Polarized scanning atmospheric corrector (PSAC) onboard the HuanjingJianzai-2 (HJ-2) A/B satellites is a cross-track scanning polarimetric remote sensor that measures the intensity and direction of light reflected by the Earth and its atmosphere by nine full polarized spectral bands from near-ultraviolet (near-UV) to shortwave infrared (SWIR). In particular, geolocation accuracy is an important factor for polarization observations. An automatic coastline inflection method (CIM) is implemented for PSAC geolocation error estimation. Over five months of globally middle or low latitude coastline area measurements are used to obtain statistical result. The results of the comparison with the Global Self-Consistent, Hierarchical, High-Resolution Geography (GSHHG) Database show that the PSAC geolocation error is smaller than 0.38 ground sample distance (GSD) or 3.25 km in 95% confidence level. In cross-track direction, the geolocation error estimation is affected by the instrument sampling characteristics, such as spatial response function (SRF). Thus, the correction method is proposed by establishing relationship between measurement radiance in CIM and offset proportion of PSAC GSD. The biases are obviously reduced after correction.

中文翻译：

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环境二号A/B星载宽幅偏振扫描大气校正器定位误差估计方法


环境箭在二号（HJ-2）A/B卫星上搭载的偏振扫描大气校正器（PSAC）是一种跨轨扫描偏振遥感器，通过九个全偏振光谱测量地球及其大气反射的光的强度和方向。波段从近紫外（near-UV）到短波红外（SWIR）。特别是，地理定位精度是偏振观测的一个重要因素。自动海岸线拐点方法 (CIM) 被用于 PSAC 地理定位误差估计。通过五个多月的全球中低纬度海岸线面积测量得出统计结果。与全球自洽分层高分辨率地理（GSHHG）数据库的比对结果表明，PSAC地理定位误差在95%置信度下小于0.38地面采样距离（GSD）或3.25 km。在跨航迹方向上，地理定位误差估计受到仪器采样特性的影响，例如空间响应函数（SRF）。因此，通过建立CIM测量辐射亮度与PSAC GSD偏移比例之间的关系，提出了校正方法。修正后偏差明显减小。