BILL HENNING, Prof LS. ACRONYMS

Transcription

1 BILL HENNING, Prof LS. ACRONYMS US 1

2 WIKIPEDIA: Also known as geodetics, geodetic engineering or geodetics engineering a branch of applied mathematics [2] and earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth (or any planet), including its gravitational field, in a three-dimensional time-varying space. Geodesists also study geodynamical phenomena such as crustal motion, tides, and polar motion. For this they design global and national control networks, using space and terrestrial techniques while relying on datums and coordinate systems. A SET OF CONSTANTS SPECIFYING THE COORDINATE SYSTEM USED FOR GEODETIC CONTROL, I.E., FOR CALCULATING COORDINATES OF POINTS ABOVE, ON OR BELOW THE EARTH. SPECIFIC GEODETIC DATUMS ARE USUALLY GIVEN DISTINCTIVE NAMES. (E.G., NORTH AMERICAN DATUM OF 1983, EUROPEAN DATUM 1950, NATIONAL GEODETIC VERTICAL DATUM OF 1929) REALIZED BY A SET OF PASSIVE MARKS OR ACTIVE STATIONS BASED ON SATELLITE ORBITAL POSITIONS 2

3 DIFFERENT APPROACHES TO DATUMS SURVEYORS GEODESISTS SURVEYORS K.I.S.S. VS. GEODESISTS OBSESIVE-COMPULSIVE COMPLEX.. Cartography LiDAR Digital Terrain Model Aerial Photography Engineering Laser Scan Model NATIONAL SPATIAL REFERENCE SYSTEM - TIES IT ALL TOGETHER Satellite Imagery Hydrography Horizontal / Vertical Control (NSRS) 3

4 GNSS CORS USER 200 DATA PROVIDERS 2000 STATIONS DAILY PROCESSING MAINTAINED IN IGS 08 (2005) TRANSFORMED TO NAD 83 DAILY AND LONG TERM DATA SERIES LOOSER POSITIONS THAN A LOCAL RTN BACKBONE CORS TO BE OWNED & OPERATED BY NGS THE NATIONAL CORS 4

5 CORS & PASSIVE MONUMENTATION 5

6 Zero Meridian -Y - Z -X GEODETIC DATUM= SURFACE ORIENTATION SCALE ORIGIN + GRAVITY X Mean Equatorial Plane -Z Y AUTONOMOUSGNSS POSITIONS ARE ECEF, XYZ IN WGS 84 (~ITRF, IGS) An ellipsoid of revolution is the figure which would be obtained by rotating an ellipse about its shorter axis. An ellipsoid of revolution describing the figure of the Earth is called a reference ellipsoid. b = 6,356, m a= meters b= meters f= 1/((a-b)/a) = GRS 80 = AN OBLATE SPHEROID a = 6,378, m 6

7 EARTH-CENTERED-EARTH-FIXED COORDINATES Z Axis Conventional Terrestrial Pole P (X,Y,Z) Earth s Surface Zero Meridian Origin (0,0,0) Center of Mass Y Z X Y Axis X Axis Mean Equatorial Plane Zero Meridian Z Axis GPS = ELLIPSOID HEIGHTS h P (X,Y,Z) = P (φ,λ,h) Earth s Surface Reference Ellipsoid λ φ Y Axis X Axis Mean Equatorial Plane 7

8 BESSEL 1841 ( ) a = 6,377, m 1/f = CLARKE 1866 ( ) a = 6,378,206.4 m 1/f = GEODETIC REFERENCE SYSTEM (GRS 80) ( Present) a = 6,378,137 m 1/f = WORLD GEODETIC SYSTEM (WGS 84) a = 6,378,137 m 1/f = THE EQUIPOTENTIAL GRAVITY SURFACE WHICH BEST APPROXIMATES, IN A LEAST SQUARES SENSE, GLOBAL MEAN SEA LEVEL. 8

