Calibration and Error Analysis of the BF-1 Demonstration GNSS-R Satellites

Abstract

The reflection signal of Global Navigation Satellite System can be applied to the research of Remote Sensing Applications (GNSS-Reflectometry, GNSS-R), which shows such advantages as all-time, all-weather, light weight, small volume and low cost. As the first generation of GNSS-R microwave remote sensing satellite in China, BF-1 demonstration satellite is capable to produce high spatial and temporal resolution wind speed observation results, which plays an significant complementary role in the measurement of global wind speed, with the continuous observation of typhoon in particular. In this paper, an introduction is made of the calibration process from the metadata of payload output to the normalized bistatic scattering cross section (NBRCS) of wind speed retrieval. The entire process involves two steps. Firstly, the metadata of payload is calibrated using the calibration load and temperature information, and then it is calibrated according to the geometry of transmitter and receiver. The errors introduced in the process of calibration are analyzed by formula derivation, based on which the total error of the calibration result is obtained as 0.74 dB. This term demonstrates the accuracy and validity of the data processing results regarding BF-1 test satellite, in addition to providing a reference for the design of the next-generation GNSS-R microwave remote sensing satellite.