April 3, 2015

In-flight Commissioning

MEGHA-TROPIQUES satellite was successfully launched on October 12, 2011.

The CNES, prime contractor for the development of SAPHIR and SCARAB instruments, responsible with ISRO of MADRAS instrument development, has conducted, together with ISRO, the first operations after switch on , on the instruments.

Since launch, CNES is receiving at the CNES expertise center, the instruments raw data and is performing the monitoring of the technological parameters for its contribution.

The CNES has realized the in-flight commissioning for the 3 instruments SAPHIR, SCARAB and MADRAS. These in-flight commissioning tasks were organised in two phases:

Phase 1: Functional tests after turning on the instruments

MADRAS, SAPHIR and GPS-ROSA instruments have been powered on immediately after launch, on October 13th, 2011.
In order to prevent from eventual out-gazing problems, SCARAB instrument was put in stand by mode from October 13th to November 3rd, then switched to nominal functioning mode on November 4th.

All SAPHIR instrument modes have been tested and several calibrations were realized during the first days in orbit.
All SCARAB instrument modes have been tested and several calibrations were realised during the first days of nominal operation. Now, monthly calibrations are performed on this instrument in order to verify the gain stability.

All the parameters tunings defined for MADRAS instrument have been performed between October 13th and November 4th, 2011.

Finally, All functional verifications of all the instruments took place during this phase which ended in January 2012.

Phase 2: Commissioning of the instruments performances and calibration

During this second phase, the following activities should take place:

  • Characterization of the in-flight performances of the instruments.
  • Characterization of the geometrical performances and adaptation of the processing parameters.
  • Characterization of the radiometric performances and adaptation of the processing parameters.
  • For SAPHIR and MADRAS, comparison with other sensors.
  • For SAPHIR and MADRAS, comparison with simulated data.

The results of these studies performed by CNES are made available:

SCA_RAD_01Noise performances
SCA_RAD_02Thermal leak correction
SCA_RAD_03Scarab Gain  
SCA_RAD_04Thermal gain sensitivity
SCA_RAD_05AP factor  
SCA_GEO_06Absolute pointing location
SCA_RAD_08Level A1/A2 comparison
SCA_RAD_09Spectral response
SCA_RAD_09Spectral response synthesis
SCA_RAD_10Scarab Thermal performances
SCA_RAD_11Scarab equation
SCA_RAD_12Scarab G1 G2 ratio  
SAP_RAD_01Radiometric sensitivity
SAP_RAD_02SAPHIR radiometric gain
SAP_RAD_03SAPHIR: dependence to pass type
SAP_RAD_04Comparison with MHS: First results
SAP_RAD_05Cold sky calibration
SAP_RAD_06OBCT in orbit behaviour
SAP_RAD_07Brightness temperature distribution
SAP_RAD_08Absolute pointing location
SAP_RAD_09Sidelobe correction
MAD_RAD_01Calibration windows
MAD_RAD_02Radiometric sensitivity
MAD_RAD_03MARFEQ thermal performances

Calibration status presented during the French-Indian Workshop in December 2012

Phase 3: In orbit monitoring

    SAPHIR long term monitoring