WSF_DISTANCE_STEPPED_GRID

grid WSF_DISTANCE_STEPPED_GRID
grid <name> WSF_DISTANCE_STEPPED_GRID
   ... Common Grid Commands ...
   size ...
   step_distance ...
   origin_index ...
   altitude ...
   origin ...
   asset ...
end_grid

Overview

The WSF_DISTANCE_STEPPED_GRID is a coverage grid that contains points that are separated by a given distance. The grid will form a user specified number of rows each of which is at a certain latitude, and is a user specified distance from adjacent rows. Each row will contain a user specified number of points, each of which is separated from its neighbors in the row by a user specified distance. All of the grid points will be at the same user specified altitude.

Common Grid Commands

grid_data_file <file-name>

Specify the name of an output file that will be created containing details of the points in this grid. The specified file is created at the end of the simulation.

central_body … end_central_body
central_body <central-body-type>
   polar_offset_angles
end_central_body

Specify the central body and related ellipsoid model to be used by simulation platforms. Options for <central body type> are the following:

  • earth_wgs72 (Earth World Geodetic System 1972): The central body ellipsoid is defined according to the WGS-72 standard.

  • earth_wgs84 (Earth World Geodetic System 1984): The central body ellipsoid is defined according to the WGS-84 standard.

  • earth_egm96 (Earth Gravity Model 1996): The central body ellipsoid is defined according to the EGM-96 standard.

  • moon: The central body ellipsoid is defined according to published lunar parameters.

  • sun: The central body ellipsoid is defined according to published solar parameters.

  • jupiter: The central body ellipsoid is defined according to published Jovian parameters.

Default earth_wgs84

polar_offset_angles <angle-value> <angle-value>

Specify the central_body’s polar offset angles (x_p and y_p, respectively) of the Celestial Intermediate Pole (CIP) with respect to the WCS (ITRS) coordinate system. Providing these values (of the order of tenths of arc-seconds) enables very highly accurate conversions between ECI and WCS coordinates.

Default 0.0 rad 0.0 rad

Note

WCS->LLA conversions are affected by central body choice, as well as sidereal motion transforms calculated in inertial (ECI) coordinate conversions.

suppress_grid_platforms <boolean-value>

This command allows for the suppression of grid asset platforms in DIS output and in distributed simulations. This suppression only applies for platforms created by a grid. This suppression is enabled by default.

Commands

size <integer> <integer>

Set the size of the grid. The first value gives the number of rows in the grid. The second value gives the number of points in each row. The resulting number of grid points will be the product of the two provided values.

step_distance <length-value> <length-value>

Specify the distance between adjacent grid points. The first value gives the separation distance between one row and the next. The second value gives the separation distance between points in the same row.

origin_index <integer> <integer>

Specify the position in the grid that is at the location given by the origin command. These values start from 0 and count from the south west corner. For example:

origin_index 0 0

would be the southwest corner, and for a grid with 4 rows and 5 points per row,

origin_index 3 4

would be the northeast corner.

origin <latitude-value> <longitude-value>

Set the origin point in the grid, the point from which the other rows and members in each row are spaced. There will be one row in the grid at the given latitude, and there will be one point in each row of the grid at the given longitude.

altitude <length-value> <altitude-reference>

Set the altitude of the grid points. <altitude-reference> can be either ‘msl’, in which case the altitude refers to a height above the mean sea level, or ‘agl’, in which case the altitude refers to a height above the ground level set by any terrain in the scenario.

asset <platform-type> <device-name>

Specify the assets associated with this grid will be instances of <platform-type> and will use the device with the name <device-name>. The given <device-name> may also be ‘none’ if the grid points are passive targets for the coverage computation in question.