束的标准轨迹,且轨迹跟踪效果良好,有较好的应用潜力。 相似文献
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针对超声波探伤试块表面裂纹长度、宽度及深度测量中遇到的测量难题.详细介绍用于长度测量的拓膜法胶样制作的标准流程.并对结果进行测量不确定度分析和测量数据验证。 相似文献
115.
航迹规划中安全走廊及参考轨迹的确定 总被引:24,自引:4,他引:20
确定安全走廊和参数轨迹是利用分层规划思想进行航迹规划时首先要解决的问题。综合考虑飞行任务,导航精度,飞行器性能等因素,利用数字地图,用动态规划方法确定了飞行器的安全走廓和参考航线。最后利用模糊数字地形进行了仿真验证。 相似文献
116.
复合固体推进剂燃速标准物质均匀性研究 总被引:1,自引:0,他引:1
采用声发射燃速测试方法研究了复合固体推进剂方坯燃速的均匀性。叙述了这种复合体系固有的非均匀特征,用改进工艺解决了这个问题,研制出了均匀性合格的复合固体推进剂燃速标准物质。 相似文献
117.
N.C. Patel S.P. Karia K.N. Pathak 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2019,63(6):1860-1881
This paper investigated the performance of the latest International Reference Ionosphere model (IRI-2016) over that of IRI-2012 in predicting total electron content (TEC) at three different stations in the Indian region. The data used were Global Positioning System (GPS) data collected during the ascending phase of solar cycle 24 over three low-latitude stations in India namely; Bangalore (13.02°N Geographic latitude, 77.57°E Geographic longitude), Hyderabad (17.25°N Geographic latitude, 78.30°E Geographic longitude) and Surat (21.16°N Geographic latitude, 72.78°E Geographic longitude). Monthly, the seasonal and annual variability of GPS-TEC have been compared with those derived from International Reference Ionosphere IRI-2016 and IRI-2012 with two different options of topside electron density: NeQuick and IRI01-corr. It is observed that both versions of IRI (i.e., IRI-2012 and IRI-2016) predict the GPS-TEC with some deviations, the latest version of IRI (IRI-2016) predicted the TEC similar to those predicted by IRI-2012 for all the seasons at all stations except for morning hours (0500 LT to 1000?LT). This shows that the effect of the updated version is seen only during morning hours and also that there is no change in TEC values by IRI-2016 from those predicted by IRI-2012 for the rest of the time of the day in the Indian low latitude region. The semiannual variations in the daytime maximum values of TEC are clearly observed from both GPS and model-derived TEC values with two peaks around March-April and September-October months of each year. Further, the Correlation of TEC derived by IRI-2016 and IRI-2012 with EUV and F10.7 shows similar results. This shows that the solar input to the IRI-2016 is similar to IRI 2012. There is no significant difference observed in TEC, bottom-side thickness (B0) and shape (B1) parameter predictions by both the versions of the IRI model. However, a clear improvement is visible in hmF2 and NmF2 predictions by IRI-2016 to that by IRI-2012. The SHU-2015 option of the IRI-2016 gives a better prediction of NmF2 for all the months at low latitude station Ahmedabad compare to AMTB 2013. 相似文献
118.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2020,65(4):1250-1262
The current paper introduces a new multilayer perceptron (MLP) and support vector machine (SVM) based approach to improve daily rainfall estimation from the Meteosat Second Generation (MSG) data. In this study, the precipitation is first detected and classified into convective and stratiform rain by two MLP models, and then four multi-class SVM algorithms were used for daily rainfall estimation. Relevant spectral and textural input features of the developed algorithms were derived from the spectral MSG SEVIRI radiometer channels. The models were trained using radar rainfall data set colected over north Algeria. Validation of the proposed daily rainfall estimation technique was performed by rain gauge network data set recorded over north Algeria. Thus, several statistical scores were calculated, such as correlation coefficient (r), root mean square error (RMSE), mean error (Bias), and mean absolute error (MAE). The findings given by: (r = 0.97, bias = 0.31 mm, RMSE = 2.20 mm and MAE = 1.07 mm), showed a quite satisfactory relationship between the estimation and the respective observed daily precipitation. Moreover, the comparison of the results with those of two advanced techniques based on random forests (RF) and weighted ‘k’ nearest neighbor (WkNN) showed higher accuracy obtained by the proposed model. 相似文献
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一般压力表主要用于液体、气体与蒸汽的压力测量,因广泛应用使得对其开展检定工作责任重大。随着压力表检定工作的深入开展,原检定规程JJG52-1999存在一些不适应的地方,国家质量监督检验检疫总局合并了JJG52-1999、JJG573-2003两个规程,于2013年6月24日发布了新规程JJG52-2013,用于弹性元件式一般压力表、压力真空表和真空表的检定工作。用新旧比对的方法分析新版检定规程的修订内容,对JJG52-2013在使用中的问题进行探讨,并在实际应用的基础上对新版检定规程提出了具体意见及建议。 相似文献