RESEARCH ON A SIMPLIFIED VECTOR TRACKING BASED GNSS/SINS DEEP INTEGRATION SYSTEM

Xia Chen ； Qingyuan Xia ； Yuming Bo ； Chaochen Wang ； Wei Tao

《Journal of Aeronautics, Astronautics and Aviation》 49卷4期 Vol.49 No.4 (2017/12) Pp. 343-354

https://doi.org/10.6125/17-0822-943

摘要

Deep integration is the promising future for the GNSS/SINS integration system. The computation load and the performance of working under the circumstance that the available satellites amount is less than 3 limit the application and development of the system. Here, this paper is about a simplified structure and the performance improvement for the vector tracking based GNSS/SINS deep integration system when the available satellites are less than 4. Two simplifications schemes are included in this architecture. The first scheme the simplified vector tracking loop using a precise clock. A chip scale atomic clock (CSAC) is employed as the time reference in the system. In this way, the navigation filter of the vector tracking loop is simplified and the state variable clock drift is removed from the state equation. The second scheme is the simplified integration filter which the clock bias and the clock drift are removed from the model using the differential measurement equations. The number of the state variables decreases from the value of 17 to 15. In the system, the navigation filter of the vector tracking loop is kept to update and complete the signal tracking. So, the integration filter can be operated at lower frequency for computation reduction. And this definitely enhances the real-time performance of the integration system. Then a semi-physical experiment system is set up, and the trajectory is designed to test and evaluate the performance of the deep integration system. The CSAC is employed as the time reference of the GNSS immediate frequency data collector. The results are presented by the navigation results of the position, velocity and attitude. The results show that the new deep integration system works well even the available satellites are less than 4. And under this condition, the conventional method's navigation solutions diverge slowly with the time.

關鍵字

chip scale atomic clock ； vector tracking ； deep integration ； computation reduction