Satellite Toolbox" elevation angles between an aircraft and satellite constellation always negative

I'm using satellite toolbox to simulate communication links between an aircraft and a satellite constellation. I used the AER function to calculate the elvation angle but it is always a negative value, is there any reason behind that even if the satellite is not yet reached the horizon?

[Abhishek]

Hi @Reham Wafaee, as per the documentation, the aer function provides the azimuth angle, elevation angle, and range of one asset to another. A negative elevation angle typically indicates that the satellite is below the horizon from the perspective of the ground station at the given time. This can occur if the satellite has not yet risen above the horizon or has already set.

To better understand how the elevation angle changes over the entire simulation period, you can plot the elevation angle against time using plot(time, el). This will help you visualize the satellite's trajectory relative to the horizon and identify when it becomes visible to the ground station.