This option is enabled when the RCS Type has been set to Bistatic. It allows the user to set a series of observation points that will be used later when inspecting the Near Field. In the following sections inside this chapter they will be covered.
When the menu item is selected, the following panel appears:
Observation Points panel
The user can add new geometry types by selecting the correct option presented in the Geometry Types list and pressing Add. Note that these geometries are just considered as "geometries" inside this panel to make it easier to manage them. When they are added to a project, the simulation will consider every point in the geometry mesh as an actual observation point. The behaviour for each kind of geometry type will be described later.
The Observation points list displays a list with every geometry added as an observation point. By default, every point and geometry added to the project is displayed in the Geometry view. This behaviour can be changed by checking or unchecking the Hide observation points checkbox item. Buttons near the list are used to modify and delete these observation points.
Edit: use this button to modify the data for a geometry using a panel similar to the one that appears when Add is pressed.
Delete: use this button to delete a previously added geometry from the observation points list.
Delete All: use this button to delete every previously added observation point. Note that this will delete everything.
Export as text: use this button to export the list of points in the selected geometry. The exported file is a text file with the X, Y, Z components for every point in CSV format.
Export file: use this button to export the current observation points as an OBS (Observation Points) File. It will be possible to import an OBS file using the Import file in other MONCROS project or in other modules that also make use of Observation Points.
It is also possible to view the list of observation points that form a geometry by selecting the geometry item from the list and pressing View. A new panel listing every point in the geometry will appear.
A cylinder requires a valid name, coordinates for the base cylinder (Base Center), its radius (Radius) and the height and angle coordinates. For the Height Coordinates, the Height and the Number of points must be specified. For the Angle Coordinates, the user must introduce whether a complete or an incomplete cylinder is to be generated by specifying the Initial angle and Final angle parameters. It is also possible to change the Number of points.
New Cylinder parameters
The user can also export the near field points to a text file (Export as text). This file can then be imported by selecting “External File” into the Geometry Types combo-box. Note that this option imports a file of points, but does not preserve the near field type (i.e. it is imported as a separate type). In order to preserve the near field type, the Export file and Import file must be used instead.
Open External File dialog
This option lets you select a line or curve of the main panel and sample it as observation points. The user has to previously select a NURBS Curve. Using the given NURBS curve the number of points to be added is a parameter.
Adding a nurbs curve of observation points
Using this option it is possible to create observation points using a surface as a reference. To create one of these geometries, a NURBS Surface has to be previously selected. This operation is usually done by selecting a previously created surface in the project, or exploding an object to select the desired surface. Then, a new geometry type is added. The number of points in U-Dimension and V-Dimension are parameters for this kind of geometry.
Adding an observation point From Surface
A line is created using the initial and final point as endpoints for the line. As a parameter, the number of points will have to be introduced. The line will be split in as many points as introduced here and every point will be considered as an observation point.
New Line parameters
To configure the parallelogram, the user can introduce the coordinates of the three points that shape the final figure. Furthermore, the number of points between vertices can be introduced (i.e. Number of points from p1 to p2).
New Parallelogram parameters
In this window, the user can create a set of observation points laid out in a grid pattern. To do so, the user needs to specify several parameters:
Name: A short name that will be used by the user to identify the created set of observation points.
Constant axis: The normal axis of the plane that will contain the grid of observation points.
Coordinate value: Value of the coordinate of the axis specified in the previous option.
For each of the axes different than the one selected in the Constant axis drop-down list, the user needs to specify the following parameters:
Initial value: Initial value of the coordinate along each axis.
Total size: The total length of the grid of observation points along the axis.
Number of points: The number of observation points along the axis.
Note: The spacing between each pair of consecutive observation points along an axis will be given by the formula spacing = (total size) / (number of points - 1). This value will be shown next to the label "Distance btw. points".
New Plane parameters
The user can introduce the coordinates of the new point.
New Point parameters
In order to build spheres, introduce the Center Point of the initial sphere. For the radius controls, the user can set the radius for the initial sphere using Initial radius. It is possible to create more than one sphere using the Radius samples. In that case, the radius increment between two consecutive spheres is controlled via Increment radius. Theta coordinates and phi coordinates let the user specify how many points to create from the sphere and whether to use the entire sphere curvature or just a slice of the sphere.
New Sphere parameters