节点文献
机载光电平台振动特性测量技术研究
Research on Vibration Characteristics of Airborne Photoelectric Platform Measurement Technique
【作者】 高紫俊;
【导师】 孟丽艳;
【作者基本信息】 大连海事大学 , 通信与信息系统, 2014, 博士
【摘要】 机载光电平台广泛应用于军事领域和公安、消防、救助打捞、环境监控等民用领域。作为飞行载体的主要探测单元,机载光电平台(“吊舱”)工作时会受到飞行载体姿态变化、振动、气流扰动等因素影响,不可避免地产生视轴晃动,影响机载红外、可见光等成像系统的成像质量。为了检验机载光电平台的性能,确定航拍图像模糊的主要影响因素,提高成像系统的图像质量,研究一种有效方法实现飞机实飞状态下机载光电平台的振动特性测量,尤其是高频角振动特性的测量具有重要意义。本文通过分析机载光电平台工作特点和振动特性,确定了微振动测试方法和测试系统需要满足的功能和指标,提出了以太阳作为参考点的有振动测量基准的测量方法,采用象限探测器阵列获取太阳像斑中心位置,基于其位置计算太阳光束相对于视轴的偏转角,进而计算出机载光电平台的相对微振角。为了提高象限探测器的位置测试精度,提出了一种基于数据库查询的象限探测器高精度光斑中心计算方法。详细介绍了高精度光斑中心计算方法的原理、数据库的建立过程以及查询过程。仿真分析和实验验证的结果表明:与通用光斑中心计算方法相比,该方法能将光斑中心位置的计算精度提高两个数量级。设计并研制了振动特性测量系统的地面实验装置,并对其主要技术指标、系统结构、模块组成等进行了论述。该装置能够实现大视场探测功能、太阳像斑采集功能、微角振动量计算功能、高频高精度测量功能。对振动测量系统的地面实验装置进行了补偿及校正,以保证实验验证的准确性。其中包括:(1)研究了系统不均匀度对光斑中心位置测试精度的影响,并对其不均匀性进行了补偿(2)分析了背景光对光斑中心位置测试精度的影响,详述了去除背景光(包含系统噪声)影响的方法和过程;(3)对象限探测器各单元之间的的串扰进行了实验研究,测试了象限探测器某一光敏单元上的光信号对其相邻单元光电响应的影响程度,利用线性补偿方法对“串扰”现象进行了去除。通过地面实验验证了本地面实验装置对太阳像斑轨迹的测量功能和微角振动的测量功能,同时对它的角度测量范围、频率测量范围和系统测量不确定度三项主要指标进行了验证。本文以挂载在救助直升机外部的光电平台作为研究对象,研究了以太阳为参考点的基于四象限探测器阵列的高精度振动特性的测量方法和测量系统。该系统具有精度高、响应快、测量范围大等特点,可以广泛应用于不同类型的飞行载体的微振动特性测试中。
【Abstract】 The airborne electro-optical platform is widely used in the military field and the public security, fire protection and civil fields such as environmental monitoring. Boresight sway is inevitably produced because of moving carrier attitude change, vibration, air turbulence and other factors on photoelectric platform which cause the influence of the imaging quality of airborne infrared and visible light imaging system. To test the performance of airborne photoelectric platform, it is important to identify the main affecting factors of the aerial image fuzzy, improve the image quality of imaging systems, research an effective method to realize the plane flying under the condition of vibration measurement of airborne photoelectric platform, especially measure the characteristics of high-frequency angular vibration.Through the analysis of the vibration characteristics of airborne photoelectric platform, the micro vibration test method and test system meeting the function and index is established. The measurement with vibration benchmark is present which use the sun as reference point. Using the four quadrant detector array, the sun spot position is obtained. The relative vibration of airborne photoelectric platform angle is calculated due to the certain relationship between the center of sun spot and deflection angle of the sun beam relative to the line of sight.Based on the general, the high precision spot center algorithm is researched, which significantly improve the accuracy of measurement of micro vibration measurement system. This paper discusses the principle of general and high precision spot center calculation method and process of database establishment and query. Simulation and experiment results show that the accuracy the spot center is two orders of magnitude improved by high precision spot center calculation method compared with the common spot center calculation method.High precision micro vibration measurement system is designed and developed in this paper. The main technical indicators, structure, module, device selection of the high precision micro vibration measurement system are discussed. The micro vibration measurement system of high precision and can realize the function of system wide field view, collect the sun spot data, micro angular vibration calculation, high speed measurement and high accuracy measurement.Compensation and correction is made on high precision micro vibration measurement system, in order to ensure the accuracy of the physical experiment. Compensation and correction are included as follows,(1) Study the effect on spot center location test of the inhomogeneous system then compensate and correct inhomogeneity on the four quadrant detector array devices and systems.(2) Analysis the effect of background light on the spot center location test, details the effect removal of background light (including system noise) method.(3) Test the influence of optical signal photoelectric response on a photosensitive unit to its adjacent element of quadrant detector and correct the "crosstalk" phenomenon using the linear compensation method.Through the field experimental verification, QD detector array vibration measuring system for the sun spot trajectory measurement function and micro angular vibration measurement function are verified, at the same time, the range of the measuring angle, frequency measurement range and measurement uncertainty of three main indexes are verified.In this paper, the photoelectric platform mounting external of rescue helicopter is taken as the research object, taking the sun as a reference point, high precision micro vibration measurement method and system based on four quadrant detector is researched. The displacement measurement system has high accuracy, fast response, wide measurement range, and can be used in different types of the micro vibration measurement of dynamic vector.
【Key words】 Airborne photoelectric platform; Four quadrant detector array; Micro vibration measurement; Image positioning; Crosstalk;