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Fixed Point Iteration Computation Of Nominal Mean Motion And Semi Major Axis Of Artificial Satellite Orbiting An Oblate Earth

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In this paper, fixed point iteration method for the computation of the semi major axis and the nominal mean motion of an artificial satellite orbiting an oblate earth is presented. The algorithm and the flowchart, along with relevant analytical expressions are presented. FPI computation of the semi major axis and the nominal mean motion for the case study orbit was performed with required estimation error, ≤ −. The results of the FPI iteration show that the algorithm converged at the second (2nd) cycle with an estimation error of-8.74134E-08 km which is less than the specified required estimation error of − km. At the convergence cycle, the semi major axis of the orbit is 27338.632605314 km and the nominal mean motion () is 0.000139670 rad/s. Meanwhile, the mean motion (n) is 0.000139683 rad/s. and the difference between n and (that is, n-) is 1.2345640E-08 rad/s. Also, the results show that the orbit semi major axis without the impact of oblate earth is 27332.341001289 km whereas the orbit semi major axis with the impact of oblate earth is 27338.632605314 which gives a difference of (27332.341001289-27338.632605314) of-6.291604025 km. Accordingly, with the oblate earth, there is an increase in the semi major axis of the orbit when compared to the case of non-oblate earth. Additional effect is that the mean motion of the satellite orbiting an oblate earth is higher or faster than the nominal mean motion of the satellite.
Journal of Multidisciplinary Engineering Science and Technology (JMEST)
ISSN: 2458-9403
Vol. 1 Issue 4, November - 2014
www.jmest.org
JMESTN42353750 13550
Fixed Point Iteration Computation Of Nominal
Mean Motion And Semi Major Axis Of Artificial
Satellite Orbiting An Oblate Earth
Ozuomba Simeon
Department of Electrical/Electronic and Computer Engineering
University of Uyo
Akwa Ibom State, Nigeria
simeonoz@yahoo.com
Abstract In this paper, fixed point iteration
method for the computation of the semi major axis and
the nominal mean motion of an artificial satellite
orbiting an oblate earth is presented. The algorithm and
the flowchart, along with relevant analytical
expressions are presented. FPI computation of the semi
major axis and the nominal mean motion for the case
study orbit was performed with required estimation
error, . The results of the FPI iteration show
that the algorithm converged at the second (2nd) cycle
with an estimation error of -8.74134E-08 km which is
less than the specified required estimation error of
 km. At the convergence cycle, the semi major
axis of the orbit is 27338.632605314 km and the
nominal mean motion ( ) is 0.000139670 rad/s.
Meanwhile, the mean motion (n) is 0.000139683 rad/s.
and the difference between n and (that is, n - ) is
1.2345640E-08 rad/s. Also, the results show that the
orbit semi major axis without the impact of oblate earth
is 27332.341001289 km whereas the orbit semi major
axis with the impact of oblate earth is 27338.632605314
which gives a difference of (27332.341001289-
27338.632605314) of -6.291604025 km . Accordingly,
with the oblate earth, there is an increase in the semi
major axis of the orbit when compared to the case of
non-oblate earth. Additional effect is that the mean
motion of the satellite orbiting an oblate earth is higher
or faster than the nominal mean motion of the satellite.
KeywordsFixed Point Iteration, Perturbed
Orbit, Artificial Satellite, Oblate Earth, Nominal
Mean Motion, Anomalistic Period, Orbital Semi
Major Axis, Seeded Secant Iteration, Anomalistic
Period, Iterative Root Finding Scheme
I. INTRODUCTION
Today, the earth is orbited by numerous artificial satellites
deployed for diverse applications ranging from
telecommunication, remote sensing, astronomical purposes,
weather forecasting, climatic studies, radar applications,
military applications and many others
[1,2,3,4,5,6,7,8,9,10,11]. The motion of each of the
satellites in their orbits is governed by planetary motion
laws postulated by Kepler [12,13,14,15,16,17,18]. The
orbital motion laws by Kepler are based on ideal case
where the earth is assumed to be a perfect sphere with
homogeneous density [19,20,21,22,23]. However, the earth
is neither spherical nor homogeneous in mass or density.
Rather, the shape of the earth has bulge at the equator and
flattening at the poles [24,25,26,27,28,29,30,31]. As such,
the shape of the earth is better modeled as oblate spheroid
[32,33,34,35,36]. The oblateness of the earth introduces
some complex motion of the satellites in their orbits. Such
orbits with the complex motions are referred to as perturbed
orbit.
Analysis of the mean motion of satellites on perturbed orbit
is quite complex; it requires iterative approach to determine
the nominal mean motion or the semi major axis of the
perturbed orbit when the anomalistic orbit period is given.
Consequently, in this paper, fixed point iteration (FPI)
method [37,38,39,40] is adapted for the computation of the
semi major axis and the nominal mean motion of an
artificial satellite orbiting an oblate earth. The FPI
flowchart is presented along with the algorithm and
requisite analytical expressions associated with the FPI
algorithm. Furthermore, sample perturbed orbit parameters
are used for numerical examples.
II. METHODOLOGY
A satellite orbit with earth geocentric gravitational
constant, and semi major axis, a , then the nominal mean
motion 󰇛󰇜, is given as;
(1)
Also, for an artificial satellite orbiting an oblate earth with
anomalistic period , P, the mean motion, is given as;

