Geometric and Vertical 2015 Geospatial Summit Marc Véronneau Canadian Geodetic Survey Surveyor General Branch Geometric Reference Frame Canada 3 Vertical Reference Frame Canada ID: 669765
Download Presentation The PPT/PDF document "Canada’s Geodetic Reference Frames:" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Canada’s Geodetic Reference Frames:Geometric and Vertical2015 Geospatial Summit
Marc Véronneau
Canadian Geodetic Survey, Surveyor General BranchSlide2
Geometric Reference Frame (Canada) … 3
Vertical Reference Frame (Canada)
… 6Questions? … 15
OutlineSlide3
Geometric Reference Frame (Canada)
Canadian Geodetic Survey
publishes coordinates in NAD83(CSRS) v6 epoch 2010.0.Each province adopted a specific version/epoch (e.g., Quebec and New Brunswick use NAD83(CSRS) v2 epoch 1997.0).Provinces can upgrade to a newer version when they are ready.Canadian Geodetic Survey has no plans to replace NAD83(CSRS).
Canadian Geodetic Survey is collaborating with the National Geodetic Survey in the realization of the new (North) American geometric reference frame.
Canadian
Geodetic Survey
will publish coordinates in the new geometric reference frame
Station reports, NRCan’s CSRS-PPP, TRX software.
Slide4
Geometric Reference Frames
ITRF88
ITRF89
ITRF90
ITRF91
ITRF92
ITRF93
ITRF94
ITRF96ITRF97ITRF2000ITRF2005ITRF2008ITRF2014*
NAD83(NSRS/CSRS)
Latitude, Longitude
a
nd Ellipsoidal Height
NAD83(Original)
Latitude and Longitude
North American Frames
NAD27Latitude and Longitude
Canada
NAD83(CSRS) v6 e. 2010.0
USA
NAD 83(2011) e. 2010.0
ITRF20xx/NAD 2022
*
scheduled
for 2015
Grid
transformation
Parameter
transformation
Equivalent
International FramesSlide5
Station Report (Example)
Select reference frame (
NAD83(CSRS))New reference frame would be added to the drop-box list
Velocities of the station with respect to the reference frame
Height of the station from adjustment of the levelling network
Height from GNSS and selected geoid model
Select coordinates type (
geographic
)Select a hybrid or gravimetric geoid model (CGG2013)Select epoch (2010.0)Slide6
Vertical Reference Frame (Canada)
Canada adopted CGVD2013 in November 2013.
Defined by a specific equipotential surface (W0 = 62,636,856 m2/s2)Realized by a geoid model (CGG2013)Compatible with GNSS technology
Canada adopted a geoid-based vertical datum because …
Cost in maintaining and expanding a levelling network for a country as vast as Canada
No access to CGVD28 in remote regions
New technologies available (e.g., GNSS, satellite gravimetry)
Distortions in CGVD28 (~1.2 m at the national scale)
Canada has the support from the provinces in the implementation of the new vertical reference system.Overall, Canadian users acknowledge that the benefits of a geoid-based datum outweigh disadvantages [HAL report, 2006]. Main concerns relate to cost in converting legacy data, and confusion in heightsSlide7
Vertical Reference Frame (Canada)
CGVD28 continues to co-exist with CGVD2013 during the transition period
Readjustment of the levelling network with constraints to coincide with CGVD2013; Publish bench marks in CGVD2013 and CGVD28; GNSS-derived orthometric heights prevail over the heights from the levelling adjustment.CGS stopped maintenance of the bench marks of the national first-order levelling network since 2002; Bench marks are not maintained by GNSS observation either. CGS cannot confirm stability of the bench marks.Canada’s geodetic infrastructure
~90 continuously tracking reference stations (federal/provincial)
~200 force-centered pillars (passive stations)
