The Argos
 system was developed by NOAA (National Oceanic and Atmospheric Administration),
NASA (National Aeronautics and Space Administration) and CNES (Centre National
d’Etudes Spatiales).The transmitters weigh a few grams
and require little energy, on average 20 to 40 mW. For this, one can use small batteries
(which unfortunately do not last long) or small solar panels. The latter solution was
chosen for Max. The transmitters emit messages that are received by satellites on polar
orbits.
 Those satellites follow a polar orbit at an
altitude of 850 km and can cover the entire globe. At a given moment, each satellite sees
all the transmitters located inside its viewing circle (diameter of 5000 km).
The Argos messages are received, are stored on magnetic recorders
located on the satellite, then are transferred to receiving stations on the ground, which
calculate location, make appropriate calculations, adjust and distribute the data. For
Europe, the receiving station is near Toulouse. |
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