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H2G2 The Earths Atmosphere

H2G2 The Earths Atmosphere

The Earth’s atmosphere is the layer of gases that surrounds the Earth; that does not dissipate due to the action of gravity; and that, seen from space, shows our planet as a sphere of bright blue color. It is important because it protects us from the dangerous...
Satellites

Satellites

Columnist Marcelo Santos talks about the benefits expected from the insertion of the L5 signal in the global positioning system Part of the modernization process of the Global Positioning System involves changing the structure of the signals transmitted by the...
Signals Runtime

Signals Runtime

We all remember the controversies surrounding the giant waves of Nazaré. Since 2011, the Australian surfer Garret McNamara broke a world record when surfing in a 30-meter-high body of water, which, with each new attempt, questions the validity of the measurements of...

Control Segment (Monitor Stations)

The GPS-System is controlled by the United States Air Force. The “master control station” (Schriever AFB) and four additional monitoring stations (on Hawaii, Ascension Islands, Diego Garcia and Kawajalein) were set up for monitoring the satellites.During August and...

GPS Satellite Orbits

Orbits of the GPS-Satellites (distances are to scale) The satellites orbit the earth with a speed of 3.9 km per second and have a circulation time of 12 h sidereal time, corresponding to 11 h 58 min earth time. This means that the same satellite reaches a certain...

Position Determination with GPS

In a considerably simplified approach, each satellite is sending out signals with the following content: I am satellite X, my position is Y and this information was sent at time Z. In addition to its own position, each satellite sends data about the position of other...