Application of GPS/GNSS in Cybermapping. Cybermapping Lab University of Texas at Dallas 2009

Transcription

1 Application of GPS/GNSS in Cybermapping Cybermapping Lab University of Texas at Dallas 2009

2 GNSS Global Navigation Satellite System (GNSS) is the standard generic term for satellite navigation systems that provide autonomous geo-spatial positioning with global coverage. A GNSS allows small electronic receivers to determine their location (longitude, latitude, and altitude) using time signals transmitted along a line of sight by radio from satellites. Receivers on the ground with a fixed position can also be used to calculate the precise time as a reference for scientific experiments. The Russian GLONASS is a GNSS in the process of being restored to full operation. The European Union's Galileo positioning system is a next generation GNSS in the initial deployment phase, scheduled to be operational in China has indicated it may expand its regional Beidou navigation system into a global system. India's IRNSS, a next generation GNSS is in developmental phase and is scheduled to be operational around G : Galileo, GLONASS, and GPS

3 GPS As of 2008 The Global Positioning System (GPS) is the only fully functional Global Navigation Satellite System (GNSS) The first GPS satellite was launched in A full constellation of 24 satellites was achieved in 1994 uses a constellation of between 24 and 32 Medium Earth Orbit satellites that transmit precise microwave signals, Enable GPS receivers to determine their: location, speed, direction, and time. developed by the United States Department of Defense. Its official name is NAVSTAR-GPS. The GPS satellite constellation is managed by the United States Air Force 50th Space Wing. Following the shooting down of Korean Air Lines Flight 007 in 1983, President Ronald Reagan issued a directive making the system available free for civilian use as a common good. Since then, GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, scientific uses, and hobbies such as geocaching. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.

4 GLONASS GLONASS - GLObal'naya NAvigatsionnaya Sputnikovaya Sistema developed by the former Soviet Union Now operated for the Russian government by the Russian Space Forces. Development on the GLONASS began in 1976, with a goal of global coverage by Beginning on 12 October 1982, numerous rocket launches added satellites to the system until the constellation was completed in Following completion, the system rapidly fell into disrepair with the collapse of the Russian economy. Beginning in 2001, Russia committed to restoring the system, and in recent years has diversified, Introducing the Indian government as a partner, and accelerated the program with a goal of restoring global coverage by 2009

5 GALILEO Named for the Italian astronomer Galileo Galilei, the positioning system is officially referred to as just "Galileo". It is also sometimes described as the "Galileo Positioning System"; however, since this abbreviates to GPS, the shorter name is preferred to avoid confusion with the U.S. GPS. Galileo is currently being built by the European Union (EU) and European Space Agency (ESA). The 3.4 billion project is an alternative and complementary to the (GPS) and the GLONASS. On November 30, 2007 the 27 EU transportation ministers involved reached an agreement that it should be operational by When in operation, it will have two ground operations centers, one near Munich, Germany, and another in Fucino, 130 km east of Rome, Italy. Since 18 May 2007, at the recommendation of Transport Commissioner Jacques Barrot, the EU took direct control of the Galileo project from the private sector group of eight companies called European Satellite Navigation Industries, which had abandoned this Galileo project in early Galileo is intended to provide more precise measurements than available through GPS or GLONASS, better positioning services at high latitudes and an independent positioning system upon which European nations can rely even in times of war or political disagreement, since Russia or the USA could disable use by others (through encryption). Like GPS, use will also be free for everyone.

6 Longitude, Latitude, Altitude Longitude mostly symbolized by lambda (λ), is the east-west geographic coordinate measurement most commonly used in cartography and global navigation. A line of longitude is a meridian and half of a great circle. Latitude, mostly symbolized by lambda phi (Φ), gives the location of a place on Earth north or south of the equator. Lines of Latitude are the horizontal lines shown running east-to-west on maps. Technically, latitude is an angular measurement in degrees (marked with ) ranging from 0 at the equator (low latitude) to 90 at the poles (90 N for the North Pole or 90 S for the South Pole; high latitude). The complementary angle of a latitude is called the colatitude. Altitude is the elevation of a point or object from a known level or datum. Common data are mean sea level, local ground level (Above Ground Level, or AGL), or the surface of the WGS-84 geoid, used by GPS. In aviation, altitude is measured in feet. For non-aviation uses, altitude may be measured in other units such as metres or miles.

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9 WAAS You've heard the term WAAS, seen it on packaging and ads for products, and maybe even know it stands for Wide Area Augmentation System. Okay, so what the heck is it? Basically, it's a system of satellites and ground stations that provide GPS signal corrections, giving you even better position accuracy. How much better? Try an average of up to five times better. A WAAS-capable receiver can give you a position accuracy of better than three meters 95 percent of the time, and is FREE. The Federal Aviation Administration (FAA) and the Department of Transportation (DOT) are developing the WAAS program for use in precision flight approaches. Currently, GPS alone does not meet the FAA's navigation requirements for accuracy, integrity, and availability. WAAS corrects for GPS signal errors caused by ionospheric disturbances, timing, and satellite orbit errors, and it provides vital integrity information regarding the health of each GPS satellite.

