1. NGS River/Valley Crossing Procedures Great Lakes Regional Height Modernization Consortium Meeting Sparta, WI September 16-17, 2014 by Dave Zenk NGS Advisor in Minnesota

2. Kendall Fancher, Team Leader, – Instrumentation Branch Chief Steve Breidenbach, Charles Geoghegan – Instrumentation Branch John Ellingson, Dave Zenk, – Advisors in Wisconsin and Minnesota Team Members

3. Review of Historical River/Valley Crossing Procedures Design of New River Crossing Method Design of New River Crossing Equipment Initial Test at NGS Instrumentation Branch Corbin Lab MNDOT Test Results Cautionary Statement Outline

4. Chapter 4 of “NOAA Manual NOS NGS 3 GEODETIC LEVELING”, 2001 Chapter 4 discusses the error theory of River/Valley Crossings and outlines several methods by which such crossings may be conducted. – Zeiss River Crossing Method (1970?) Section 4.3 – Fischer Method (1929) Section 4.4 Historical Review

5. 2 identical level instruments each equipped with a rotating wedge device and mounted on a single tripod head. Sighting to a target column with 2 targets and a height stud. Zeiss River Crossing Equipment

6. Rotating Wedge Device allowed line of sight to be angled (not shifted) upward or downward by up to 200 arc-seconds with an accuracy of 0.2 arc-seconds. By carefully measuring the angular deviations to upper and lower targets and accounting for instrument collimations, one could conduct First Order Class 1 River Crossings up to 1 km or more. Zeiss River Crossing Equipment

7. Fischer Method The Fischer Level was equipped with a precise tilting screw with which the line of sight could be angled (not shifted) upward or downward by up to 200 arc-seconds with an accuracy of 0.5 arc-seconds. Similar targets as for Zeiss. Not recommended for First Order.

8. The Zeiss Method and Fischer Method each produced good results when all procedures were followed. Complete field observing routines required about 1 day. Good Results, Slow

9. Existing River/Valley Crossing procedures do not meet customers needs. Existing procedures do not include the use of digital leveling systems. Required specialized instruments (Zeiss River Crossing Equipment) are no longer commercially available. The “Instructions for Ordinary Leveling Instruments” (Fischer level) relies upon an instrument which is no longer commercially available. NGS customers have a need to conduct this activity and are looking to us for guidance. Why NGS Needed a New Method

10. Design river/valley crossing data collection/analysis procedures and forms which enable our customers to conduct this type of activity, achieving 1st order precision, while using commercially available instrumentation along with specialized equipment readily fabricated at the average machine shop. Field test new procedures, comparing against a standard (Zeiss river crossing procedure) and report on results. Publish new river/valley crossing procedures in the form of a technical paper and make available to our customers for use as a viable alternative to current river crossing procedures. In future revision of NOS-NGS 3 incorporate the new river/valley crossing procedure into the document as a replacement to the existing procedures. Expected Outcomes for New Method

11. NGS Instrumentation Branch studied the existing methods and adopted the following guiding principles – Dual simultaneous reciprocal observations – Precise vertical angle measurements – Sighting Targets – Readily available or easily constructed equipment Design of New Method

12. NGS Instrumentation Branch – Adopted the use of modern digital readout theodolites, to replace the leveling tools and their attachments. – Designed a set of sighting targets which could be locally constructed. – Created a set of field observations and computations procedures. – Conducted an initial test at their Corbin Lab Facility. – Conducted additional field testing. – Awaiting analysis and official approval of new method. Design of New Method

13. Geometry and Math Total Station C D Side 1 0.000 1.580 0.462 X 0.000 0.511 0.659 Y Total Station Backsight = 0.566 Foresight = -1.002 Elevation Difference = -0.436 meters + 58.5” + 45.5” - 35.0” - 42.5”

14. Calculate by proportion what would the rod reading have been with a total station angle of 0⁰-00’-00” (-35.0”) --------------------------- (+58.5”) – (-35.0”) (X) --------------------- (0.659 – 0.511) = (-35.0”) --------------------------- (93.5”) (X) ----------- (.148) = X = (0.148) (-35.0” / 93.5”) X = 0.055 m Rod = 0.511 + 0.055 Rod = 0.566 meters Side 1 – backsight rod

