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guidance, flight mechanics and trajectory optimization

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Hence, the boundary condition<br />

OAI f’“,jd =o (2.4.51)<br />

results. Setting a_R<br />

/ y<br />

du If<br />

=,& an: substituting<br />

JR<br />

-- /& 22 =o<br />

into (2.4.51) provides<br />

z -- ~~=O<br />

ON p,jd =o (2.4.52)<br />

av Y<br />

which indicates that the gradient of@,x,y) <strong>and</strong> the gradient of ~~x,Y/I<br />

are co-linear along the curve t(x,~j=O.<br />

Eqs. (2.4.46), (2.4.49), (2.4.51) <strong>and</strong> (2.4.52) are different but<br />

equivalent representations of the boundary condition that theg function<br />

must satisfy when the terminal point is required to lie on the curve<br />

ptx,p=o * From this boundary condition the transversality condition<br />

which the Calculus of Variations requires can be derived. This is shown<br />

next.<br />

From Eq. (2.4.45B) it follows that the optimal slope must satisfy<br />

af<br />

T<br />

sle<br />

+y<br />

=O<br />

(2.4.53)<br />

at all points (x,t/) including the terminal point. Using this equation,<br />

Eq. (2.4.45B) becomes<br />

/=o (2.4.54)<br />

<strong>and</strong> must also hold at every point including the terminal point. Combining<br />

Eqs. (2.4.51), (2.4.53) <strong>and</strong> (2.4.54) provides<br />

which is the transversality condition which the optimal solu%ion must satisfy;<br />

that is, Eq. (2.4.55) s p ecifies which of the points along pl.~,#)=Ois the<br />

point for which the integral J is a minimum.<br />

74

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