Saturday, April 4, 2009

Trip

The trip via each waypoint is 6217 mile long. The path was chosen to pick up the ocean current to the United States used by the early traders to this country. Currents for the trip during the summer months are favorable South from Spain/Portugal to the Western Coast of Africa, turning Northwest to near Puerto Rico and on to Tybee Island, Georgia.

Currents will be monitored in near real time from the NOAA satellites at http://www.oscar.noaa.gov/ . If an early summer hurricane or storm should be encounterd, a new set of trip waypoints will be downloaded over the Iridium link. Worse comes to worse, the boat will be stopped until conditions improve.

Simulated Trip

Before the actual trip is undertaken, a simulated trip with actual route coordinates will be done.

The distance between each waypoint was divided into 100,000 points and the latitude and longitude were calculated. These points were then inserted into NEMA 0183 GPRMC sentences that would normally be received from the GPS system. The simulated sentences will be fed to the vessel's control computer over a serial port that normally receives the output of the GPS receiver.

Several type of problems will be introduced at various points to simulate anticipated problems such as the control computer losing control, unexpected shutdown, or loss of total power.

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