Measuring GPS EIRP in Real-Time with a Spaceborne GNSS-Reflectometry Remote Sensing System

This paper presents a unique technique which uses a spaceborne GNSS receiver system to measure GPS EIRP in real time and then uses it to improve the calibration of NBRCS for GNSS-Reflectometry observations. It includes two steps: precise gain calibration of satellite GNSS antenna using on-orbit measurements, and dynamic GPS EIRP calibration with a spaceborne system. For the CYGNSS mission, it successfully recovers the flagged measurements (~37% of the entire dataset) to be included in the standard science data products and further improves the mission's science data quality.