涌浪及降雨影响下的GNSS海面反射信号建模

The simulation of global navigation satellite system (GNSS) signal reflected from the ocean surface mostly uses wind-driven wave spectrum, which ignores the effect of swell and rain in real complex environment. For this reason, a model of GNSS signal reflected from the ocean surface under the effect of swell and rain is proposed. First, Elfouhaily spectrum, swell spectrum and rain spectrum are simulated respectively. The effects of swell and rain on GNSS-R signal are analyzed form the perspective of wave spectrum. Then, the method of modeling the GNSS-R signal after introducing the factors of swell and rain is designed. The noise model is established. Finally, the delay-Doppler maps(DDM) and dely waveform(DW) simulated in the spaceborne scenario are analyzed and compared with the results of the UK TDS-1 measured data. The validation results show that the swell mainly forms the large-scale rough sea surface which has great influence on the GNSS-R signal, while the rain has little influence on the GNSS-R signal. The simulated DDM has good consistency with the measured data, and the correlation coefficient between simulated DW and measured data is 0.92, which is better than the comparison result of the uncorrected model. The simulated reflected signal is more real, which proves the feasibility and effectiveness of the proposed GNSS-R signal modeling method. It has certain reference significance and practical value for the modeling of GNSS-R signal in real complex environment and the application of GNSS-R spaceborne detection.