Sea-level rise is a key indicator of climate change and accurately monitoring it is essential for climate science, policy-making, and protecting low-lying regions at risk. Satellite remote sensing has become an efficient tool for surveying sea level change at global and regional scales. TOPEX/Poseidon, a series of modern high-precision ocean altimeter satellites marks the beginning of the satellite altimeter era. Presently, Jason-CS/Sentinel-6 is the new advanced generation of high-precision altimeters. The application of satellite altimetry can be used to measure sea surface topography with high accuracy and reliability and further to support ocean forecasting systems, environmental monitoring and climate monitoring. The Jason-CS/Sentinel-6 satellites will extend the satellite data record through at least 2030, providing a nearly 40-year record of sea-level data.