Algorithms for improving the position determination of an UAV equipped with a single-frequency GPS receiver for low-altitude photogrammetry

The article presents the results of research on the development of a method for improving the positioning accuracy of an UAV equipped with a single-frequency GPS receiver for determining the linear elements of exterior orientation in aerial photogrammetry. Thus, the paper presents a computational strategy for improving UAV position determination using the SPP code method and the products of the IGS service. The developed algorithms were tested in two independent research experiments performed with the UAV platform on which an AsteRx-m2 UAS single-frequency receiver was installed. As a result of the experiments, it was shown that the use of IGS products in the SPP code method made it possible to improve the accuracy of the linear elements to the level of about ± 2 . 088 m for X coordinate, ± 1 . 547 m for Y coordinate, ± 3 . 712 m for Z coordinate.Thepaperalsoshowsthetrendofchangesintheobtainedaccuracyindetermininglinearelements ofexteriororientationintheformofalinearregressionfunction.Finally,thepaperalsoappliestheSBAS correctionsmodelfortheimprovementofUAVpositioncalculationanddeterminationoflinearelements ofexteriororientation.Inthiscase,theimprovementintheaccuracyofdeterminingthelinearelements ofexteriororientationisabout ± 1 . 843 m for X coordinate, ± 1 . 658 m for Y coordinate, ± 7 . 930 m for Z coordinate. As the obtained test results show, the use of IGS products and SBAS corrections in the SPP code methodmakesitpossibletoimprovethedeterminationofUAVpositionsfortheuseinaerialphotogrammetry.