GNSS and Total Station Survey

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1. CE 642A Laboratory course in Infrastructure Engineering & Management Instructor – Prof. Balaji Devaraju Submitted by- Abhijeet Prataprao More Arun Pratap Singh…
  • 1. CE 642A Laboratory course in Infrastructure Engineering & Management Instructor – Prof. Balaji Devaraju Submitted by- Abhijeet Prataprao More Arun Pratap Singh Harsh Kumar Manav Nihal Navin
  • 2. Lab1: Map Reading Objective- To understand map numbering system and to study various details on topographic map. • Topographic maps provides the graphical portrayal of objects present on the surface of the earth. These maps provide the preliminary information about a terrain and thus very useful for engineering works. For most part of India, topographic maps are available which are prepared by the Survey of India. To identify a map of a particular area, a map numbering system has been adopted by Survey of India. The system of identification is as follows: • An International Series (within 4° N to 40° N Latitude and 44° E to 124° E Longitude) at the scale of 1: 1,000,000 is being considered as base map. The base map is divided into sections of 4° latitude x 4° longitude and designated from 1 (at the extreme north-west) to 136, covering only land areas and leaving any 4° square if it falls completely in the sea
  • 3. • For Indian Topographic maps, each section is further divided into 16 sections (4 rows by 4 columns), each of 1° latitude x 1° longitude (1:250,000), staring from a letter A (North-West corner) and ending on P, column-wise. These degree sheets are designated by a number and an alphabet
  • 4. • These degree sheets are further sub-divided in the following ways: Each sheet is divided into four parts (2 rows by 2 columns),, each of 30' latitude x 30' longitude (1:100,000) designating them by cardinal directions NW, NE, SW, and SE.
  • 5. • Degree sheets have also been divided into 16 sheets (4 rows by 4 columns), each 15' latitude x 15' longitude (1:50,000) and numbered from 1 (at the north-west corner of the particular degree sheet) to 16 column wise. • Each 1:50,000 scale sheet contains four (2 rows by 2 columns) 1:25,000 sheet ( 7' 1/2 latitude x 7' 1/2 longitude ) which are numbered NW, NE, SW, and SE.
  • 6. Conventional Symbols:
  • 7. Lab 2: Reconnaissance and handheld GNSS survey Objective: To perform a reconnaissance survey using traditional methods and using a handheld GNSS receiver. • Before any survey work is done, it is important to know about the area that needs to be surveyed. this procedure is called reconnaissance. Trimble Juno 3B :The Trimble Juno 3B handheld computer is an economical solution that includes an integrated GPS, digital camera, and optional cellular connectivity. • We have three option in the juno 3B for data collection in the form of of point generic, line generic and polygon generic. • Accuracy of juno 3B is in the few metres, it is the single frequency device.
  • 8. Procedure: • First we will establish the step length of each person that can be later used to reckon the distance travelled. • We can download the compass app. • Go around the area to find out the points which are intervisible to each other and at the same time provide the access to the features which we want to map. • Now using the trimble juno handheld GNSS receiver mark the control points. • Mark the features that are visible from each of the handheld GNSS receiver.
  • 9. N
  • 10. Lab 3: Levelling using Autolevel • Objective: To carry out levelling operation using Automatic level and familiarize with the operation of the instrument. • Equipment : Nikon/ Leica autolevel , levelling staff , tripod. • Theory - Levelling is a branch of surveying, the object of which is to find the elevations of given points with respect to a given or assumed datum, and to establish points at a given or assumed datum. Use to draw the contour map.
  • 11. Procedure : 1. Identify the benchmark and put the levelling staff at bench mark. 2. Calculate the distance from the benchmark and installed the tripod, autolevel 3. After instrument installment levelling was done. 4. After levelling of instrument we take the back sight reading. 5. After Back sight reading taken , Intermediate sight reading were taken if required. Lastly Fore sight were taken at the changing point or turning point.
  • 12. Illustration: Lab 3 – Levelling using Autolevel Station Point B.S I.S F.S H.I R.L Remark A B.M. 1.07 129.479 128.409B.M=128.409m TP2 1.485 127.994 B TP2 1.52 129.514 127.994Change point TP3 1.46 128.054 C TP3 1.535 129.589 128.054Change point TP4 1.66 127.929 D TP4 1.45 129.379 127.929Change point CP1 1.3 128.079 CP2 1.385 127.994 CP10 1.265 128.114 CP3 1.255 128.124 Note: All dimensions are in meter.
