dc.creator | Biagojević, Dragan | |
dc.date.accessioned | 2019-11-22T12:56:43Z | |
dc.date.available | 2019-11-22T12:56:43Z | |
dc.date.issued | 2003 | |
dc.identifier.uri | https://grafar.grf.bg.ac.rs/handle/123456789/1788 | |
dc.description.abstract | Predmet ovog rada predstavljaju mogućnosti NAVSTAR GPS satelitskog sistema za uspostavljanje
gradske geodetskih referentne osnove. U odgovoru na ovo pitanje sprovedeno je istraživanje čija se
suština sastoji u analizi relativnih geometrijskih GPS modela za kratka međustanična rastojanja.
Realizacija lokalnih referentnih sistema na području naseljenih mesta konkretizovana je pre svega
modelom pasivne gradske GPS mreže i dvostrukim razlikama faznih pseudodužina kao osnovnim
memim veličinama. Na osnovu prethodne ocene tačnosti merenja pokazano je da za prosečne
atmosferske uslove i međustanična rastojanja manja od 10km funkcionalni model sadrži samo
koordinate i fazne neodređenosti kao nepoznate paramétré. Sprovedeni eksperimenti potvrdili su da je
samo povremeno neophodno uvođenje dodatnog zenitnog troposferskog paramétra po staničnom paru.
Stohastički model dvostrukih razlika detaljno je razrađen obuhvatanjem vremenske korelacije i
eksperimentalnim odredivanjem parametara kovarijacionih modela pojedinih izvora grešaka. Izvedeni
su i teorijski izrazi za tačnost relativnog pozicioniranja na nivou pojedinačnih GPS vektora i mreže
GPS vektora. Njihova validnost proverena je analizom i obradom GPS merenja u test mrežama
Novoselo i Lapovo. Za ilustraciju koncepta pasivne geodetske osnove korišćene su već realizovane
gradske GPS mreže Kraljeva i Zrenjanina. Na osnovu eksperimentalnih rezultata siedi da je sa memim
sesijama dužine 30-60min moguée postici tačnost od 3-6mm za relativne položaje tačaka, i 5-10mm za
visinske razlike, pri čemu je ocenjeno da preciznost može biti dvostruko bolja.
Moguénost realizacije lokalnih referentnih sistema pomoću malog broja stalno operativnih GPS
stanica ispitana je kroz model aktivne gradske GPS osnove. U tu svrhu sproveden je eksperiment koji
predstavlja simulaciju mreže permanentnih stanica za područje Beograda, i u kojem je primenjena
metoda virtuelnih referentnih stanica. Rezultati eksperimenta pokazuju da je tačnost linearne
interpolate diferencijalnih korekcija bolja od 5mm za međustanična rastojanja od 40-50bn. Tačnost
pozicioniranja novih tačaka ocenjena je pomoću poznatih koordinata iz državne referentne GPS
mreže. Otkriveno je da se tačnost položaja stabilizuje na konstantnu vrednost nakon 15min merenja,
dok je u slučaju visina neophodno da merna sesija traje bar 25min. Za ponovljivost rezultata
pozicioniranja utvrđena je gomja granica od 3cm po položaju i 8cm po visini, pri čemu se ove
vrednosti mogu usvojiti kao pokazatelji tačnosti kinematičkog pozicioniranja na nivou verovatnoće od
99%. Uz već utvrđeno minimalno trajanje meme sesije ostvarena je tačnost statičkog pozicioniranja
bolja od 10mm i 15mm za položaje i visine respektivno.
Posebna pažnja posvećena je osiguranju i kontroli kvaliteta. U okviru metrološkog obezbeđenja GPS
prijemnika i antena defmisan je i eksperimentalno verifikovan osnovni program ispitivanja. On se
sastoji u utvrđivanju stabilnosti oscilatora, srednjih položaja faznih antenskih centara i preciznosti
praćenja GPS signala, i podjednako je primenljiv u pasivnim i aktivnim gradskim GPS mrežama. Za
praćenje integriteta opažanja na permanentnim stanicama praktično je implementiran sistem kvaliteta
zasnovan na Kalmanovom filtern i rekurzivnom DIA postupku. Eksperimentalno je utvrđeno da je na
taj način moguće pouzdano otkrivanje veoma malih grubih grešaka u kodnim merenjima, i eliminacija
faznih skokova čija je vrednost svega 1cyc. | sr |
dc.description.abstract | The subject of this thesis represents the possibility of NAVSTAR GPS satellite system for realization
of local geodetic reference frame in urban environment. Research conducted to answer this question,
led in essence to analysis of relative geometric GPS models suitable for so called short interstation
distances.
