Hi @Narcano

Welcome to the Orekit forum!

The problem is that you are assuming that the spacecraftâ€™s position is given in topocentric frame. However, I donâ€™t think that you used `TopocentricFrame`

as the reference frame of the spacecraftâ€™s orbit. I would recommend you to directly use `s.getFrame()`

when defining the spacecraft frame in `getElevation()`

method. Indeed, the `frame`

argument of this method is the frame in which the position is defined. So, by using `s.getFrame()`

you are at 100% sure to have the good one.

You can therefore easily calculate the elevation and azimuth angles of the spacecraft from the topocentric frame using:

```
// compute elevation
final double elevation = FastMath.toDegrees(c.getElevation(s.getPVCoordinates().getPosition(), s.getFrame(), s.getDate()));
// compute azimuth
final double azimuth = FastMath.toDegrees(c.getAzimuth(s.getPVCoordinates().getPosition(), s.getFrame(), s.getDate()));
```

In addition, to have the distance of the satellite from your station the easiest solution in your situation (i.e., with a topocentric frame and a spacecraft state) is to use `c.getRange()`

. Please find an example below

```
// compute range
final double range = c.getRange(s.getPVCoordinates().getPosition(), s.getFrame(), s.getDate());
```

I hope these comments will help you.

Best regards,

Bryan

.