Analysis of the use of low-cost GNSS receivers for navigation purposes

V diplomski nalogi smo analizirali natančnost določitve položaja z uporabo nizkocenovnih enofrekvenčnih GNSS sprejemnikov za potrebe v navigaciji. Meritve smo opravili z dvema nizkocenovnima enofrekvenčnima sprejemnikoma, za primerjavo pa smo imeli tudi meritve geodetskega dvofrekvenčnega sprejemnika, kjer smo uporabili samo valovanje L1. Delovanje sprejemnikov smo preizkusili v relativnem načinu, z baznimi vektorji pri kratkih razdaljah. Uporabili smo dve metodi, statično in kinematično, saj smo hoteli preizkusiti, kako bi se instrumenti obnesli pri navigacijskih nalogah, kjer bi potrebovali nekaj centimetrsko natančnost.In this diploma thesis the accuracy of the position determination through low-cost single-frequency GNSS receivers in terms of navigation has been analysed. The measurements have been carried out by two low-cost single-frequency GNSS receivers and (later) compared to the measurements made by a geodetic dual-frequency GNSS receiver, where only the L1 carrier has been taken into account. The receivers were tested in relative positioning mode, using short baseline vectors. The measurements have been processed in static and kinematic mode to see, how efficient the instruments would be in tackling navigation tasks that require an accuracy of a few centimetres

Combining point clouds from mobile and aerolaser scanning for creating a 3D model of a street row of buildings

Glavni cilj magistrske naloge je bila raziskava obdelave in združevanja oblakov točk mobilnega (MLS) in aerolaserskega skeniranja (ALS). Z združevanjem oblakov MLS in ALS dobimo večje število informacij o skeniranem okolju in se izognemo določenim pomanjkljivostim vsakega od sistemov. Združen oblak točk pokriva celotno skenirano površje razen atrijev, ki jih z nobenim od sistemov ne moremo doseči. Najprej smo raziskali različne možnosti registracije oblakov točk MLS v programu Terrasolid in na testnem območju na osnovi odstopanj na kontrolnih točkah določili najboljši postopek. Oblaku točk MLS smo nato dodali oblak točk ALS in dobili združen oblak točk. Za avtomatsko modeliranje stavb iz združenega oblaka točk MLS in ALS na trgu nismo našli ustreznega programa, zato smo v programu Terrasolid na avtomatski način izdelali modele stavb le iz oblaka točk ALS. Nato smo na primeru izbrane kompleksnejše stavbe iz združenega oblaka točk ročno izdelali njen model, ki smo ga z vidika natančnosti in podrobnosti primerjali z avtomatsko izdelanim modelom. Na koncu v obliki razprave povzamemo težave pri zajemu in obdelavi podatkov, združevanju oblakov točk MLS in ALS ter modeliranju stavb.The main goal of the master\u27s thesis was to research the processing and merging of point clouds from mobile (MLS) and airborne laser scanning (ALS). By merging MLS and ALS point clouds, we obtain more information about the scanned environment and avoid certain limitations of each system. The merged point cloud covers the entire scanned surface except for atriums, which cannot be reached by either of the systems. Initially, we explored various options for registration of MLS point clouds in the Terrasolid software and determined the best process based on deviations at control points in a test area. We then added ALS point clouds to the MLS point cloud to obtain the merged point cloud. We did not find an appropriate program for automatic building modeling from the merged MLS and ALS point cloud on the market, so we used Terrasolid to automatically create building models only from the ALS point cloud. We manually created the model of a selected complex building from the merged point cloud and compared its accuracy and detail with the automatically created model. Finally, in the form of a discussion, we summarized the problems with data acquisition and processing, merging MLS and ALS point clouds, and building modeling