University of Baghdad College of Science Department of Astronomy and Space ORBIT DETERMINATION FROM THREE ANGLES OBSERVATIONS IN THE PRESENCE OF PERTURBATIONS A Thesis Submitted to the Department of Astronomy and Space College of Science University of Baghdad In partial fulfillment requirements of the Degree of Doctor of Philosophy In Astronomy and Space By AHMED KADIR IZZET ZAINAL Supervised Dr. Akram Y. AL saati Dr. Abdulrahman H. ALmohammedy April 1, 2007 Rabi' Awwal 14, 1428 ﺩﺍﺪﻐﺑ ﺔﻌﻣﺎﺟ ﻡﻮﻠﻌﻟﺍ ﺔﻴﻠﻛ ءﺎﻀﻔﻟﺍﻭ ﻚﻠﻔﻟﺍ ﻢﺴﻗ ﺕﺎـﺑﺍﺮﻄـﺿﻻﺍ ﺩﻮﺟﻮﺑ ﺕﺍﺪـﻫﺎـﺸﻣ ﺙﻼﺛ ﻦﻣ ﺕﺍﺭﺍﺪﻤﻟﺍ ﺪـﻳﺪﺤﺗ ءﺎـﻀـﻔﻟﺍﻭ ﻚـﻠـﻔﻟﺍ ﻢـﺴـﻗ ﻰﻟﺇ ﺔـﻣﺪـﻘﻣ ﺔـﺣﻭﺮـﻁﺃ ﻡﻮـﻠـﻌـﻟ ﺍ ﺔـﻴـﻠـﻛ ﺩﺍﺪـﻐـﺑ ﺔـﻌـﻣﺎـﺟ ﻞﻴﻧ ﺕﺎﺒﻠﻄﺘﻣ ﻦﻣ ءﺰﺟ ﻲﻫﻭ ءﺎﻀﻔﻟﺍﻭ ﻚﻠﻔﻟﺍ ﻡﻮﻠﻋ ﻲﻓ ﺔﻔﺴﻠﻓ ﻩﺍﺭﻮﺘﻛﺪﻟﺍ ﺔﺟﺭﺩ ﻞﺒﻗ ﻦﻣ ﻞـﻨـﻳﺯ ﺕﺰـــﻋ ﺭﺩﺎــﻗ ﺪـــﻤـﺣﺍ ﻑﺍﺮﺷﺈﺑ ﺭﻮﺘﻛﺪﻟﺍ ﺭﻮﺘﻛﺪﻟﺍ ﻱﺪﻤﺤﻤﻟﺍ ﻦـﻴـﺴﺣ ﻦـﻤـﺣﺮـﻟﺍ ﺪﺒـﻋ ﻲـﺗﺎـﻋﺎﺴﻟﺍ ﺲﻧﻮـﻳ ﻡﺮـﻛﺃ ۲۰۰۷ ﻥﺎﺴﻴﻧ ۱ ۱٤۲۸ ﻝﻭﻷﺍ ﻊﻴﺑﺭ ۱٤ Abstracts The roots of angles only orbit determination extend back to the time of Laplace late 1700; most of today’s astrodynamics community has been uncertain as to applicability of angles only estimation techniques for accurate earth satellite orbit determination. A new procedure has been developed for the general solution of the minimal angles-only problem which an orbit is determined from three line of sight observations. The procedure basis assumes two of the unknown ranges and using Lambert problem to find the middle position; Newton-Raphson used to obtain the solution. Multiple solutions are completely new, in such a way the solutions already existing are not obtained again. This procedure avoids the limitations of the classical method (Laplace, Gauss) and a number of test problem have been explained for different celestial object and earth satellites. Two types of perturbations ( oblateness of earth and third body) effects on earth satellites orbital elements are discussed and a comparison is made between them. The ground trace of an artificial satellite, affected by perturbations due to oblateness of the earth, and the moon and the sun as a third body is determined throw one period. Acknowledgements I wholeheartedly appreciate the unwavering support of my advisors Dr. Akram Saati and Dr. Abdulrahman Al mohammedy. It is an honor to have worked with men of such brilliance, dedication, and vision. I am also indebted to head of department Dr. Ali Talib for his understanding when I needed him the most. I appreciate fellow graduate student Salman Zedan for helping me My family father mother brothers and my wife’s were always willing to provide input on design decisions and refused to ever allow me to become discouraged. I thank them all for their assistance Ahmed List of symbols symbols Definitions a Semi-major axis a acceleration c a Earth radius e c Speed of light E Eccentric anomaly e Eccentricity f flatting G Gravitational constant H Elevation J Bessel function k L Motion constant M Mean anomaly n Mean motion N Number of solution p Half semi latus rectum distance P Period of motion d p Momentum m P Radiation solar power O R Observer position vector r Orbital position vector r Turning point of motion ± T Time periapase passage U Potential energy V Velocity V Radial velocity R V Transfer velocity T I α Declination δ Right ascension Θ Subtended angle sb ι Inclination λ Longitude ρ Ranges (slant range vector) ρ Satellites distance from moon m ρ Satellites distance from sun s υ True anomaly Φ Perturbation function ω Arguments of periapse Ω Right ascension of ascending node II List of tables Table Page Definition number number 1.1 Classical orbital elements 28 5.1 data and results for minor planet 683 lanza 93 5.2 data and results for minor planet 40 Harmonia 94 5.3 data and results for Longs orbit 96 5.4 data and results for McCuskeys 97 5.5 data and results for swifts comet 1880v 98 5.6 data and results for minor planet Ceres 99 5.7 data and results for parabolic orbit 100 5.8 data and results for minor planet 1986 PS1 102 5.9 data and results for minor planet 1990 TG4 103 5.10 data and results for minor planet 1986 PT 104 5.11 data and results for minor planet PZ1 105 5.12 data and results for minor planet PO 106 5.13 data