10 How GPS works? Here's how GPS works in five logical steps: 1. The basis of GPS is "triangulation" from satellites. We're using the word "triangulation" very loosely here because it's a word most people can understand, but purists would not call what GPS does "triangulation" because no angles are involved. It's really "trilateration." Trilateration is a method of determining the relative positions of objects using the geometry of triangles. 2. To "triangulate," a GPS receiver measures distance using the travel time of radio signals. 3. To measure travel time, GPS needs very accurate timing which it achieves with some tricks. 4. Along with distance, you need to know exactly where the satellites are in space. High orbits and careful monitoring are the secret. 5. Finally you must correct for any delays the signal experiences as it travels through the atmosphere.

11 Who benefits from WAAS? Currently, WAAS satellite coverage is only available in North America. There are no ground reference stations in South America. For some users in the U.S., the position of the satellites over the equator makes it difficult to receive the signals when trees or mountains obstruct the view of the horizon. WAAS signal reception is ideal for open land and marine applications. WAAS provides extended coverage both inland and offshore compared to the land-based DGPS (differential GPS) system. Another benefit of WAAS is that it does not require additional receiving equipment, while DGPS does. Other governments are developing similar satellite-based differential systems. In Asia, it's the Japanese Multi-Functional Satellite Augmentation System (MSAS), Europe has the Euro Geostationary Navigation Overlay Service (EGNOS). Eventually, GPS users around the world will have access to precise position data using these and other compatible systems.

12 ACRONYMS US

13 NATIONAL SPATIAL REFERENCE SYSTEM The National Spatial Reference System (NSRS) is that component of the National Spatial Data Infrastructure (NSDI) - [ which contains all geodetic control contained in the National Geodetic Survey (NGS) Data Base. This includes: A, B, First, Second and Third-Order horizontal and vertical control, Geoid models such as GEOID 99, precise GPS orbits and Continuously Operating Reference Stations (CORS), and the National Shoreline as observed by NGS as well as data submitted by other Federal, State, and local agencies, Academic Institutions and the private sector

14 NATIONAL SPATIAL REFERENCE SYSTEM ACCURATE -- cm accuracy on a global scale MULTIPURPOSE -- Supports Geodesy, Geophysics, Land Surveying, Navigation, Mapping, Charting and GIS activities ACTIVE -- Accessible through Continuously Operating Reference Stations (CORS) and derived products INTEGRATED -- Related to International services and standards (e.g. International Earth Rotation Service, International GPS Service etc.)

15 METADATA METADATA IS DATA ABOUT DATA DATUMS NAD 27, NAD 83(1986), NAD83 (199X), NGVD29, NAVD88 UNITS Meters, U.S. Survey Feet, International Feet, Chains, Rods, Pole ACCURACY A, B, 1st, 2nd, 3rd, 3cm, Scaled

16 METADATA?? Horizontal Datum?? Plane Coordinate Zone?? Units of Measure?? How Accurate??

17 DATUMS A set of constants specifying the coordinate system used for geodetic control, i.e., for calculating coordinates of points on 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)

18 HORIZONTAL DATUMS 8 Constants 3 specify the location of the origin of the coordinate system. 3 specify the orientation of the coordinate system. 2 specify the dimensions of the reference ellipsoid

19 VERTICAL DATUMS A set of fundamental elevations to which other elevations are referred.

20 THE ELLIPSOID MATHEMATICAL MODEL OF THE EARTH N b a S a = Semi major axis b = Semi minor axis f = a-b = Flattening a

21 ELLIPSOID - GEOID RELATIONSHIP H = Orthometric Height (NAVD 88) h = Ellipsoidal Height (NAD 83) N = Geoid Height (GEOID 99) H = h - N H h TOPOGRAPHIC SURFACE Ellipsoid GRS80 Geoid N PERPENDICULAR TO ELLIPSOID GEOID99 PERPENDICULAR TO GEOID (PLUMBLINE) DEFLECTION OF THE VERTICAL DEFLEC99

22 UNITED STATES ELLIPSOID DEFINITIONS BESSEL 1841 a = 6,377, m 1/f = CLARKE 1866 a = 6,378,206.4 m 1/f = GEODETIC REFERENCE SYSTEM (GRS 80) a = 6,378,137 m 1/f = WORLD GEODETIC SYSTEM (WGS 84) a = 6,378,137 m 1/f =

23 HORIZONTAL DATUMS BESSEL LOCAL ASTRO DATUMS ( ) CLARKE 1866 NEW ENGLAND DATUM ( ) U.S. STANDARD DATUM ( ) NORTH AMERICAN DATUM ( ) NORTH AMERICAN DATUM OF 1927 OLD HAWAIIAN DATUM PUERTO RICO DATUM ST. GEORGE ISLAND - ALASKA ST. LAWRENCE ISLAND - ALASKA ST. PAUL ISLAND - ALASKA AMERICAN SAMOA 1962 GUAM 1963 GRS NORTH AMERICAN DATUM OF 1983 (As of June 14, 1989)

