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

Chapter 2 / Target Modelling
_ _
the launcher. The remaining velocity components are ignored. This
velocity is converted into components with respect to the Alignment frame
such that the target initially flies directly towards the launcher.
X
T
I A T
A I A I XA
T
( 0 ) : =
⎛
⎜ ( P ) , ( − T ( P ) ⋅ P&
) , ( 0 )
⎝
t
TARGET
2-6
T
=
1
t
⇒
t
3
T
⎞
⎟
⎠
T
Equation 2.2-2
From §16.15, the Alignment to Target LOS frame transformation is defined
by the initial position of the target. For crossing targets, the initial target
state is provided with respect to the Alignment frame and is used directly.
TARGET
2.2.2 Target Acceleration Models
=
T
T
⎞
2 ⇒ XT
⎟
⎝
⎠
⎛
T
I A T I A
I A
( 0 ) : = ⎜ ( Pt
) , ( P&
t ) , ( P&
&
t )
Equation 2.2-3
The generic target acceleration demand models are mutually exclusive and
are selected by setting the variable TAGACC:
• 0 Stationary target
• 1 Constant linear acceleration in the Alignment frame
• 2 Constant linear acceleration in the Target Velocity frame
• 3 Sinusoidal weave in the Target Velocity frame
• 4 Square wave weave in the Target Velocity frame
• 5 PN onto defending radar and launcher
• 6 PN with superimposed sinusoidal weave
• 7 PN with superimposed square wave weave
These models are defined in TG_DYNAMICS. The acceleration demand
DEMACC (AD) is set at the leading edge of the simulation reference clock,
and is then subject to a ZOH over the integration period (∆tI). This demand
passes through a 1 st order lag representing the finite dynamics of the target.
For Target Model 1 the dynamic lags are applied to the demanded
acceleration acting along the Alignment axes. For Target Models 2 to 7 the
dynamic lags are applied to the demanded acceleration acting along the
Target Velocity axes. If the target time constant is set to zero, or a value
that cannot be modelled accurately using the simulation integration period,
the dynamic lag is ignored,