and results for minor planet 1973 SC2 107 5.14 data and results for minor planet 1966 (834) 108 5.15 data and results for minor planet 1966 (834) 109 5.16 data and results for periodic comet (HMP) 110 5.17 data and results for periodic comet (HMP) 1948 111 5.18 data and results for Mars 112 5.19 data and results for Venus 113 5.20 data and results for artificial satellite 1 115 5.21 data and results for artificial satellite 2 116 5.22 data and results for artificial satellite 3 117 5.23 data and results for artificial satellite 4 119 5.24 data and results for artificial satellite 5 120 III Lists of figure Figure Page Definition number number 1.1 Ellipse with axis 4 1.2 Keplers second law 5 1.3 Elliptical orbit 5 1.4 The right ascending declination inertial coordinate system 9 1.5 Earths curvature 10 1.6 Velocities versus trajectory 11 1.7 Conic section geometry 13 1.8 Elliptical geometry 13 1.9 Definition of argument of periapse (ω) 17 1.10 Elliptical geometry 17 1.11 Introduction of the auxiliary angle E 21 1.12 Hyperbolic reference area 21 1.13 Position and velocity vectors 22 1.14 Inclination tilt 24 1.15 Right ascension of the ascending node 25 1.16 Vernal equinox 26 1.17 Argument of perigee 27 1.18 Orbit in space 29 1.19 The deviation of the earth into time zones 34 1.20 The rotating earth in an inertial coordinate system 35 1.21 The geometric model of the earth 36 1.22 A cross section of the adopted earth model 37 1.23 A cross section of the adopted earth model with geodetic 38 latitude as a variable 2.1 Representation of orbit determination 43 2.2 Vector triangle relation dynamical center 45 2.3 A heliocentric orbit 45 2.4 Triangular area 49 5.1,a,b,c Perturbation by oblateness of earth on earth satellite 1 122 5.2,a,b,c Perturbation by oblateness of earth on earth satellite 2 123 5.3,a,b,c Perturbation by oblateness of earth on earth satellite 3 124 5.4,a,b,c Perturbation by oblateness of earth on earth satellite 4 125 5.1,d Perturbation by third body on earth satellite 1 126 5.2,d Perturbation by third body on earth satellite 2 126 IV 5.3,d Perturbation by third body on earth satellite 3 126 5.4,d Perturbation by third body on earth satellite 4 126 5.1,e,f Perturbation by third body and oblatness of earth on 127 earth satellite 1 5.2,e,f Perturbation by third body and oblateness of earth on 127 earth satellite 2 5.3,e, f Perturbation by third body and oblateness of earth on 128 earth satellite 3 5,4,e,f Perturbation by third body and oblateness of earth on 128 earth satellite 4 5.5 a Perturbation by oblateness of earth on earth satellite 5 129 5.5 b Perturbation by third body and oblateness of earth on 129 earth satellite 5 5.5 c Perturbation by third body and oblateness of earth on 129 earth satellite 5 5.6 Perturbation by third body and oblateness of earth on 130 earth satellite in one period V Contents Contents page number Chapter one: introduction to orbital mechanic 1 1.1 History of laws of motion 1 1.1.1 Early cosmology 1 1.1.2 Astronomy 2 1.2 Definition of the orbit determination process 7 1.3 Orbital motion 9 1.4 Orbit geometry 12 1.5 The two body problem 13 1.6 The orbit 15 1.7 Other conics 19 1.8 Relation between speed and velocity 21 1.9 Coordinate reference system and orbital elements 23 1.10 The orbit in space 29 1.11 The orbital elements and the initial condition 31 1.12 Physical working units and constants 32 1.13 Stations coordinate 36 1.14 Review 39 Chapter two: method of orbit determination 43 2.1 Angle only orbit determination 44 2.2 Laplaces method 46 2.3 Gausses method 47 2.4 Range-iteration method 51 Chapter three: the theory 54 3.1 Lamberts orbital boundary – value problem 54 3.2 New procedure 58 3.3 Elements conversion to and from position and velocity 64 Chapter four: perturbations 71 4.1 Introduction 71 4.2 Enke- type equations of motion 73 4.3 Lagrange and Gaussian perturbation equation 75 4.4 Perturbation on artificial earth satellite 81 4.4.1 Oblateness perturbations 81 4.4.2 Lunisolar perturbations 86 4.4.3 Atmospheric drag 90 4.4.4 Radiation pressure 91 4.4.4 Relativistic effect 91 VI
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