Argos is a satellite-based system which collects, processes and disseminates environmental data from fixed and mobile platforms worldwide.
The system was born in 1978 under a Memorandum of Understanding (MOU) between the French Space Agency (CNES), the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA), originally as a scientific tool for collecting and relaying meteorologic and oceanographic data from around the world. Many remote automatic weather stations report via Argos and the system is a key component of many global research programs.
Since the late 1980s Argos transmitters have routinely been deployed on a large number of marine mammals and sea turtles and continues to serve as the most important tool for tracking long distance movements of both coastal and oceanic species.
Transmitters are programmed to send signals at periodic intervals to two ARGOS satellites flying on polar orbits 850 km above the earth. Both are circling the planet fourteen times a day. They pick up the signals and store them on-board and relay them in real-time back to earth. More than 40 L band antennas located at all points of the globe collect the data from satellites. Data are either received in real-time by a regional antenna in the path of the satellite or stored on-board and relayed to the nearest global antennas. There are three main receiving stations in Wallops Island and Fairbanks in the United States and Svalbard in Norway and two global processing centers, one located just outside of Toulouse in Southwestern France, and the other near Washington DC, in the USA.
The system was during many years a key element in all the long duration balloon flights performed by the CNES balloon group, specially in the overseas launch campaigns. When the balloon was in visibility of one of the satellites that carried the system, the ARGOS beacon allowed the transmission of scientific data and housekeeping information at a rate of 400 bits per second. Also, the successive locations of the system allowed to track the route of the balloons in flight.