9 Geopotential Numbers allow for LEVEL SURFACES AND ORTHOMETRIC correction of leveling differences to account for different gravity surfaces HEIGHTS (equipotential surfaces) along leveling routes. Level Surfaces P W P Mean Sea Level Plumb Line Geoid W O P O Ocean Level Surface = Equipotential Gravity Surface (W) H (Orthometric Height) = Distance along plumb line (P O to P) Geopotential (C P ) = W P -W O EQUAL FORCE APPLIED DOES NOT PRODUCE A LEVEL SURFACE AN EQUAL ENERGY SURFACE DOES CONSTITUTE A LEVEL SURFACE THEREFORE, AN EQUIPOTENTIAL SURFACE, DEFINED HERE AS GRAVITATIONAL ENERGY IS DENOTED AS A GEOID OR A SURFACE UPON WHICH WATER WILL NOT FLOW UNLESS ACTED UPON BY OUTSIDE FORCES. THERE ARE AN INFINITE AMOUNT OF EQUIPOTENTIAL SURFACES, HOWEVER A GEOID SURFACE THAT BEST APPROXIMATES GLOBAL MEAN SEA LEVEL IN A LEAST SQUARES SENSE IS THE GEOID OR 0 DATUM SURFACE. 9

10 H 88 = h 83 N 12a 10

11 .THE TILT OF NAVD 88 RELATIVE TO THE GRAVIMETRIC GEOID NAVD 88 = USING NAD 83 ELLIPSOID HEIGHTS WITH THE HYBRID GEOID FOR ORTHO HEIGHTS H88 = h83 N12a -NAD 83 (HARN) USE GEOID O3 -NAD 83 (CORS 96) USE GEOID 09 -NAD 83 (2007) USE GEOID 09 -ITRF USE SCIENTIFIC GEOID (USGG) -NAD 83 (2011) USE GEOID 12a 11

12 WHAT DATA IS USED IN HYBRID GEOID MODELS? LONG WAVELENGTH (GLOBAL) GEOPOTENTIAL MODEL: 1MIN. X1 MIN. GRID (EGM 2008, GRACE, GOCE) MEDIUM WAVELENGTH (REGIONAL) SURFACE GRAVITY MEASUREMENTS SHORT WAVELENGTH: (LOCAL, 26,000 GPS ON BENCH MARKS, DIGITAL ELEVATION MODELS -1 ARCSECOND X 1 ARCSECOND GRID) CORRECTOR SURFACE: GRAVIMETRIC GEOID TO HYBRID GEOID EGM08 + NGSDEM99 +KMS98 (Andersen and Knudsen 1998) offshore Free-air gravity anomaly (FAGA) field with the GSFC00.1 model (Wang 2001) IGS08/NAD83 ORIGIN TRANSFORMATION NAVD 88 BIAS (-52 CM) TILT (0.15 PPM, 327 AZIMUTH) LOCAL GPS/LEVELING/GEOID MISFIT EXAMPLE: USGG CONVERSION SURFACE = GEOID16b 12

13 13

14 HYBRID & GRAVIMETRIC GEOID HEIGHT MODELS, AND CONVERSION SURFACES USING GPS ON BM DATA Earth s Surface h h h h H H N H N h H Ellipsoid N N H N Hybrid Geoid Gravimetric Geoid Gravimetric Geoid systematic misfit to BM s but best fits true heights Hybrid Geoid converted to fit local BM s, so best fits NAVD 88 heights Conversion Surface model of systematic misfit derived from BM s in IDB 14

15 4 HYBRID GEOID MODELS ACROSS BALTIMORE COUNTY, MD WHAT ABOUT CONVERTING TO/FROM NAVD 88? A CONVERSION WILL BE PROVIDED BETWEEN NAVD 88 AND THE NEW DATUM ONLYTHE WHERE IN NEW YORK THE DIFFERENCE BETWEEN NAVD 88 AND NEW RECENT GEOPOTENTIAL DATUM COULD BE AROUND 1.3 FEET. (NAVD WOULD HAVE A GNSS ELLIPSOID HEIGHTS EXIST TO88PROVIDE GREATER NUMERIC MODERN VALUE) HEIGHTS IN THE NEW DATUM 15

16 CLARKE 1866 GRS80 &WGS84 Earth Mass Center Approximately 236 meters GEOID SCIENTIFIC 4 D (LATITUDE, LONGITUDE, ELLIPSOID HEIGHT, VELOCITY) COORDINATES CHANGE WITH TIME (E.G. ITRF14, ITRF08) 16

