@ARTICLE{Skeivalas_Jonas_An_2020,
 author={Skeivalas, Jonas and Paršeliūnas, Eimuntas and Putrimas, Raimundas and Šlikas, Dominykas},
 volume={vol. 27},
 number={No 1},
 journal={Metrology and Measurement Systems},
 pages={131-140},
 howpublished={online},
 year={2020},
 publisher={Polish Academy of Sciences Committee on Metrology and Scientific Instrumentation},
 abstract={The possibilities to improve values of the satellite orbit elements by employing the pseudo-ranges and differences of carrier phase frequencies measured at many reference GPS stations are analysed. An improvement of orbit ephemeris is achieved by solving an equation system of corrections of the pseudo-ranges and phase differences with the least-squares method. Also, equations of space coordinates of satellite orbit points expressed by ephemeris at fixed moments are used. The relation between the accuracy of the pseudo-ranges and phase differences and the accuracy of the satellite ephemeris is analysed. Formulae for estimation of the influence of the ephemeris on the measured pseudo-ranges and phase differences and for prediction of the accuracy of the pseudo-ranges and phase differences were obtained. An influence of the covariance between single orbit parameters on the accuracy of the pseudo-ranges and phase differences is detected.},
 type={Article},
 title={An influence of the covariance between single orbit parameters on the accuracy of observations of the pseudo-ranges and phase differences},
 URL={http://ochroma.man.poznan.pl/Content/115052/PDF/10_MMS_1_2020.pdf},
 doi={10.24425/mms.2020.131721},
 keywords={Global Positioning System, ephemeris, Doppler effect, dispersion, geodesy},
}