How to get Link Time

Select a new scenario and give it a suitable title and description. Click “OK” for the analysis time that is given.

Insert a default facility and satellite.

Insert a default sensor and assign it to the facility, repeat for the satellite.

Close or minimize the insert window.

In the object browser menu, right click on the icon for the facility and select “properties”. In the new window that appears either, input the coordinates of the facility or left click on the map where the facility should be. Branch menu to the left, select the “description” and give the facility a relevant title and description, in this case: title = University of Strathclyde. Left click “Apply”. Note: to change the name of an object as it appears in the “object browser” you must left click the name of the object you wish to change the name of and then edit it, this is worth doing if you are creating a large scenario and so is good practice to start now, also it makes the tags used in graphs and data tables easier to follow. Also the title used must not contain spaces.

Without closing the properties window, double left click on the “sensor 1” in the object browser window located to the left of the screen. Note: this brings up the properties window for the sensor 1 which is attached to the facility. Again give this a relevant title and description, in this example: title = STAC. Left click “OK”.

Return to the object browser and double left click the “satellite1” icon, give the satellite a title and a description. Left click “basic” and then “orbit”, input the data for the satellite’s orbit, for a basic analysis this is all that is required. If you wish to change the length of time to perform the analysis then untick the box “use scenario analysis period” and input the length of time you would like, leave it as the 24 hour period it gives you for just now. Leave coordinate type as “classical” and “coord system ref” as “ICRF”. Left click “OK”.

Now setup the sensor2 on the satellite in the same way as setting up the facility sensor, give it an appropriate title and description.

In the “2D graphics” window , the facility and satellite should both have different coloured outlines surrounding them.

In the top menu bar, left click “analysis” and then left click “access”. The “access” window will now have appeared. In the top row, the title “access for:” field will be filled with a default object from your scenario, it might be the satellite or the facility, this is the object that you are providing an access for. In the “Object Browser” click on the sensor attached to the facility and then ctrl click on the sensor attached to the satellite, the result of this is that the two sensors will be highlighted. In the “Associated objects” window the other objects in the scenario are shown. Click on the [+] box to open the branch menu and select the sensor of that object, whether it is the satellite or the facility. With the sensor selected, click “compute”. Now click the “select object” button and select the object that was not being worked on (ie. If satellite was in the “Access for:” field then select the facility now, and vice versa). Select the sensor on the new object in the “Associated objects” window and select the sensor of that object, click “compute”, ensure that the “compute” button is now unpressable (ie. click it till you can’t!). In the bottom left of the screen there will be tabs with the titles of the windows you have not closed, select the “2D graphics” tab. On the map there should be a thin line that plots the orbit of the satellite and any location on this plot that the satellite is able to be seen by the facility will be lined in heavily, also as the satellite passes over this region a straight line will connect the satellite to the facility. In the menu toolbar of STK there are “player” buttons that control the animation of the simulation, click the green play arrow. Notice the satellite will follow the orbit path along the screen, if it is an orbit with eccentricity then the distance from the Earth will be shown by the satellite moving slower and then faster the closer to Earth it is. As the satellite covers the part of it’s orbit that it can communicate with the facility at, a coloured straight line will join the two. Notice that the satellite will make a number of passes and then disappear, this is because of the length of time set as the analysis window. To change it, return to the properties of the satellite and edit the option for the analysis time length.

Click on the tab marked “access”, if you have closed this window then re-open it by selecting “analysis” from the toolbar and then selecting “access”. To the right of the “Associated objects” window there are two headings of buttons, “Reports” and “Graphs”, left click on “access” in the Reports section. This will bring up a log table witht the data of the analysis you have performed. It can be saved as a notepad file. “AER” provides the ‘azimuth’, ‘elevation’ and ‘range’ of the orbit at particular times, this is a detailed log and should be saved, it provides the min and max for the orbit conditions given to it.