ETRI Journal

Electronics and Telecommunications Research Institute (한국전자통신연구원)
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Time Synchronization Error and Calibration in Integrated GPS/INS Systems

  • Ding, Weidong (Satellite Navigation and Positioning Group, School of Surveying and Spatial Information Systems, University of New South Wales) ;
  • Wang, Jinling (Satellite Navigation and Positioning Group, School of Surveying and Spatial Information Systems, University of New South Wales) ;
  • Li, Yong (Satellite Navigation and Positioning Group, School of Surveying and Spatial Information Systems, University of New South Wales) ;
  • Mumford, Peter (Satellite Navigation and Positioning Group, School of Surveying and Spatial Information Systems, University of New South Wales) ;
  • Rizos, Chris (Satellite Navigation and Positioning Group, School of Surveying and Spatial Information Systems, University of New South Wales)
  • Received : 2006.11.20
  • Published : 2008.02.28
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Abstract

The necessity for the precise time synchronization of measurement data from multiple sensors is widely recognized in the field of global positioning system/inertial navigation system (GPS/INS) integration. Having precise time synchronization is critical for achieving high data fusion performance. The limitations and advantages of various time synchronization scenarios and existing solutions are investigated in this paper. A criterion for evaluating synchronization accuracy requirements is derived on the basis of a comparison of the Kalman filter innovation series and the platform dynamics. An innovative time synchronization solution using a counter and two latching registers is proposed. The proposed solution has been implemented with off-the-shelf components and tested. The resolution and accuracy analysis shows that the proposed solution can achieve a time synchronization accuracy of 0.1 ms if INS can provide a hard-wired timing signal. A synchronization accuracy of 2 ms was achieved when the test system was used to synchronize a low-grade micro-electromechanical inertial measurement unit (IMU), which has only an RS-232 data output interface.

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