GNSS carrier phase ambiguity resolution based on integrity restriction in ambiguity domain

Carrier phase ambiguity resolution of Global Navigation Satellite System (GNSS) is a key technology for high-precision navigation and positioning, and it is a challenge for applications which require both high accuracy and high integrity. This paper proposes efficient ambiguity resolution methods based on integrity restriction using Fixed Failure rate Ratio Test (FF-RT) and Doubly Non-central F-distribution Ratio Test (DNF-RT), and derives the related processing models and numerical algorithms compared with the traditional Ratio Test (RT) method. Firstly, the integer ambiguity resolution and validation procedures, especially the Least squares AMBiguity Decorrelation Adjustment (LAMBDA) estimation and RT validation are analyzed. Then the quality evaluation using success rate, the FF-RT method using Integer Aperture (IA) estimation and the NDF-RT method are proposed. Lastly, the simulation and analysis for LAMBDA using RT, FF-RT and DNF-RT methods are performed. Simulation results show that in case of unbiased scenario FF-RT and DNF-RT have similar performances, which are significantly better than RT. In case of biased scenario it is difficult for FF-RT to predict the biased success rate thus it should not be used for bias detection, while DNF-RT can detect biases in most cases except for the biases are approximate or equal to integer, which has the important benefit for early detection of potential threat to the position solution.     

一种用于实时数字稳像的全分辨率运动补偿方法

以室外视频监控中帧间平移运动为研究对象,提出一种基于平衡位置修正与自适应存储帧更新的实时全分辨率数字稳像方法。首先利用卡尔曼滤波在线估计镜头的主动运动,预先确定抖动图像补偿后的平衡位置;然后针对图像补偿后产生的空白区域,通过选择合适的参考帧及预存帧构成存储帧队列,根据存储帧队列的覆盖范围对平衡位置进行修正,实现修正后空白区域像素的全部拼接填补;最后以修正后的平衡位置为基准,根据同时满足左上、右上、左下和右下4个偏移方向的原则对参考帧队列进行自适应在线更新,用最新采集帧替换时间上较早、空间内容上冗余的参考帧,使得存储帧队列在有限长度内保证尽可能大的空间覆盖。本文提出的方法可以满足实时数字全分辨率稳像的要求,适用于集成式、嵌入式等各类视频监控系统。      

基于CO2浓度监测的飞机火警探测方法

目前飞机普遍采用感温、感烟火警探测方法,其存在误报率高的缺陷.分析了发生火灾时气态燃烧产物的生成规律,提出了以CO_2气体为火警探测参量,通过准确监测环境中CO_2气体浓度的变化,进行飞机火警探测的方法;根据飞机飞行所处环境条件的特殊性,研究了基于非色散红外(NDIR)吸收原理的CO_2气体浓度监测的飞机火警探测方法应用于飞机上所面临的温度补偿难题;根据飞机火警探测器测量电压与环境温度、参比电压之间的关系,采用偏最小二乘(PLS)法建立飞机火警探测器温度补偿模型;根据飞机火警探测器测量电压与CO_2气体浓度之间的关系,采用PLS法建立CO_2气体浓度计算模型;研究了基于CO_2气体浓度监测的报警算法,为飞机火警探测提供了一种新的方法.     

Study of the radiation fields in LEO with the Space Application of Timepix Radiation Monitor (SATRAM)

We present the analysis of data taken by the Space Application of Timepix Radiation Monitor (SATRAM). It is centred on a Timepix detector (300?$\mathrm{\mu }$m thick silicon sensor, pixel pitch 55?$\mathrm{\mu }$m, 256?×?256 pixels). It was flown on Proba-V, an Earth observing satellite of the European Space Agency (ESA) from an altitude of 820?km on a sun-synchronous orbit, launched on May 7, 2013. A Monte Carlo simulation was conducted to determine the detector response to electrons (0.5–7?MeV) and protons (10–400?MeV) in an omnidirectional field taking into account the shielding of the detector housing and the satellite. With the help of the simulation, a strategy was developed to separate electrons, protons and ions in the data. The measured dose rate and stopping power distribution are presented as well as SATRAM’s capability to measure some of the stronger events in Earth’s magnetosphere. The stopping power, the cluster height and the shape of the particle tracks in the sensor were used to separate electrons, protons and ions. The results are presented as well. Finally, the pitch angles for a short period of time were extracted from the data and corrected with the angular response determined by the simulation.     

