Three dimensional modeling of GNSS ocean reflection signal

In the application of GNSS-R technology, the reflection signal source is needed to test the receiver in order to reduce costs. The signal model is the core of GNSS-R signal source. In this paper, GPS reflection signal from sea surface is taken as the research object. Firstly, the appropriate signal phases are selected according to the correlation power distribution of the reflection signal in the ZV model. Then the equations are solved. And the result curve of the equations is approximated by numerical fitting method, so as to obtain the normalized amplitude corresponding to different phases. Finally, the time delay and doppler frequency offset of the specular point signal, with respect to the direct signal, are calculated. Thereby, three-dimensional parameters of the 100 reflection signals, namely the pseudo-code delay, Doppler frequency and amplitude, could be obtained. And it is verified by the correlation processing, which show the effectiveness of the method.