(2)
The mean motion is related to the nominal mean motion,
󰇛󰇜 as follows; 󰇣󰇛󰇜
󰇛󰇜 󰇤 (3)
Then, the semi major axis (a) can be expressed in terms of n
and as follows;
󰇣󰇛󰇜
󰇛󰇜 󰇤 (4)
󰇣󰇛󰇜
󰇛󰇜 󰇤 (5)
Journal of Multidisciplinary Engineering Science and Technology (JMEST)
ISSN: 2458-9403
Vol. 1 Issue 4, November - 2014
www.jmest.org
JMESTN42353750 13551
Let f() and g() denote functions of a in cycle k which
are given as follows;
= 󰇛󰇜
󰇣󰇛󰇜
󰇛󰇜󰇛󰇜 󰇤 (6)
󰇛󰇜
󰇣󰇛󰇛󰇜󰇜
󰇛󰇜󰇛󰇜 󰇤 󰇛󰇜 (7)
The algorithm and the flowchart (Figure 1) for the fixed
point iteration (FPI) used in the computation of the semi
major axis and the nominal mean motion of artificial
satellite orbiting an oblate earth are given as follows;
Step 1: The initial parameters;
Step 1.1: Counter for the cycle, k = 0
Step 1.2: Set the tolerance error, 

Step 1.3:
󰇛
󰇜 󰇡 
󰇢 (8)
Step 2 Compute the next root, 
󰇛󰇜
󰇣󰇛󰇜
󰇛󰇜󰇛󰇜 󰇤
(9)
Step 3:
󰇛󰇜
󰇣󰇛󰇜
󰇛󰇜󰇛󰇜 󰇤 
󰇛󰇜 (10)
Step 4:
Step 4.1:
Step 4.1.1:
If 󰇛󰇜 then
Step 4.1.2:
󰇛󰇜
Step 4.2:
If however, 󰇛󰇜 , then
Step 4.2.1:
 
Step 4.2.2:
Step 4.2.3:
Repeat step 2 to step 4
Figure 1: The flowchart for the Fixed Point Iteration (FPI) computation of the semi major axis and the nominal mean motion
of artificial satellite orbiting an oblate earth
󰇡
󰇢󰇡󰇡
󰇢
󰇢
Start
Input 
󰇛󰇜
󰇩󰇛󰇛󰇜󰇜
󰇛󰇜󰇛󰇜 󰇪 󰇛󰇜

