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guidance, flight mechanics and trajectory optimization

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Since the quantity Q(-k+) is independen$ of the control action<br />

(see (2.5.117)), a*cons%raint on -e(+Z,) is equivalent to a constraint<br />

on the quantity ff ;,' .' Let<br />

then from (2.5.117) <strong>and</strong> (2.5.125)<br />

with<br />

w(t)= a7<br />

(2.5.126)<br />

% = 2, ;: (2.5.127)<br />

Thus A is to be selected so that the simultaneous solution of the 5 <strong>and</strong> w<br />

equations, which satisfies the boundary conditions of Eq. (2.5.124) <strong>and</strong><br />

(2.5.LZ'7), provides a value of WJ(t,) which satisfies the terminal<br />

constraint. As in the previous case, the solution will usually require<br />

iteration. However, the matrix A is again negative semi-definite <strong>and</strong><br />

this condition will aid in the iteration process.<br />

2.5.3.3 Partially Qbservable Case<br />

The problem is to select the control a to minimize the functional<br />

subject to the state equation<br />

E (J) = E {l:fTQ t + UrQ, U) dt + S&L 2+ (2.5.128)<br />

0<br />

2 = H#GU + n4f<br />

<strong>and</strong> a termi,nal constraint on E (z+ $1 In this case, however, observations<br />

of the state variable x are made continuously as represented by the<br />

observation equation<br />

Y' hdx+JL<br />

(2.5.129)<br />

where q is a Gaussian white noise with zero mean <strong>and</strong> variance r(t) ;<br />

that is,<br />

& (qj = O<br />

143<br />

(2.5.130)

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