1. Beate Klinger, and Torsten Mayer-Gürr, “The role of accelerometer data calibration within GRACE gravity field recovery: Results from ITSG-Grace2016”, Advances in Space Research, vol. 58, Nov. 2016, pp. 1597–1609.

It should be noted that our calibration approach aims at removing effects of instrument imperfections (cf. Sections 4.2 and 4.3) on the gravity field recovery. Hence, the used calibration equation does not guarantee to model these imperfections (e.g. temperature-induced bias drifts, misalignment) in a physical correct way, and will probably also absorb other not-modeled effects.

In this paper we only show results for GRACE-A, as very similar results have been obtained for GRACE-B. 【间接说明两颗星是独立做的calibration】

(p.1058) This is the only link between what the instrument actually measures (e.g., radiance, in the form of digital counts) and what one wants to measure (e.g., radiance). (p.1058) Conversion to at-sensor spectral radiance and/or top-of-atmosphere (TOA) reflectance is the fundamental steps to compare products from different sensors.

Calibration 的分类

See TanDEM-X at eoportal

  • Internal calibration
  • Geometric calibration
  • Antenna pointing
  • Antenna model verification
  • Radiometric calibration
    • see here: Radiometric Calibration and Corrections
      • “Radiometric correction is done to calibrate the pixel values and/ correct for errors in the values. The process improves the interpretability and quality of remote sensed data. Radiometric calibration and corrections are particularly important when comparing multiple data sets over a period of time.”
      • “The value recorded for a given pixel includes not only the reflected or emitted radiation from the surface, but also the radiation scattered and emitted by the atmosphere. In most cases we are interested in only the actual surface values. To achieve these values, radiometric calibration and correction processes must be applied.”