The Level-0 CAL product is outputted during Level-0 processing and is an internal product only. It is not available to users and is considered only as an input to Level-1 CAL processing.

There are two types of Level-0 CAL products depending on the calibration modes: CAL1 products and CAL2 products. CAL1 mode measures the internal delay of the SRAL instrument through measuring the impulse response. CAL2 mode measures the gain of the receive chain.

A SRAL L0 product contains the following calibration parameters:

• L0_CAL1_LRM_IQ: L0 CAL1 using Point Target Response (PTR) calibration measurements in LRM mode for I,Q configuration

• L0_CAL1_SAR: L0 CAL1 using PTR calibration measurements in SAR mode

• L0_CAL2_SAR: L0 CAL2 using Gain Profile Range Window calibration measurements in SAR mode

• L0_CAL1_LRM_I2Q2: L0 CAL1 using Point Target Response (PTR) calibration measurements in LRM mode for I2+Q2

The three first calibration parameters (L0_CAL1_LRM_IQ, L0_CAL1_SAR and L0_CAL2_SAR) are used as input to the Level-1 processing. The last one ( L0_CAL1_LRM_I2Q2) is not used as input to level-1 processing, it is only a "support" calibration parameter.

See Calibration page for further information.