The following images show a comparison between two heave solutions from the CodaOctopus F180 Attitude and Positioning System. Also shown on the graph is the heave as determined from Real Time Kinematic GPS processing. The Online Heave is the real time solution that is used by the multibeam system aboard OMG's launch, the CSL Heron. The iHeave is the F180's recursive filter solution that is available with a 350 seconds latency. The RTK data was collected using two dual frequency Trimble 5700 GPS receivers. The GPS positional fix is then rotated using pitch and roll data from the F180. The RTK Heave values are also reduced to zero mean so that they are comparable to the other heave solutions. The Orientation and Speed graphs are shown below the heave graphs as a reference.

In this short time series, the Online Heave appears to perform well around the 100 second mark. At this point the period of the heave's 'ringing' coincidently matches with the speed change.

February 2, 2005 -- steveb at omg.unb.ca