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

Chapter 8 / Simulation
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8.1 The Role of Simulation
The current expectation of a Customer is to fund a limited number of trials
thereby obtaining sufficient data to validate a sophisticated simulation. The
simulation is then used to provide performance assessments over the entire
missile and launcher operation envelope. After delivery of a weapon system
these simulations are often used to assess proposed enhancements leading to
mid-life updates.
Sub-system models capable of delivering accurate performance predictions
for modern weapon systems are usually highly complex. The multinational
nature of today’s weapon programs means that validated sub-system models
are often provided by sub-contractors. Whilst produced with contractually
agreed interfaces, and to an agreed accuracy, they all too often ignore
computational load when used at the system performance level. The
solution to this is a simulation that supports alternative sub-system models
with different levels of complexity.
Automatic weapon selection with the highest kill probability from a range of
ordnance demands communication between the launcher and the missile
through high bandwidth digital links. No longer can simulations be isolated
to the missile, or the launcher, they must encompass pre-launch targeting,
fire solutions, and post launch communication in multiple target
environments. As a consequence both simulation cost and development
duration have increased. By taking advantage of the synergy between
weapon systems this may be reduced, particularly in the air-launched
environment where a single aircraft may support a number of missile types.
Missile software is becoming so complex that it must be tested in a
simulation capable of stimulating embedded missile code. The downside is
how to verify that the application software replicates algorithms designed to
meet the weapon system technical requirements. Alternatively, application
software can be modelled independently and used to generate input stimuli
and reference outputs. This data is then used to verify that application
software is functioning correctly using an off-line test harness that proves
only that isolated test entities are functioning correctly. Further testing is
needed on target processors, or HWIL facilities, to resolve timing and
integration issues. These are interim solutions awaiting reliable automatic
code generation from simulation models used to prove the design.
8.2 The Scope of Modern Simulation
The office of the US Secretary for Defense is supporting an initiative
whereby simulation is used to reduce risk prior to Contract issue, the first
project being the JSF. The aim of this initiative is to identify conflicting
system requirements, assess requirements against risk, capability vs
affordability, and the development of large system architectures.
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