Engineering Geodesy II

Transcription

1 Engineering Geodesy II Exercise: Design and preanalysis of networks Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 1

2 Goals of the Exercise Becoming acquainted with the pre-analysis tool of the LTOP software Getting experience in error propagation in elongated tunnel- and shafts networks Preparation for bidding at the Swissmetro invitation to tender Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 2

3 Software Options for Adjustment / Analysis LTOP swisstopo, official Swiss governmental adjustment software Trinet und Trinet+ (3D-Ausgleichung), by Moritz Wittensöldner & Sebastian Kracher, Fachhochschule Nordwestschweiz CAPLAN + NETZ2X: (Cremer Auswertung und Planerstellung) for adjustment of geodetic networks. Cremer Programmentwicklung GmbH NEPTAN (Technet GmbH) Berlin Matlab: N = A' * A; Q = Inv(N); dx = Q *(A' * L); Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 3

4 Documents Instructions : see handout pre-analysis using LTOP (German & English) Documentation of LTOP WIN: EG II Website or at the Swisstopo Website: ftware.parsys downloadlist.7018.downloadfile.tmp/ltopd.pdf LTOP WIN: Editor for the parameter file (.dat) LTOP can also used via the internet: (webservice) (access with gmtuser[1...10] and user_gmt[1...10]) documentation: Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 4

5 Introduction Exercise Maximal Line of Sight Maximal line of sight in a tunnel A B R min = 7000 m M minimal clearance to wall is 1 m due to refraction! Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 5

6 LTOP required data Requirements for a pre-analysis: approximation values for all network coordinates configuration of the network, observations (Messelemente, A-matrix) a priori assumptions of all observations not necessary: measured values (Messwerte) coordinate file (*.koo): approximate coordinates of all network nodes observation file (*.mes): network configuration; for a pre-analysis no observations are necessary parameter file (*.dat): key parameters for the adjustment, includes a priori accuracy assumptions Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 6

7 LTOP File Formats Coordinate File: *.KOO $$PK ** comment line A A A A A A A format is explained in detail: Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 7

8 LTOP File Formats Observation File: *.MES $$ME STA0000 APA0320 STA0320 RIA0000 RIA0640 DPA0000 DPA0640 STA0640 RIA0320 RIA0960 DPA0320 DPA0960 STA0960 RIA format is explained in detail: ST: station AP: azimuth to e.g. A0320, RI: direction [GON], DP: horizontal distance [m], DS: slope dist. Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 8

9 Exercise analyses of four different of tunnel driving surveying strategies. comparison of different surveying set-ups with their configuration and resulting error propagation comparison of the a priori confidence ellipses at km (break through error) four alternative strategies, see exercise documentation files: 1.koo - 4.koo 1.mes - 4.mes 1.dat - 4.dat LTOP - results: Listing *.prn File containing information for plotting *.ipl Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 9

10 instrument station Listing File: *.PRN LTOP File Formats repetition of approximate coordinates influence of mean error to the transverse deviation LAGE - ABRISS MITTL. FEHLER A PRIORI VON REDUZIERTEN DISTANZEN, RICHTUNGEN UND AZIMUTEN ************* DISTANZ-GRUPPE ZENTR. A B C M.F. F. 1KM EDM MM 1.00 MM 1.00 MM/KM 0.00 MM/KM MM RICHTUNGEN MM 5.00 CC 5.00 CC AZIMUTE MM CC CC NR PUNKT TYP NP OR/BEOB. GR KORR. VERB. M.F. ZI NABLA WI GI AZI. AUS DIST. AUS QUER. G/M CC/MM CC/MM CC/MM % CC/MM CC/MM KOORD.(G) KOORD.(M) MM target A0000 AZIMUTE A0320 N * A0320 N A * UNEND. NICHT BESTI A0640 N * UNEND. NICHT BESTI A0320 N DISTANZEN A UNEND. NICHT BESTI A0640 N * is a new point Distance measured also in other direction a priori mean error of observation confidence: how much control does this observation have? 100% = reference point standardized residuals w i < 3.5 nabla: how large could be an undetected error? Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 1

11 LTOP File Formats Listing File: *.PRN (continued) above tolerance AEUSSERE ZUVERLAESSIGKEIT UND MITTLERE FEHLERELLIPSEN A PRIORI ************************************************************** PUNKT TYP TK NA NB AZI(NA) NH NR.A NR.B NR.H DY DX DH MFA MFB MFAZ MFH MM MM G MM MM MM MM MM MM G MM A ** UNEND A ** UNEND A ** UNEND A ** UNEND ** A ** UNEND ** A ** UNEND ** A ** UNEND ** A ** UNEND ** A ** UNEND ** A ** UNEND ** confidence rectangle, characterizes geometry, NA = big, NB = small side direction of confidence rectangle which observation number is responsible for the rectangle side change of coordinates between approximate and adjusted error ellipse a priori Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 1

12 Improvement of the network Meeting the requirements of the contracting body (client): standard deviation at breakthrough: < 6 cm improvement of the network configuration Improvement by lessening the a priori accuracies? If so, then justify your assumptions! try out different strategies to meet the requirements Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 1

13 Use a gyroscope? tachymetric accuracy for directions: 5 cc gyroscope accuracy: 15 cc At which length of the traverse (Polygonzug) is the use of a gyro justified from the accuracy point of view? 5 mgon n < 1.5 mgon n = number of polygon points With n < 9 every 2-3 km a gyroscope measurement would improve accuracy significantly Further aspects to consider: reliability, costs, time Geodätische Messtechnik - Prof. Dr. H. Ingensand ETH Zürich 1