To solve the problem of time synchronization and frequency calibration among different stations in an integrated multi-target tracking system, two methods using global positioning system(GPS) through observing one or more GPS satellites in common view are put forward. Calculation formulas are derived, the impacts on time synchronization of error sources such as ephemeris error, satellite clock error, ionospheric error, tropospheric error, multi-path effects and receiver’s hardware delay are analyzed. To validate time synchronization and frequency calibration precision, some related tests were got. Comparing with Cesium clock, it shows that nanosecond level time synchronization can be obtained and the precision of frequency calibration is better than 5.0×10-11 using GPS. More precise time synchronization and frequency calibration can be achieved by using multi-satellites in common view than using single satellite.
Zhao Junxiang, Li Jianhui, Chang Qing, Zhang Qishan.Study on GPS timing and frequency calibration method and the test results[J] JOURNAL OF BEIJING UNIVERSITY OF AERONAUTICS AND A, 2004,V30(08): 762-766