摘要
随着月球探测、火星探测以及小行星与彗星等小天体探测计划的实施,深空探测已成为21世纪航天技术发展的热点和重点领域。自主导航技术是深空探测任务必需的关键技术之一,可视化技术是深空探测任务方案设计与论证的重要辅助手段。本文以深空小天体探测为背景,结合国家863计划课题的研制任务,以NASA“深度撞击”小天体接近与撞击探测任务为参考,重点对小天体探测中的光学自主导航与可视化技术进行了深入研究,主要工作与创新点包括:
1.基于摄影测量成像与定位理论初步形成一种小天体探测光学自主导航方案。
(1)在深入分析小天体接近阶段导航特点的基础上,探讨了运用数字图像特征提取与匹配技术及摄影测量空间后方交会理论进行深空探测器自主导航、制导与控制(Guidance,Navigation and Control,GN&C)的技术途径,初步形成了一种基于光学测量的小天体探测自主导航方案。通过提取与跟踪导航相机拍摄到的小天体表面上的导航目标并辅以激光测距设备测量探测器与导航目标之间的距离,在轨进行导航参数的解算。
(2)研究了基于图像处理技术的导航目标在轨提取与跟踪的方法。系统阐述了导航图像在轨处理的内容和流程,提出了一种基于图像分块和灰度局部方差的导航目标在轨提取算法,并利用图像匹配技术实现了导航目标的跟踪。
(3)建立了自主导航参数的光学测量模型,研究了基于导航相机和激光测距设备的观测量进行探测器自主导航参数计算的过程和方法,分析并比较了探测器和小天体相对位置和姿态参数的测量算法,推导了探测器瞄准撞击点位置矢量在自主导航不同阶段的计算方法,分析了本文提出的导航方案的导航精度及影响因素。
2.以“深度撞击”任务为背景研究并实现了小天体探测可视化的部分关键技术。
(1)提出了一种基于图形硬件优化的深空目标三维建模与可视化方法,针对图形硬件的特点设计了基于索引机制的深空目标模型数据组织方式,避免了大量冗余数据的处理,提高了模型绘制的效率,实现了对复杂深空目标的三维实时绘制;
(2)利用粒子系统技术逼真再现了小天体撞击的效果,根据GPU的并行处理特性设计了基于GPU通用计算技术(GPGPU)的大规模粒子系统,可以很大程度地增加粒子系统实时仿真应用中的粒子数量,并具有远高于普通粒子系统的实时渲染效率,从而大大提高了小天体撞击效果可视化的逼真程度。
(3)集成了本文完成的可视化算法,对小天体接近与撞击的全过程进行了可视化模拟,取得了较好的效果。
With the implementation of Moon, Mars and small celestial bodies (such as asteroid and comet) exploration, Deep space exploration becomes the hotspot and significant filed of the development for spaceflight technology in the 21st century. Spacecraft autonomous navigation technology is a regarded key technology in the deep exploration fields. The Visualization technology plays an important role in designation and demonstration for the missions of deep Space exploration. With the supports of 863 Program, this dissertation detailed analyzes the autonomous optical navigation and visualization of the small celestial bodies exploration. The main work and innovations are listed as follows:
1. An autonomous navigation system scheme for small celestial bodies exploration is proposed based on the theory of photogrammetry and the technology of image processing
(1) Based upon the detailed analysis on characteristics of navigation during small celestial body approaching phase, an autonomous navigation system scheme based on the theory of optical measurement is designed. Several visual small features on the surface of small celestial body are extracted from the images taken by the navigation camera, which are also tracked robustly and accurately. The distance from probe to those navigation targets are measured using the laser range finder. And then the navigation parameters are computed on board.
(2) An investigation is made on the extraction and tracking method of targets on board on the basis of navigation image processing, technology. The content and flow of navigation image processing is expatiated systemically. An algorithm for on board extraction of navigation targets is put forward based on image decomposition and local gray variance. The tracking of navigation targets is realized by the technology of image matching.