某型航空发动机锯齿冠涡轮叶片叶冠间隙扩展规律研究

以某型航空发动机锯齿冠涡轮叶片实际外场叶冠间隙监控数据为统计样本,开展了叶片叶冠间隙扩展规律的统计分析与研究,包括叶冠间隙扩展典型规律和扩展速率的统计分析,松动叶片数量与叶冠间隙的对应关系以及叶冠出现间隙的发动机使用情况的统计分析。结果表明:叶冠间隙存在稳态扩展和异常扩展阶段,且松动叶片数量与叶冠总间隙之间存在一定的比例关系,可为叶冠间隙外场监控提供参考和依据。     

航空智能发动机发展需求及关键控制技术

介绍了航空智能发动机的概念及国外发展背景,智能发动机的需求和未来所面临的技术挑战,并且分析了智能发动机所需的关键控制技术,最后根据现代航空发动机的特点,详细研究分析了使现阶段航空发动机更加智能化并且易于实现的关键控制技术。     

舰船燃气轮机气路测量参数的理论选择方法

针对舰船燃气轮机气路性能监测诊断的有效性要求,归纳总结了气路测量参数选择要求,提出了1套系统完整的燃气轮机气路测量参数的理论选择方法。在可测量和易测量要求及测试精度要求的初步选择基础上,依次采用影响系数、相关系数和条件数对气路测量参数的敏感性、相关性和诊断误差等进行了分析,最终从理论上选择了某舰船3轴燃气轮机气路性能监测诊断的测量参数。实例表明该理论方法具有一定的通用性和工程应用价值,对燃气轮机气路测量参数的选择有一定的指导作用。     

设计保证体系建设和审查的若干专题研究之二——设计保证体系建设研究

阐述了国内民用航空器主机研制企业建立设计保证体系的必要性,介绍了中外适航当局对设计保证体系的法规要求,分析了国外企业建设设计保证体系的成功经验。在此基础上,详细阐述了国内企业如何建设设计保证体系的思路和方法,给出了设计保证文件体系从手册到程序的基本框架,并结合我国设计保证体系建设现状,给出了设计保证体系建设和审查的一些建议。     

启发式多无人机协同路网持续监视轨迹规划

研究了旋翼无人机组在路网环境下的协同持续监视问题。基于最优化原理定义了路网持续监视问题。通过简化路网离散过程、考虑传感器识别准确度、引入不确定度度量,提出面向事件的路网持续监视问题建模方法。针对路网持续监视轨迹规划问题的特殊性,设计了一种启发式多无人机协同轨迹规划算法。通过理论分析和仿真对比,表明了算法的可行性、准确性和通用性。所提算法作为对当前路网巡逻方法的扩充,不仅可解决实际路网移动持续监视任务,也为基于图模型的持续数据采集、连续覆盖等任务提供一种解决方案。     

大规模应变监测值获取技术研究

针对全机静强度试验过程中获取应变监测值的问题,提出一种适用解决该问题的方法。全机静强度试验过程中,需要对一万个左右的应变片进行监控。在试验之前,需要提供试验工况下每个应变片的理论计算值作为监测值,筛选出重点关注部位,方便与试验值进行对比。由于应变片数量大,根据有限元结果,手工获取应变监测值效率低且易出错。从应变变换和应变插值的基本理论出发,详细介绍了快速获取应变监测值的方法,并基于HyperWorks有限元前后处理软件开发出一套应变监测值获取工具,实现了在单元面内和面外对应变进行插值,提高了应变监测值计算精度,克服了传统基于自然网格有限元模型方法带来的计算繁琐、效率低、局部计算精度不足的缺点,大大降低了应变监测值数据的准备难度。