High-precision and independent time-keeping type ground time service instrument used on ground in complex environment

The invention relates to a high-precision and independent time-keeping type ground time service instrument used on the ground in a complex environment, relating to a high-precision time-keeping technology and solving the problem of high time keeping and service precision in the complex environment. Input ends of a GPS (global positioning system) / GLONASS (global navigation satellite system) time demodulation circuit and a Big Dipper time demodulation circuit receive satellite antenna signals, an input end of a B-code time demodulation circuit is a B-code input end, the output ends of the GPS / GLONASS time demodulation circuit, the Big Dipper time demodulation circuit and the B-code time demodulation circuit are all connected with input ends of a time measurement circuit and a time correction and keeping circuit, the first output end of the time correction and keeping circuit is simultaneously connected with the input end of a time service circuit and the fourth input end of the time measurement circuit, the second output end of the time correction and keeping circuit is connected with the fifth input end of the time measurement circuit, the serial port ends of the GPS / GLONASS time demodulation circuit, the Big Dipper time demodulation circuit and the B-code time demodulation circuit are respectively connected with a first serial port end, a second serial port end and a third serial port end of a control circuit, and a constant-temperature crystal oscillation signal output end of a crystal oscillation module is connected with the fourth input end of the time correction and keeping circuit. The time service instrument is suitable for the complex environment.