Underwater GPS

[justleesa]

One of our instructors has a UW GPS and it works up to 50 fsw...don't know the brand and it looks military to me.

 

[Scubadawg]

Taking GPS underwater is like taking a compass in to space.....

 

[Mako Mark]

I actually have an underwater cellphone.

I bought it for two dollars at "toys R us" and keep it in my BCD pocket, whenever someones computer or watch starts beeping UW, I drag it out and pretend to talk, nod my head etc.

It fools about 50% of divers.

 

[justleesa]

I actually have an underwater cellphone.

I bought it for two dollars at "toys R us" and keep it in my BCD pocket, whenever someones computer or watch starts beeping UW, I drag it out and pretend to talk, nod my head etc.

It fools about 50% of divers.

:rofl: !!!

 

[GeekDiver]

Fivetide

Buetooth is limited to 5 ft or so range by design so wouldn't be of much help. There defined as a PAN (personal area network) device. If they had more than a 5 ft range it would end up disrupting communications for your co-workers who also may use bluetooth.

bet theres not many on the board who know where the name bluetooth comes from? (without looking it up on the internet first)

 

[DoUDive2]

One of our instructors has a UW GPS and it works up to 50 fsw...don't know the brand and it looks military to me.

Ask him what it is and where he got it. I like to keep up to date on things like this.

Chris

 

[Ragnar]

I figure the Navy has to have developed somehing to assist with undewater navigation. I was thinking along the lines of of ULF wave triangulation. The problem with that is that those waves travel at different speeds through waters with differing salt content which would make the system fairly inaccurate without a very large number of reference points. Also ULF waves have been linked in a corrolary (not causal) fashion with disruption to marine life.

Don't know a thing about U-boats, but I bet they use some type of inertial nav. Once it's initialized with GPS, or the coordinates are input manually on the surface and it knows it's present position, all future movement can be calculated from the forces felt on the laser gyros. In airplanes there are sometimes three of these which all cross check each other. Now the question is.........how in the hell did they do it back in the forties!!!....Hmmmm......

 

[justleesa]

Ask him what it is and where he got it. I like to keep up to date on things like this.

Chris

Sorry, I missed this one.

I know he got it from a military buddy....when I see him the next time I'll ask.

 

[The Kraken]

Don't know a thing about U-boats, but I bet they use some type of inertial nav. Once it's initialized with GPS, or the coordinates are input manually on the surface and it knows it's present position, all future movement can be calculated from the forces felt on the laser gyros. In airplanes there are sometimes three of these which all cross check each other. Now the question is.........how in the hell did they do it back in the forties!!!....Hmmmm......

Needle, ball, air speed, magnetic heading, and cellestial navigation.

 

[DoUDive2]

... all future movement can be calculated from the forces felt on the laser gyros. In airplanes there are sometimes three of these which all cross check each other. Now the question is.........how in the hell did they do it back in the forties!!!....Hmmmm......

The directional gyro was actually used on aircraft back in the 1930s. So, the concept of gyroscopic (inertial) air navigation is a very old technology. Of course, for me to compare today's ring laser gyro to a directional gyro is like comparing a modern home to a bear cave.

The forties, however, is when modern air navigation really took hold. From the 20s to the 40s air navigation transitioned from airway lights (originally bonfires stoked by Post Office stations across the country) to 4 course radio transmitters located strategically between towns. In the 40s, the airway lights were made electric and the 4 course radio transmitters were replaced by the very high frequency omnirange (VOR) transmitters. Airway lights were eventually phased out, but VORs are still used today to define most of the federal airways that cross the United States. The LOng RAnge Navigation (LORAN) system was also introduced in the 1940s. Long flights over water typically relied upon a whisky compass, an airspeed indicator, an altimeter, and a navigator familiar with celestial navigation techniques (sun or star fixes).

Inertial systems are useful for redundancy and ocean crossings, but even today, they rarely provide the primary means of air navigation. This is because they accumulate errors over time if they are not updated with "absolute" navigation reference. Radio-navigation systems (like VOR, LORAN, and GPS) provide "absolute" navigation references and can be used to periodically update inertial navigation systems. Submarines are able update their inertial navigation systems by measuring variations in local gravity along the sea floor. I'm fairly certain that this technology is not available to the sport diver yet. ;-)

Chris