Thesis - Leigh Moody.pdf - Bad Request - Cranfield University

Chapter 2 / Target Modelling
_ _
2.4.4 Weave Motion
This trajectory is a characterised version of Target Trajectory 7 with
motion constrained to the horizontal plane with an initial state,
T
( ( ) ) T T
16 _ 000 , 0 , 0 , 300 , 0
X : =
−
2-14
5
Equation 2.4-7
After 3 s of constant velocity flight, the acceleration demand is set to,
[ [ ( ) T
TV
36 , 41 ⇒ A : 0 , 64 , 64
t ∈
=
D
Equation 2.4-8
The resulting weave is not monochromatic since low frequency PN is
applied to ensure that the target motion is predominantly about X A .
2.5 Target Trajectories for Performance Assessment
Target trajectories 3 (fly-past with dog-leg) and 7 (weaving) were selected
to assess guidance law and state observer performance.
2.5.1 Target Trajectory 3 - Definition
For guidance studies, a 400 m/s constant velocity, crossing target, with a 9 g
avoidance manoeuvre applied normal to its velocity vector equally allocated
between yaw and pitch, activated when the missile is 2 s from impact. For
tracking studies, the missile is not launched and the manoeuvre is extended,
starting after 37 s using the following demanded acceleration profile.
TV
[ 0 , 37 [ ⇒ AD
: 03
t ∈
=
Equation 2.5-1
At 37 s the target turns away from the missile launcher, diving from an
altitude of 5 km to some 3 km to add to the radar clutter,
P & ≤ −100
⇒ A : =
XA
t
TV
D
( ) T
0 , 64 , 64
Equation 2.5-2
As the turn develops and the velocity of the target parallel to X A increases
the target climbs at 9 g until it is climbing at 60°.