An enhanced tightly-coupled integrated navigation approach using phase-derived position increment (PDPI) measurement

Abstract

In this paper, an enhanced tightly coupled navigation approach using pseudorange, Doppler and carrier phase measurements is proposed. Firstly, the PDPI vector is obtained by differencing time-differenced carrier phase measurements between satellites. Then, the difference between PDPI and position increment derived from SINS recursion is determined. Finally, navigation system states are adjusted by the precise difference of position increment. Compared with time-differenced carrier phase measurements, the introduction of precise PDPI measurements, derived from time-differenced carrier phase, can increase computation efficiency without iteration calculations. A field vehicular test is performed to verify the proposed approach.In comparison with the method using pseudorange and Doppler measurements, the PDPI-aided method improves performance of navigation system significantly. On one hand, since high-precise PDPI measurement is added in the new approach, accuracy of the integrated navigation system is improved. The results show horizontal position error is reduced by 56.9% and horizontal velocity error is reduced by 39.2%. Vertical velocity error is reduced by 81.0% and the heading error is reduced by 19.3%. On the other hand, the PDPI measurement in this new approach establishes the relationship between two successive epochs, which leads to a smoothing effect.