Geosynchronous
orbit.

Geosynchronous and Geostationary
Orbit
A geosynchronous orbit may be defined as one with an orbital
period (the time needed to orbit once around the Earth) that matches
the rotation rate of the Earth. This is a sidereal day, which
is 23 hours 56 minutes and 4 seconds in length, and represents the
time taken for the Earth to rotate once about its polar axis relative
to a distant fixed point. This is about four minutes shorter than
the common day length of 24 hours, which is relative to the sun.
A geostationary orbit is a special case of a geosynchronous
orbit. A satellite is in a geostationary orbit when it appears stationary
from the point of view of an observer on the Earth's surface. This
can only occur when:
Thus, a geosynchronous satellite will be geostationary only with
the additional restrictions of it being in a circular orbit situated
over the equator.
The following parameters are always true for any geostationary
satellite:
Parameter

Value

Height above equator

35,785 km (22,236 miles)

Orbit radius

42,155 km (26,194 miles)

Orbit circumference

264,869 km (164,582 miles)

Arc length per degree

736 km (457 miles)

Orbital velocity

11,066 km/hr= 3.07 km/sec (6,876 miles/hr)

Source: Eumetstat 