☁️Sky Map

The Sky Visibility Map provides a historical representation of the visibility of the GNSS satellites of a given reference station across the sky in the previous 24 hours.

The Sky Visibility Map color coding indicates how good the satellite observation is within a given sky sector. Shades of green indicate a reasonably good / ideal visibility, shades of yellow indicate less optimal visibility and shades of red indicate sub optimal visibility, which can indicate sky obstructions caused by buildings, trees, mountains, etc. in the vicinity.

Plain white sectors are areas where no satellites were observed nor expected at all. It is normal to have an area in the sky where no satellite signals are received. That area is called polar hole and it exists because GNSS orbits do not cover Earth's poles, leaving a blank area in the Northern part of the sky in the northern Earth hemisphere or a blank area in the southern part of the sky in the southern Earth hemisphere.

The visibility is calculated based on how many satellites were visible in a given sector vs. how many satellites were expected to be visible in that sector (i.e. when a satellite is known to be there but the station did not observe it).

The map is split into 149 sectors which are spread across 9 elevation ranges from horizon (0°) to zenith (+90°) and can help to identify areas where the sky is obstructed.

Here's an example of a station with good visibility. The only bad visibility is in low elevations of the Southeast for a patch of the sky where a building obstructs the sky. Note that the white areas in the north region are expected for stations on the northern hemisphere.

Station has good visibility all over except for a patch in the SE, at lower elevation where a building is known to be blocking the sky.

On the other hand, here is an example of a station placed on a window sill. Half the sky is completely blocked by the building where the antenna is located while the other half has somewhat acceptable reception (with low elevation satellite tracking being bad across the whole horizon):

Station placed on a window sill showing bad sky visibility.

With the help of the sky map, you can identify obstructions at your antenna location. If possible, you can then improve the satellite signal reception by changing the environment.