R&S SMW-K44 User Manual page 57

Satellite Navigation
Table 8-3: Impact of the Earth Obscuration References on the visible satellites
"Earth Obscuration References > Local Horizon"
"Local Horizon"
"Earth Tangent"
Remote command:
[:SOURce<hw>]:BB:GNSS:SV:SELection:EOBScuration:REFerence
on page 254
Earth Obscuration Offset ← SV Selection Criteria
Sets the satellite's elevation mask angle. The angle is applied relative to the selected
horizon, see
Satellites that are below the elevation mask angle are obscured. They are invisible for
the GNSS receiver at the selected location.
Obscured satellites are displayed in the "Signal Monitor" view but not simulated. A test
receiver cannot use obscured satellites for determining its position; it has to search for
satellites with better visibility.
See, for example, the figures in
User Manual 1178.6379.02 ─ 01
"Earth Obscuration References > Earth Tangent"
The horizon is a horizontal plane that is perpendicular to the nadir.
For locations with attitudes above the sea level, the horizontal plane
is parallel shifted at the selected attitude.
The "Local Horizon" type is suitable, if you simulate receivers located
at low altitude. For example, for pedestrian and automotive applica-
tion.
The horizon is the surface of a right circular cone, where:
●
The vertex of the cone is at the receiver position.
●
The cone axis is along the nadir.
●
The cone surface is made of lines that are tangential to the earth
surface.
The "Earth Tangent" type is suitable, if you simulate receivers located
at higher altitude, where satellites with negative elevations are also
visible. A typical example is a GNSS receiver mounted on low earth
orbit (LEO) object.
Earth Obscuration References.
Table
Satellite's Constellation
8-3.
Satellites Settings
57