Provincial High Precision Networks, Commercial RTK
Use of CGVD2013 (still early stage)
Federal agencies (e.g., NRCan (floodplain mapping), Transport (airport), Environment Canada (inland water;
transboundary waters))Provincial agencies initiated migration to CGVD2013Slide8
North American Vertical Datums (Now)
CGVD28 (Levelling; GNSS/HTv2.0) =>
CGVD2013 (Geoid m
odel)
NAVD 88 (Levelling; GNSS/Geoid12A)
IGLD 85
(Levelling)
Courtesy of the International Joint Commission
Transboundary WatersSlide9
North American Vertical Datum (Objective)
Geoid Model
W0 = 62,636,856 m
2
/s
2
A unified height system for North America based on the equipotential surface:
W
0 = 62,636,856 m2/s2This surface is materialized by a geoid model which integrates satellite, airborne, and surface gravity data.CGS and NGS agreed on this definition.This definition is already adopted in Canada (CGVD2013).Mexico and countries in Central America and Caribbean agreed on this definition.Coordinating Committee for the Great Lakes and St-Lawrence River System proposed to define IGLD2020 on this surface.IERS and IAU had already adopted this reference surface in their conventions.Slide10
Canada’s Levelling network
1906-1928
1929-1939
1940-1965
1966-1971
1972-1981
1982-1989
1990-2007
Constraints
: Continental (32)
:
Newfoundland (4)
:
Prince Edward Island (1)
:
Iles de la Madeleine (1)
:
Ile
d’Anticosti
(1)
:
Vancouver Island (2)
:
Gauges (12)Slide11
Active Stations Processed at CGSSlide12
T
he difference between NAVD 88 and CGVD2013
HCGVD2013
–
H
NAVD 88
Conversion between NAVD 88 and CGVD2013
Conduct a GNSS survey on bench marks having NAVD 88 elevation
Published elevations at common bench marksGEOID12A - CGG2013 (above image)C.I.: 10 cmSlide13
CSRS-Precise
Point Positioning (PPP)
: Process GPS RINEX files to provide
stand-alone coordinates
(latitude, longitude, ellipsoidal height and orthometric height
). Works any where in the world. [on-line]
GPS-H
: Convert ellipsoidal heights to orthometric heights (makes use of any geoid models, works with different types of coordinate systems (geographic, UTM, MTM and Cartesian), and different geometric reference frames (NAD83(CSRS) and ITRF
)). Could also convert between vertical datums. [on-line and desktop]TRX: Transform coordinates between different geometric reference frames (e.g., NAD83(CSRS), ITRF), epochs and coordinate systems (e.g., geographic, UTM, MTM, Cartesian). [on-line and desktop]Some NRCan’s toolsSlide14
Height: 101.61 m
Precision: ±
0.01 mEpoch: 2013.2Type of height: OrthometricHeight system: CGVD2013Height frame: CGG2013H = 23.126 ± 0.007 m CGVD2013(CGG2013) Epoch 2013.2
Labelling Heights
Type of height: Orthometric (H), dynamic (
H
d
), normal (
Hn), ellipsoidal (h), geoid (N)Height Reference System: NAD83, ITRF, CGVD28, CGVD2013, NAVD 88Height Reference Frame: CSRS v., Geoid modelPrecision (e.g., ± 0.05 m)Epoch (e.g., 2012.75)HHeight: 91.256 mPrecision: ± 0.007 mEpoch: 2013.2Type of height: Ellipsoidal (geodetic)
Height system: NAD83Height frame: CSRS (version if available)
h = 23.126 ± 0.007 m
NAD83(CSRS) Epoch 2013.2
h
Geoid Height
:
-10.354
m
Precision: ±
0.015
m
Epoch:
Static
Model: CGG2013
Frame: NAD83(CSRS)
N = -10.354
± 0.015 m CGG2013, NAD83(CSRS)
NSlide15
NRCan Contacts:Philippe Lamothe (phlamoth@nrcan.gc.ca)
Marc Véronneau (
marcv@nrcan.gc.ca)Mike Craymer (craymer@nrcan.gc.ca)General information:Web: http://www.nrcan.gc.ca/earth-sciences/geomatics/geodetic-reference-systems/10781Email: information@geod.nrcan.gc.ca
Phone: 1-613-793-2102
QUESTIONS?