15. Similarly, compute Side 1 Foresight to opposite bank of river. Elevation Difference = backsight – foresight – Elevation Difference is affected by Earth’s curvature and atmospheric refraction. – Instrument has collimation errors. Geometry and Math

16. Observe all angles with telescope in direct and reversed positions (face 1 / face 2). – Eliminates instrument collimation errors. Simultaneously observe all angles from both sides of river. – Mitigates (or eliminates) effects of curvature and refraction. Observe multiple sets of angles – Eliminates small random errors of sighting and reading. Error Control

17. Errors Caused by Angular Resolution Limits River Crossing Wedge & Total Station

18. Error caused by 0.2” angular error at varying distances 0.2” X Distance to Target (in meters)Error (in meters) 30 m0.00003 m = 0 100 m0.0001 m 300 m0.0003 m 500 m0.0005 m 1000 m0.0010 m 2000 m0.0019 m

19. Error caused by 0.5” angular error at varying distances Distance to Target (in meters)Error (in meters) 30 m0.00007 m = 0 100 m0.0006 m 300 m0.0007 m 500 m0.0012 m 1000 m0.0024 m 2000 m0.0048 m 0.5” X

20. Error Budget Total Station C D Side 1 X 0.000 0.511 0.659 Y Total Station Backsight = 0.566 Foresight = -1.002 Elevation Difference = -0.436 meters

21. Assume 0.1 mm error in each target height Assume 0.5 second vertical angle error Operator error controlled by rejection limit from mean C+R will be eliminated by dual-simultaneous observations Compute 30 meter BS and 300 meter FS Compute 30 meter BS and 1000 meter FS Compute 30 meter BS and 2000 meter FS All quantities are added/subtracted so error propagates as square root of sum of squares Error Budget

22. Backsight error = sum of 4 errors = sqrt [(0.0001 2 ) + (0.0001 2 ) + (0 2 ) + (0 2 )] = 0.00014 m Foresight error = sum of 4 errors = sqrt [(0.0001 2 ) + (0.0001 2 ) + (0.0007 2 ) + (0.0007 2 )] = 0.00100 m dH Error = sqrt [(0.00014 2 ) + (0.00100 2 )] = 0.00101 m Error Budget at 300 meters

23. Backsight error = sum of 4 errors = sqrt [(0.0001 2 ) + (0.0001 2 ) + (0 2 ) + (0 2 )] = 0.00014 m Foresight error = sum of 4 errors = sqrt [(0.0001 2 ) + (0.0001 2 ) + (0.0024 2 ) + (0.0024 2 )] = 0.00340 m dH Error = sqrt [(0.00014 2 ) + (0.00340 2 )] = 0.00340 m Error Budget at 1000 meters

24. Backsight error = sum of 4 errors = sqrt [(0.0001 2 ) + (0.0001 2 ) + (0 2 ) + (0 2 )] = 0.00014 m Foresight error = sum of 4 errors = sqrt [(0.0001 2 ) + (0.0001 2 ) + (0.0048 2 ) + (0.0048 2 )] = 0.00679 m dH Error = sqrt [(0.00014 2 ) + (0.00679 2 )] = 0.00679 m Error Budget at 2000 meters

25. Operator error = inability to sight the target, read the instrument, and record the angle. For digital theodolites the error is in the sighting, since the instrument reads the angle. Transcription errors are eliminated by recording the angles to a data collector. Error Budget

26. If operator can sight target within σ = 2”, then if 16 sets are turned: σ mean = 2” / [sqrt(16)] σ mean = 0.5” If operator can sight target within σ = 1”, then if 4 sets are turned: σ mean = 1” / [sqrt(4)] σ mean = 0.5” Error Budget

