The Latest Application to Determine Tide Height in a Large-Scale Sea Using Shipborne GPS Based on Precise Point Positioning and EGM 2008

Abstract

Luo, X.; Gao, J.; Jin, X.; Li, J., and Chu, F., 2015. The latest application to determine tide height in a large-scale sea using shipborne GPS based on precise point positioning and EGM2008.GPS data dedicated to tidal level are usually processed using differential techniques. Unfortunately, the precision of resulting kinematic positions is baseline-length dependent. So, high precision tidal level measurements using differential GPS techniques are limited to coasts, lakes, and rivers. Recent improvements in GPS satellite products (orbits, clocks, and phase biases) make Precise Point Positioning (PPP) technique reach cm-level in three dimensions. At same time, EGM2008 determine the sea level also reached centimeter level. So Precise Point Positioning technique with EGM2008 opens up tidal level measurements without Tidal Gauges. This paper recalls the concept of PPP technique and discusses the precision of GPS shipborne positioning. Tidal data of large-scale sea are calculated from PPP and EGM2008. Some results are gotten. (1) Compliance of tidal height, which obtained from measurements and model, increases in sequence as distance apart from seashore increases. (2) The Cycle, amplitude of the tide calculated by PPP and EGM2008 is more obvious, the performance characteristics more clearly, solving characteristics and theoretical tidal level characteristics match well. (3) Marine gravity measurements result shows that FAA (Free-air anomaly) and BG (Bouguer anomaly) calculated from PPP are similar with those from conventional method, but depth from former is better than that from latter.From above results, PPP technique is a feasible method to determine tidal height.