(3) The optical measure principle of navigation parameters is founded. The method and process on computation of navigation parameters are investigated according to the observation of navigation camera and laser range finder. Comparisons and discussions on measuring algorithms for relative position and attitude between the probe and the small celestial body are brought forward. The computation method of Impactor Targeting Vector (ITV) in the different phases of navigation is proposed. The precision of our autonomous navigation system scheme and influencing factors are analyzed.
2. The main contents and key technologies on the visualization of small celestial body exploration are investigated with the background of small celestial body approaching and impacting.
(1) A method of space objects modeling and visualization is put forward based on the graphics hardware. Aiming at the characteristics of graphics hardware, an index mechanism is introduced to optimize the data structure of space objects, which can facilitate the redundant management effectively and improve the .efficiency of visualization dramatically. Real-time rendering of complex space objects is carried out based on the proposed method.
(2) The impact result between small celestial body and the impactor probe is simulated vividly by making use of particle system technology. According to the characteristics of multiple passages of GPU, Anew realization of particle system is proposed based on the GPGPU(General-Purpose Computing on Graphics Hardware), which is probable to increase a numerous of particles in the real-time simulation to enhance the reality of the scene. The particle system based on GPU has a great ability in real-time simulation than the ordinary particle systems.
(3) By integrating the proposed algorithms, the whole course of small celestial body approaching and impact is simulated visually.
引文
[1]欧阳自远,李春来,邹永廖等.深空探测进展与开展我国深空探测的思考[J].国际太空,2003,2:2-6
[2]叶培建,彭兢.深空探测与我国深空探测展望[J].中国工程科学,2006,8(10):13-18
[3]欧阳自远.中国深空探测的起步与前景[C].宇航技术发展高峰论坛,北京:2007
[4]李竞.行星的新定义[J].科技术语研究,2006,8(3):49-52
[5]徐伟彪,赵海斌.小行星深空探测的科学意义和展望[J].地球科学,2005,20(11):1183-1190
[6]徐伟彪,胡中为.论彗星空间探测的科学目标[J].南京大学学报(自然科学版),2006,42(1):1-10
[7]http://neo.jpl.nasa.gov
[8]Victoria Garshnek,David Morrison,Frederick M.Burkle.The mitigation,management,and survivability of asteroid/comet impact with Earth[J].Space Policy,2000,16:213-222
[9]Jack G.Hills,M.Patrick Goda.Damage from comet-asteroid impacts with earth[J].Physica D 1999,133:189-198
[10]张乃通,李晖,张钦宇.深空探测通信技术发展趋势及思考[J].宇航学报,2007,28(4):786-793
[11]文援兰,王威,曾国强,.地面站对月球探测器的导航[J].国防科技大学学报,2001,23(6):33-37
[12]Daniel G.Kubitschek,Nickolaos Mastrodemos,Robert Werner,Deep Impact Autonomous Navigation:The Trials of Targeting the Unknown[C]29th ANNUAL AAS GUIDANCE AND CONTROL CONFERENCE,Breckenridge,Colorado 2006
[13]NIKOS MASTRODEMOS,DANIEL G.KUBITSCHEK,STEPHEN P.SYNNOTT.AUTONOMOUS NAVIGATION FOR THE DEEP IMPACT MISSION ENCOUNTER WITH COMET TEMPEL 1[J].Space Science Reviews,2005(117):95-121
[14]林来兴.从深度撞击探测器看空间拦截技术的发展[J].航天控制,2006,24(1):92-96
[15]http://celestiamotherlode.net
[16]李红军,朱雪平.美国“深度撞击”实验对天战的启示[J].国防科技,2005,10:43-46