  • 13. • Arithmetic check for Level • Source of error 1. Instrumental Errors- Under sensitive bubble, Errors in staff graduation, Loose tripod head, Telescope not parallel to bubble tube 2. Collimation Error- Collimation error occurs when the collimation axis is not truly horizontal when the instrument is level. 3. Error due to Curvature & Refraction 4. Other Errors sum of B.S. − sum of F.S. = last RL - First RL 17.510 -17.505 = 0.005 = 128.414-128.409
  • 14. Lab 4:Control Survey using traverse with Total Station • Objective- To carry out a traverse survey using a total station to establish control for mapping the features and also familiarize with the operation of the instrument. • Equipment- Total station. It uses electronic transit theodolite in conjunction with electronic distance meter (EDM). It is also integrated with microprocessor, electronic data collector and storage system. The instrument is used to measure- sloping distance, horizontal angles, vertical angles and elevation. Magnification: 30X Display: QVGA, 16 bit colour, TFT LCD, Backlit (320 X 240 pixel) • Accuracy- length- 1.5 mm + 2 parts per million over a distance of up to 1,500m angle – 1”
  • 15. Set up & level at CP 1 Choose the reference direction Angle measurement with respect to the reference line. Measurement of horizontal angle & elevation. Set up & level at CP 2 Take the backsight reading from the next control point Repeat the procedure. Computation of interior and exterior angles. Compute the departure and latitude. Compute the closure error. Distribute the error using Bowditch method. Flowchart
  • 16. • Closure error - Sum of all interior angles = (n-2)180֯ Sum of exterior angle = (n+2)180֯ • Latitudes and Departures- Departure (x) = d sin A Latitude (y) = d cos A Sum of all latitudes = 0 Sum of all departures = 0 Let P denote the perimeter of the traverse survey and ex and ey denote the closure error in departures and latitudes, respectively, then the quality of the survey can be reported as- linear error of closure (e) Relative precision= 1: 𝑝 𝑒 = 𝑒 𝑥 2 + 𝑒 𝑦 2
  • 17. • Distribution of closure error by Bowditch method- Bowditch rule is applied for corrections in latitude and departure. As per this rule, the error is proportional to the length of the side. Correction in latitude/northing = −𝑒𝑦 𝑝 × d Correction in departure/easting = −𝑒𝑥 𝑝 × d Illustration: Total error in latitude= -0.001969 Total error in departure= -0.019164 Total parameter= 364.58 Correction in latitude = 0.001969 364.58 × 38.959 = 0.0002104 Note: Correction value is added to the observed value to get the corrected value.
  • 18. CP POINT LINE DISTANCE ANGLE LATITUDE DEPARTURE CORRECTION IN LATITUDE CORRECTION IN DEPARTURE 4 B BC 38.959 68.51277 8 14.270 36.251 0.000210444 0.002047894 5 C BD 48.358 18.41861 1 45.880 15.279 0.000261211 0.00254193 6 D DE 123.181 257.1236 11 -27.451 -120.083 0.00066538 0.006475028 8 E EF 69.69 159.7847 22 -65.397 24.081 0.000376442 0.00366328 9 F FA 44.96 98.61916 7 -6.738 44.452 0.000242859 0.002363339 3 A AB 39.433 0.000000 39.433 0 0.000213004 0.00207281 SUM 364.58 -0.001969 -0.019164 0.001969 0.019164
  • 19. Lab 5 & 6: Total station feature mapping Set up the total station. Key in the coordinates of CP Enter the coordinates of back sight and measure the error Take as it is reference Take the reading of all near features from control point using measure topo.
  • 20. Lab 7: GNSS Surveying Objective: To take GNSS reading on control points. Trimble R-10 GNSS Receivers Trimble R-10 collects more accurate data faster and easier. This system provides surveyors with a powerful way to increase data collection. It have improved protection against sources of interference and spoofed signals. GNSS processing engine enables surveyors to measure points more quickly. R10 can survey previously inaccessible points, reduce occupation time and record faster and safer measurements than ever before.
  • 21. Connected the R-10 with the controller using Bluetooth. Perform reading for near about 20 to 30 minutes. The GNSS data (in a static mode) of the control points. The data in Trimble Business Center (TBC) is processed by using the R3 base station data. The detailed report is generated with TBC. Procedure:
  • 22. Data from TBC Vector Components (Mark to Mark) From: ZIITK Grid Local Global Easting 423466.408 m Latitude N26°31'09.43601" Latitude N26°31'09.43601" Northing 2933422.826 m Longitude E80°13'54.70799" Longitude E80°13'54.70799" Elevation 66.777 m Height 66.777 m Height 66.777 m To: cp3 Grid Local Global Easting 423600.490 m Latitude N26°30'42.82907" Latitude N26°30'42.82907" Northing 2932603.405 m Longitude E80°13'59.72913" Longitude E80°13'59.72913" Elevation 63.966 m Height 63.966 m Height 63.966 m Vector ΔEasting 134.082 m NS Fwd Azimuth 170°21'51" ΔX -75.417 m ΔNorthing -819.421 m Ellipsoid Dist. 830.590 m ΔY 381.390 m ΔElevation -2.811 m ΔHeight -2.811 m ΔZ -734.000 m
  • 23. Transformation of coordinates from Local to UTM The transformation formula is: UTM = M x TS + Translation Since this is a 2-D transformation, the translation is two parameters and the rotation matrix M is four parameters. So, in total there are six parameters to % be estimated. Therefore, we will need atleast six equations.
  • 24. 𝐸 𝑁 = 𝑀11 𝑀12 𝑀21 𝑀22 𝑒 𝑛 + 𝑇1 𝑇2 𝐸1 = 𝑀11 𝑒1 + 𝑀12 𝑛1 + 𝑇1 (eq.1) 𝐸2 = 𝑀11 𝑒2 + 𝑀12 𝑛2 + 𝑇1 (eq.2) 𝐸3 = 𝑀11 𝑒3 + 𝑀12 𝑛3 + 𝑇1 (eq.3) 𝑁1 = 𝑀21 𝑒1 + 𝑀22 𝑛1 + 𝑇2 (eq.4) 𝑁2 = 𝑀21 𝑒2 + 𝑀22 𝑛2 + 𝑇2 (eq.5) 𝑁3 = 𝑀21 𝑒3 + 𝑀22 𝑛3 + 𝑇2 (eq.6) Translation Rotation TS readings UTM coordinates
  • 25. Lab 8 & 9: Mapping with QGIS • QGIS is a free and open-source cross-platform desktop geographic information system (GIS) application that supports viewing, editing, and analysis of geospatial data. • Developer(s): QGIS Development Team • Initial release: July 2002 • Version : 3.4.1 "Madeira" (November 2, 2018; 2 months ago)
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