星颤与对地定位和成像质量关系研究

发布时间：2018-05-08 00:28

本文选题：星颤 + 在轨标定　；参考：《武汉大学》2013年博士论文

【摘要】：随着我国民用测绘卫——ZY-3(资源三号)的发射成功,我国的国产卫星测绘事业又向前迈出了坚实的一步,踏上了新的台阶。而对于卫星在轨运行后的诸多问题,也成为关系卫星应用潜力和卫星设计指标和性能认证的核心,更是卫星发射目的能否达标的重要标志。卫星在轨成像与在轨标定等问题是从卫星几何和辐射两个方面对卫星在轨运行状况和性能进行衡量。星颤是CCD(Charge-Coupled Device,简称CCD)成像系统在轨成像质量不高、卫星系统参数变化等问题的主导因素。基于摄影测量、遥感、空间动力学、空间几何学、卫星设计工程等诸多领域的有机综合,从这两个方面研究了星颤对卫星成像系统成像质量和对地定位精度的影响。星颤会导致成像系统成像时,出现弥散斑发散、成像错位、像元畸变等情况,从而卫星成像图像质量不高。同时,还会出现焦距变化、像主点位置偏移、光学成像系统畸变等问题。总之,星颤导致上述问题出现多大的误差,关系卫星是否能达到预定成像指标的关键。本文拟通过数字仿真、定量反演等手段,从星颤的定义、星颤的可检测性、星颤图像的模拟、星颤几何标定、卫星颤振图像质量评价、卫星颤振图像恢复等一系列问题,系统地研究了卫星颤振对在轨成像质量和定位精度的影响。本文研究的主要内容： 1、星颤的定义。星颤不同于卫星振动,卫星振动会导致卫星成像系统发生刚体变形等问题,利用仪器可以有效检测。而星颤问题则更为复杂。目前,无论是位置还是姿态传感器还都无法精确获取,这也是本文采用定量反演的主要原因。 2、星颤的可检测性。目前,虽然无法利用仪器实时获取在轨颤振的幅度和频率等衡量指标,但是可以利用高速小面阵CCD获取在轨颤振成像图像序列,通过提取每一帧图像对比参考帧图像,根据卫星成像运动模型,计算成像系统位置和姿态的变化。 3、星颤标定问题。本文推导了卫星颤振对地定位几何模型。通过建立卫星成像系统内方位模型,数值模拟了摄影方位元素变化对定位精度的影响。基于SPOT5卫星数据模拟,对单像后方交会和自检校光束法标定进行了仿真实验。 4、卫星在轨成像MTF (Modulation Transfer Function,简称MTF)的计算。MTF作为衡量成像系统成像质量的重要指标,通常在实验室内可利用软硬件进行测量。但这些方法受到空间成像环境限制而无法使用。本文通过选取图像上特殊地物,利用这些地物对比度明显的特点,反演计算成像系统成像质量MTF值。 5、国家图像解译评定量化尺度(National Imagery. Interpretability Rating Scale,缩写为NIIRS)图像质量评价体系。图像质量评价作为获取卫星成像图像质量好坏的评价指标,也反应了卫星成像系统的成像性能。相比于主、客观图像质量评价方法,基于NIIRS的图像质量评价方法,可以定性和定量地分析整个成像链路的成像质量。因此,通过模拟实验,验证了NIIRS体系对星颤图像的有效评价。 6、星颤图像的恢复。星颤会导致成像质量下降,而基于MTF的MIF(Modified Inverse Filter,简称MIF)滤波方法可以有效恢复星颤图像。同时,还可以有效补偿卫星成像质量MTF。通过模拟实验,基于图像分析建立二维MTF,利用MIF滤波恢复模型,对颤振图像进行恢复,对比经典Wiener滤波方法,表明基于MTF的MIF滤波的恢复方法要优于Wiener滤波恢复方法。
[Abstract]:With the successful launch of China's civil surveying and mapping guard - ZY-3 (resource three), China's domestic satellite surveying and mapping business has taken a solid step forward and stepped on a new step, and many problems after the orbit of the satellite have become the core of the satellite application potential, the satellite design index and performance certification, and the satellite launch. It is an important sign that the object can reach the standard. The problems of satellite orbit imaging and orbit calibration are the measurement of the operating conditions and performance of the satellite from two aspects of satellite geometry and radiation. The star tremor is the leading factor of the CCD (Charge-Coupled Device, CCD) imaging system with low orbit imaging quality and the change of satellite system parameters. The influence of star tremor on imaging quality and location accuracy of satellite imaging system is studied from these two aspects in many fields, such as photogrammetry, remote sensing, spatial dynamics, space geometry, satellite design engineering and many other fields.
When the star tremor leads to the imaging system imaging, the dispersion of diffuse spots, the dislocation of the imaging, the aberration of the pixel and so on, the image quality of the satellite image is not high. At the same time, the focal length changes, such as the shift of the main point position, the aberration of the optical imaging system, and so on. In this paper, a series of problems such as the definition of the star tremor, the detectability of stellar fibrillation, the simulation of stellar tremor, the calibration of stellar tremor, the quality evaluation of the satellite flutter image and the recovery of the satellite flutter image are proposed by digital simulation and quantitative inversion, and the quality and positioning precision of the satellite flutter on orbit imaging are systematically studied. The influence of degree.
The main contents of this paper are as follows:
1, the definition of stellar tremor is that star tremor is different from satellite vibration. Satellite vibration will lead to rigid body deformation of satellite imaging system, which can be detected effectively by instrument. The problem of star tremor is more complex. At present, the position and attitude sensor can not be obtained accurately. This is the main reason for this paper to use quantitative inversion.
2, the detectability of stellar tremor. At present, although the instrument can not use the instrument to get the measure of the amplitude and frequency of the chatter in real time, we can use the high speed small surface array CCD to obtain the sequence of the on track flutter imaging image, and calculate the position and posture of the imaging system by extracting each frame image to compare the reference frame image and according to the satellite imaging motion model. Change.
3, satellite chatter calibration problem. This paper derives the geometric model of the satellite flutter to ground positioning. By establishing the azimuth model in the satellite imaging system, the influence of the variation of the azimuth element on the positioning accuracy is numerically simulated. Based on the SPOT5 satellite data simulation, the simulation experiments are carried out for the single image resection and the calibration of the self-examination light beam method.
4, the calculation of the satellite in orbit imaging MTF (Modulation Transfer Function, abbreviated as MTF) is an important index to measure the imaging quality of the imaging system, and usually can be measured by software and hardware in the laboratory. But these methods are restricted by the space imaging environment and can not be used. The imaging quality MTF value of the imaging system is calculated by inversion.
5, the image quality evaluation system of the National Imagery. Interpretability Rating Scale, the abbreviation as NIIRS). The image quality evaluation as the evaluation index for obtaining the image quality of the satellite imaging, also reacts the imaging ability of the satellite imaging system. The image quality evaluation method of NIIRS can qualitatively and quantitatively analyze the imaging quality of the entire imaging link. Therefore, the effective evaluation of the NIIRS system for the image of the star tremor is verified by the simulation experiment.
6, the recovery of the image of the star tremor will lead to the degradation of the imaging quality, and the MTF based MIF (Modified Inverse Filter, abbreviated MIF) filtering method can effectively restore the image of the star tremor. At the same time, the satellite imaging quality MTF. can be effectively compensated by the simulation experiment, the two-dimensional MTF based on the image analysis, the recovery model of the MIF filter and the flutter map. Compared with the classical Wiener filtering method, it is shown that the MTF based MIF filtering method is better than the Wiener filter recovery method.

【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：P236

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