:orphan:

.. ****************************************************************************
.. CUI
..
.. 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_SAM_LAUNCH_COMPUTER
-----------------------

.. model:: launch_computer WSF_SAM_LAUNCH_COMPUTER

.. parsed-literal::

   launch_computer <name> WSF_SAM_LAUNCH_COMPUTER
      ... :command:`launch_computer` Commands ...
      ... :model:`WSF_LAUNCH_COMPUTER` Commands ...
      ... `WSF_SAM_LAUNCH_COMPUTER Commands <Commands>`_ ..
   end_launch_computer

Overview
========

:model:`WSF_SAM_LAUNCH_COMPUTER` implements a launch computer for a surface-to-air missile system, and tabulates the
expected time to intercept for a missile fired at some down-range and altitude away from the shooter, assuming the
target does not maneuver during missile flight.  Expected time of flight is obtained as an interpolated
four-dimensional table lookup.  The independent value arrays (lateral offsets, altitudes, ranges, speeds) are provided
prior to the intercept results (within the intercept_envelope_ block) obtained under the defined set of
independent conditions.

The :command:`weapon_tools` application assists with creation of launch computers of this type.
(See :command:`SAM_LAUNCH_COMPUTER_GENERATOR`).

.. block:: WSF_SAM_LAUNCH_COMPUTER

Commands
========

.. command:: lateral_offsets <distance-values> end_lateral_offsets

   Provides a listing of the lateral offsets used as the first independent variable (slowest-changing index) in the
   intercept_envelope_ which follows.  Lateral offset is the horizontal distance with which the target would overfly
   the launcher if the current track is maintained.  Values are to be provided in increasing order, and the effect is
   assumed symmetrical about the launcher's line-of-sight axis.

.. command:: altitudes <altitude-values> end_altitudes

   Specifies the target altitudes used as the second independent variable in the intercept_envelope_ below.  May be
   uneven but must be in increasing numerical order.

.. command:: ranges <range-values> end_ranges

   Specifies the ground ranges used as the third independent variable in the intercept_envelope_.  May be uneven but
   must be in increasing numerical order.

.. command:: speeds <speed-values> end_speeds

   Specifies the target speeds used as the fourth independent variable in the intercept_envelope_.  May be uneven
   but must be in increasing numerical order.

.. command:: intercept_envelope  ... end_intercept_envelope

   This block contains the data that defines the intercept envelope.  By convention, any unsuccessful intercept point may
   be omitted from the tabulation, and a time-of-flight of -1.0 seconds (a miss) is assumed.  The five index values given
   in the example below are printed out by the class weapon_tools generator, and are used to assure proper indexing when
   the data is read in by the stream parser.

   ::

     intercept_envelope
        # "intercept" intercept_index lateral_offset_index
        #    lateral_offset_value altitude_index altitude_value
        #    ground_range_index ground_range_value speed_index
        #    speed_value time_of_flight_value
        intercept 0 0 0 m 0 300 m 0 0 m 1 50 m/s 31.3536 sec
        intercept 1 0 0 m 0 300 m 0 0 m 4 200 m/s 19.9911 sec
        intercept 2 0 0 m 0 300 m 0 0 m 5 250 m/s 20.5551 sec
        intercept 3 0 0 m 0 300 m 0 0 m 6 300 m/s 21.9581 sec
        intercept 4 0 0 m 0 300 m 0 0 m 7 350 m/s 23.5001 sec          .
        .
        .
        .
     end_intercept_envelope

.. command:: interpolation_test ... end_interpolation_test

   For debug purposes only, and optional.  Inside this block one may place one or more 'lateral_offset <distance-value>',
   'altitude <distance-value>', 'target_speed <speed_value>' and 'ground_range <distance_value>' specifications.  Each
   time the keyword 'test' appears, the most recent value of (offset, altitude, speed, range) is saved off as a test
   point, and stored into a test point array.  After the launch computer is initialized, each of these test points will be
   evaluated, and the corresponding interpolated time-of-flight value will be printed to the screen.  The example given
   below saves off three points for testing.

   ::

     interpolation_test
        lateral_offset 4000 m
        altitude       2000 m
        ground_range  10000 m
        target_speed    120 m/s
                test
        ground_range  20000 m
                test
        lateral_offset 2000 m
                test
     end_interpolation_test