24 THE GEOID AND TWO ELLIPSOIDS GRS80-WGS84 CLARKE 1866 Earth Mass Center Approximately 236 meters GEOID

25 COMPARISON OF DATUM ELEMENTS NAD 27 NAD 83 ELLIPSOID CLARKE 1866 GRS80 a = 6,378,206.4 m a = 6,378,137. M 1/f = /f = DATUM POINT Triangulation Station NONE MEADES RANCH, KANSAS EARTH MASS CENTER ADJUSTMENT 25k STATIONS 250k STATIONS Several Hundred Base Lines Appox. 30k EDMI Base Lines Several Hundred Astro Azimuths 5k Astro Azimuths Doppler Point Positions VLBI Vectors BEST FITTING North America World-Wide

26 NAD 27 and NAD 83

27 NAD 83 NETWORK PROBLEMS NOT GPSABLE POOR STATION ACCESSIBILITY IRREGULARLY SPACED POSITIONAL ACCURACY

28 HIGH ACCURACY REFERENCE NETWORKS GPSABLE Clear Horizons for Satellite Signal Acquisition EASY ACCESSIBILITY Few Special Vehicle or Property Entrance Requirements REGULARLY SPACED Always within Km HIGH HORIZONTAL ACCURACY A-Order (5 mm + 1:10,000,000) B-Order (8mm + 1:1,000,000)

29 HIGH ACCURACY REFERENCE NETWORKS

30 WORLD GEODETIC SYSTEM 1984 TR World Geodetic System It s Definition and Relationships with Local Geodetic Systems ( DATUM = WGS 84 RELEASED - SEPTEMBER 1987 BASED ON OBSERVATIONS AT MORE THAN 1900 DOPPLER STATIONS DATUM = WGS 84(G730) 5 USAF GPS Tracking Stations 5 DMA Evaluation Stations Datum redefined with respect to the International Terrestrial Reference Frame of 1992 (ITRF92) +/- 20 cm in each component (Proceedings of the ION GPS-94 pgs ) DATUM = WGS 84(G873) 5 USAF GPS Tracking Stations 7 NIMA Evaluation Stations Datum redefined with respect to the International Terrestrial Reference Frame of 1994 (ITRF94) +/- 10 cm in each component (Proceedings of the ION GPS-97 pgs )

31 MY SOFTWARE SAYS I M WORKING IN WGS-84 Unless you doing autonomous positioning (point positioning +/ meters) you re probably NOT in WGS-84 Project tied to WGS-84 control points obtained from the Defense Department -- Good Luck! You re really working in the same reference frame as your control points -- NAD 83?

32 VERTICAL DATUMS 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)

33 COMPARISON OF VERTICAL DATUM ELEMENTS NGVD 29 NAVD 88 DATUM DEFINITION 26 TIDE GAUGES FATHER S POINT/RIMOUSKI IN THE U.S. & CANADA QUEBEC, CANADA BENCH MARKS 100, ,000 LEVELING (Km) 102,724 1,001,500 GEOID FITTING Distorted to Fit MSL Gauges Best Continental Model

34 NGVD 29 and NAVD 88

35 INTERNATIONAL TERRESTRIAL REFERENCE SYSTEM DEVELOPED AND MAINTAINED BY THE INTERNATIONAL EARTH ROTATION SERVICE PARIS, FRANCE FROM: ( VERY LONG BASELINE INTERFEROMETRY - (VLBI) SATELLITE LASER RANGING - (SLR) GLOBAL POSITIONING SYSTEM - (GPS) DOPPLER ORBITOGRAPHY AND RADIO POSITIONING INTEGRATED BY SATELLITE - (DORIS)

36 INTERNATIONAL TERRESTRIAL REFERENCE SYSTEM GEOCENTRIC +/- 3 to 4 CM MODELS FOR PLATE TECTONICS STATION VELOCITIES POSITIONAL STANDARD ERRORS REALIZED AS THE INTERNATIONAL TERRESTERIAL REFERENCE FRAME (ITRF)

37 TECTONIC MOTIONS

38 HORIZONTAL TECTONIC MOTIONS

39 VERTICAL TECTONIC MOTIONS

40 NAD 83 and ITRF ITRF NAD 83 Earth Mass Center 2.2 m (3-D) dx,dy,dz GEOID

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42 GEODETIC CONTROL NETWORK OF MONUMENTED POINTS PRECISELY MEASURED IN ACCORDANCE WITH STANDARD PROCEDURES MEET ACCURACY SPECIFICATIONS ADJUSTED TO TIE TOGETHER DOCUMENTED FOR MULTIPLE USE

43 IMPROVING POSITIONAL ACCURACY TIME NETWORK LOCAL NETWORK SPAN ACCURACY ACCURACY NAD Meters First-Order (1 part in 0.1 million) NAD Meter First-Order(1 part in 0.1 million) HARN Meter B-Order(1 part in 1 million) A-Order (1 part in 10 million) CORS Meter - Horizontal 0.04 Meter - Ellipsoid Height

