:orphan:

.. ****************************************************************************
.. CUI//REL TO USA ONLY
..
.. The Advanced Framework for Simulation, Integration, and Modeling (AFSIM)
..
.. The use, dissemination or disclosure of data in this file is subject to
.. limitation or restriction. See accompanying README and LICENSE for details.
.. ****************************************************************************

WSF_CHAFF_WEAPON
----------------

.. model:: weapon WSF_CHAFF_WEAPON

**Script Class**: :class:`WsfChaffWeapon`

.. parsed-literal::

   weapon <name> :model:`WSF_CHAFF_WEAPON`
      ... :ref:`Platform_Part_Commands` ...
      ... :ref:`Articulated_Part_Commands` ...
      ... :model:`WSF_EXPLICIT_WEAPON` Commands ...

      ejector <name>
         ... `Chaff Ejector Commands`_ ...
      end_ejector

      ... additional ejector definitions

      cloud_update_interval_ ...
      draw_cloud_approximations_ ...
      launched_platform_type_ ...

   end_weapon

Overview
========

:model:`WSF_CHAFF_WEAPON` represents a weapon that dispenses :model:`chaff parcels <WSF_CHAFF_PARCEL>`, consisting of a large number of shorted tuned dipole
antennas cut to lengths designed to create a desired RCS response across a frequency range of interest. One or more dispensed chaff
parcels combine to form a chaff cloud, which is generally used as a radar countermeasure in either corridor-laying or self-protection
mode. 

A chaff cloud is not a simulation entity, only an aggregation of parcels used to calculate a bistatic presented area to the interacting 
transmitter and receiver.

A chaff weapon is a :model:`WSF_EXPLICIT_WEAPON` that creates parcels (each modeled as individual platforms) dispensed by 
a system of one or more ejectors. Each ejector is given a unique name and can be independently configured to specify quantity and type
of parcels, location on the platform, and ejection velocity.

Commands
========

.. command:: cloud_update_interval <time-value>

   If non-zero, specifies a periodic time interval at which the simulation will update the state (position, velocity, size, etc.)
   of dispensed chaff parcels. If zero, parcels will only be updated when necessary to determine their state. See :command:`mover.update_interval`
   for movers.

   **Default:** 0.0

.. command:: draw_cloud_approximations <boolean-value>

   If true, will use :class:`WsfDraw` to draw an ellipsoid representing cloud approximations for debugging purposes. Can be used to
   visualize the presented area of the cloud used in RCS calculations.

   **Default:** false

.. command:: launched_platform_type <string-reference>

   Although required in :command:`WSF_EXPLICIT_WEAPON <WSF_EXPLICIT_WEAPON.launched_platform_type>` this command is optional for 
   :model:`WSF_CHAFF_WEAPON`. Can be specified to add user-defined scripts to dispensed parcels, or other custom
   :command:`platform` commands. However, it is an error to define a :command:`mover` or :command:`radar_signature` on this platform type, since these 
   components are modeled internally to the simulation.

   **Default:** If none is specified, a dummy WSF_PLATFORM type will be used.

Chaff Ejector Commands
======================

.. command:: quantity <integer-value>

   Specifies the number of parcels that are initially available in the ejector.

   **Default:** 10

.. command:: parcel_type <string-reference>
  
   Specifies the type of :model:`chaff parcel <WSF_CHAFF_PARCEL>` that this ejector dispenses. The specified value must represent
   a valid parcel type that must be defined when this ejector is initialized in the simulation.

   **Default:** No default. Must be specified.

.. command:: location <x length-value> <y length-value> <z length-value> <length-units>

   Specifies the location of the ejector in the entity coordinate system of the dispensing platform.
   
   **Default:** 0 0 0 meters

.. command:: ejection_velocity <speed-value>
.. command:: ejection_elevation <angle-value>
.. command:: ejection_azimuth <angle-value>

   Specifies the magnitude, azimuth, and elevation of the vector in the entity coordinate system that represents the additional 
   velocity, relative to the dispensing platform, provided by the launching mechanism. Similar to :command:`WSF_EXPLICIT_WEAPON.launch_delta_v`
   except specified in spherical rather than cartesian coordinates.

   **Default:** 15.0 m/s, 0.0 deg, 0.0 deg