Spaceborne Gps-r Number Of Key Technologies

Global Position System (GPS) provides shared navigation location data resources of L band microwave for users all over the world. In the last decade, using GPS reflection (GPS-R) signals for oceanographic remote sensing becomes a new development direction in GPS applications. The new oceanographic remote sensing means has the following useful features: no dedicated signals transmitter is required; the GPS signal frequency is reused; spatio-temporal resolution is high; the price of GPS-R system is low. Spaceborne GPS-R system becomes a new tool for global oceanographic remote sensing.In this thesis, some key techniques on spaceborne GPS-R ocean remote sensing application are analyzed formally. The main innovation works are followed:According to practical requeirement which is GPS-R ocean remote sensing parameters estimated real-time on orbit, on board estimation methods for specular point position and extents of time delay and Doppler shift for scattering points in glistening zone are given. This lays favorable foundation of on board GPS-R receiver software design;A judgement rule is submitted to judge whether the specular point which is the center of glistening zone is visible to spaceborne GPS-R receiver. The visibility influences of LEO satellite height and spaceborne GPS-R downward antenna's configurations in oceanographic remote sensing have been discussed. The research presents theory basement for spaceborne GPS-R system design;Based on the characters of GPS reflections (GPS-R) signals from ocean, the location algorithm of large targets on ocean surface with spaceborne GPS-R are set up. The localization principle and error of the algorithm are given. The problem which brings high location error resulting from GPS-R signals time delay zero derivatives is solved. The research presents theory basement for establishing the new spaceborne GPS-R location system in the future.