Royal Navy says quantum navigation test a success

Post by paulmd » Wed, Jun 07, 2023, 6:32 PM UTC

jchallis wrote: post #13

This is the most obvious practical application of my PhD topic. A Bose Einstein Condensate is an extremely sensitive detector of gravity- a nuclear submarine could use it to make an ultra-accurate map of the world based on variations in the gravitational constant g. This would remove one of the primary reasons subs need to surface , in order to GPS lock. It’s a naval chart that would not require surfacing. A French p…

Post by pnpnp » Wed, Jun 07, 2023, 6:39 PM UTC

kebman wrote: post #196

LgWoodenBadger wrote: post #132

Earlier quoted context omitted.

Oh come on... "On 8 January 2005 at 02:43 GMT, San Francisco collided with an undersea mountain about 364 nautical miles (675 km) southeast of Guam while operating at flank (maximum) speed at a depth of 525 feet (160 m)." https://en.wikipedia.org/wiki/USS_San_Francisco_(SSN-711)

So, here's an anecdote of a sub that miraculously survived a head on collision. What's your point? From the same article: “The collision was so serious that the vessel was almost lost; accounts detail a desperate struggle for positive buoyancy to surface after the forward ballast tanks were ruptured.” I doubt these are problems any submarine crew wants to deal with, even at slow speeds. Besides, one sharp edge at the…

Post by crispyambulance » Wed, Jun 07, 2023, 6:43 PM UTC

jchallis wrote: post #13

This is the most obvious practical application of my PhD topic. A Bose Einstein Condensate is an extremely sensitive detector of gravity- a nuclear submarine could use it to make an ultra-accurate map of the world based on variations in the gravitational constant g. This would remove one of the primary reasons subs need to surface , in order to GPS lock. It’s a naval chart that would not require surfacing. A French p…

Post by timthelion » Wed, Jun 07, 2023, 6:50 PM UTC

jedc wrote: post #220

jchallis wrote: post #13

This is the most obvious practical application of my PhD topic. A Bose Einstein Condensate is an extremely sensitive detector of gravity- a nuclear submarine could use it to make an ultra-accurate map of the world based on variations in the gravitational constant g. This would remove one of the primary reasons subs need to surface , in order to GPS lock. It’s a naval chart that would not require surfacing. A French p…

Former submariner here with a quibble on this: > one of the primary reasons subs need to surface , in order to GPS lock While getting a GPS position is helpful, the primary reason a submarine goes to periscope depth regularly is for communications. The Navy needs to send information to submarines and know that they'll get it and take action within a certain timeframe. That's by far the primary driver.

Post by andromeduck » Wed, Jun 07, 2023, 7:41 PM UTC

crispyambulance wrote: post #235

jchallis wrote: post #13

This is the most obvious practical application of my PhD topic. A Bose Einstein Condensate is an extremely sensitive detector of gravity- a nuclear submarine could use it to make an ultra-accurate map of the world based on variations in the gravitational constant g. This would remove one of the primary reasons subs need to surface , in order to GPS lock. It’s a naval chart that would not require surfacing. A French p…

I don't understand how this would work. Do we somehow already have that super-accurate "map of g"? Wouldn't one already have to exist to be able to use quantum navigation? Moreover, would it not also require integration with a gyro and a lot of history to be able to know, for instance, which place it's at of many in any given ocean where g = 9.8100023? Does g really vary that much that you can figure out where you ar…