󰇛󰇜
󰇣󰇛󰇛󰇜󰇜
󰇛󰇜󰇛󰇜 󰇤

󰇛󰇜
NO
YES
Output k,

,
󰇛󰇜
,
󰇛󰇜
Stop
Journal of Multidisciplinary Engineering Science and Technology (JMEST)
ISSN: 2458-9403
Vol. 1 Issue 4, November - 2014
www.jmest.org
JMESTN42353750 13552
III RESULTS AND DISCUSSION
A sample numerical computation was performed for the
orbit of a hypothetical artificial satellite orbiting an oblate
earth, where the orbit parameters are as follows:
i. Eccentricity (e) = 0.0025;
ii. Earth Geocentric Gravitational Constant (μ) =
3.986005 x 
iii. Inclination Angle (i) = 0 degree
iv. Anomalistic Period (P) = 12.5 hours
v. Constant (K1) = 66,063.1704 
FPI computation of the semi major axis and the nominal
mean motion for the case study orbit was performed with
required estimation error, . The results of the
FPI iteration show that the algorithm converged at the
second (2nd) cycle with an estimation error of -8.74134E-
08 km which is less than the specified required estimation
error of  km. At the convergence cycle, the semi
major axis of the orbit is 27338.632605314 km and the
nominal mean motion ( ) is 0.000139670 rad/s.
Meanwhile, the mean motion (n) is 0.000139683 rad/s. and
the difference between n and (that is, n - ) is
1.2345640E-08 rad/s. Also, the results show that the orbit
semi major axis without the impact of oblate earth is
27332.341001289 km whereas the orbit semi major axis
with the impact of oblate earth is 27338.632605314 which
gives a difference of (27332.341001289-27338.632605314)
of -6.291604025 km . Accordingly, with the oblate earth,
the semi major axis is larger and hence, in order to
maintain the given anomalistic period , the mean motion
(n) has to be larger than the nominal mean motion (). In
this case, the difference, n - is 1.2345640E-08 rad/s.
That means, the case study artificial satellite orbiting an
oblate earth has men motion that is faster (by a value of
1.2345640E-08 rad/s) than what it would have been if the
earth is not oblate.
Table 1 The result of the FPI computation of the semi major axis and the nominal mean motion for the case study orbit of an
artificial satellite orbiting an oblate earth (the required estimation error, )
Semi major axis
g() (km)
Estimation
Error
Nominal mean
motion (no)
Mean motion (n )
Difference between n
and
Cycle
 (km)
 (km)
f() (km)
(rad/s)
n (rad/s)
n- (rad/s)
0
27332.341001289
27338.633347090
-6.29235E+00
0.000139718
0.000139683
-3.5882947E-08
1
27338.633347090
27338.632605314
7.41776E-04
0.000139670
0.000139683
1.2351325E-08
2
27338.632605314
27338.632605402
-8.74134E-08
0.000139670
0.000139683
1.2345640E-08
3
27338.632605402
27338.632605402
0.00000E+00
0.000139670
0.000139683
1.2345641E-08
4
27338.632605402
27338.632605402
0.00000E+00
0.000139670
0.000139683
1.2345641E-08
5
27338.632605402
27338.632605402
0.00000E+00
0.000139670
0.000139683
1.2345641E-08
6
27338.632605402
27338.632605402
0.00000E+00
0.000139670
0.000139683
1.2345641E-08
IV. CONCLUSION
Fixed Point Iteration (FPI) computation of the semi major
axis and the nominal mean motion of an artificial satellite
orbiting an oblate earth is presented. The algorithm and the
flowchart, along with relevant analytical expressions are
presented. A hypothetical artificial satellite orbiting an
oblate earth was used as a case study. The results showed
that the algorithm converged at the 2nd iteration. Also, the
oblate earth causes an increase in the semi major axis of the
orbit when compared to the case of non-oblate earth.
Additional effect is that the mean motion of the satellite
orbiting an oblate earth is higher or faster than the nominal
mean motion of the satellite.
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Planets, asteroids, and comets all obey strict behavior in their orbits about the Sun. We’ll study Mercury, Mars, and Halley’s comet to understand this behavior.
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Maximum likelihood estimations for the parameters of extreme value distributions are discussed in this paper using fixed point iteration. The commonly used numerical approach for adressing this problem is the Newton-Raphson approach which requires differentiation unlike the fixed point iteration which is also easier to implement. Graphical approaches are also usualy proposed in the literature. We prove that these reduce in fact to the fixed point solution proposed in this paper. 2000 AMS Classification: 62F10; 62N02.
