基于拉格朗日插值法的ATS射频信号衰减修正研究

对自动测试系统中射频信号通路的衰减修正进行了研究。为解决现有修正方法操作复杂、后期维护困难的问题,提出了基于拉格朗日插值的方法来实现射频信号衰减的修正,在保证修正数据准确度的前提下既减少了修正的工作量又降低了系统后期维护的难度,并通过算例和验证了该方法的可行性。     

基于波长调制谐波信号主峰拟合的气体浓度测量方法

为了提高激光波长调制光谱法(WMS)测量气体浓度的速度和准确度,首次提出了一种通过对吸收光谱谐波信号的主峰进行拟合的气体浓度测量方法。在该方法中,只扫描吸收光谱谐波信号的主峰部分来获得谐波信号(WMS-2f/1f)的峰值点。因为缩减了吸收光谱的扫描范围,所以扫描速度得到了提高。通过对吸收光谱谐波信号(WMS-2f/1f)的主峰部分进行多项式拟合,进一步提高了测量精度。详细讨论了多项式阶数的确认方法,以及拟合数据长度对测量结果的影响。通过测量不同情况下的二氧化碳浓度验证了该方法的有效性。     

运载火箭风场高精度拟合方法

针对运载火箭风场传统拟合方法精度低的问题，提出一种基于最少参数神经网络的高精度拟合方法。该方法将运载火箭飞行高度作为网络输入，将风场的速度和朝向作为网络输出，在满足精度要求下使用最少的网络层数和神经元个数完成风场拟合，并给出了隐层节点数的下界公式。和传统的最小二乘多项式拟合及其分段形式相比，最少参数神经网络只使用一套框架即可完成风速和风向的拟合，并提高了拟合精度。大量仿真结果充分说明了所提出方法的有效性、简洁性和鲁棒性。     

A compressing and saving method for structured grid data based on block construction

The increasing grid data in CFD simulation has brought some new difficulties and challenges, such as high storage cost, low transmission efficiency. In order to overcome these problems,a novel method for compressing and saving the structured grid are proposed. In the present method,the geometric coordinates of the six logical domains of one grid block is saved instead of all grid vertex coordinates to reduce the size of the structured grid file when the grid is compressed. And all grid vertex co...     

多防线要地防空体系目标拦截能力评估

应用排队论计算目标沿某方向进袭要地的突防概率。应用插值算法，使离散的各方向目标进袭要地的突防概率形成一条近似表达突防概率关于目标进袭方向的函数曲线，得出单一防线防空火力网拦截能力的数学描述，进而得出目标进袭多条防线的突防概率。仿真实验验证了该方法的可行性。     

一种基于试验数据的发动机特性曲线拟合

准确的发动机特性曲线是其性能计算的基础。文章讨论了多种情况的特性曲线插值方法:在工作点位置区间内,对小数据情况引入了新的插值方法；多数据时,采用三次样条插值方法进行插值；在工作点位置区间外,数据较多时,基于最小二乘法进行不同工作点的拟合；当工作点位置数据较少,利用新的插值方法在区间内引入虚拟工作点增加数据点,后按照数据较多的情况处理。所得结果与实际数值比较,精度较高,具有一定的参考价值。     

POBI interpolation algorithm for CYGNSS near real time flood detection research: A case study of extreme precipitation events in Henan,China in 2021

In late 2016, NASA launched the first constellation of the global navigation satellite system reflectometry (GNSS-R) small satellites called the Cyclone Global Navigation Satellite System (CYGNSS). The stable data quality and continuous free availability of CYGNSS scientific data provided a new method for flood monitoring. However, owing to the pseudorandom distribution of CYGNSS data, researchers must always choose between high temporal resolution and high spatial resolution during the performance of flood monitoring based on CYGNSS data. For floods caused by extreme precipitation with sudden and short durations, the current flood mapping based on CYGNSS data cannot be updated in near real time. However, the near real time update of the flood distribution range is meaningful for postdisaster emergency response and rapid rescue. This study aimed to address this problem using a newly proposed spatial interpolation method based on previously observed behaviour (POBI). First, a method for calculating the surface reflectivity of the CYGNSS was introduced, followed by the principle of the POBI spatial interpolation method. The applicability of the POBI method in Henan Province, China, was then analysed, and by using the flood in Henan Province, China, in July 2021 as an example, the feasibility of CYGNSS near real time flood mapping based on the POBI method was evaluated. Based on the results, near real time and 3 km flood distribution monitoring results can be obtained using the proposed new method. The results were evaluated using MODIS (Moderate Resolution Imaging Spectroradiometer) images and compared with the observations of SMAP (Soil Moisture Active Passive) and GPM (Global Precipitation Measurement) in the same period. The results show that the flooded areas obtained by CYGNSS correspond to the inundated areas in MODIS images and are also in high agreement with the SMAP. In addition, CYGNSS allows for finer mapping and quantification of inundation areas and flood duration. Moreover, we also discussed the potential of CYGNSS to detect floods in shorter periods of time (a few hours) and did a preliminary evaluation using precipitation data from meteorological stations. The results are also highly consistent.