44 GEODETIC CONTROL DATA SHEET National Geodetic Survey, Retrieval Date = MARCH 11, 2002 AO0192 *********************************************************************** AO0192 FBN - This is a Federal Base Network Control Station. AO0192 DESIGNATION - DERBY AO0192 PID - AO0192 AO0192 STATE/COUNTY- TX/FRIO H = h - N = (-24.28) = AO0192 USGS QUAD - DERBY (1982) AO0192 AO0192 *CURRENT SURVEY CONTROL AO0192 AO0192* NAD 83(1993) (N) (W) ADJUSTED AO0192* NAVD (meters) (feet) ADJUSTED AO0192 AO0192 X , (meters) COMP AO0192 Y - -5,524, (meters) COMP AO0192 Z - 3,051, (meters) COMP AO0192 LAPLACE CORR (seconds) DEFLEC99 AO0192 ELLIP HEIGHT (meters) GPS OBS AO0192 GEOID HEIGHT (meters) GEOID99 AO0192 DYNAMIC HT (meters) (feet) COMP AO0192 MODELED GRAV- 979,174.2 (mgal) NAVD 88 AO0192 AO0192 HORZ ORDER - B AO0192 VERT ORDER - FIRST CLASS II AO0192 ELLP ORDER - THIRD CLASS I

45 GEODETIC CONTROL DATA SHEET AO0192.The horizontal coordinates were established by GPS observations AO0192.and adjusted by the National Geodetic Survey in May AO0192 AO0192.The orthometric height was determined by differential leveling AO0192.and adjusted by the National Geodetic Survey in June AO0192.WARNING-GPS observations at this control monument resulted in a GPS AO0192.derived orthometric height which differed from the leveled height by AO0192.more than one decimeter (0.1 meter). AO0192 AO0192.The X, Y, and Z were computed from the position and the ellipsoidal ht. AO0192 AO0192.The Laplace correction was computed from DEFLEC99 derived deflections. AO0192 AO0192.The ellipsoidal height was determined by GPS observations AO0192.and is referenced to NAD 83. AO0192 AO0192.The geoid height was determined by GEOID99. AO0192 AO0192.The dynamic height is computed by dividing the NAVD 88 AO0192.geopotential number by the normal gravity value computed on the AO0192.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 AO0192.degrees latitude (g = gals.). AO0192 AO0192.The modeled gravity was interpolated from observed gravity values.

46 GEODETIC CONTROL DATA SHEET AO0192; North East Units Scale Converg. AO0192;SPC TXSC - 4,103, , MT AO0192;UTM 14-3,182, , MT AO0192 AO0192: Primary Azimuth Mark Grid Az AO0192:SPC TXSC - DERBY AZ MK AO0192:UTM 14 - DERBY AZ MK AO0192 AO AO0192 PID Reference Object Distance Geod. Az AO0192 dddmmss.s AO0192 DERBY AZ MK AO0192 DERBY RM METERS AO0192 AO0194 PTS 32 LS TEX C METERS AO0192 AO0670 DILLEY RAD MAST APPROX.11.7 KM AO0192 DERBY RM METERS AO0192 AO0193 DERBY RM METERS AO0192 DERBY AZ MK AO0192 AO0530 DERBY RM METERS AO AO0192 AO0192 SUPERSEDED SURVEY CONTROL AO0192 AO0192 ELLIP HT (m) GP( ) 4 2 AO0192 NAD 83(1986) (N) (W) AD( ) 1 AO0192 NAD (N) (W) AD( ) 1 AO0192 NGVD (m) (f) ADJ UNCH 1 2 AO0192 AO0192.Superseded values are not recommended for survey control. AO0192.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums.

47 GEODETIC CONTROL DATA SHEET AO0192_MARKER: DS = TRIANGULATION STATION DISK AO0192_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT AO0192_STAMPING: DERBY 1935 AO0192_MARK LOGO: CGS AO0192_MAGNETIC: O = OTHER; SEE DESCRIPTION AO0192_STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO AO0192+STABILITY: SURFACE MOTION AO0192_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR AO0192+SATELLITE: SATELLITE OBSERVATIONS - February 28, 1998 AO0192 AO0192 HISTORY - Date Condition Report By AO0192 HISTORY MONUMENTED CGS AO0192 HISTORY GOOD CGS AO0192 HISTORY GOOD CGS AO0192 HISTORY GOOD NGS AO0192 HISTORY GOOD CGS AO0192 HISTORY GOOD NGS AO0192 HISTORY GOOD NGS AO0192 HISTORY GOOD USAF AO0192 HISTORY GOOD USPSQD AO0192 HISTORY GOOD NGS AO0192 HISTORY GOOD AO0192 HISTORY GOOD NGS AO0192 HISTORY GOOD NGS AO0192 HISTORY GOOD NGS AO0192 AO0192 STATION DESCRIPTION AO0192 AO0192'DESCRIBED BY COAST AND GEODETIC SURVEY 1935 (CIA)

