MIL-HDBK-1211(MI)
CHAPTER 1
INTRODUCTION
Background information is finished regarding the need for missile flight simulations, and brief descriptions are
given of their character, purpose, and implementation. The purpose, scope and organization of the handbook are
described.
namic and environmental conditions. Miss distance is often
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BACKGROUND
used as a measure of missile system performance. In general,
Surface-to-air missile systems are developed to meet
the smaller the miss distance, the greater the probability of
specified operational requirements. In a broad sense these re-
killing the target. The mathematical analysis of missile flight
quirements include the size of the defended area and lethali-
is complex and involves nonlinearities, logic sequences, sin-
ty. In addition, the conditions under which the missile
gular events, and interactions among multiple subsystems.
system is to operate are specified to include the environment
Computer simulation techniques are ideally suited to this
and characteristics of the threat (target). The defended area
task.
and threat characteristics determine the missile range and al-
titude requirements. The speed and maneuverability of the
1-1.1 DESCRIPTION OF A MISSILE FLIGHT
target influence the speed and maneuverability required of
SIMULATION
the missile. The target signature-emitted or reflected elec-
A missile flight simulation is a computational tool that
tromagnetic radiation-and the operational environment in-
calculates the flight path and other important parameters of
fluence the design of the missile guidance system, and likely
a missile as it leaves the launcher and engages a target. A
threat countermeasures are particularly important in estab-
simulation is based on mathematical models of the missile,
lishing guidance system characteristics. The required lethal-
target and environment, and these mathematical models
ity, generally expressed as kill probability, translates to
consist of equations that describe physical laws and logical
requirements for missile guidance accuracy, dynamic air-
sequences. The missile model includes factors such as mis-
frame maneuver characteristics, counter-countermeasures
sile mass, thrust aerodynamics, guidance and control, and
capability, and fuzing and warhead characteristics. The kill
the equations necessary to calculate the missile attitude and
probability requirements are usually stated as the probability
flight path. The target model is often less detailed but in-
of achieving specific levels of damage to the target under
cludes sufficient data and equations to determine the target
specified engagement conditions.
flight path, signature+ and countermeasures. The model of
Department of Defense (DoD) procedures for acquiring
the environment contains, at a minimum, the atmospheric
and supporting missile systems establish key milestones at
characteristics and gravity. Clouds, `haze, sun position, and
which both program management and technical decisions
terrain or sea surface characteristics are included if they are
must be made. From the initial formulation of the concept for
important to the purpose of the simulation. Sometimes
a new missile system to the end of the life cycle of the mis-
breadboarded components or actual missile hardware is used
sile, there is a continuous need to predict the performance of
instead of mathematical models of certain missile sub-
alternative designs of the missile that meet changing opera-
systems.
tional requirements and to introduce improvements that meet
The physical laws in the simulation are those governing
the evolving threat (Refs. 1, 2, and 3). An increasingly im-
the motion of the missile and target and those affecting any
portant source of information for decision makers is missile
simulated subsystems. For example, the equations of motion
flight simulation. The major missile system performance
of the missile determine the acceleration, velocity, and posi-
measures, kill probability and size of area to be defended,
tion resulting from the forces due to gravity. thrust, and aero-
can be predicted by modeling how the missile approaches
dynamics. Other equations governing physical processes
the target (missile flight) and how the warhead fragments
may be required to simulate subsystems such as the target
impact the vulnerable components of different target types
tracking system or the missile control system.
under all dynamic and environmental conditions. Most mis-
The simulation logic controls conditional events. Examp-
sile system evaluators choose to simplify the evaluation pro-
les of time-related, conditional events are initiation of tar-
cess by modeling missile flight separately, with its own
get maneuvers, decoy deployment, and changes in guidance
performance measure. As described later in this handbook,
phases. Examples of events that depend on other events are
many missile development and evaluation objectives can be
the action to be taken if the commanded missile maneuver
satisfied by considering only missile flight. One of the prin-
exceeds the specified limits set for the missile and termina-
cipal objectives of modeling missile flight is to predict how
tion of the simulation when the missile reaches its closest ap-
close the missile will approach the target under varying dy -
proach to the target.
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