[17]http://deepspace.jpl.nasa.gov/dsn/
[18]http://www.news.cn
[19]周剑敏,张洪华.基于UKF的深空探测光学自主导航方法[J].航天控制,2007,25(2):41-46
[20]刘宇飞.深空自主导航方法研究及在接近小天体中的应用[D].哈尔滨:哈尔滨工业大学,2007
[21]黄翔宇.探测器自主导航方法及在小天体探测中的应用研究[D].哈尔滨:哈尔滨工业大学,2005
[22]孙军伟.月球探测器自主导航与控制方法研究[D.哈尔滨:哈尔滨工业大学,2006
[23]房建成,宁晓琳,田玉龙.航天器自主天文导航原理与方法[D].北京:国防工业出版社,2006
[24]张汉清.基于OpenGL的月球探测器可视化仿真[D].西安:西北工业大学,2007
[25]罗丹.空间试验及仿真可视化通用支撑平台的研究与实现[D].长沙:国防科学技术大学,2005
[26]S.Bhaskaran,D.Desai and P.J.Dumont et al.Orbit Determination Performance Evaluation of the Deep Space 1 Autonomous Navigation System.Proceedings of the AAS/AIAA Spaceflight Mechanics Meeting,Monterrey,CA,Feb.9-12,1998,AAS 98-193:1295-1314
[27]S.Bhaskaran,J.E.Riedel and S.P.Synnott.Autonomous Nucleus Tracking for Comet/Asteroid Encounters:The STARDUST Example.1998 IEEE Aerospace Conference,Aspen,CO,Mar.21-28,1998.Proceedings,Piscataway,NJ,Institute of Electrical and Electronics Engineers,1998,2:353-365
[28]A.E.Marini,G.D.Racca and B.H.Foing.SMART-1 Technology Preparation for Future Planetary Missions.Advaces in Space Research.2002,30(8):1895-1900
[29]S.Bhaskaran,J.E.Riedel and S.P.Synnott.Demonstration of Autonomous Orbit Determination around Small Bodies.Proceedings of the AAS/AIAA Astrodynamics Conference,February 14-17,1995,Halifax,Nova Scotia,Canada.Advances in the Astronautical Sciences Series,1996,90(2):1297-1308
[30]J.Kawaguchi,T.Hashimoto,T.Misu and S.Sawai.An Autonomous Optical Guidance and Navigation around the Asteroid.47th International Astronautical Congress October 7-11,1996,Beijing,China
[31]T.Kubota,T.Hashimoto and J.Kawaguchi,et al.An Autonomous Navigation and Guidance System for MUSES-C Asteroid Landing.Acta Astronautica.2003,52:125-131
[32]T.Misu,T.Hashimto and K.Ninomiya.Optical Guidance for Autonomous Landing of Spacecraft.IEEE Transaction on Aerospace and Electronic Systems.1999,35(2):459-473
[33]J.D.Lafontaine.Autonomous Spacecraft Navigation and Control for Comet Landing.Journal of Guidance,Control and Dynamics.1992,15(3):567-576
[34]A.E.Johnson,Y.Cheng and L.H.Matthies.Machine Vision for Autonomous Small Body Navigation.IEEE Aerospace Conference Proceedings.2000,7:661-671
[35]www.stkchina.com
[36]张祖勋,张剑清.数字摄影测量学[M].武汉:武汉测绘科技大学出版,1996:118-120
[37]陈静.图像配准特征点提取算法研究[D].南京:南京理工大学,2006
[38]章毓晋.图像处理和分析(图象工程上册)[M].北京:清华大学出版社,1998:72-100
[39]罗军辉.Matlab7.0在图像处理中的应用[M].北京:机械工业出版社,2005:121-154
[40]冈萨雷斯.数字图像处理[M].北京:电子工业出版社,2006:78-102
[41]辛瑞红.运动目标的检测与跟踪研究[D].北京:北京交通大学,007
[42]唐仁圣.空中目标实时跟踪算法研究及系统设计[D].重庆:重庆大学,2004
[43]安建虎.相关跟踪与特征匹配技术研究[D].北京:中国科学院沈阳自动化研究所,2002
[44]张世杰.基于单目视觉的航天器相对导航理论与算法研究[D].哈尔滨:哈尔滨工业大学,2005
[45]Tesi di laurea.Real-Time Machine-Vision Based Position and Orientation Sensing System for UAV Aerial Refueling[D].Morgantown,USA:West Virginia University,2006
[46]Nikolas Trawny,Anastasios I.Mourikis,Stergios I.Roumeliotis.Coupled Vision and Inertial Navigation for Pin-Point Landing[C].NASA Science and Technology Conference 2007
[47]Mourikis,A.I.,Trawny,N.,Roumeliotis,S.I.,Johnson,A.and Matthies,L.,"Vision Aided Inertial Navigation for Precise Planetary Landing:Analysis and Experiments," Proc.Robotics Systems and Science Conference,June 2007.
