engleski

Configuration Aspects for LocataNet Networks in Displacement Monitoring

This thesis focuses on implementing Locata positioning system for displacement monitoring of structures, with emphasis on different LocataNet network configurations and their impact on positioning quality and ability to detect sub- centimeter level displacements. For the purpose of displacement monitoring, a software for simulation of different LocataNet configurations has been developed. The developed software was used to analyze a priori positioning quality in different LocataNet configurations, which provided the recommendations to be used in the establishment of LocataNet networks. Precision and accuracy of Locata single difference (SD) and double difference (DD) carrier phase measurements were estimated on the basis of experimental test measurements. The achieved precision of SD carrier phase measurements was 0.036 cycles, which equates to 4.3 mm, while the achieved precision of DD carrier phase measurements was 0.028 cycles, which equates to 3.4 mm. The achieved accuracy of both SD and DD carrier phase measurements was approximately 0.06 cycles which corresponds to 7 mm. There were two cases tested for displacement determination using Locata stan-alone without additional signals from GNSS satellites. In order to determine continuous displacements, the least square estimation (LSE) of positioning solution for each measurement epoch was used. For periodical determination of displacements, batch least square (BLS) estimation of position solutions was used. LSE show the capacity to determine a centimeter level horizontal displacement using SD carrier phase measurements and sub-centimeter level horizontal displacements using DD carrier phase measurements. BLS estimation showed the capacity to determine the centimeter level displacements either using SD or DD carrier phase measurements. Locata positioning system was applied for displacement measurement on the railway bridge “Sava” in Zagreb, where centimeter level vertical displacements were detected.

displacements ; Locata ; LocataNet ; optimization ; simulation

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