# Improving Smartphone GNSS Positioning Accuracy Using Inequality Constraints
## 3 Kalman Filter with Inequality Constraints
### Solution of Inequality Constraint
The results indicate that the positioning accuracy of all the smartphones in the cooperative system improved. Considering the 95 th percentile of the horizontal error, the improvement percentages were 34.27%, 75.58%, and 23.66% for the three smartphones in the static dataset, and 15.90%, 5.55%, and 0.17% for those in the dynamic dataset. This method could be applied to smartphone cooperative positioning in the future. Methodology, Z.P. and C.G. ; software, Z.P. ; validation, Z.P., R.S. and L.G. ; writing--original draft preparation, Z.P. ; writing--review and editing, Y.G. and R.S. ; funding acquisition, Z.P. All authors have read and agreed to the published version of the manuscript. This research was funded by the Postgraduate Research and Practice Innovation Program of Jiangsu Province (KYCX21_0132). Due to restrictions, data are only available upon request. The authors declare no conflict of interest. ## References

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