27. Combined Effect of C+R Combined (c+r) Equations (from textbooks): c+r = 0.574 M 2 M is distance in miles c+r = 0.574 (0.186) 2 = 0.019 feet c+r = 0.0206 F 2 F is distance in thousands of feet c+r = 0.0206 (0.984) 2 = 0.020 feet c+r = 0.0675 K 2 K is distance in kilometers c+r = 0.0675 (0.300) 2 = 0.006 meters Assume a 300 meter imbalance of BS and FS 300 meters = 0.300 km = 984 feet = 0.186 miles

28. Combined Effect of C+R So, for a 300 meters imbalance in BS and FS distances, we should expect a measured difference in height to be affected by 0.006 meters in each direction. Example – consider known BM “A” is 99.000 meters, and known BM “B” is 98.00 meters. BS =1.000 FS = 2.006 c+r = 0.006 c+r = 0 99.000 98.994 dH = -1.006 meters BS =1.006 FS = 2.000 c+r = 0 c+r = 0.006 98.994 98.000 dH = +0.994 meters A B A B

29. Overall Leveling / River Crossing Diagram River 300 m A B C D EF G H I J All lines are double-run leveling River bank 40 m

30. Limits and Tolerances Examination of: – “FGCS Specifications and Procedures to Incorporate Electronic Digital/Bar-Code Leveling Systems” and – “Standards and Specifications for Geodetic Control Networks” shows several limits and tolerances that could be applied to the new procedure, including: – Least count of theodolite – Number of repeat measurements – Rejection limits from mean – Loop closure Limits and Tolerances

31. Order/ClassLimit (mm) 1/1(3mm ) * sqrt (km) 1/2(4mm ) * sqrt (km) 2/1(6mm ) * sqrt (km) 2/2(8mm ) * sqrt (km) 3(12mm ) * sqrt (km) Rejection Limits from Mean by Order/Class of Leveling Note: at least 2mm will be tolerated for shorter lines See Table 3.1 on page 3-7 of NOAA Manual NOS NGS 3 Geodetic Leveling

32. Limits and Tolerances Order/ClassClosure (mm) 1/1(4mm ) * sqrt (km) 1/2(5mm ) * sqrt (km) 2/1(6mm ) * sqrt (km) 2/2(8mm ) * sqrt (km) 3(12mm ) * sqrt (km) Loop Closures by Order/Class of Leveling Note: at least 4mm will be tolerated for shorter loops See Table 3.1 on page 3-7 of NOAA Manual NOS NGS 3 Geodetic Leveling

33. Limits and Tolerances The least count (L.C.) and standard deviation (S.D.) of the optical total station must be capable of delivering the tolerances as specified for the Order and Class of the leveling in which the crossing will be included (see Table 3-1). Example: What least count and standard deviation would be needed for a 290 meter crossing in a second order, class 1 leveling survey? Table 3-1 requires 6mm x √K The total tolerance for error would be 6 x √.290 = 3.23 mm The error occurs due to angles to bottom and top targets, so each error can be ½ of the total error. Therefore, each angle must be measured to achieve 1.6 mm of error. The angular error β = tan­ -1 (0.0016/290) = 1.1 seconds Because each angle is to be measured 8 times, then the instrumental precision may be estimated from the following equation: σ mean = σ o /√n 1.1 seconds = σ 0 /√8 σ o = 1.1 x √8 σ o = 3.1 seconds The required standard deviation of the measured angles should therefore be +/- 3.1 seconds.

34. Limits and Tolerances Required Standard Deviation (S.D.) by Order/Class and Width Crossing Width (meters)Item1/11/22/12/23 100 - 300S.D. seconds1.42.23.13.96.2 300 - 600S.D. seconds1.11.42.32.84.2 600 - 1000S.D. seconds0.81.11.72.33.4 1000 - 1500S.D. seconds0.70.81.42.02.8 1500 - 2000S.D. seconds0.60.71.11.72.5 Recommended Least Count (L.C.) by Order/Class and Width Crossing Width (meters)Item1/11/22/12/23 100 - 300L.C. seconds0.10.51.0 300 - 600L.C. seconds0.10.5 1.0 600 - 1000L.C. seconds0.1 0.5 1.0 1000 - 1500L.C. seconds0.1 0.5 1.0 1500 - 2000L.C. seconds0.1 0.5

