5208 KB72 KB197320252021Khelouf, NoureddineMedjahed, Sid AhmedNiati, AbdelhalimTaibi, Habibštevilka:3letnik:65str. 440-458ISSN:0351-0271DOI:10.15292/geodetski-vestnik.2021.03.459-471COBISSID_HOST:81566467URN:URN:NBN:SI:doc-GCWLSI2JenZveza geodetov SlovenijeGeodetski vestnikbackward integrationbroadcast ephemeridesforward integrationintegracija naprejintegracija nazajmetoda Runge-Kuttaoddajanje efemeridpospešek zaradi vpliva Lune in SoncaRungeKutta methoduni-solar accelerationImplementation of the variation of the lunisolar acceleration into glonass orbit CALCULUS| Uporaba variacij pospeška zaradi vpliva Lune in Sonca pri izračunu tirnic satelitov GLONASS|In the differential equation system describes the motion of GLONASS satellites (rus. Globalnaya Navigazionnaya Sputnikovaya Sistema, or Global Navigation Satellite System ), the acceleration caused by the luni-solar traction is often taken as a constant during the period of the integration. In this work-study, we assume that the acceleration due to the luni-solar traction is not constant but varies linearly during the period of integration following this assumption; the linear functions in the three axes of the luni-solar acceleration are computed for an interval of 30 min and then implemented into the differential equations. The use of the numerical integration of Runge-Kutta fourthorder is recommended in the GLONASS-ICD (Interface Control Document) to solve for the differential equation system in order to get an orbit solution. The computation of the position and velocity of a GLONASS satellite in this study is performed by using the Runge-Kutta fourth-order method in forward and backward integration, with initial conditions provided in the broadcast ephemerides fileV sistemu diferencialnih enačb, ki opisuje gibanje satelitov GLONASS (rus. Globalnaya Navigazionnaya Sputnikovaya Sistema), se pospešek, ki ga povzroča vpliv Lune in Sonca pogosto upošteva kot konstanta v obdobju integracije. V pričujoči raziskavi predpostavljamo, da pospešek zaradi vpliva Lune in Sonca ni konstanten, temveč se v obdobju integracije linearno spreminja. Po tej predpostavki izračunamo linearne funkcije v treh oseh pospeška zaradi vpliva Lune in Sonca za interval 30 minut in jih nato implementiramo v diferencialne enačbe. V dokumentu GLONASS-ICD (angl. Interface Control Document) je za določitev tirnice priporočena uporaba numerične integracije Runge-Kutta četrtega reda za reševanje sistema diferencialnih enačb. Izračun položaja in hitrosti satelita GLONASS je v tej študiji izveden z metodo Runge-Kutta četrtega reda pri integraciji naprej in nazaj, pri čemer so začetni pogoji navedeni v datoteki s satelita oddanih efemeridTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaZveza geodetov Slovenije