48 CONTINUOUSLY OPERATING REFERENCE STATIONS (CORS) Installed and Operated by various Federal-State-local Agencies NOAA/National Geodetic Survey NOAA/OAR Forecast Systems Lab U.S. Coast Guard - DGPS/NDGPS Corps of Engineers - DGPS FAA - WAAS/LAAS (Future) State DOTs County and City Academia Private Companies CHL1 - CAPE HENLOPEN, DE

49 CONTINUOUSLY OPERATING REFERENCE STATIONS (CORS) Variety of Geodetic Quality Dual-Frequency Antennas and Receivers Allen-Osborne (SNR 8000 & SNR 12 ACT) Ashtech (UZ-12, Z-XII3) Leica (SR9500 & CRS1000, LEIAT5, RS500) CHL1 - CAPE HENLOPEN, DE Trimble (4000SS, 4700, 5700)

50 CONTINUOUSLY OPERATING REFERENCE STATIONS (CORS) Some stations provide real-time code phase observations post-process carrier phase observations Free access via Internet (RINEX-2 Format) More than 190 Station National Network

51 CONTINUOUSLY OPERATING REFERENCE STATIONS (CORS) NGS PROVIDES Reference Site Survey Monumentation Horizontal and Vertical NSRS Connections NAD 83, ITRF94, ITRF96, ITRF97, ITRF00 Coordinates Network Data Collection - Hourly & Daily Daily 3D Network Integrity Adjustment Public Data Distribution - Internet ( 7 Year On-Line Data Holding

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55 CORS DATA SHEET ***ITRF 00*** ARANSAS PASS 3 (ARP3), TEXAS Antenna Reference Point(ARP): ARANSAS PASS 3 CORS ARP PID = AF9488 ITRF00 POSITION (EPOCH ) Published by the IERS in Mar X = m latitude = N Y = m longitude = W Z = m ellipsoid height = m ITRF00 VELOCITY Published by the IERS in Mar VX = m/yr northward = m/yr VY = m/yr eastward = m/yr VZ = m/yr upward = m/yr

56 CORS DATA SHEET ***NAD 83*** ARANSAS PASS 3 (ARP3), TEXAS NAD_83 POSITION (EPOCH ) Transformed from ITRF96 (epoch ) position in Apr X = m latitude = N Y = m longitude = W Z = m ellipsoid height = m NAD_83 VELOCITY Predicted with HTDP_2.0 in Apr., VX = m/yr northward = m/yr VY = m/yr eastward = m/yr VZ = m/yr upward = m/yr

57 CORS DATA QUALITY

58 OPUS WHAT IS IT? On-line Positioning User Service Provide GPS users faster & easier access to the National Spatial Reference System (NSRS)

59 OPUS HOW DOES IT WORK? Submit RINEX file through NGS web page Processed automatically with NGS computers & software With respect to 3 suitable National CORS Solution via in minutes

60 OPUS HOW DO I USE IT? Go to OPUS web page Enter your address Use browse feature to select RINEX file on your computer Select antenna type from menu Enter antenna height in meters Option to select State Plane Zone Click UPLOAD Check your in a few minutes

61 Note: Your solutions will be archived and be publicly available. Your address will not be retained once the solution is ed to you.

62 PLANE COORDINATE SYSTEMS STATE PLANE AND UNIVERSIAL TRANSVERSE MERCATOR GRID COORDINATES ARE A DIRECT MATHEMATICAL CONVERSION FROM LATITUDE AND LONGITUDE TO A CARTESIAN NORTHING AND EASTING (Y & X) COORDINATE SYSTEM, AND MUST MAINTAIN THE SAME DATUM TAG [e.g. NAD 83(1993)] AS THE LATITUDE AND LONGITUDE NATIONAL OCEAN SERVICE

63 UNIVERSAL TRANSVERSE MERCATOR (UTM) The Universal Grids: Universal Transverse Mercator (UTM) and Universal Polar Stereographic (UPS) - TM Transverse Mercator Projection Zones 6 o Longitude World-Wide Northing Origin (0 meters- Northern Hemisphere) at the Equator Easting Origin (500,000 meters) at Central Meridian of Each Zone NAD 27 and NAD 83 both defined in meters NAD 27 to NAD 83 shift = meters for U.S. NATIONAL OCEAN SERVICE

64 STATE PLANE COORDINATE SYSTEMS NOAA Manual NOS NGS - 5 State Plane Coordinate System of Lambert Conformal Conic and Transverse Mercator Projections International, State and County Boundaries NAD 27 - Coordinates in U.S. Survey Feet NAD 83 - Coordinates Metric w/state Defined Foot Conversion 1 Meter = U.S. Survey Feet 1 Meter = International Feet NAD 27 to NAD 83 VERY large Positional Shifts

65 Tangent Plane Single Point of Contact TANGENT PLANE COORDINATE SYSTEM

66 LAMBERT CONFROMAL CONIC WITH 2 STANDARD PARALLELS STANDARD PARALLELS n Approximately 158 miles s NATIONAL OCEAN SERVICE 0 CENTRAL MERIDIAN