35. Setup 2 marks 300 meters apart – OBSERVATORY and MITCHELL Ran levels between them – elevation difference = 1.01319 m Setup theodolites and observed 20 sets of D+R angles on target sets. Computed elevation differences from angular measurements – OBSERVATORY to MITCHELL = 1.01298 m – compared to leveling difference = 0.00021 meters See diagram and tables to follow Corbin Baseline Test

36. Total Station K OBSERVATORY MITCHELL T1 = 1.53051 T2 = 0.50432 J M N n k j m Height Diff = ? SIDE B SIDE A 0.50021 0.50038 Forward Run from Side A to Side B

37. Total Station K OBSERVATORY MITCHELL T1 = 1.53051 T2 = 0.50432 J M N n k j m Height Diff = ? SIDE B SIDE A 0.50021 0.50038 Backward Run from Side B to Side A

38. Forward Run from Side A to Side B OBSERVATORY to MITCHELL Compute vertical angles j, k, m,n from the zenith angles. Compute distances J, K, M, N by proportion. Angles (for Set 15) j = 0°-52’-48.2” k = 4°-17’-46.0” m = 0°-05’-05.8” n = 0°-01’-21.4” Distances (for Set 15) J = 0.50021 (j ) / (j + k) = 0.08505 m K = 0.50021 (k) / (j + k) = 0.41516 m M = 0.50038 (m) / (m + n) = 0.39519 m N = 0.50038 (n) / (m + n) = 0.10519 m Plate-to-Plate = J – N = -0.02014 m Height Diff = T1 + J – N – T2 = 1.00605 m Backward Run from Side B to Side A MITCHELL to OBSERVATORY Compute vertical angles j, k, m,n from the zenith angles. Compute distances J, K, M, N by proportion. Angles (for Set 15) j = 0°-05’-10.8” k = 0°-01’-14.0” m = 0°-54’-40.0” n = 4°-09’-01.6” Distances (for Set 15) J = 0.50021 (j ) / (j + k) = 0.40402 m K = 0.50021 (k) / (j + k) = 0.09619 m M = 0.50038 (m) / (m + n) = 0.09007 m N = 0.50038 (n) / (m + n) = 0.41031 m Plate-to-Plate = N – J = 0.00629 m Height Diff = T2 + N – J – T1 = -1.01990 m Average Height Difference from OBSERVATORY to MITCHELL = 1.01298 m Leveled Height Difference = 1.01319 m

39. General Recon Recommendations Careful Recon and Setup will make the River Crossing easier.

40. River 300 m 1000 1001 All lines are double- run leveling River bank 1004 1005 1002 1003 River Crossing Diagram

41. Total Station OBSERVATORY MITCHELL Height Diff = ? SIDE B SIDE A General Recon / Setup Pointers Height Diff should be about 15-30 cm LOWER TARGET A to LOWER TARGET B should be about 15-30 cm Total Station River Lines of Sight as high as practical

42. Target Construction NGS has adopted a recommended target MNDOT has modified it for local construction and materials

43. NGS Adopted Targets 6” 12”

44. MNDOT Adopted Targets Cut at 3” width Available for $12 each at FastSigns in Minnetonka, MN or nationwide Dibond material – metal faces sandwiched on 1/16” plastic center. Durable in outdoor exposure. Available in any color combinations.

45. MNDOT Adopted Targets 80/20 Inc. T-Slotted Extrusions Clear Anodized Aluminum Alloy Framing 1530-LITE-97 1.5” x 3.0” x 72” $125 http://www.8020.net/Product- Catalog_2012.asp Permanently mount the 3” piece Add angle clip to back of 9” piece and clamp on if needed Mount 2 Targets per column Also available from Graingers, Inc. catalog pages 250-252 1.5” x 3” Mfg #1530 Grainger # 5JTC1 72” $123.40

