GPS Flashcards
What does GPS stand for
Global Positioning system
what are the 3 elements of a gps system
the satellites transmitting position information, ground stations controlling the satellites, and a personal receiver, which collects and computes the location
how many satellites are required for an accurate fix
4 satilties
how does gps work out location
by taking the time a signal takes to reach your receiver and the speed of light it gives the distance from the satellite. adding 4 more satellites narrows this down to a single location in 3d space
How do gps calculate speed
by comparing two fixes distance, and mesuring the time between fixes
what is the hdcp
horizontal dilution of precision
do you want to have a high or low HDCP to get a good gps fix
a low HDCP
what should you do before using a waypoint from a pilot guide with a GPS
plot the waypoint on a chart to ensure it is what it says it is.
what is the SOG
Speed overground
what is the TTG
time to go, estimated time before arrival at next waypoint
what is the XTE
cross-track error
what is the COG
Course overground
what is the VMG
Velocity Made Good
What is the cross-track error used for
the cross-track error is used for alerting the skipper if the vessel is outside of a certain margin of error from the planned course.
what is the vilocity made good
the speed along the course, taking account for tacking or not going straight towards it
