The WEOS System is composed of three segments, namely, space, ocean, and ground. The space segment consists of a 50 kg satellite placed in an 800 km polar orbit, with its attitude is stabilized by means of gravity gradient torque to keep the antennas for communications facing the earth surface. 

The ocean segment is composed of several probes attached to whales living in many oceanic regions. In each probe a GPS receiver is installed as the position sensor. In addition underwater sensors for pressure, temperature, geomagnetic field, and sound are mounted and their data stored. When a whale surfaces the data is sent in 400MHz telemetry to the satellite together with an identification code and the position data of the GPS receiver. The electric power necessary for the electronics of the probe will be generated by utilizing the motion of the whale in the sea.

Chiba Institute of Technology is responsible for designing, building and operating WEOS.