Shore-based GNSS-R Multi-source Sea Surface Altimetry Research

GNSS-R,which is one of new remote sensing technology, receives and processes GNSS signals reflected by Earth surface to observe the Earth parameters, and has advantages including no transmitter, low-volume, light-weight, low-cost, high time-spatial resolution, and wide application, et.al. At present, it has been used to measure sea surface height, wind speed and soil moisture, et.al.Based on the method which measures the sea surface height using signal from single GNSS satellite, this thesis studies the retrieval method, which utilizes signals from all satellites of multi-system, to improve retrieval performance and reliability. The most important significance is to improve monitoring for marine meteorology and warning for bad weather.First, the thesis introduces the concept of GNSS-R and basic theories; analyzes the generating, receiving and processing of GNSS signals; studies estimating method of specular point of GNSS-R based on the basic geometry of GNSS-R; moreover, verifies the feasibility of multi-satellites observation for sea surface height by simulation.Then, the thesis studies the traditional model using C/A code to measure seas surface height and its errors caused by atmospheric delay and sea surface roughness. For atmospheric delay error, the thesis uses theoretical model whose parameters can be obtained from navigation message to correct. For the error resulted from sea surface roughness, two methods, which are correcting the location of peak of correlation power and differentiating the correlation power, are proposed. Based on the method using single-satellite signals, the thesis proposes a weighted-average method, which uses reflected signals from multi satellites of GPS and BeiDou system to retrieve sea surface height.At last, the thesis introduces the software receiver which uses GPS and BeiDou to measure sea surface height. This receiver includes the display area of platform information, the input area of processed raw data file, the control area of receiver, the display area of processed results, the sky view of GPS/BeiDou satellites, and the display area of correlation power. Through the software receiver above, the accuracy of proposed method is analyzed using coastal data, and the validity of the method is also verified. Those works are meaningful for the development of GNSS-R altimetry.