The timing system in traditional astronomic surveying have many flaws.Its structure is complicated

its operation is fussy and its portability is poor.A timing system based on temperature compensation clock chip DS12C887 is designed.The structure and identities of basic components are briefly introduced.The theory of measuring time and working process are introduced.The framework and principium of time compare subsidiary system are introduced.A lot of experiments are carried out and 22d time error data is recorded

to analyze the precision of the timing system.Those experiments prove that the timing system is accurate

steady

highly automatic.It can be used for outdoor astronomic surveying and other time services.