Chapter
When the representation of the Earth passes the ellipsoid of revolution to the geoid, the transformation uses spherical harmonics. The gravitational potential of the Earth, the geopotential, is presented as a limited expansion gathering the geodynamical parameters.
Book
This book provides a chronological introduction to the science of motion and rest based on the reading and analysis of significant portions of Galileo’s Dialogues Concerning Two New Sciences, Pascal’s Treatise on the Equilibrium of Fluids and the Weight of the Mass of Air, Newton’s Mathematical Principles of Natural Philosophy, and Einstein’s Relativity. Each chapter begins with a short introduction followed by a reading selection. Carefully crafted study questions draw out key points in the text and focus the reader’s attention on the author’s methods, analysis and conclusions. Numerical and laboratory exercises at the end of each chapter test the reader’s ability to understand and apply key concepts from the text. Space, Time and Motion is the second of four volumes in A Student’s Guide through the Great Physics Texts. This book grew out of a four-semester undergraduate physics curriculum designed to encourage a critical and circumspect approach to natural science while at the same time preparing students for advanced coursework in physics. This book is particularly suitable as a college-level textbook for students of the natural sciences, history or philosophy. It might also serve as a textbook for advanced high-school or home-school students, or as a thematically-organized source-book for scholars and motivated lay-readers. In studying the classic scientific texts included herein, the reader will be drawn toward a lifetime of contemplation.
Article
We consider a homogeneous fluid of viscosity v confined within an oblate spheroidal cavity of arbitrary eccentricity E marked by the equatorial radius d and the polar radius d √1-E2 with 0<E<1. The spheroidal container rotates rapidly with an angular velocity Ω0 about its symmetry axis and precesses slowly with an angular velocity Ωp about an axis that is fixed in space. It is through both topographical and viscous effects that the spheroidal container and the viscous fluid are coupled together, driving precessing flow against viscous dissipation. The precessionally driven flow is characterized by three dimensionless parameters: the shape parameter E , the Ekman number Ek=v /(d2|Ω| 0 and the Poincaré number Po=±|Ωp|/ |Ω0|. We derive a time-dependent asymptotic solution for the weakly precessing flow in the mantle frame of reference satisfying the no-slip boundary condition and valid for a spheroidal cavity of arbitrary eccentricity at Ek≪1. No prior assumptions about the spatialoral structure of the precessing flow are made in the asymptotic analysis. We also carry out direct numerical simulation for both the weakly and the strongly precessing flow in the same frame of reference using a finite-element method that is particularly suitable for non-spherical geometry. A satisfactory agreement between the asymptotic solution and direct numerical simulation is achieved for sufficiently small Ekman and Poincaré numbers. When the nonlinear effect is weak with |Po| ≪ 1, the precessing flow in an oblate spheroid is characterized by an azimuthally travelling wave without having a mean azimuthal flow. Stronger nonlinear effects with increasing |Po| produce a large-amplitude, time-independent mean azimuthal flow that is always westward in the mantle frame of reference. Implications of the precessionally driven flow for the westward motion observed in the Earth's fluid core are also discussed.
Article
The article presents a way of solving the problem of planetary motion, or, the Kepler problem, without using the transition. The governing equation is solved for the components of the velocity vector in Cartesian coordinates. Substitution for speed in the law of energy conservation yields the equation of the trajectory. A time implicit closed formula for the azimuth is derived. An Excel application is presented that simulates the motion by solving the azimuth equation numerically without using programming.