The Polarization CrossFire (PCF) suite onboard the Chinese GaoFen-5(02) satellite has been sophisticatedly composed by the Particulate Observing Scanning Polarimeter (POSP) and the Directional Polarimetric Camera (DPC). Among them, DPC is a multi-angle sequential measurement polarization imager, while POSP is a cross-track scanning simultaneous polarimeter with corresponding radiometric and polarimetric calibrators, which can theoretically be used for cross comparison and calibration with DPC. After the data preprocessing of these two sensors, we first select local homogeneous cluster scenes by calculating the local variance-to-mean ratio in DPC’s Level 1 product projection grids to reduce the influence of scale differences and geometry misalignment between DPC and POSP. Then, taking the observation results after POSP data quality assurance as the abscissa and taking the DPC observation results under the same wavelength band and geometric conditions as the same ordinate, a two-dimensional radiation/polarization feature space is established. Results show that the normalized top of the atmosphere (TOA) radiances of DPC and POSP processed data at the nadir are linearly correlated. The normalized TOA radiance root mean square errors (RMSEs) look reasonable in all common bands. The DPC and POSP normalized radiance ratios in different viewing zenith angle ranges at different times reveal the temporal drift of the DPC relative radiation response. The RMSEs, mean absolute errors (MAEs), relative errors (REs), and scatter percentage of DPC degree of linear polarization (DoLP) falling within the expected error (EE = ±0.02) of POSP measured DoLP are better than 0.012, 0.009, 0.066, and 91%, respectively.

Photodetector spectral responsivity is usually affected by photosensitive surface temperatures. The Photosensitive Surface Temperatures (PSTs) of the long wavelength-type InGaAs detector used in the Polarized Scanning Atmospheric Corrector (PSAC), which adopts an active Constant-Current Cooling (CCC) scheme, can be changed with ambient temperature. To correct this responsivity temperature characteristic, a Responsivity Temperature Dependence Correction (RTDC) model was established with parameters obtained using an instrument-level experiment. Moreover, a detector-level experiment under ambient conditions was also explored to acquire model parameters. The instrument-level and detector-level experimental results show that the responsivity of a PSAC 2250 nm channel operating on orbit (PST ≈ −65 °C) with a 35 °C PST difference is reduced by approximately 1.2% and 1.5% compared with a laboratory-based radiometric test (PST ≈ −30 °C). The 1.08% responsivity change (−61 °C < PST < −38 °C) in the temperature drift simulation experiment is reduced to approximately 0.38% and 0.34%, respectively. The consistency between the two experimental results preliminarily verifies the substitutability of this detector-level experiment for this type of detector. The RTDC experiments are applicable to other spaceborne remote sensors. The detector-level experiment explored herein provides a reference for realizing RTDC under ambient temperature conditions at low costs.