Carrier phase difference technology, or RTK technology, is a real-time dynamic positioning technology based on global positioning system (GPS). Conventional GPS measurement methods, such as static, fast static and dynamic measurement, need to be solved afterwards to obtain centimeter level accuracy. RTK is a measurement method that can obtain centimeter level positioning accuracy in real time in the field, which is a major milestone of GPS application, It brings a new dawn for all kinds of control survey, topographic mapping, engineering lofting, marine and cadastral survey, and greatly improves the efficiency of field work.