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TitleModernization of Canada's Geodetic Vertical Datum
AuthorHains, D; Véronneau, M; Huang, J
SourceInternational Association of Geodesy Scientific Assembly, 150th Anniversary of the IAG, Book of Abstracts; 2013 p. 95
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20130106
PublisherInternational Association of Geodesy
MeetingInternational Association of Geodesy Scientific Assembly; Potsdam; DE; September 1-6, 2013
Mediapaper; on-line; digital
File formatpdf
ProvinceBritish Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Subjectsgeophysics; remote sensing; satellite geodesy; global positioning system
ProgramGeodetic Survey, Canadian Spatial Reference System
AbstractFor more than a century, the levelling technique has served Canada well in realizing and maintaining its vertical datum through a network of some 90,000 benchmarks an-chored to the ground and stable structures. Despite this large number of benchmarks, the coverage remains fairly sparse in southern Canada and is basically nonexistent in northern Canada. Furthermore a substantial number of these benchmarks have disappeared or can be considered unstable. Levelling remains the most precise technique to determine height differences locally but it is inefficient and costly when surveying a country as large as Canada.
Global Navigation Satellite Systems such as GPS offer an efficient and precise alternative for height determination at any location globally. These heights are referenced to an ellipsoid, which is a simple mathematical representation of the Earth that, unfortunately, does not provide meaningful elevations. A geoid model, the separation between the ellipsoid and the geoid, allows the transformation from these ellipsoidal heights to orthometric heights that are compatible with levelling-derived heights and referenced to the mean sea level. With the introduction of the Canadian Geodetic Vertical Datum of 2013 (CGVD2013) in November, Canada will now define its vertical datum by an equipotential surface (geoid) and realize it by a geoid model covering all of North America (land, lakes and oceans). This modernization of the vertical datum will replace the levelling- and benchmark-construct CGVD28. An equipotential value has been chosen with the United States government that will be used by both nations for the coming decade.
Summary(Plain Language Summary, not published)
NRCan is responsible for the Canadian Spatial Reference System, a national standard that enables high accuracy positioning and geodetic measurements of the dynamic Earth. An essential component of the Canadian Spatial Reference System is the height reference system, enabling determination of heights above sea-level, critical for water management. Modernization of the height reference system will take place in 2013, using an innovative approach, the geoid. Geoid modelling is profoundly reliant on the synthesis of gravity measurements of many types.