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

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Chapter 2 / Target Modelling
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Chapter 2
TARGET MODELLING
When dealing with specific applications selection of typical airborne targets
is a subjective topic often surrounded by implacable argument. As air-to-air
and air-defence missile system complexity increases so does target selection
for design and performance proving. When dealing with tracking
algorithms realistic target dynamics and flight regimes transition are more
important than physical airframe characteristics that are important for sensor
development.
The aim was to create a simulator within the program infrastructure capable
of functioning in isolation, providing target trajectories for internal use and
other off-line applications. Combined with the initialisation,
characterisation and wire-frame visualisation software in the program
infrastructure this simulator provides a powerful tool for target trajectory
synthesis.
§2 deals with the creation of complex target trajectories from relatively
simple dynamic models. Elemental acceleration demand models are
selected from which it is possible to create a wide range of trajectories in
Earth referenced Cartesian space. Demands in Target Velocity axes are
filtered using local integrators, before transformation, and centralised state
integration.
Idealised trajectories are always needed for design proving. Here
trajectories are required with dynamics matched to the IMM filters for
initialisation, proving and tuning purposes. These are in stark contrast to
trajectories that are capable of exposing target state observer shortcomings
that are based on weaves and dog-leg avoidance manoeuvres.
§2 concludes with a general discussion, initially covering the models
required for this research. Natural extensions to these models are then
explored in the context of AMIS air-to-air scenario generation based on the
author’s considerable experience in this field.
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