Određivanje komponenti disperzija vremenski varijabilnih grešaka u GPS određivanju koordinata

Abstract

Korišćenjem potpuno novog pristupa u istraživanju rezidualnih uticaja na relativno GPSpozicioniranje, koji podrazumijeva primjenu dvofaktorske hijerarhijske klasifikacije saslučajnim efektima, bez interakcija, u integralnom sagledavanju tih uticaja zajedno sačisto slučajnim uticajima, korišćenjem jednog linearnog modela, dobijene su pouzdaneANOVA ocjene. Na osnovu istih, primjenom metode momenata, dobijene su definitivneocjene komponenti disperzija relativnih koordinata e, n i u. Za potrebe istraživanja,korišćeni su GPS podaci prikupljeni sa intervalom registracije od 30 s na krajnjimstanicama pet baznih linija različitih dužina (5.6, 13.6, 40, 129.5 i 281.9 km), u tokučetvorogodišnjeg perioda (2008-2011). Istraživanje je sprovedeno pojedinačno nadvremenskim serijama koja uključuju fiksna rješenja dobijena samo za period obdanice,period noći i cjelodnevni period. Pri razmatranju cjelodnevnog ponašanja rezidualnihuticaja, ispostavilo se da su srednje vrijednosti standarda zajedničkog uticaja rezidualatroposferske i jonosferske refrakcije, koje odgovaraju koordinatama e, n i u, redom,sljedeće: 0.1104, 0.0952 i 0.3709 mm/km. Što se tiče uticaja reziduala "far-field"višestruke refleksije, srednje vrijednosti standarda, podrazumijevajući isti redosljednavođenja, su: 4.1, 5.7 i 11.8 mm. Zajednički uticaj reziduala "near-field" višestrukerefleksije i reziduala ekscentriciteta i varijacija faznih centara antena prijemnika, poistom redosljedu prikaza, karakterišu sljedeće srednje vrijednosti standarda: 2.7, 4.1 i 12.1 mm. ANOVA ocjene imaju zanemarljiv stepen korelacije i, kao i standardirazmatranih komponentnih rezidualnih uticaja, posjeduju sezonski karakter, dostižućimaksimume u ljetnjim, a minimume u zimskim mjesecima.

By using a fully new approach in researching residual effects on relative GPSpositioning, which implies applying of two-way nested classification with randomeffects, with no interactions, in an integral consideration of these effects along with purerandom effects, through using a linear model, reliable ANOVA estimates were obtained.Based on those estimates, applying the method of moments, definitive variancecomponents of relative coordinates e, n and u were obtained. For the research purpose,GPS data collected with the registration interval of 30 s, at the ending stations of fivebaselines with different lengths (5.6, 13.6, 40, 129.5 i 281.9 km), during the full fouryearperiod (2008-2011), were used. The research was conducted individualy by usingmonthly time series that included fixed solutions obtained only for daytime, nighttimeand whole-day period. In consideration of whole-day behaviour of the residual effects, itturned out that the mean standard deviations of the joint effect of tropospheric andionospheric residual, corresponding to the coordinates e, n and u, are, respectively, thefollowing: 0.1104, 0.0952 and 0.3709 mm/km. As for the "far-field" multipath residualeffect, the mean standard deviations, assuming the same order of presentation, are: 4.1,5.7 and 11.8 mm. The joint effect of the "near-field" multipath and receiver antennaphase center offsets and variations residuals, in the same order of view, arecharacterized by the following mean standard deviations: 2.7, 4.1 and 12.1 mm. TheANOVA estimates are with a negligible degree of correlation and, as well as standarddeviations of the considered component residual effects, have a sesonal pattern,reaching their maximums in the summer, and the minimums in the winter months.