Kvalitetsundersøgelse af GNSS RTK-måling
Forfattere
Jensen, Mikael ; Steenfeldt, Regitze
Semester
4. semester
Udgivelsesår
2008
Antal sider
117
Abstract
Projektet undersøger kvaliteten af GNSS RTK-målinger, dvs. satellitbaseret positionsbestemmelse med realtidskorrektioner. Foranalysen forklarer, hvordan GNSS RTK fungerer, og hvilke kommercielle RTK-tjenester der findes i Danmark. Tre landinspektører er interviewet om deres brug af GNSS RTK og deres forventninger til fremtidige anvendelser. Hovedanalysen behandler fire spørgsmål: 1) Hvor mange epoker (korte måleøjeblikke) en GNSS-måling bør bestå af; her fandtes 10 epoker som det optimale. 2) Hvordan afstanden til nærmeste referencestation påvirker nøjagtigheden ved brug af kommercielle RTK-tjenester; alle tjenester blev påvirket af afstanden, og SpiderNet var bedst ved korte afstande. GPSnet.dk med GPS var bedst i planen (horisontal nøjagtighed) fra 7 km, og GPSnet.dk med GPS/GLONASS var bedst i koten (højde) fra 3 km. 3) Nøjagtighed ved måling med GPS kontra GPS/GLONASS med egen basestation; her gav GPS/GLONASS ingen forbedring, og egen basestation havde den fordel, at korte afstande gav bedre nøjagtighed end kommercielle RTK-tjenester. 4) Om initialiseringstiden (tiden til at opnå en stabil RTK-løsning) påvirkes af tjenesten og/eller afstanden; GPS Referencen var den eneste, hvor tiden steg med afstanden, og den var langsomst, mens GPSnet.dk var hurtigst, dog med beskeden forskel.
This project assesses the quality of GNSS RTK measurements, meaning satellite-based positioning with real-time corrections. The preliminary analysis explains how GNSS RTK works and which commercial RTK services are available in Denmark. Three land surveyors were interviewed about how they use GNSS RTK and their hopes for future applications. The main analysis covers four questions: 1) How many epochs (short measurement intervals) a GNSS measurement should include; 10 epochs were found to be optimal. 2) How the distance to the nearest reference station affects accuracy when using commercial RTK services; all services were affected by distance, and SpiderNet performed best at short distances. GPSnet.dk with GPS was best in the horizontal plane from 7 km, and GPSnet.dk with GPS/GLONASS was best for height accuracy from 3 km. 3) Accuracy when measuring with GPS versus GPS/GLONASS using an own base station; GPS/GLONASS did not improve results, and an own base station had the advantage that short distances yielded better accuracy than commercial RTK services. 4) Whether initialization time (the time to reach a stable RTK solution) is influenced by the service and/or distance; GPS Referencen was the only one where time increased with distance and was the slowest, while GPSnet.dk was the fastest, although the difference was small.
[Dette resumé er genereret ved hjælp af AI]