Visual SAT-Flare Tracker 3D

1.0 SATELLITE SURFACE MODELLING - WINDOW
 
This window allows the user to model the satellite's surfaces by means of specifically oriented mirrors. The windows is composed by several frames and a set of Design Draw Options (at the right side) as shown in the following picture:

Image
Fig. 1
 
The window contains the following frames:
1.1 WORKING SATELLITE - Frame
 
This frame reports the working satellite, which is the satellite whose surfaces are being modelled. The working satellite can be selected by means of the Satellite window, which can be opened also by means of the Select Satellites button at the bottom centre of the window.

1.2 SATELLITE ORIENTATION - Frame
 
Operative satellites usually employ attitude control systems to keep themselves correctly oriented, depending on their duty. As an example, the IRIDIUM satellites are kept oriented with the Z axis vertically (along the Earth centre) and with the X axis along the orbit direction. However, other orientations may be more convenient for other kind of satellites. Old orbiting satellites or out-of-service satellities may be, however, without any working attitude control and their orientation no more controlled.
In order to take advantage of the satellite geometry to predict light reflections, it is necessary to know exactly how the satellity is oriented. This program version supports the following satellite orientations (which can be selected by means of this frame):
1.2.1 Vertical, Along Track - Orientation

This option keeps the satellite's Z axis along the Earth centre, and the X axis along the orbit (see note 1). Many LEO satellites uses this kind of orientation.

1.2.2 Vertical, Along a Target - Orientation

Not documented.

1.2.3 V-SUN - Orientation

This option keeps the satellite's Z axis along the Earth centre and the X axis toward the Sun (see note 1). This kind of orientation may be useful to model mobile structures that are oriented toward the Sun, such as the solar panels, rather than the satellite's main body.

1.2.3 Rotating - Orientation

This option allows the program to deal with satellites without attitude controls and that are fast rotating around a fixed axis. Since the satellite is fast rotating (rotation period in the order of a few seconds or less), the knowledge of the rotation angle at a given time is not really important for a visual observer, who can though observe a whole rotation in just a few seconds. In this case, the knowledge of the rotation axis is enough to compute the Earth locations where reflections are visible.
The direction of the rotation axis can be entered manually or can be determined automatically if at least three reflections have been observed coming from the same reflective surface. Please see this section to know more details about the model of fast rotating satellites.


1.2.3 None - Orientation

This option allows the program to deal with satellites without attitude control that are not rotating considerably within the period of investigation. According to this mode, the satellite orientation is kept fixed with respect to the stars, and this means that the direction of its surfeces is fixed as well. This allows the surface direction to be expressed directly by means of the Right Ascension and Declination of the celestial point toward which the surface normal is pointing.

Note 1. Only the Z-axis is oriented along the assigned direction, while the second axis is rotated close as much as possible to the second target vector (in the right Z-X plane). Both the axes can not be oriented toward their assigned directions if these ones are not perpendicular each other.

1.3 SATELLITE SURFACES - Frame
 
This frame allows the user to manage all the defined surfaces and to add new ones. The frame consists of a main list, where all the existing surfaces are listed, and of the following buttons:

1.4 SURFACE PARAMETERS - Frame
 
This frame contains the data fields necessary to set the surface parameters of the selected surface. These fields are:
1.4.1 Surface Orientation

The orientation of a satellite's surface is specified by giving the direction of its normal vector. Such normal can be defined by means of two different coordinate systems, depending on the satellite orientation mode:

1.5 MIRROR TRIMMING - Frame
 
This frame contains three sliders that can be used to graphically adjust the surface angles. As soon as one of these slider is moved, the new configuration is employed to update the graphical Main Window. The first two sliders can be used to adjust respectively the Angle / RA angle and the Titl / DEC angle. The third slider, instead, can be used with fast rotating satellites to see where the reflected ray impacts the Earth surface by rotating the satellite around its rotation axis by a given angle. To make this slider active, it is necessary to check the Sel option at its top.

1.6 SELECTED SATELLITE ACTIONS - Frame
 
This frame contains a few functions that will be performed only on the selected satellites. Please see the Satellite Window to learn how to select satellites. These functions are:

1.7 DESIGN DRAW OPTIONS - Column
 
This column contains some additional options that can be useful to support the modelling of fast rotating satellites:
1.8 BUTTONS
 
The window contain the following buttons:
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By Simone Corbellini