67 TRANSVERSE MERCATOR SCALE > 1 SCALE EXACT SCALE EXACT SCALE < 1 SCALE > 1 0 CENTRAL MERIDIAN

68 LAMBERT CONFROMAL CONIC WITH 2 STANDARD PARALLELS The Convention of the Sign of the Convergence Angle is Always From Grid To Geodetic Convergence angles ( ) always positive East Convergence angles ( ) always negative West 0 CENTRAL MERIDIAN

69 LAMBERT CONFROMAL CONIC WITH 2 STANDARD PARALLELS Grid Scale Factor SCALE > 1 SCALE EXACT n SCALE < 1 STANDARD PARALLELS SCALE EXACT s SCALE > 1 0 CENTRAL MERIDIAN

70 Apex of Cone Southern Standard Parallel EASTING ( x ) Northern Standard Parallel Convergence Angle Parallel of Grid Origin FALSE NORTHING = 4,000,000 FALSE EASTING = 600,000 NORTHING ( y ) -5,000 5,000-4,000-3,000-2,000 6,000 7,000 8,000-1, ,000 10,000 1,000 2,000 3,000 4,000 5,000 11,000 12,000 13,000 14,000 15,000 6,000 5,000 4,000 3,000 2,000 1, ,000 15,000 14,000 13,000 12,000 11,000 10,000 Central Meridian

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73 COORDINATE CHANGES (STATE PLANE) STATION: DERBY TEXAS SOUTH CENTRAL ZONE (NAD 27/NAD 83) Northing Easting Converg Angle Scale Factor 103, ft. 596, ft. -0 o ,103, m. 587, m. -0 o (13,463, ft)* (1,925, ft)* (13,463, ft)# (1,925, ft)# (26.93) (3.85) * Converted using U.S. Survey Foot, 1 M = Ft. # Converted using International Foot, 1 M = Ft.

74 WHAT YOU NEED TO USE THE STATE PLANE COORDINATE SYSTEMS N & E STATE PLANE COORDINATES FOR CONTROL POINTS AZIMUTHS - Conversion from Astronomic to Geodetic - Conversion from Geodetic to Grid (Mapping Angle) DISTANCES - Reduction from Horizontal to Ellipsoidal Sea-Level Reduction Factor - Correction for Grid Scale Factor - Combined Factor

75 STATE PLANE COORDINATE COMPUTATION DERBY N = 3,182, meters E = 487, meters Orthometric Height (H) = meters Geoid Height (N) = meters Laplace Correction = Grid Scale Factor (k) = Meridian Convergence (γ) = - 0 o Observed Astro Azimuth (α A ) = 253 o Horizontal Distance (D) = meters

76 STATE PLANE COORDINATE COMPUTATION N 1 = N + (S g x cos α g ) E 1 = E + (S g x sin α g ) Where: N = Starting Northing Coordinate E = Starting Easting Coordinates S g = Grid Distance α g = Grid Azimuth

77 REDUCTION TO THE ELLIPSOID D H h N S R Earth Radius 6,372,161 m 20,906,000 ft. S = D x R R + h h = N + H Earth Center S = D x R R + N + H

78 REDUCTION TO THE ELLIPSOID R = N 1 - e 2 cos 2 cos 2 α N = c (1 - e 2 cos 2 ) 1/2 c = a 2 /b

79 REDUCTION TO ELLIPSOID S = D x [R / (R + h)] D = meters (Measured Horizontal Distance) R = 6,372,162 meters (Mean Radius of the Earth) h = H + N (H = 158 m, N = - 24 m) = 134 meters (Ellipsoidal Height) S = [6,372,162 / 6,372, ] S = x S = meters

80 REDUCTION TO GRID S g = S (Geodetic Distance) x k (Grid Scale Factor) S g = x = meters

81 COMBINED FACTOR CF = Ellipsoidal Reduction x Grid Scale Factor (k) = x = CF x D = S g x = meters

82 GRID AZIMUTH COMPUTATION α g = α A + Laplace Correction - γ = 253 o (Observed Astro Azimuth) + (- 1.7) (Laplace Correction) = 253 o (Geodetic Azimuth) (Convergence Angle) = 253 o The convention of the sign of the convergence angle is always from Grid to Geodetic

83 STATE PLANE COORDINATE COMPUTATION N 1 = N + (S g x cos α g ) E 1 = E + (S g x sin α g ) N 1 = 4,103, ( x Cos 253 o ) = 4,103, ( x ) = 4,103, ( ) = 4,103, meters E 1 = 587, ( x Sin 253 o ) = 587, ( x ) = 587, ( ) = 586, meters

84 GROUND LEVEL COORDINATES I WANT STATE PLANE COORDINATES RAISED TO GROUND LEVEL GROUND LEVEL COORDINATES ARE NOT STATE PLANE COORDINATES!!!!!

