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guidance, flight mechanics and trajectory optimization

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Using this notation, Eq. (2.4.3) can be rewritten as<br />

Rho, yo’ = M/y 1<br />

Y<br />

f(;u,, y. , y;)AX +g ~(.q,~~x4~J, f(;~lii;o~,(2-4-6)<br />

L” I<br />

I..& Q(z,,, fil b e the minimum value of the summation xi, j&d, f/‘(&i))AX<br />

where the arguments X, <strong>and</strong> jf, , again denote the starti&point of the<br />

Note from the grid size in Sketch (2.4.2) <strong>and</strong> Eqs. (2.4.4) to (2.4.5) that<br />

Y,=/ {y,-%+A%-o+/]but that<br />

the optimal curve connecting<br />

Y, can take any value from 0 to 10. Suppose<br />

the points(x,,#,) <strong>and</strong> (~$,)r/) has been calculated<br />

<strong>and</strong> the functionR(z,,y,)<br />

using the Principle of Optimality<br />

to the right) allows the optimalevaluated<br />

for&=/ <strong>and</strong> # =o,/,z,...,/o.<br />

<strong>and</strong> the &rid (which is partially<br />

Then,<br />

shown<br />

solution to the original problem<br />

(namely the value of R(xor yo)<br />

to be located.<br />

30<br />

<strong>and</strong><br />

Again letting<br />

fi =+ ffi'dp<br />

it follows that Rt~~,p) is given by<br />

P . \<br />

2.6<br />

I.0<br />

0'<br />

Sketch (2.4.3)<br />

That is, the slopeb(,/ at the point (X,,f,/,, would be selected so that the<br />

sum of the two terms !?'cr,,y,, $)A)L + RJZ, ,p) is a minimum where $ =Y,+$'A%.<br />

This is exactly the computational procedure which was followed in the example<br />

problems of the preceding sections.<br />

Equation (2.4.8) can be developed directly from Eq. (2.4.6) by noting<br />

that the operation miy means the minimization is to be performed over all<br />

slopes & with i running from Oto 9. Thus,<br />

M/A/ 5 M/A/<br />

Y' y:* (i-0,9)<br />

Now, substituting this expression into (2.4.6) provides<br />

1 9<br />

63<br />

(2.4.7)<br />

(2.4.8)

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