Local reference frame realization in urban areas is firstly demonstrated in terms of pasive GPS
network model and phase double differences. Based on apriori accuracy assessment, it is shown that
normal atmospheric conditions and interstation distances less than lOhn lead consequently to
functional model consisting of point coordinates and phase ambiguities as only uknown parameters.
Experimental results have confirmed that there was only an occasional need for introduction of
additional zenith tropospheric parameter per baseline. On the other side, detailed stochastic model of
phase double differences is presented, including time correlation and experimentaly derived
parameters of the covariance model for various error sources. Theoretical expressions for relative
positioning accuracy are also shown on baseline and network level. The validity was checked by
analysis and assessment in the frame of the test networks Novoselo and Lapovo. Pasive frame concept
was illustrated with city GPS networks of Kraljevo and Zrenjanin. Results clearly show the possibility
of reaching the horizontal and vertical accuracy of 3-6mm and 5-10mm respectively, based on
measurement sessions of at least 30-60min, and with the level of precision which might be better by
factor of nearly two.
The possibility for realization of local reference system using small number of permanently operated
GPS stations is investigated in terms of active urban GPS network model. For research purposes, an
experiment was carried out, whith simulation of permanent GPS network for Beograd area and virtual
stations method of positioning. Results show that simple linear interpolation is quite adequate in order
to obtain virtual measurements with accuracy of 5mm for interstation distances of 40-50 fon. Known
coordinates of national zero order GPS network was used to assess the positional accuracy of new
points. It was discovered that horizontal position accuracy tends to stabilize after 15min, in
comparison with measurement session of at least 25min necessary for stabilization of the heights
accuracy. Worst case scenario for repeatebility delivered values of 3cm for positions and 8cm for
heights, which can be assumed as kinematic positioning accuracy with probability level of 99%.
Minimum duration of measurement session mentioned above was capable of obtaining high static
positioning accuracy of 10mm and 15mm for positions and heights respectively.
Special attention is devoted to quality assurance and quality control. Metrological assurance of GPS
receiver and antena was proposed and experimentaly verified, with few well defined basic procedures.
The program is based on estimation of local oscilator stability, mean phase center location and
precision of GPS signal tracking, and it is equaly applicable in pasive and active urban GPS networks.
For integrity monitoring of permanent observations quality system was implemented, based on
Kalman filtering and recursive DIA procedure. It was experimentaly confirmed that the system is
capable of reliable detection of very small gross errors in code measurements, as well as elimination of
cycle slips with magnitude of only 1 eye in phase measurements. | en |
dc.language.iso | sr | sr |
dc.relation | info:eu-repo/grantAgreement/MESTD/MPN2006-2010/15007/RS// | |
dc.rights | openAccess | sr |
dc.rights.uri | https://creativecommons.org/licenses/by-nc-nd/4.0/ | |
dc.subject | Global Positioning System | en |
dc.subject | functional model | sr |
dc.subject | stochastic model | sr |
dc.subject | mixed model | sr |
dc.subject | stochastic process | sr |
dc.subject | components of variance | sr |
dc.subject | Kalman filter | sr |
dc.subject | quality assurance | sr |
dc.subject | quality control | sr |
dc.subject | hypothesis testing | sr |
dc.subject | pasive reference frame | sr |
dc.subject | active reference frame | sr |
dc.subject | reference system | en |
dc.title | Mogućnosti globalnog pozicionog sistema za uspostavljanje geodetske referentne osnove u gradovima | sr |
dc.type | doctoralThesis | sr |
dc.rights.license | BY-NC-ND | sr |
dc.identifier.fulltext | https://grafar.grf.bg.ac.rs/bitstream/id/6847/bitstream_6847.pdf | |
dc.identifier.rcub | https://hdl.handle.net/21.15107/rcub_grafar_1788 | |
dc.type.version | publishedVersion | sr |