17 INTERNATIONAL TERRESTRIAL REFERENCE SYSTEM THE GOLD STANDARD FOR THE VERY HIGHEST ACCURACY GEODESY AND GEOPHYSICS SURVEYING IS THE INTERNATIONAL TERRESTRIAL REFERENCE FRAME (ITRF). THE ITRF IS PRODUCED BY THE INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEM SERVICE (IERS). MANY ORGANIZATIONS PARTICIPATE IN THIS EFFORT BY CONTRIBUTING RESULTS FROM VARIOUS TECHNOLOGIES INCLUDING GNSS. (SEE FOR MORE INFORMATION). 17

18 DEVELOPED AND MAINTAINED BY THE INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEM SERVICE PARIS, FRANCE ( VERY LONG BASELINE INTERFEROMETRY - (VLBI) SATELLITE LASER RANGING - (SLR) GLOBAL POSITIONING SYSTEM - (GPS) DOPPLER ORBITOGRAPHY AND RADIO POSITIONING INTEGRATED BY SATELLITE - (DORIS) ITRF89, ITRF90, ITRF91, ITRF92, ITRF93, ITRF94, ITRF95, ITRF96, ITRF97, ITRF2000, ITRF2005, ITRF2008, ITRF2014 GEOCENTRIC +/- 3 to 4 CM MODELS FOR PLATE TECTONICS STATION VELOCITIES POSITIONAL STANDARD ERRORS REALIZED AS THE INTERNATIONAL TERRESTERIAL REFERENCE FRAME (ITRF) 18

19 INTERNATIONAL TERRESTRIAL REFERENCE FRAME 4 GLOBAL INDEPENDENT POSITIONING TECHNOLOGIES INTERNATIONAL TERRESTRIAL REFERENCE FRAME 4 GLOBAL INDEPENDENT POSITIONING TECHNOLOGIES INTERNATIONAL GLOBAL NAVIGATION SATELLITE SYSTEMS SERVICE (IGS) INTERNATIONAL LASER RANGING SERVICE (ILRS) INTERNATIONAL VERY LONG BASELINE SERVICE (IVS) INTERNATIONAL DORIS SERVICE (IDS) 19

20 SILVER SPRING, MD ITRF 2000 NAD 83 20

21 NAD 83 VELOCITIES (GOLD) SANTA CRUZ, CA ITRF 2000 VELOCITIES (BLUE) THE INTERNATIONAL GNSS SERVICE (IGS) THE INTERNATIONAL GNSS SERVICE (IGS) PARTICIPATES IN THE IERS AND PRODUCES DENSIFIED, GNSS-ONLY REALIZATIONS OF THE ITRF. 21

22 GPS REALIZATION OF THE ITRF REFERENCE FRAME WORLD GEODETIC SYSTEM DATUM = WGS 84 DATUMRELEASED = WGS 84(G730) - SEPTEMBER 1987(1762) DATUM =Stations WGS 84 DATUM = Tracking WGS 84(G873) DATUM = WGS 84(G1150) 5 USAF GPS BASED ON OBSERVATIONS AT MORE 5 USAF GPS Tracking Stations Datum redefined with respect to the International DATUM = WGS 84(G1674) ITRF 2008 EPOCH DMA Evaluation Stations THAN 1900 DOPPLER STATIONS 7 NIMA Evaluation Stations Terrestrial Reference Frame ofrespect 2000 (ITRF00) Datum redefined with respect to the International Datum redefined with to the International 0.01 M SHIFT Datum redefined with respect to the +/- 2 cm in each component TerrestrialHOW Reference Frame of 2008 (ITRF08, epoch ) Terrestrial Reference Frame of 1992 (ITRF92) +/- 20 MANY WGS 84s International Terrestrial Reference Frame of (Proceedings of the ION GPS-02) +/- 1 cm in each component cm in each component (ITRF94) +/- 10 in each component HAVE(Proceedings THERE BEEN???? of the IONcm GPS-94 pgs ) (Proceedings of the ION GPS-97 pgs ) 22

23 Federal Register Notice: Vol. 60, No. 157, August 15, 1995, pg Use of NAD 83/WGS 84 Datum Tag on Mapping Products DATUM TAGS AND EPOCHS Frame Type Frame Name Ref. Epoch Antenna PCV Type* Data Duration Global ITRF RelAnt Global ITRF00 (NGS's soln) RelNGSAnt present Plate-fixed NAD 83 (CORS96) RelNGSAnt present Global IGS AbsIGS08Ant Global IGS08 (NGS's soln) AbsIGS08Ant (ongoing) Plate-fixed NAD 83(2011) AbsIGS08Ant (ongoing) 23