[48]Trawny,N.,Mourikis,A.,Roumeliotis,S,Johnson,A.and Montgomery,J.,"Vision-Aided Inertial Navigation for Pin-Point Landing using Observations of Mapped Landmarks,"Journal of Field Robotics,2006.
[49]Huang Xiangyu,Cui Hutao,Cui Pingyuan.An autonomous optical navigation and guidance for soft landing on asteroids[J].Acta Astronautica 54(2004) 763-771
[50]程杨,杨涤.向小天体着陆的自主导航研究[J]高技术通讯,2002,12(8):42-46
[51]李爽,崔祜涛,崔平远.着陆小天体的自主GNC技术[J]宇航学报,2006,27(1):21-26
[52]黄翔宇,崔祜涛,崔平远.探测器着陆小天体的自主光学导航研究[J].电子学报.2003,31(5):659-661
[53]张晨.基于星跟踪器的航天器姿态确定方法研究[D].武汉:华中科技大学,2005
[54]孙兆伟.基于姿态敏感器的卫星自主导航与融合定姿方法研究[D].哈尔滨:哈尔滨工业大学,2004
[55]王勇 姜挺等.基于单位四元数描述的单像空间后方交会[J].测绘科学技术学报,2007,24(2):133-135
[56]徐青,吴寿虎等.近代摄影测量[M].北京:解放军出版社,2000:10-15
[57]江延川.解析摄影测量学[M].郑州:测绘学院教材
[58]李德仁,袁修孝.误差处理与可靠性理论[M]武汉:武汉大学出版社,2002:404-406
[59]张汉清.基于OpenGL的月球探测器可视化仿真[D].西安:西北工业大学,2007
[60]蓝朝桢.近地空间环境三维建模与可视化技术[D].郑州:解放军信息工程大学,2005
[61]Dave Shreineq Mason Woo.OpenGL编程指南[M].北京:人民邮电出版社,2005:45-56
[62]Rechard S.wright,Benjamin Lipchak.OpenGL超级宝典[M].北京:人民邮电出版社,2005:370-384,565-575
[63]刘镪.火焰和头发的动态模拟算法研究.北京:燕山大学硕士学位论文,2006
[64]柳有权.基于物理的计算机动画及其加速技术的研究[D].北京:中国科学院研究生院,2005
[65]吴恩华,柳有权.基于图形处理器(GPU)的通用计算[J].计算机辅助设计与图形学学报,2004,16(5):601-612
[66]吴恩华.图形处理器用于通用计算的技术、现状及其挑战[J].软件学报,2004,15(10):1493-1504
[67]Lutz Latta.Building a Million Particle System.Massive Development GmbH,2004
[68]A.Kolb and L.Latta,C.Rezk-Salama.Hardware-based Simulation and Collision Detection for Large Particle Systems[J].Graphics Hardware(2004)
[69]许楠,郝爱民,王莉莉.一种基于GPU的粒子系统[J]计算机工程与应用,2006,42(19):77-79
[70]张汉清,张科.基于GPU粒子系统的战场实时雨雪效果模拟[J]计算机仿 真,2007,24(10):200-203
[71]郗晓宁,王威.近地航天器轨道基础[M].长沙:国防科技大学出版社,2003:78-86
[72]J.K.Miller,A.S.Konopliv and P.G.Antreasian,et al.Determination of Shape,Gravity,and Rotational State of Asteroid 433 Eros[J].Icarus,2002,155:3-17