Argos is a satellite based communication system that can track the route of a fishing vessel, large migrations of birds and other animals, or can monitor environmental sensor data (atmospheric pressure, sea temperature, animal heart rates) from animals or devices equipped with an Argos tag. These tags are lightweight RF radio systems equipped with multiple sensors (e.g. depth, temperature and light) and they will be mounted on wildlife as to register the trail of the migrating animals. This pattern combined with the sensor's logged measurements will allow scientists to investigate what drives the migration of these animals. What makes Argos unique is the ability to locate the animal anywhere on Earth utilizing the Doppler effect.