85 GROUND LEVEL COORDINATES PROBLEMS RAPID DISTORTIONS PROJECTS DIFFICULT TO TIE TOGETHER CONFUSION OF COORDINATE SYSTEMS LACK OF DOCUMENTATION

86 GROUND LEVEL COORDINATES IF YOU DO TRUNCATE COORDINATE VALUES SUCH AS: N = 13,750, ft becomes 50, E = 2,099, ft becomes 99, AND

87 STATUS OF NAD 27 AND NAD 83 STATE PLANE COORDINATE LEGISLATION - APRIL, 2000 NO SPCS EXISTING NAD 27 ENACTED NAD 83 SPC LEGISLATION LEGISLATION LEGISLATION (4) (3) (45) District of Columbia Alabama Alaska Maryland (S) Oklahoma (S) Hawaii Arkansas Arizona (I) Massachusetts (S) Oregon (I) Nebraska Illinois California (S) Michigan (I) Pennsylvania (S) Puerto Rico Colorado (S) Minnesota Rhode Island Connecticut (S) Mississippi (S) South Carolina (I) I = International Feet and Meters Delaware(S) Missouri South Dakota 1 m = feet Florida (S) Montana (I) Tennessee (S) S = U.S. Survey Feet and Meters Georgia (S) Nevada Texas (S) 1 m = feet Idaho (S) New Hampshire Utah (I) Indiana (S) New Jersey Vermont Iowa New Mexico (S) Virginia (S) Kansas New York (S) Washington (S) Kentucky (S) North Carolina (S) West Virginia Louisiana North Dakota (I) Wisconsin (S) Maine Ohio Wyoming

88 Autonomous Positioning: Before May 1, m C/A Code on L1 Selective Availability HORIZONTAL = 100 meters VERTICAL = 156 meters 1996 Federal Radionavigation Plan Section A2-1, Part B

89 Standalone Positioning: Since May 1, m C/A Code on L1 No Selective Availability

90 Standalone Positioning: By m Better resistance to interference C/A Code on L1 C/A Code on L2 New Code on L5

91 GLOBAL POSITIONING SYSTEM GPS BLOCK III Potential Future Developments satellites Second and Third Civil Frequency ( MHZ & MHZ) More Robust Signal Transmissions Real-Time Unaugmented 1 Meter Accuracy Initial Launches ~ 2005 Complete Replacements ~ 2011

92 GLOBAL NAVIGATION SATELLITE SYSTEMS (GNSS) POTENTIAL FUTURE DEVELOPMENTS ( ) GPS MODERNIZATION - BLOCK III GLONASS ENHANCEMENTS (K & M) EUROPEAN UNION - GALILEO 80+ Satellites Second and Third Civil Frequency - GPS No Signal Encryption - GLONASS & GALILEO More Robust Signal Transmissions Real-Time Unaugmented 1 Meter (or better!) Accuracy

93 NAD 83 READJUSTMENT HARN COMPLETION - SEPTEMBER 1997 (Indiana) GPS HEIGHT MODERNIZATION OBSERVATIONS ( ) (Texas observed 1998 ) ( COMPLETE GPS NAD 83 3-D ADJUSTMENT ( ( ) REMOVAL OF SMALL REGIONAL DISTORTIONS (3-6 CM) UNIFORM COORDINATE TAG NAD 83 (NSRS)

94 NAD 83 READJUSTMENT

95 NAD 83 READJUSTMENT ONLY GPS DATA CONTINUOUSLY OPERATING REFERENCE STATIONS FEDERAL BASE NETWORK COOPERATIVE BASE NETWORK AIRPORT SURVEYS USER DENSIFICATION NETWORK SPECIAL SURVEYS

96 NEW STANDARDS FOR GEODETIC CONTROL Two accuracy standards ( local accuracy adjacent points network accuracy relative to CORS Numeric quantities, units in cm (or mm) Both are relative accuracy measures Do not use distance dependent expression Horizontal accuracies are radius of 2-D 95% error circle Ellipsoidal/Orthometric heights are 1-D (linear) 95% error

97 DATUM TRANSFORMATIONS 1. WHAT DATUM ARE THE EXISTING COORDINATES ON? 2. WHAT DATUM DO I WANT THE NEW COORDINATES ON? 3. HOW LARGE A GEOGRAPHICAL AREA DO I WANT TO CONVERT AT ONE TIME? 4. HOW MANY POINTS ARE COMMON TO BOTH DATUMS? 5. WHAT IS THE DISTRIBUTION OF THE COMMON POINTS? 6. HOW ACCURATE ARE THE EXISTING COORDINATES? 0.1 Foot 1.0 Foot 10. Feet 7. HOW ACCURATE DO I WANT THE NEW COORDINATES?

98 DATUM TRANSFORMATIONS MOLODENSKY Converts latitude, longitude and ellipsoidal height to X,Y,Z Earth-Centered Coordinates. Applies a 3-dimensional change in the origin (dx, dy,dz) Applies a change in the size and shape of the reference ellipsoid Converts new X,Y,Z Earth-Centered Coordinates back to latitude, longitude and ellipsoidal height

99 DATUM TRANSFORMATIONS MOLODENSKY For continental regions accuracy can be +/- 8 to 10 meters Does not model network distortions very well. Assumes heights in both systems are ellipsoidal (NAD 27 did not have ellipsoidal heights).

