# Ground Speed

Ground speed is the term used to measure the horizontal speed of an aircraft relative to the ground. To help put this term into perspective, imagine a group jet charter heading vertically towards the sun. This aircraft would have a ground speed of zero.

## Calculating the Ground Speed

The ground speed of an aircraft can be determined by the vector sum of the aircraft’s airspeed and the current wind conditions. The current wind speed and direction include:

• Tailwind
• Crosswind

The ground speed of a group jet charter also takes into account the air mass, which may be moving over the ground due to wind. An airspeed indicator can determine that aircraft’s speed relative to the air mass. When the air mass is in motion, there are other tools are required to calculate the ground speed. Examples include:

• Navigation using landmarks
• Radio-aided position location
• Inertial navigation system
• GPS
• E6B flight computer
• Ground speed radar

## Airspeed vs. Ground Speed

Airspeed and ground speed have two separate definitions. On a windy day, for example, an aircraft may have a higher airspeed than ground speed. The information passengers typically receive through the private jet charter entertainment system provides the aircraft’s ground speed rather than their airspeed.