46. MNDOT Adopted Targets Angle Clip – 1.5” x 1.5” x 5.5” with 2 holes 0.375” diameter. Corners to be radiused and edges smoothed for safe handling. Hilman #11356 48” length $6.50 at Lowe’s T-Nut & Flanged Button Head Socket Cap Screw, Pkg. of 15. $15.98 at Grainger. Grainger #2RCT7 80/20 Inc #3320-15

47. MNDOT Adopted Targets 2 permanently mounted retro- reflectors on reverse side of target columns (needed only if researching robotic operation) Measured Separation 2” x 3.5” steel top cap (with 5/8” x 11 threaded hole for all target columns) 2” x 3.5” steel bottom cap (with 5/8” x 11 threaded hole for short target columns)

48. MNDOT Adopted Targets Springfield 90817 $9.45 at Amazon Make a hole or a slot in target column. Insert thermometer probe cable within center hollow. Protect thermometer probe cable from abrasion with foam wrap.

49. MNDOT Adopted Targets Leveling Rod Level SECO #7321-050 Standard Rod Level SECO #5001-10 Heads-Up Rod Level SECO #5001-21 Need to have one well-adjusted rod leveling device per target column Post Level JOHNSON #175-O

50. MNDOT Adopted Targets Need 2 Tall Target Sets and 2 Short Target Sets Total Cost about $1750 Short Target mounts on Tripod Tall Target rests directly on benchmark Target Columns $450 Arrow Targets $100 Retro Prisms $1200

51. Bottom of Short Target Rod

52. Bottom of Tall Target Rod

53. Top of Target Rod

54. Prism Attachment

55. Thermometer Attachment

56. Measuring Target Separations Zero-in on target by carefully raising and lowering the level instrument. Read adjacent bar code rod. Repeat several times to get average. Measure both targets and bottom plate. Subtract to get target separations. Example Readings Upper Target: 1.83927 m 1.83904 m 1.83905 m Average = 1.93912 m Example Readings Lower Target: 0.65961 m 0.65968 m 0.65940 m Average = 0.65956 m Target Separation = 1.27956 m Bar-code level and rod ? ? ? Note: For this method, the optical line- of-sight need not be adjusted to exactly match the digital line of sight.

57. Measuring Target Separations

58. Adjust Optical/Digital Line of Sight Setup 1 – Optically sight an exact bottom or top edge of a specific stripe or block on the digital bar-code rod. Obtain digital reading. Setup 2 – Invert the rod. Optically sight the same exact edge of the specific stripe or block on the digital bar-code rod. Obtain a second digital reading. Calculate the discrepancy by subtracting the digital rod readings. Any discrepancy should be adjusted by moving the crosshair reticle up or down slightly and repeating the test.

59. DL = L (α) (T2 – T1) – L = length – Aluminum α = 0.000023 m/m C – T1 = standard temperature (C) – T2 = actual temperature (C) – DL = change in length (m) Correct for Temperature

60. Example: – Length = 1.27956 m at 80⁰F (27⁰C) – Correct to length at 68⁰F (20⁰C) DL = 1.27956 (0.000023) (27 - 20) DL = 0.00021 m Length = 1.27935m at 68⁰F (20⁰C) Correct for Temperature

61. Detailed Notes for MNDOT Rods TALL WHITE ROD UPPER TARGETLOWER TARGETBOTTOM PLATE 1.839270.659610.12797 1.839230.659500.12798 1.839210.659570.12794 1.839040.659680.12783 1.839020.659550.12787 1.839000.659520.12788 1.839010.65950 1.839050.65949 1.839050.65940 AVERAGE 1.839100.659540.12791 UPPER TO LOWER =1.17956 LOWER TO BOTTOM =0.53162 Corrected to 68F UPPER TO LOWER =1.17937 LOWER TO BOTTOM =0.53154 NOTE: Rods measured at 80 degrees F (27C) Corrected to 68 degrees F (20C) Coeff of Expansion for Aluminum = 0.000023 m/m C TALL WHITE ROD UPPER PRISMLOWER PRISMBOTTOM PLATE 1.705630.69642 1.705610.69654 1.705610.69662 1.705710.69662 1.70560.69652 1.705730.69658 1.705680.69668 1.705760.69664 1.705760.69667 AVERAGE 1.705680.696590.12788 UPPER TO LOWER =1.00909 LOWER TO BOTTOM =0.56871 Corrected to 68F UPPER TO LOWER =1.00893 LOWER TO BOTTOM =0.56862 NOTE: Rods measured at 80 degrees F (27C) Corrected to 68 degrees F (20C) Coeff of Expansion for Aluminum = 0.000023 m/m C

