English: Every 10 days, Jason-1 measures the height of more than 90% of the world's ice-free ocean with its radar altimeter and completes 127 revolutions, or orbits, around Earth.

To measure sea surface height it is necessary to know satellite's exact position in its orbit and the distance between the satellite and the ocean's surface. Corrections are made for variable amounts of water vapor in the lower atmosphere and free electrons in the upper atmosphere, which can delay the altimeter's microwave pulses.

The sea height caused by gravity (the geoid) is mathematically removed in order to create maps of ocean surface topography.