24 ITRF2014, IGS14, AND NAD 83 IN 2016, THE IERS RELEASED AN UPDATED REALIZATION FOR THE ITRF CALLED THE ITRF2014. THE ITRF2014 IS EXPRESSED THROUGH THE COORDINATES AND VELOCITIES OF 158 MARKS PLUS SUPPORTING INFORMATION. OTHER ORGANIZATIONS CAN TAKE THIS INFORMATION, ADD DATA FROM THEIR OWN MARKS, PERFORM THEIR OWN ADJUSTMENT AND ALIGN IT TO THE ITRF2014. THIS IS CALLED DENSIFYING THE REFERENCE FRAME. WHILE THESE DENSIFICATION VARIANTS ARE FORMALLY CONSISTENT WITH THE ITRF2014, THEY ARE UNIQUE FROM THE ITRF2014 IN THE STRICTEST SENSE; THEREFORE, THEY ARE GIVEN UNIQUE NAMES. ITRF REALIZATION CHANGES 24

25 DENSIFICATION IGS 14 THE INTERNATIONAL GNSS SERVICE (IGS) PARTICIPATES IN THE IERS AND PRODUCES DENSIFIED, GNSS-ONLY REALIZATIONS OF THE ITRF. THE IGS14 WILL INCLUDE COORDINATES AND VELOCITIES FOR 252 SITES, BUT SHOULD ALSO BE THOUGHT OF AS INCLUDING UPDATED GNSS EPHEMERIDES, ANTENNA MODELS AND OTHER SUPPORTING INFORMATION. AS RELEASE DATE NEARS, INFORMATION WILL BE MADE AVAILABLE BY THE IGS (SEE 25

26 CLASSICAL, PRACTICAL & SCIENTIFIC DATUMS HORIZONTAL 2 D (LATITUDE AND LONGITUDE) [E.G. NAD 27, NAD 83 (1986)] VERTICAL 1 D (ORTHOMETRIC HEIGHT) (E.G. NGVD 29, NAVD 88, LOCAL TIDAL) GEOMETRIC 3 D (LATITUDE, LONGITUDE AND ELLIPSOID HEIGHT) FIXED AND STABLE - COORDINATES SELDOM CHANGE [E.G. NAD 83 (1991), NAD 83 (2007), NAD 83 (2011) ] 4 D (LATITUDE, LONGITUDE, ELLIPSOID HEIGHT, VELOCITIES) COORDINATES CHANGE WITH TIME (E.G. ITRF14, IGS08, NEW NATREF2022) HORIZONTAL/ GEOMETRIC: NAD 83 ITRS WGS 84 NATRF 2022 VERTICAL/GEOPOTENTIAL: NGVD 29 NAVD 88 NAPGD 2022 PROJECTIONS FROM DATUMS: SPC UTM LDP 26

27 U.S.HORIZONTAL DATUMS NORTH AMERICAN DATUM 1983 (1986 PRESENT) NORTH AMERICAN DATUM 1927 ( ) NORTH AMERICAN DATUM ( ) U.S. STANDARD DATUM ( ) NEW ENGLAND DATUM ( ) ALASKA DATUMS (17 Different ) BESSEL ELLIPSOID ( ) EASTERN OBLIQUE ARC WITH NEW ENGLAND DATUM

28 U.S. STANDARD DATUM OF cgi-bin/moin.cgi/transcontinentaltriangulation?highlight=%28transcontinental%29 NAD 1913 TO NAD NAD 27 becomes the 2nd continuous, continental scale datum of the United States 98TH MERIDIAN SURVEY 141ST MERIDIAN 28

29 FIRST CIVILIAN DATUMS DESIGNED TO BE CONSISTENT WITH SPACE-BASED OBSERVATIONS (GPS) FIRST CIVILIAN DATUMS TO BE BEST-FITTING GLOBALLY NOT LOCALLY FIRST GEODETIC REFERENCE SYSTEMS TO BE FULLY AUTOMATED FIRST GEODETIC REFERENCE SYSTEMS TO BE AVAILABLE FREE FROM WWW ONLY REFERENCE SYSTEM TO FREELY INTEGRATE DATA FROM OUTSIDE SOURCES NAD 27 NAD 27 Φ= 39o λ = 98o h = m Azimuth α = 255o