100 MOLODENSKY TRANSFORMATION (

101 I NEED TO TRANSFORM BETWEEN WGS 84 AND NAD 83 Federal Register Notice: Vol. 60, No. 157, August 15, 1995, pg Use of NAD 83/WGS 84 Datum Tag on Mapping Products

102 DATUM TRANSFORMATION IDEAL METHOD SATISFIES ALL USERS REQUIREMENTS CAPABLE OF TRANSFORMING LARGE HOLDINGS OF COORDINATE DATA NEAR-REAL TIME APPLICATIONS SIMPLE - METHOD SHOULD NOT REQUIRE AN EXPERT OR DECISIONS TO BE MADE ACCURATE

103 NADCON DESIGNED TO SATISFY THE MAJORITY OF THE IDEAL METHOD DESIGN AND IS DEFINED AS THE NATIONAL STANDARD. Federal Register Notice: Vol. 55, No. 155, August 10, 1990, pg Notice to Adopt Standard Method for Mathematical Horizontal Datum Transformation DESIGN CRITERIA: Relies only on NGS archived data existing in both NAD 27 and NAD 83 Provides consistent results, both forward and inverse Fast Not tied to NGS Data Base Small - Fit on PC Accurate 15 cm (1 sigma) in Conterminous U.S. NAD 27 - NAD 83(1986) 5 cm (1 sigma) per State/Region NAD 83 (1986) - HARN

104 NADCON = = = = = = = = = = = = = = = = = = = = = =

105 COORDINATE COMPARISON NAD 27 to NAD 83(1993) TR World Geodetic System Its Definition and Relationship with Local Geodetic Systems ADJUSTED vs. TRANSFORMED Station: DERBY LATITUDE LONGITUDE PUBLISHED MOLODENSKY m m THIS CORRESPONDS TO A POSITIONAL DIFFERENCE OF m (8.95 ft)

106 COORDINATE COMPARISON NAD 27 to NAD 83(1986) NADCON ADJUSTED vs. TRANSFORMED Station: DERBY LATITUDE LONGITUDE PUBLISHED NADCON m m THIS CORRESPONDS TO A POSITIONAL DIFFERENCE OF 0.133m (0.44 ft)

107 COORDINATE COMPARISON NAD 83 (1986) to NAD 83(1993) NADCON ADJUSTED vs. TRANSFORMED Station: DERBY LATITUDE LONGITUDE PUBLISHED NADCON m m THIS CORRESPONDS TO A POSITIONAL DIFFERENCE OF m (0.03 ft)

108 GPS NETWORKS TO SUPPORT GIS GPS SURVEY DATA OBSERVE TO NATIONAL STANDARDS TIES TO CORS, HARN and LOCAL BMs QUALITY MONUMENTATION

109 GPS NETWORKS TO SUPPORT GIS CLASSICAL Lots of control points spaced at regular intervals (1-3 miles) CONTEMPORARHY CORS and Monumentation as needed

110 GPS NETWORKS TO SUPPORT GIS CLASSICAL

111 GPS NETWORKS TO SUPPORT GIS 21 st CENTURY

112 CLASSICAL GPS NETWORKS PROS Monumentation usually established in only 1 or 2 GPS survey campaigns Complete coverage No time lag for users access to control CONS Large initial cost Continual network maintenance Monumentation destroyed or disturbed before they re used

113 CONTEMPORARHY GPS NETWORKS PROS Minimal permanent monumentation Project control established when and where needed Costs spread over time CONS Qualified staff to coordinate user requirements Time lag to establish project control

114 GPS NETWORKS TO SUPPORT GIS GPS SURVEY DATA BLUE - BOOK SUBMISSION OF DATA FOR INCLUSION IN NSRS OR DATA MAINTAINED AT THE LOCAL LEVEL

115 GPS NETWORKS TO SUPPORT GIS BLUE-BOOK PROS DATA MAINTAINED IN NSRS IN PERPETUTITY UNIVERSAL DATA ACCESS VIA NGS WEB SITE GOOD HOUSEKEEPING SEAL OF APPROVAL CONS INCREASED INITIAL COST (15-20%) SLIGHT INCREASE IN INITIAL DATA PROCESSING TIME

116 GPS NETWORKS TO SUPPORT GIS LOCAL MAINTENANCE PROS DECREASED INITIAL SURVEY COSTS LOCAL CONTROL OF ALL DATA CONS READJUSTMENTS TO FUTURE REFERENCE FRAME CHANGES MUST BE DONE AT THE LOCAL LEVEL DATA MAY BE DIFFICULT TO LOCATE FOR NON-LOCALS

117 GOOD COORDINATION BEGINS WITH GOOD COORDINATES GEOGRAPHY WITHOUT GEODESY IS A FELONY

118 References: