The Effect Of Ocean Tide Loading On GPS Precision Measurements In Shangong Province

With the rapid development of space technology such as GPS, GPS in the field of geodesy and geophysics has been widely used, the observation techniques of high precision is getting more and more attention. Ocean tide loading is cyclical movement that is caused by the gravitational effects of the sun, the moon and other celestial bodies. It will have a negligible impact on the ground in the study of high-precision data processing. Based on this, with the example of SDCORS station, this article will study the effects of ocean loading on precision measurement GPS stations in Shandong Province displacement and GPS baseline, then it will calculate the difference between different ocean models and observation time periods with different tides load research data influence, in addition, it will study the characteristic signal of ocean loading clarify the feasibility of this approach based on the use of Fourier and wavelet multi-resolution spectral analysis theory.The specific research results are as follows:(1) Based on station data of SDCORS, the article has calculated the ocean loading effect on GPS high precision measurement in Shandong district. The results show that the ocean tide loading effects on coastal GPS station displacement can reach to cm level, and the largest will reach to 2.4 cm; ocean tide loading effects on inland station is far less than the coastal station, the coastal stations are about 2 to 3 times larger than inland station. The load on the GPS station has the biggest influence in vertical direction, about 2 to 3 times larger than the east-west and north-south direction.(2) The article has calculated the influence of GPS baseline with the CORS station building in Shandong district. Results show that ocean loading effects on GPS baselines in Shandong district is millimeter commonly, the relative influence between the 10-8-10-9, ocean loading effects is related to the baseline and GPS baseline length and the location of the station.(3) With the example of the three tidal models of NAO99 b, FES2004 and CSR4.0, we studied the differences between global ocean models of GPS high precision measurement. We have gotten the conclusion that three ocean models in Shandong area of GPS measurement are in the same order of magnitude, the influence of NAO99 b tidal model correction value is bigger, The difference between FES2004 model and CSR4.0 model is very small in coastal GPS station, in inland station, the three models are similar.(4) The article has calculated the effects of ocean loading with different observation period of data. For a longer time continuous observation station, the results show that the ocean loading of station coordinates correction is not very big, but for GPS short cycle precision measurement, the correction of the ocean loading displacement influence on GPS stations in Shandong district is bigger. It is consistent with the periodic principle of ocean loading, so the ocean loading effects must be considered in a short cycle and high precision measurement of.(5) The article has analyzed the impact of ocean loading on SDCORS through Fourier spectrum. From the analysis of one month’s data, the energy of half tide is the biggest and the cycle is obvious. The article has extracted the characteristic signal with the theory of wavelet multi-resolution and analyzed the influence of the amplitude of the half tidal wave and show the feasibility of this approach.