30 NAD 27 ELLIPSOID CLARKE 1866 A = 6,378,206.4 M 1/F = DATUM POINT TRIANGULATION STATION MEADES RANCH, KANSAS ADJUSTMENT 25K STATIONS SEVERAL HUNDRED BASE LINES AZIMUTHS 5K ASTRO AZIMUTHS NAD 83 GRS80 A = 6,378,137. M 1/F = NONE EARTH MASS CENTER 250K STATIONS APPOX. 30K EDMI BASE SEVERAL HUNDRED ASTRO DOPPLER POINT POSITIONS VLBI VECTORS BEST FITTING NORTH AMERICA WORLD-WIDE 30

31 LONGITUDE SHIFTS BETWEEN NAD 27 AND NAD 83(1986) Velocity Field NAD 83 CORS (2011)IGS08 EPOCH VELOCITIES IGS08 epoch ~1270 CORS w/ suff. data and linear velocities 31

32 CHANGES IN HORIZONTAL NAD 83 POSITIONS NAD 83(2011) EPOCH NAD 83(CORS96) EPOCH approx. 2 cm error (based on σ in old solution) avg. horizontal shifts: E = 0.09 (± 5.84) cm N = 2.03 (± 5.98) cm combination of position and velocity differences due mostly to updated velocities (including up to 8 more years of data) 1270 CORS w/ suff. data and linear velocities CHANGES IN VERTICAL NAD 83 POSITIONS NAD 83(2011) EPOCH NAD 83(CORS96) EPOCH NAD 83(2011) epoch NAD 83(CORS96) epoch avg. vertical shifts: U = (± 2.09) cm combination of position and velocity differences from additional data, tectonics assuming vertical velocity 0.00 in NAD 83(CORS96) ~1270 CORS w/ suff. data and linear velocities 32

33 NY NAD 83 POSITIONAL CHANGES NAD 27 to NAD 83 (1986) ~ 30 m NAD 83 (1986) to NAD 83 (1996, 2001 HARN) ~ 0.17 m NAD 83 (1996, 2001 HARN) to NAD 83 (2007) ~ m NAD 83 (2007) to NAD 83 (CORS 96) epoch 2002 ~ 0.01 m NAD 83 (COR 96) epoch 2002 to NAD 83 (2011) epoch 2010 ~ <0.01 m horiz., maybe 2 cm h (mostly from change in datum epoch) [NAD 83 (2011) TO NATRF2022 ~ 1 m HORIZ.!, 1.2 m h!] 33

34 RTN AND NGS FOUNDATION CORS WILL BE THE PRIMARY ACCESS TO THE NSRS CORS NETWORK CONTINUED GROWTH ACTIVE SITES USED IN NAD 83(2011) 34

35 FOUNDATION CORS LINK TO ITRF AT SITES CO-LOCATED WITH VLBI, SLR, DORIS, THEN GEOGRAPHIC GAPS ~10 IN CONUS + AK, HW AND US TERR. LIMITED INTERNATIONAL DRILLED BRACED MONUMENTS TIME-LINE: ~2 SITES/YEAR START FY10-11 POSSIBLE SITES MAGENTA OVALS DEFINING REFERENCE STATIONS IN NAD 83 NAD 83 (1986) : 250,000 PRIMARILY TRIANGULATION, NO GPS NAD 83 (2007): 80,000 ALL GPS NAD 83 (BACKBONE): DOZEN +/- PLANNED, NGS OWNED & OPERATED, MOSTLY WITH IGS SITES 35

36 OBSERVED CHANGES IN CORS POSITIONAL COORDINATES COORDINATES WILL BE RIGOROUSLY REVIEWED EVERY 6 MONTHS. ON A WEEKLY BASIS IF A PROBLEM WITH A SITE IS IDENTIFIED, SITE FLAGGED AS PROBLEM, E.G. CURRENTLY DO NOT HAVE AN AUTOMATED WAY TO DEAL WITH EARTHQUAKE OFFSETS/ VELOCITY CHANGES, UNDOCUMENTED/UNEXPLAINED EQUIPMENT CHANGE WHAT AMOUNT OF CHANGE/TOLERANCE ARE PERMITTED? WILL REMAIN 2 CM HORIZONTAL, 4 CM VERTICAL NAD 83 WILL REMAIN 1 CM HORIZONTAL, 2 CM VERTICAL GLOBAL ALL USERS SHOULD USE IGS08 CONSISTENT ABSOLUTE ANTENNA PCV VALUES 36

