STK SEET can display magnetic-field contour lines for a satellite, missile, or launch vehicle. The contour lines are displayed as field line footprint locations on the ground in the 2D Graphics window, and as field-line maps in the 3D Graphics window.
STK SEET can also display contours of the South Atlantic Anomaly (SAA) in 2D and 3D graphics windows. At low altitudes, the Earth's magnetic field is approximately a tilted dipole pattern. Energetic electrons and protons trapped in this field form the Radiation Belts, also known as the Van Allen Belts. Because the centroid of the magnetic dipole pattern is offset from the Earth's center, a portion of the inner Radiation Belts is closer to the Earth than elsewhere. This is the South Atlantic Anomaly (SAA). The SAA first appears off the South Atlantic coast of Brazil at an altitude of approximately 350 km, with a latitudinal spread of approximately 30o and a longitudinal spread of approximately 60o. The SAA region spreads eastward and westward with increasing altitude until at approximately 1300 km altitude it encircles the Earth completely, with a latitudinal spread of approximately 120o.
The 2D Graphics SEET Environment properties page controls basic display preferences for these line maps and contour displays.
Options for STK SEET Environment - Magnetic Field Contour Line
| Field | Description |
|---|---|
| Show 2D | Show the field contour line passing through the vehicle in the 2D graphics window. |
| Show 3D | Show the field contour line passing through the vehicle in the 3D graphics window. |
| Color | Select the color with which the field contour line will be displayed. |
| Line Style | Set the style of the field contour line. |
| Line Width | Set the width of the field contour line. |
| Show L-shell value label | Check to show the value of the L-shell that identifies field lines (or, particle drift shells). |
Options for STK SEET Environment - South Atlantic Anomaly Contour
| Field | Description |
|---|---|
| Show at Vehicle Altitude | Select to display the SAA contour at the current vehicle altitude. |
| Show at Constant Altitude | Select to display the SAA contour at a specified altitude and then enter the desired altitude. |
| Show 2D | Select to display the SAA contour in the 2D graphics window. |
| Show 3D | Select to display the SAA contour in the 3D graphics window. |
| Fill | Select to fill the area of the contour in the 2D and 3D graphics windows with the color selected for the satellite on the 2D Graphics Attributes properties page. You can adjust the Translucency of the fill using the slider bar or by entering the desired value directly. |
Outside the altitude range of 400 km through 1700 km , the SAA contours will not display.