No. The earth bulges slightly at the equator due to spin; equatorial diameter is ~40 km (26 miles) greater than the polar.
Isn't one second of arc at the equator roughly 100ft?
1° = 60 nm
1´ = 1 nm = 2000yds
1´´ = 2000 / 60 = 33.3 yds = 100 ft.
Yep.
If the crust of the earth moved in relation to the core would that in any way affect the position of global positioning sattelites in retation to the earth's surface?
The each satellite's time reference would change by some incredibly small amount (probably how they discovered the shift in the first place), but that would have be done in a few hours before everything was back in sync.
If it did would that be like plotting your course on a clear surface over the chart and shifting the chart slightly under the course and wind up hitting someting you normally would have missed?
That's pretty hazardous. Submarines are extremely cautious when it comes to navigation.
I see. A decimal point error.
1"(second)= 1000ft
0.1"= 100ft and 0.01"= 10ft and 0.003" would be 3ft?
Wasn't suggesting that plotting actually done on clear film over chart. Would be stupid.
Was thinking that slight global shift and increase in rotation speed might cause error in beginning reference point. But trianulation with GPS should not be affected.
Thanks. A little clearer now.
One other point: You can't use GPS underwater (GPS requires multiple reception of UHF signals from several satellites.)
So, underwater, you're still using essentially dead-reckoning from speed and course assumed from the instruments. Yes, those instruiments are good, much better than the iron compass and gyros and pitlog (submerged speed sensor) of old, but it's just more accurate dead reckoning.
If the mountain underwater wasn't on the chart -> there's no way you're goign to be able to plot a course around it, and (if it's slope underwater is steep enough) there's no way you're going to spot it in time even IF the fathometer was pinging.
Which, in deep ocean transits at high speed, is normally off.