HR: 0800h
AN: G41B-0362    [Abstracts]
TI: Integration of the Canadian Gravity Standardization Network with the Canadian Spatial Reference System: Challenges and opportunities
AU: * Henton, J
EM: jhenton@NRCan.gc.ca
AF: Geodetic Survey Division, Canada Centre for Remote Sensing, Natural Resources Canada, 615 Booth Street, Ottawa, ON K1A 0E9 Canada
AU: Craymer, M
EM: craymer@NRCan.gc.ca
AF: Geodetic Survey Division, Canada Centre for Remote Sensing, Natural Resources Canada, 615 Booth Street, Ottawa, ON K1A 0E9 Canada
AU: Liard, J
EM: jliard@NRCan.gc.ca
AF: Geodetic Survey Division, Canada Centre for Remote Sensing, Natural Resources Canada, 615 Booth Street, Ottawa, ON K1A 0E9 Canada
AU: Duval, R
EM: rduval@NRCan.gc.ca
AF: Geodetic Survey Division, Canada Centre for Remote Sensing, Natural Resources Canada, 615 Booth Street, Ottawa, ON K1A 0E9 Canada
AU: Klatt, C
EM: cklatt@NRCan.gc.ca
AF: Geodetic Survey Division, Canada Centre for Remote Sensing, Natural Resources Canada, 615 Booth Street, Ottawa, ON K1A 0E9 Canada
AB: The primary role of the Geodetic Survey Division (GSD) is to maintain, continuously improve, and facilitate efficient access to the Canadian Spatial Reference System (CSRS). This includes the responsibility to maintain the Canadian Gravity Standardization Net (CGSN) that provides datum control for gravity observations across Canada. The current primary network and complementary control stations of the CGSN have been mainly established and maintained using relative gravimetry linked to only a few absolute gravity stations. However, with recent improvements in absolute gravimeters it has become tenable to modernize and subsequently maintain the CGSN utilizing primarily absolute gravimetry (AG) techniques. Additionally, as measurement and processing accuracies have increased, the Division is now in an era in which the time-variability of our observations (positions and gravity) must be considered. In order to better contribute to the definition of the vertical component of a highly accurate, multi-purpose, active and integrated CSRS, the GSD is developing a set of recommendations for CGSN integration with geometric reference stations (VLBI, continuous and episodic GPS). The establishment and maintenance of this modernized CGSN will be commensurate with international standards and trends. To meet the above goals, efforts are now underway to densify the array of absolute gravity observations in Canada. Within Canada, the most significant movement for most of the landmass will be vertical motion, as demonstrated by current models and analyses. It is therefore critical to be able to monitor and confirm height variations over time. Absolute gravimetry, which is independent of GPS, can also play a complimentary role in detecting vertical movements through repeated observations at certain sites. These capabilities should prove useful to the maintenance of a new gravity-based height-reference system. In order to monitor the temporal variations in gravitational potential resulting from regional glacial isostatic adjustment, an array of absolute gravity sites has been established in eastern Canada. These sites are all co-located with high-precision GPS and serve as a monitoring network for deformation studies of the Canadian landmass. Preliminary results also exhibit general agreement among the uplift rates for GPS vertical velocities, gravity trends, and predictions of vertical crustal motion from postglacial rebound models.
DE: 1200 GEODESY AND GRAVITY
DE: 1211 Non-tectonic deformation
DE: 1243 Space geodetic surveys
DE: 1244 Standards and absolute measurements
DE: 1295 Integrations of techniques
SC: Geodesy [G]
MN: Fall Meeting 2005