What submarine navigation aids are currently developed ?

[Externet]

That autonomous submarine searching for the missing Boeing 777 aircraft in the south Indian sea; tracing a search pattern can steer by its compass/autopilot, and maintain or change headings, read its water-relative speed; but how does it know its position coordinates ?

 

Marine currents can produce a sustantial position deviation specially after several hours spent only in descent/ascent.

 

Or is its position known from external tracking by its mothership sonar linked to time 'stamps' ?

[studiot]

In space, the air or on land we deploy base stations that transmit EM signals for positioning purposes.

Many base stations these days are satellites.

 

Underwater, these EM signal do not propagate well.

 

Luckily acoustic signals do. So we do the equivalent. Setting up acoustic transmitter base stations and using these signals.

 

A classic text on this subject is

 

Underwater Acoustic Positioning Systems

 

by Milne.

Edited April 16, 2014 by studiot

[Endy0816]

The Bluefin-21 has a GPS, fiber optic laser gyro inertial navigation system, Doppler velocity log, synthetic vision system and Ultra-Short Baseline acoustic positioning system.

 

http://www.bluefinrobotics.com/products/bluefin-21/

http://defensesystems.com/articles/2014/04/14/navy-bluefin-auv-maylasia-flight-370.aspx

 

I recall laser gyro's being the mainstay on the sub I was on. Bluefin's advert page highlights that as well.

Edited April 17, 2014 by Endy0816

[Enthalpy]

As the Bluefin is a mapping sonar, it knows very accurately its speed versus the Ocean floor. This gives it the displacement precisely.

 

Acoustic references are used to retrieve heads of oil wells on the Ocean floor for instance, or to position actively oil rigs. It's uncommon when exploring a new area.

 

Bigger military submarines have other means, some being known. Rather common presently are gravity gradients, created by geographic features like subaquatic mountains, and measured by sensitive gradiometers. This gives an absolute position. Maybe the many gravity-mapping satellites are meant to produce navigation maps for submarines, not just for pure science.

http://en.wikipedia.org/wiki/Gravity_gradiometer

 

Magnetometers and magnetic gradiometers have been used as well for navigation, but mainly in an attempt to detect submarines. In principle, one could compare the measured field with a map to know the absolute position.