62. TALL YELLOW ROD UPPER TARGETLOWER TARGETBOTTOM PLATE 1.843090.627740.12763 1.843150.627710.12770 1.843150.627790.12776 1.843160.627890.12790 1.843130.627780.12799 1.843140.627760.12804 1.843020.627760.12786 1.843110.627790.12784 1.843130.627770.12792 AVERAGE 1.843120.627780.12785 UPPER TO LOWER =1.21534 LOWER TO BOTTOM =0.49993 Corrected to 68F UPPER TO LOWER =1.21515 LOWER TO BOTTOM =0.49985 NOTE: Rods measured at 80 degrees F (27C) Corrected to 68 degrees F (20C) Coeff of Expansion for Aluminum = 0.000023 m/m C Detailed Notes for MNDOT Rods TALL YELLOW ROD UPPER PRISMLOWER PRISMBOTTOM PLATE 1.704720.6622 1.704710.66234 1.704630.6623 1.704820.6623 1.704820.66226 1.704810.66222 1.704770.66216 1.704740.66218 1.704830.66218 AVERAGE 1.704760.662240.12788 UPPER TO LOWER =1.04252 LOWER TO BOTTOM =0.53436 Corrected to 68F UPPER TO LOWER =1.04236 LOWER TO BOTTOM =0.53427 NOTE: Rods measured at 80 degrees F (27C) Corrected to 68 degrees F (20C) Coeff of Expansion for Aluminum = 0.000023 m/m C

63. Target Separations @68F Arrow TargetsTall White Rod Tall Yellow Rod Short White Rod Short Yellow Rod Upper Target 1.17937 m1.21515 mn/a Lower Target 0.53154 m0.49985 mn/a Bottom Plate Prism TargetsTall White Rod Tall Yellow Rod Short White Rod Short Yellow Rod Upper Prism 1.00893 m1.04236 mn/a Lower Prism 0.56862 m0.53427 mn/a Bottom Plate

64. Hastings Bridge Area – Plan for new BM’s (July 2014) – Conduct leveling (July 2014) – Conduct 3 River Crossings (July- August 2014) 2 across the Mississippi River 1 along the south shore (verify w/ double-run leveling) MNDOT River Crossing Validation

65. Hastings Bridge Area Leveling River 300 m 1001 Control Leveling Plan 1001 to 1003 double-run leveling on same bank of river 1003 to 1007 double-run leveling across bridge River bank 1004 1002 1003 1006 1005 1007 1008 River Crossings Plan 1002 to 1008 use new River Crossing Procedure 1008 to 1004 use new River Crossing Procedure 1004 to 1002 use new River Crossing Procedure Verification Plan Summation of 3 River Crossings should = 0.000 m Comparison of River Crossings to 2/1 Leveling

66. Hastings Bridge Crossings

68. There are measurements on 2 benchmarks, 2 instruments, 2 rods, 2 setups, 4 targets, and 4 prisms to manage. Need to create a reasonable method to keep all the data correct. A sketch with filenames and point numbers is needed. Avoid 1000-series numbers (reserved for regular level line bench marks). River Crossing Point Naming

69. Yellow RodWhite Rod Setup # 1 – Triangle Targets 2301 - 2324 2401 - 2424 2101 - 2124 2201 - 2224 3101 - 3124 3201 - 3224 3301 - 3324 3401 - 3424 2000 low series 3000 low series Yellow Rod White Rod

70. River Crossing Point Naming 2501 - 2524 2601 - 2624 3701 - 3724 3801 - 3824 Setup # 2 – Triangle Targets 2701 - 2724 2801 - 2824 3501 - 3524 3601 - 3624 2000 high series 3000 high series Yellow Rod White Rod

