Development of Static Differential Method GNSS CORS UDIP for Monitoring Land Subsidence in Semarang Demak

Semarang is the capital of Central Java province, located in the northern coast of Java, with an area of about 373.67 km(2), and a population of about 1.5 millions. Urban development has grown very rapidly in the trade, industry, real estate and settlement. That has induced several environmental problems, one of which is Land Subsidence. The subsidence rate is usually a small magnitude, reaching the millimeter level. To measure such a small level of subsidence rate, both Static Differential Method using dual-frequency GPS Receiver and strategic data processing will be applied. The data will be processed using scientific software GAMIT 10.6 with precise ephemeris and differencing techniques to eliminate tropospheric refraction and lonosfer error. This Paper will mainly discuss the development of Static Differential using CORS (Continuously Operating Reference Stations) UDIP for monitoring land subsidence. Land Subsidence analysis will be performed using the t test. The Objective of this research is to comprehensively determine the distribution of land subsidence rate both spatially and temporally in Semarang Demak.