4:30 PM - 4:45 PM
[HTT14-05] A WL-assisted unified DISB-fixed method for RTK positioning in severe constrained observational conditions
Keywords:GNSS, RTK positioning, Inter-system bias, GNSS-constrained observational condition
At present, many global navigation satellite systems (GNSS) can be used for (real-time kinematic) RTK positioning. Moreover, the use of differential inter-system bias (DISB) calibration on overlapping frequencies can effectively reduce the problem of insolvability in RTK positioning when combining these systems in a severely constrained observational (SCO) condition. However, even though the problem can be overcome in such a condition, bad satellite geometry is often inevitable. In the meantime, the potential effect of large multipath on the ambiguity resolution (AR) is hardly reduced by the bad satellite geometry. Using wide-lane (WL) combinations is an effective means to reduce the effect of multipath on the AR. Therefore, this study proposes a WL-assisted unified DISB-fixed method with a cascading AR for a SCO condition. The method adopts a selection of WL combinations to make the number of overlapping frequencies as large as possible. Experimental results show that, in a SCO condition, even though the use of DISB calibration can significantly reduce the problem of insolvability, using multiple frequencies is still required to improve the AR performance; moreover, using the WL combinations can improve the AR performance when large multipath is present. The results of the rover data show that the percentage of the number of fixed solutions for a multiple-frequency case can be further improved by 10% after using use of WL combinations.