Instruments

The Saral mission inludes two payloads : AltiKa and Argos. The AltiKa payload integrates a high-resolution single frequency AltiKa altimeter (Ka-band) that includes a dual frequency radiometer function shared on a common antenna and two locations systems (LRA, Doris).

Saral instruments (AltiKa payload highlighted in red). Credits Isro.
  • AltiKa, a Ka-band altimeter

    The altimeter named AltiKa onboard Saral uses a single frequency in Ka-band. It is the first oceanographic altimeter using such a high frequency. It is much less affected by the ionosphere than one operating at Ku-band, and has greater performance in terms of vertical resolution, time decorrelation of echoes, spatial resolution and range noise. But its main drawback is that Ka-band electromagnetic waves are sensitive to rain.

  • AltiKa, a dual frequency radiometer

    The radiometer onboard Saral is included in the AltiKa instrument since it shares the same antenna. It operates in dual-frequency (23.8 and 37 GHz) to correct altimetry measurements from wet troposphere crossing effects.

  • Doris

    The Doris system uses a ground network of beacons, which send signals to a receiver on Saral. These data are used to keep permanent track of the satellite's precise position on its orbit. With the Diode software, the very precise real-time location and velocity of the satellite are directly computed on-board.

  • LRA

    The LRA is an array of mirrors that provide a target for laser tracking measurements from the ground. By analyzing the round-trip time of the laser beam, we can locate where the satellite is on its orbit.