guidance, flight mechanics and trajectory optimization

‘i
can be determined.
If the angular-rate control system is operating, the approximate
range-rate and range equations for periods of LOS thrusting are
where a1 is the acceleration along the line of sight. The corresponding
expression for r is thus
and
If the desired limits of z are rrn," L t L -zmaX
(2.8)
dT
and if the slope zt
is positive at t = 0, then the LOS thrusting is initiated whenever Z-L r,,,
and terminated whenever r = rm,, . If the slope of $$ is negative at t=O,
then I will continue to decrease up to the point at which $z changes sign.
(Figure 2.3) In this case, the minimum value to which + will be driven
must be predicted so that
thrusting can begin
sufficiently early to
r
prevent 2- = T,,, .
The point at which
reaches its minimum
value is determined
by solving Equation (2.8)
with cft C-= = 0 . The result
is
r -- ----___
mm
k
A
Motion of T
Figure 2.3
.?
IN”
=; [-/j -.!Y]
and the corresponding value of 7;r,,, obtained by substituting this time is
the equation for 7 is:
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