37 37

38 A SET OF FUNDAMENTAL ELEVATIONS TO WHICH OTHER ELEVATIONS ARE REFERRED. DATUM TYPES TIDAL DEFINED BY OBSERVATION OF TIDAL VARIATIONS OVER SOME PERIOD OF TIME (MSL, MLLW, MLW, MHW, MHHW ETC.) GEODETIC EITHER DIRECTLY OR LOOSELY BASED ON MEAN SEA LEVEL AT ONE OR MORE POINTS AT SOME EPOCH (NGVD 29, NAVD 88, IGLD85 ETC.) HISTORY OF VERTICAL DATUMS IN THE USA PRE-NATIONAL GEODETIC VERTICAL DATUM OF 1929 (NGVD 29): THE FIRST GEODETIC LEVELING PROJECT IN THE UNITED STATES WAS SURVEYED BY THE COAST SURVEY FROM 1856 TO TRANSCONTINENTAL LEVELING COMMENCED FROM HAGERSTOWN, MD IN GENERAL ADJUSTMENTS OF LEVELING DATA YIELDED DATUMS IN 1900, 1903, 1907, AND (SOMETIMES REFERENCED AS THE SANDY HOOK DATUM) NGS DOES NOT OFFER A UTILITY WHICH TRANSFORMS FROM THESE OLDER DATUMS INTO NEWER ONES (THOUGH SOME USERS STILL WORK IN THEM!) 38

39 1ST GENERAL ADJUSTMENT ND GENERAL ADJUSTMENT

40 3RD GENERAL ADJUSTMENT TH GENERAL ADJUSTMENT

41 MEAN SEA LEVEL DATUM OF 1929 NATIONAL GEODETIC VERTICAL DATUM OF 1929 (As of July 2, 1973) NORTH AMERICAN VERTICAL DATUM OF 1988 (As of June 24, 1993) NGVD 29 VERTICAL DATUM NGVD 29 NATIONAL GEODETIC VERTICAL DATUM OF 1929 ORIGINAL NAME: SEA LEVEL DATUM OF 1929 ZERO HEIGHT HELD FIXED AT 26 TIDE GAUGES NOT ALL ON THE SAME TIDAL DATUM EPOCH (~ 19 YRS) DID NOT ACCOUNT FOR LOCAL MEAN SEA LEVEL VARIATIONS FROM THE GEOID THUS, NOT TRULY A GEOID BASED DATUM 41

42 NAVD 88 DEFINITION: THE SURFACE OF EQUAL GRAVITY POTENTIAL TO WHICH ORTHOMETRIC HEIGHTS SHALL REFER IN NORTH AMERICA*, AND WHICH IS METERS (ALONG THE PLUMB LINE) BELOW THE GEODETIC MARK AT FATHER POINT/RIMOUSKI (NGSIDB PID TY5255). REALIZATION: OVER 500,000 GEODETIC MARKS ACROSS NORTH AMERICA WITH PUBLISHED HELMERT ORTHOMETRIC HEIGHTS, MOST OF WHICH WERE ORIGINALLY COMPUTED FROM A MINIMALLY CONSTRAINED ADJUSTMENT OF LEVELING AND GRAVITY DATA, HOLDING THE GEOPOTENTIAL VALUE AT FATHER POINT/RIMOUSKI FIXED

43 ORTHOMETRIC HEIGHTS COMPARISON OF VERTICAL DATUM ELEMENTS NGVD 29 DATUM DEFINITION TIDAL DATUM EPOCH BENCH MARKS LEVELING (Km) GEOID FITTING 26 TIDE GAUGES IN THE U.S. & CANADA NONE 100, ,724 Distorted to Fit MSL Gauges NAVD 88 FATHER SPOINT/RIMOUSKI QUEBEC, CANADA ,000 1,001,500 Best Continental Model 43

