Tidal Height Retrieval Using Globally Corrected GPS in the Amundsen Gulf Region of the Canadian Arctic

摘要

The recent evolution of global Wide Area Differential GPS (WADGPS) networks has greatly increased the already high level of interest in GPS technologies by the hydrographic community. The aim of this paper is to evaluate one of these WADGPS systems, the C & C Technologies Globally Corrected GPS (GcGPS) C-Nav, as an instrument for tidal height retrieval in the Canadian Arctic. The C-Nav receiver was mounted aboard the Canadian Coast Guard Ship (CCGS) Amundsen for her 14-month over-wintering expedition in the Northwest Passage. C-Nav height data were collected in Franklin Bay, North West Territories, over February to April 2004. Data were collected over a 40-day period to ensure the capture of all significant wavelength tidal effects. rnAs a ‘true’ vertical reference, Knudsen K320 sub-bottom profiling sonar depth data were collected. The 1 Hz CNav data were processed and decimated down to 6-minute epochs, thus speeding the filter processing to obtain realtime data latency. Over the course of the research period, the standard deviation of the C-Nav data was 4.3 cm, when compared to the ‘true’ tidal signature given by the K320. This level of positioning is commensurate with International Hydrographic Organization (IHO) Special Order surveys. In addition, the benefits of the C-Nav solution were apparent in capturing the phase lag of the tides due to sea ice effects. Tidal predictions using common software applications such as the Unix based program Xtide, yielded standard deviations of 5.3 cm.