71. River Crossing Point Naming 4101 - 4124 4201 - 4224 5301 - 5324 5401 - 5424 Setup # 1 – Prism Targets 4301 - 4324 4401 - 4424 5101 - 5124 5201 - 5224 4000 low series 5000 low series Yellow Rod White Rod

72. River Crossing Point Naming Setup # 2 – Prism Targets 4701 - 4724 4801 - 4824 4501 - 4524 4601 - 4624 5501 - 5524 5601 - 5624 5701 - 5724 5801 - 5824 4000 high series 5000 high series Yellow Rod White Rod

73. River Crossing Observations

74. If the air refracts the forward sight down by 0.002 m, it also refracts the backward sight down by 0.002 m. The effect on the height differences is equal, but opposite. Therefore, the average eliminates the error. A plot of the individual results should show the effect - - - > Effectiveness of Dual-Simultaneous Observations

75. This plot is messy, but it shows that when the forward sight (red) increases, the backward sight (blue) decreases a similar amount. The average (green) line is shown. Ideally, these plots should be mirror-flipped images like the faces. But not every sighting is perfect. (this is actual data from Hastings River Crossing August 13, 2014)

76. Example Data from Hastings River Crossing YELLOW Setup 1WHITE Setup 1Diff = 2x(c+r)Average Ht Diff -0.562820.53316-0.02966-0.54799 -0.562650.53294-0.02971-0.54779 -0.563650.53611-0.02754-0.54988 -0.563880.53422-0.02967-0.54905 -0.564120.53440-0.02972-0.54926 -0.563540.53410-0.02945-0.54882 -0.563550.53397-0.02958-0.54876 -0.563500.53395-0.02954-0.54873 -0.564220.53381-0.03041-0.54901 -0.563730.53444-0.02929-0.54909 -0.564080.53551-0.02857-0.54980 Averages -0.563640.53424-0.02938-0.54892 Note: C+R formula predicts 0.0137 meters, Therefore expect 2 x 0.0137 = 0.02734 meters

77. Example Data from Hastings River Crossing YELLOW Setup 1 WHITE Setup 1 Average Ht Diff Diff = 2x(c+r) Check for Outliers

78. Example Data from Hastings River Crossing Lower Target to Lower Target ForwardBackwardAve Run 1-0.563640.53424-0.54894 Run 2-0.563450.53317-0.54831 diff-0.00063 Bench Mark to Bench Mark ForwardBackwardAve Run 1-0.595330.56593-0.58063 Run 2-0.595140.56486-0.58000 diff-0.00063 Allowable 1/13mm (sqrt KM) =0.00222 DISTANCES (m)Setup 1Setup 2 Yellow BS12.880 Yellow FS440.919440.579 White BS20.72820.745 White FS432.441432.574 RUNNING LENGTHSSetup 1Setup 2 Yellow453.798453.459 White453.169453.319

79. Hastings Bridge Crossing Results River ForwardBackwardAverage Run 1-0.150450.12400-0.13722 Run 2-0.151100.12295-0.13703 diff-0.00020 ForwardBackwardAverage Run 10.42591-0.461570.44374 Run 20.42699-0.462520.44476 diff-0.00102 ForwardBackwardAverage Run 1-0.595330.56593-0.58063 Run 2-0.595140.56486-0.58000 diff-0.00063 ForwardBackwardAverage Run 10.44861 *-0.446640.44762 Run 20.4460-0.44590.44595 River Crossing 1 (8-06-2014) River Crossing 3 (8-20-2014) River Crossing 2 (8-13-2014) 2/1 Leveling 450 meters 408 meters 454 meters ForwardBackwardAverage Run 1-0.1340 Run 2 2/1 Leveling Using Arrow Targets Manual pointings Allowable 1/1 = 3mm(√.450km) = 0.00201 m Actual = 0.0017 m OK Allowable 1/1 = 3mm(√1.312 km) = 0.00343 m Actual = 0.00106 m OK Loop Closure BRENNA 2014 TBM 1 TBM 2 Note: * = suspect data Allowable 1/1 = 3mm(√2.572 km) = 0.0048 m Actual = 0.0031 m OK

