Analysis on Influencing Factors of Ocean Water Vapor Estimated from Shipborne GNSS Measurements

Using shipborne GNSS (global navigation satellite system) method to detect ocean water vapor content can rich the quantity and density of ocean water vapor observations. In this study, the specialized research using measured data from the Indian Ocean voyage experiment was conducted about the ocean precipitable water vapor (PWV) based on precise point positioning(PPP) technology, which mainly analyzed the coupling relationship between GNSS height and PWV, calibrated the height result accuracy of kinematic GNSS and analyzed the influence of different algorithms on PWV valuations. Main conclusions are as follows:①choices over the fixed ambiguity method or floated, multi-systems processing mode or single-system have small influences on the PWV estimation, but choices over different kinds of software and products of satellite ephemeris and clock have big influences, magnitude at 2~4 mm;②there is a coupling relationship between height and PWV, and a preliminary estimating shows that the PWV valuations root mean square (RMS) error increases 1 mm with the height RMS error rising about 24mm;③the height results of inertial measurement unit (IMU) and PPP have a high correlation that the correlation coefficient is as high as 99% and the magnitude of differences is better than 30mm, and then the accuracy requirements of height for ocean water vapor estimating based on kinematic GNSS is satisfied.