4 ms·
What would you do with the g measurement to get your location? Can g deltas be matched to sea floor contour maps? Otherwise it seems like subs would have to be
by rogers18445 3y ago
What would you do with the g measurement to get your location? Can g deltas be matched to sea floor contour maps? Otherwise it seems like subs would have to be following g-mapped routes.
- etrautmann 3y agoWith a highly detailed map, it becomes a statistical fitting problem, to locate yourself based on an estimate of position history using intertidal measurements and your time history of gravitational measurements, starting from an initial position estimate. I would imagine this could be quite accurate.
- tehlike 3y agoPretty much a slam application.
- etrautmann 3y agoexactly - presumably a subset of the full SLAM challenge if a detailed map already exists and you're just localizing within it
- quickthrower2 3y agoDead reckoning with gravitational adjustments?
- etrautmann 3y agoOops fat fingers - s/intertidal/inertial
- unhammer 3y agowhat a strangely fitting typo though :-)
- jchallis 3y agoA typical sub drifts by only a few tens of meters per day - obviously this builds up . The point of the BEC gravity map is to reduce this inaccuracy an order of magnitude, thereby extending the subsurface range of the subs.
- rogers18445 3y agoBut how would you do this? Sensor fusion with inertial sensors is well understood, how do you fuse g into the equation to improve things?
- themeiguoren 3y agoBy having a base map of the gravity of the ocean floor. Picture a contour map, but for values of g. Same as if you were navigating based on a physical contour map of the ocean floor, except that getting an accurate depth like that in deep waters isn’t possible, and in shallow waters requires sonar.
- wongarsu 3y agoI'd assume features below the sea floor have a much bigger impact than surface features. Large iron deposits, volcanic activity, natural gas deposits, whatever the LLSVPs are, etc. But you could use ships to correlate gravity measurements with GPS locations and make an accurate map that way. You don't need to map the entire ocean, just enough locations to allow subs to occasionally recalibrate their position.
- closewith 3y ago>LLSVP Large low-shear-velocity provinces, for anyone else wondering: https://en.wikipedia.org/wiki/Large_low-shear-velocity_provinces https://en.wikipedia.org/wiki/Large_low-shear-velocity_provi...