80. Hastings Bridge Crossing Results River ForwardBackwardAverage Run 1-0.149220.12538-0.13730 Run 2-0.151780.12496-0.13837 diff0.00107 ForwardBackwardAverage Run 10.42768-0.461120.44440 Run 20.42825-0.461910.44508 diff-0.00068 ForwardBackwardAverage Run 1-0.594210.56710-0.58065 Run 2-0.59816 *0.56739-0.58277 diff0.00212 River Crossing 1 (8-06-2014) River Crossing 3 (8-20-2014) River Crossing 2 (8-13-2014) 2/1 Leveling 450 meters 408 meters 454 meters ForwardBackwardAverage Run 1-0.1340 Run 2 2/1 Leveling Using Prism Targets Autolock pointings BRENNA 2014 TBM 1 TBM 2 Allowable 1/1 = 3mm(√1.312 km) = 0.00343 m Actual = 0.00086 m OK Loop Closure Allowable 1/1 = 3mm(√.450km) = 0.00201 m Actual = 0.0012 m OK ForwardBackwardAverage Run 10.44861 *-0.446640.44762 * Run 20.4460-0.44590.44595 Note: * = suspect data Allowable 1/1 = 3mm(√2.572 km) = 0.0048 m Actual = 0.0031 m OK Note: This slide contains data that is suspect due to malfunctioning autolock (caused by operator error).

81. Hastings Bridge Crossing Results River ForwardBackwardAverage Run 1-0.148550.12448-0.13652 Run 2-0.148730.12430-0.13651 diff0.00000 ForwardBackwardAverage Run 10.42875-0.460520.44463 Run 20.42782-0.462060.44494 diff-0.00031 ForwardBackwardAverage Run 1-0.595220.57806 *-0.58664 * Run 2-0.595660.56714-0.58140 diff-0.00524 River Crossing 1 (8-27-2014) River Crossing 3 (8-27-2014) River Crossing 2 (8-27-2014) 2/1 Leveling 450 meters 408 meters 454 meters ForwardBackwardAverage Run 1-0.1340 Run 2 2/1 Leveling Using Prism Targets Autolock pointings BRENNA 2014 TBM 1 TBM 2 Allowable 1/1 = 3mm(√1.312 km) = 0.00343 m Actual = 0.00010 m OK Loop Closure Allowable 1/1 = 3mm(√.450km) = 0.00201 m Actual = 0.00116 m OK ForwardBackwardAverage Run 10.44861 *-0.446640.44762 * Run 20.4460-0.44590.44595 Note: * = suspect data Allowable 1/1 = 3mm(√2.572 km) = 0.0048 m Actual = 0.0025 m OK Note: surveyor reports Bobcat working in area causing vibrations.

82. Hastings Bridge Crossing Results River ForwardBackwardAverage Run 10.4298-0.46510.4474 Run 2 River Crossing 1 (8-27-2014) 2/1 Leveling 450 meters Using Prism Targets Autolock pointings BRENNA 2014 TBM 1 TBM 2 Allowable 1/1 = 3mm(√.450km) = 0.00201 m Actual = 0.00145 m OK ForwardBackwardAverage Run 10.44861 *-0.446640.44762 * Run 20.4460-0.44590.44595 Note: * = suspect data Single prism on FIXED Height Tripods and automated rounds ForwardBackwardAverage Run 10.4301-0.46290.4465 Run 2 River Crossing 1 (9-2-2014) 2/1 Leveling Allowable 1/1 = 3mm(√.450km) = 0.00201 m Actual = 0.00055 m OK ForwardBackwardAverage Run 10.44861 *-0.446640.44762 * Run 20.4460-0.44590.44595

83. The new total station-based procedure has NOT yet been officially adopted and approved by NGS. Users may NOT yet submit results of surveys using these procedures to NGS as part of Bluebook surveys. Cautionary Statement

84. Questions The End