44 NAVD 88 COMPARED TO MSL NAVD 88 LMSL ( ) Units = CM NAVD 88 NORTH AMERICAN VERTICAL DATUM OF 1988 WAS A POLITICAL CHILD: ONE HEIGHT HELD FIXED AT FATHER POINT (RIMOUSKI, CANADA) HEIGHT CHOSEN WAS TO MINIMIZE 1929/1988 DIFFERENCES IN USGS MAPS & TO BE ALIGNED TO THE IGLD. THUS, THE ZERO HEIGHT SURFACE OF NAVD 88 WASN T CHOSEN FOR ITS CLOSENESS TO THE GEOID (BIASED 0.5 M) 44

45 NAVD 88 (CONTINUED) USE OF ONE FIXED HEIGHT REMOVED LOCAL SEA LEVEL VARIATION PROBLEM OF NGVD 29 USE OF ONE FIXED HEIGHT DID OPEN THE POSSIBILITY OF UNCONSTRAINED CROSS-CONTINENT RANDOM & THEORETICAL ERROR BUILD UP BUT THE H=0 SURFACE OF NAVD 88 WAS SUPPOSED TO BE PARALLEL TO THE GEOID (BUT IS TILTED FROM 0.16 M TO M) TIDAL DATUMS HEIGHTS MEASURED ABOVE LOCAL MEAN SEA LEVEL NATIONAL TIDAL DATUM EPOCH; 19 YEAR SERIES ENCOMPASSES ALL SIGNIFICANT TIDAL PERIODS INCLUDING 18.6 YEAR PERIOD FOR REGRESSION OF MOON S NODES AVERAGES OUT NEARLY ALL METEOROLOGICAL, HYDROLOGICAL, AND OCEANOGRAPHIC VARIABILITY LEVELING IS USED TO DETERMINE RELATIONSHIP BETWEEN BENCH MARKS AND TIDAL GAUGES 45

46 NATIONAL WATER LEVEL OBSERVATION NETWORK WATER LEVEL PLUS: WIND SPEED/DIRECTION BAROMETRIC PRESSURE AIR/WATER TEMP. CONDUCTIVITY/TEMP TSUNAMI/STORM SURGE DATA TRANSMISSION NWLON TIDAL BENCH MARKS NEED GNSS LOCATIONS 46

47 ACCESSING WATER LEVEL DATA FROM COOPS COOPS TIDAL BM S 47

48 COOPS TIDAL BM S 48

49 49

50 THE SHORTCOMING OF NAD 83. NAD 83 (2011) h WILL BE ABOUT +1.2 M (4.0 +/-) GREATER IN VALUE THAN NATRF2022 h IN NEW YORK STATE MOVE GEOCENTER TO IGS GEOCENTER AT SOME EPOCH OF TIME. COORDINATES WILL BE IDENTICAL TO IGS AT THIS EPOCH OF TIME, BUT WILL THEN DIVERGE, BECAUSE: NATRF2022 WILL BE FIXED ON NORTH AMERICAN PLATE (RELATIVE TO ROTATION ABOUT THE EULER POLE) AND NOT CHANGE RELATIVE TO CRUSTAL MOTION. THERE WILL BE AN INTRA-FRAME VELOCITY MODEL (IFVM) TO ACCOUNT FOR NON-EULERIAN MOVEMENT. ASSIGN VELOCITIES TO THE STATIONS ACCESSED THROUGH THE CORS NETWORK ( FOUNDATION CORS. 50

51 51

52 52

53 NORTH AMERICAN PLATE CORS ROTATION 53

54 CHANGE IN h 54

55 NEW NATIONAL VERTICAL DATUM:2022(?) WHY ISN T NAVD 88 GOOD ENOUGH ANYMORE? NAVD 88 SUFFERS FROM USE OF BENCH MARKS THAT: ARE ALMOST NEVER RE-CHECKED FOR MOVEMENT DISAPPEAR BY THE THOUSANDS EVERY YEAR ARE NOT FUNDED FOR REPLACEMENT ARE NOT NECESSARILY IN CONVENIENT PLACES DON T EXIST IN MOST OF ALASKA WEREN T ADOPTED IN CANADA WERE DETERMINED BY LEVELING FROM A SINGLE POINT, ALLOWING CROSSCOUNTRY ERROR BUILD UP. RE-LEVELING WOULD COST 200 MILLION TO 2 BILLION $$ WHY ISN T NAVD 88 GOOD ENOUGH ANYMORE? NAVD 88 = 0.00 NAVD 88 WILL BE 0.4 M (1.3 ) +/- GREATER IN VALUE THAN THE NEW VERTICAL DATUM IN NEW YORK STATE 55

