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Precise Orbit Determination of Global Navigation Satellite System of ...

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Chapter 8 Geostationary <strong>Orbit</strong> <strong>Determination</strong> And Prediction During <strong>Satellite</strong> Maneuvers<br />

= G M (<br />

m m<br />

It is known that<br />

1<br />

xmx+ ymy+ zmz −<br />

/ )<br />

( x − x) + ( y − y) + ( z −z)<br />

( xm + ym + zm)<br />

2 2 2 2 2 2 3 2 (8-32)<br />

m m m<br />

2 2 2 2 2 2<br />

i i i i i i i i<br />

| r − r| = ( x − x) + ( y − y) + ( z − z) = r − 2(<br />

x x+ y y+ z z) + r<br />

and r r<br />

i >> , then<br />

1 1 �<br />

2<br />

2(<br />

xx i + yy i + zz i ) r �<br />

= �1<br />

−<br />

2 + 2 �<br />

| ri − r| ri<br />

� ri<br />

ri<br />

�<br />

and<br />

ri⋅ r xx i + yy i + zz i<br />

cosδ = =<br />

rr rr<br />

thus<br />

i<br />

1 1 � ��<br />

−2ri⋅r r 2 ��<br />

�<br />

= �1<br />

+ �(<br />

) + ( )<br />

2 ��<br />

| ri − r| ri<br />

��<br />

�� ri<br />

ri<br />

�� ��<br />

i<br />

1<br />

−<br />

2<br />

1<br />

−<br />

2<br />

⋅ ��<br />

⋅<br />

��<br />

= + + � − �<br />

��<br />

�� +<br />

1 � r �<br />

i r 3 rir 2 1 r 2<br />

�1<br />

( ) ( ) Λ<br />

2 2<br />

�<br />

ri<br />

��<br />

ri<br />

2 ri<br />

2 ri<br />

��<br />

�<br />

2<br />

3<br />

1 r r 1 3 2 r 3 5 2 �<br />

= �1<br />

+ cos δ + 2 ( − + cos δ) + 3 ( − cosδ + cos δ) + Λ �<br />

ri<br />

� ri<br />

ri<br />

2 2 ri<br />

2 2 �<br />

R GM i i � 2<br />

3<br />

r 1 3 2 r 3 5 3 �<br />

i = �1<br />

+ 2 ( − + cos δ) + 3 ( − cosδ + cos δ) + Λ �<br />

(8-33)<br />

ri<br />

� ri<br />

2 2 ri<br />

2 2 �<br />

Removing the constant term in Eq.(8-33), Eq.(8-33) becomes<br />

R<br />

i<br />

GM i i � 2<br />

3<br />

r 1 3 2 r 3 5 3 �<br />

= � ( − + cos δ) + ( − cosδ + cos δ) + Λ<br />

2<br />

3<br />

�<br />

(8-34)<br />

ri<br />

��<br />

ri<br />

2 2 ri<br />

2 2 ��<br />

In the equations above subscript i means s or m, i.e. the Sun and the Moon respectively. The relations between δ<br />

and satellite orbit parameters are shown in the following figure.<br />

γ<br />

O<br />

ε<br />

δ<br />

S/M<br />

N<br />

i<br />

100<br />

N´<br />

<strong>Orbit</strong> Plane<br />

i -<br />

Sat.<br />

Figure 8-1 Relations between <strong>Satellite</strong> and Sun/Moon<br />

ε<br />

Sun /Moon <strong>Orbit</strong> Plane<br />

Equator<br />

In Figure 8-1 ε is the obliquity <strong>of</strong> the ecliptic. The arc between γ and N ′ is defined as Ω. The arc between<br />

satellite and N ′ as v + ω . The arc between γ and Sun/Moon as v′ + ω ′ ,

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