There are five altimetry satellites currently in service:

• Two satellites - Jason-1 and Jason-2- with a relatively short repeat cycle (10 days), able to observe the same spot on the ocean frequently but with relatively widely-spaced ground tracks (315 kilometres at the equator). Currently, Jason-2 is located on the former orbit of Topex/Poseidon (before 2002) and Jason-1 (before February 2009). The Jason-1's orbit is shifted midway between its original ground tracks (corresponding to those of Topex/Poseidon after 2002). Jason-1 and OSTM/Jason-2 also have a time lag of 5 days.
• One satellite, Saral,  on a 35-day repeat cycle, on the same ground-track as ERS-1&2 and Envisat (during its repetitive orbit, before 2010/10); it is complentary to Jason-2 ground tracks.
• One satellite - Cryosat-2 - with an altimeter (Siral) ables to work with an interferometric mode, with a high orbit  inclination of 92° to satisfy the scientific requirements for observing the poles and the ice sheets, and with an orbit non-sun-synchronous (commonly used for remote-sensing satellites).
• And HY-2A, with a 14-day orbit.