56 THE PROBLEM WITH PASSIVE MARKS. BASED ON PURE GRAVIMETRIC GEOID, ACCURATE TO 1 CM VIA GRAV-D PROJECT VERTICAL DATUM BROUGHT TO SITE AT 2 CM IN WELL-MODELED AREAS. ACCURACY (ALLOWS 1 CM h ERROR) ACCESSABILITY: BROUGHT TO A PROJECT SITE VIA ACTIVE REFERENCE STATIONS (NATIONAL CORS OR RTN), (ALTERNATIVE: LOCALIZE TO BMs PREVIOUSLY TIED TO THE DATUM-CAVEAT EMPTOR)) DENSIFIED TO PROJECT ACCURACY NEEDS AT SITE (E.G., DIGITAL LEVELING). 56

57 USING NATRF2022 ELLIPSOID HEIGHTS WITH THE GRAVIMETRIC GEOID FOR ORTHO HEIGHTS H88 = h83 N12a H22 = h22 NUSGG USING THE GRAVIMETRIC GEOID 57

58 NAVD 88 NAPGD UNITS = METERS A CONVERSION WILL BE PROVIDED BETWEEN NAVD 88 AND THE NEW DATUM ONLY WHERE RECENT GNSS ELLIPSOID HEIGHTS EXIST TO PROVIDE MODERN HEIGHTS IN THE NEW DATUM WHAT ABOUT CONVERTING TO/FROM NAVD 88? WHAT ABOUT THE PASSIVE MARKS? SECONDARY ACCESS (USE AT YOUR OWN RISK) PASSIVE MARKS THAT HAVE BEEN TIED TO THE NEW VERTICAL DATUM NGS WILL PROVIDE A DATA SHARING SERVICE FOR THESE POINTS, BUT THEIR ACCURACY (DUE TO EITHER THE QUALITY OF THE SURVEY OR THE AGE OF THE DATA) WILL NOT BE A RESPONSIBILITY OF NGS 58

59 GNSS TO ANY DATUM GNSS ECEF X,Y,Z (WGS 84 & PZ90) NAD 83 (φ,λ,h) SPC N,E,h NATRF2022 (φ,λ,h) + GEOID 12a GEOID USGG 22 = SPC N,E,H OR CALIBRATE TO 4-5 SITE POINTS IN THE DESIRED DATUM. THIS IS USED TO LOCK TO PASSIVE MONUMENTATION IN THE PROJECT AREA. NGS GEODETIC TOOL KIT THE ENTIRE NGS TOOLKIT WILL BE INTEGRATED EVENTUALLY: 59

60 NADCON 5.0 ERROR GRAPHICS: ERRORS ARE NO LONGER GENERALIZED (E.G. 15 CM IN CONUS ) 60

61 ACCURACY STATED AS 2.0 CM AT 1 VERTICAL DATUM CONVERSIONS TO THE NORTH AMERICAN-PACIFIC GEOPOTENTIAL DATUM 2022 VERTCON : NGVD 29 NAVD 88 TIME DEPENDENT GEOID = GEOID2022 GRAVCON : NAVD 88 NAPGD 2022 RECOMMEND PERFORMING PROJECT SURVEY IN THE CURRENT VERTICAL DATUM AND THEN CALCULATING AN OFFSET BETWEEN THE DATUMS FOR ALL POINTS LOCATED WITH LEGACY VERTICAL DATUM VALUES 61

62 GEOSPATIAL DATA REQUIRES METADATA! ON JUNE 20, THE M/V ZHEN HUA 13 DELIVERED NEW CRANES FROM CHINA TO THE PORT OF BALTIMORE METADATA NEEDED: BY NAVIGATING THE WATERS OF - CHESAPEAKE LOCAL TIDALBAY DATUM REFERENCE (LMSL) - TIDE INFO. - LOCAL NAD 83 & NAVD 88 CONTROL - CHANNEL BATHYMETRY - BRIDGE DIMENSIONS - BRIDGE ELEVATION- DATUM & ACCURACY - SHIP SQUAT - CRANE HEIGHT FROM KEEL - WATER CURRENTS/ WAVE CHOP NYSAPLS 2018 WORKSHOPS: DATUMS, GNSS FOR PROJECT CONTROL, USING OPUS MANY MORE TOPICS AT: 62