• CNES (Centre National d'Etudes Spatiales, France)
• NASA (National Aeronautics & Space Administration, USA)
• NOAA (National Oceanic & Atmospheric Admin., USA)

ARGOS has been used to monitor: sea currents snow stations World Weather Watch ships weather balloons river water flow volcano activity movements of animals

Spring Migration of Porcupine Caribou

Some animals which have been tracked by satellite are: polar bears caribou muskoxen elephants camels turtles sharks sea mammals like whales wolves birds like swans and eagles

Satellite Locations of Collared Porcupine Caribou - April 1987 to March 1988

The Satellites:

There are 2 satellites about 850 km (527 miles) above the Earth. Both circle the Earth from the North pole to the South pole 14 times a day. They take just 101 minutes to go completely around the Earth.

Each satellite can "see& an area of Earth over 5,000 km (3,000 miles) wide at once, but since it is travelling so fast, it sees any one collar for only 10 to 14 minutes each time it passes overhead.

The satellite records the signal's location relative to itself then makes sure it knows where itself is, using 11 beacons on earth. It can locate a collar signal to at least 1,000 meters. From a distance of about 850 kilometers, that's pretty good. The information is then sent to one of 3 ground stations in Fairbanks, Alaska, Wallops Island, Virginia, and Lannion, France.