标题： 荣沃伊任务中偏振GNSS-R传感器的校准 显示英文标题

标题： Calibration of the Polarimetric GNSS-R Sensor in the Rongowai Mission

摘要： 偏振GNSS-R系统配备了一个额外的极化通道，能够增强分离植被和地表散射效应的能力，从而提高GNSS-R陆地遥感应用，如植被和森林区域的土壤湿度反演和生物量估算。然而，这些应用的有效性依赖于偏振GNSS-R传感器的准确校准。在Rongowai任务中，一种新开发的下一代GNSS-R接收器（NGRx）安装在新西兰国内航空公司的一架飞机上，以在其商业航班期间收集数据。NGRx同时处理多GNSS卫星信号，并利用双通道（LHCP和RHCP）天线，从而提高空间覆盖范围和反演精度。双极化天线还提供了检查偏振GNSS-R系统的可能性。本文开发了一种新方法，通过将内陆湖泊和海洋的测量结果与模型结果进行比较，对Level-1功率测量和机载天线交叉极化增益进行校准。校准结果使同极化反射率反演的不确定性降低了34%。校准后的交叉极化和同极化反射率通过其统计分布和1.5公里分辨率的空间映射进行了检验，涵盖了多种土地表面类型和入射角。这些结果验证了校准方法的有效性，并为未来的陆地科学应用铺平了道路。 显示英文摘要

摘要： Polarimetric GNSS-R systems, equipped with an additional polarization channel, offer enhanced capabilities for separating vegetation and surface scattering effects, thereby improving GNSS-R land remote sensing applications such as soil moisture retrieval in vegetated and forested areas and biomass estimation. However, the effectiveness of these applications relies on accurate calibration of the polarimetric GNSS-R sensor. In the Rongowai mission, a newly developed Next Generation GNSS-R Receiver (NGRx) is installed on a domestic Air New Zealand airplane to collect data during its commercial flights. The NGRx processes multi-GNSS satellite signals simultaneously and utilizes a dual-channel (LHCP and RHCP) antenna, thereby improving spatial coverage and retrieval accuracy. The dual-polarized antenna also provides the possibility to examine the polarimetric GNSS-R system. In this article, a new methodology is developed to calibrate the Level-1 power measurement and the on-board antenna cross-pol gain by comparing measurements from inland lakes and ocean with modeled results. The calibration results in a 34% decrease in the uncertainty in co-pol reflectivity retrieval. The retrieved cross-pol and co-pol reflectivity after calibration are examined by their statistical distribution and spatial mapping with 1.5 km resolution, with multi-land surface types and incidence angles. These results validate the effectiveness of the calibration method and pave the way for future terrestrial science applications.