TAP is a satellite-based precise point positioning service developed by Tersus GNSS, which allows users to achieve centimeter-level high-precision positioning worldwide. With TAP , the GNSS rover receiver will not need to work with the local RTK base station or CORS, but directly receives corrections broadcast by the satellites, such as ephemeris error, satellite clock error, etc. TAP meets the demand of centimeter-level high-precision positioning in areas without or with poor network coverage, such as oceans, deserts, mountains, high altitudes, etc.