An Isro (Indian Space Research Organization) satellite, Saral (Satellite with ARgos and ALtika), embarks the AltiKa altimeter (working in Ka-band, 35 GHz), built by Cnes, as well as a Doris instrument. Signal frequencies in the Ka-band will enable better observation of ice, rain, coastal zones, land masses (forests, etc.), and wave heights.

The Saral mission is an essential component of the altimetry constellation from 2013 onwards, re-occupying the long-term ERS and Envisat ground track. Saral/AltiKa also provides the first demonstration of Ka-band altimeter capabilities for fine resolution along-track applications, including for coastal and inland water applications, which will be further developed for the future Swot mission. Its central objectives are:

  • to carry out precise, repetitive global measurements of sea surface height for:

    • developing operational oceanography;
    • improving understanding of the climate and developing forecasting capabilities;
    • operational meteorology,
    • coastal, inland waters and ice applications.

  • to ensure, in association with Jason-2, the continuity of the ocean observation,
  • to meet the requirements expressed by various international ocean and climate study programmes, and contribute to building a global ocean observing system.

From its launch on February 2013 to July 2016, Saral/AltiKa has a repetitive orbit. Due to technical issues on the reaction wheels from March 2015, CNES and ISRO have decided to pursue this mission with a new phase named “SARAL-DP” for SARAL-Drifting Orbit". From July 2016, and during this drifting phase, the repetitive ground track are no more maintained and with the natural decay of the orbit, the ground track will drift.


Satellite  Saral
Launch on  25/02/2013
End Date 
Altitude  ~800 km
Inclination  98.55°
Repetitivity  35 days
Agency  Isro/Cnes
Goals  Observe the oceans.

Saral, La vigie des océans (video in french). Credits Cnes.

Further information:

Calval Plans

  • Saral/AltiKa Joint Calval Plan (pdf): This is the plan objective for Saral satellite during and beyond the calibration/validation phase, conducted by the two partners Cnes and Isro project teams.