No Barney, sextant isn't the name for one of your pages.

[Bruce]

I get sent all kinds of stuff, just got his link. Writing content is sinking to new lows.

Did I just wake up from a ten year nap or has this guy just realized the GPS, or electronics in general do fail?

Damn, now here did I put that sextant?

http://maritimeprofessional.com/Blogs/M ... rrors.aspx

The Global Positioning System is highly precise, but not error-free


The Global Positioning System (GPS) was initiated by the US Department of Defense (DOD) as a position-finding system to be used for military purposes. Originally, it was envisaged for use by nuclear submarines so that they could better aim their ballistic missiles.

The system was so good that it rapidly expanded to other military uses. When other federal agencies and foreign governments learned of the system and clamored for access, DOD made a somewhat degraded version publicly available. After further pressure was asserted, DOD made the high-precision signals available to all users. Russia has its own version of GPS called GLONASS, although its constellation of satellites is not as large as that of the United States (currently 24).

China, Japan, India, and the European Union have initiated their own GPS programs. GPS receivers are now fairly inexpensive and have become ubiquitous. They are found on the bridge of almost every ocean-going ship in the world and are so relied upon that many mariners fear that traditional methods of position-finding, such as use of the sextant, will no longer be practiced.

While GPS is capable generally of identifying the position of the receiver within several meters, the accuracy may be degraded in a variety of manners. Because the radio signal transmitted by the satellite is weak, it is readily subject to interference.

This interference may be generated by a number of sources. Space weather, such as solar flares, may disrupt the signal. Metal in the vicinity of the receiving antenna may degrade the signal (this is a particular problem for portable GPS devices used in cars and on boats). Man-made electro-magnetic interference (EMI) is a growing problem. In 2001, GPS reception in and around Moss Harbor, California was blocked. It took about a month to determine that this interference was caused by a defective television antenna on a recreational yacht docked at a local marina. Similar accidental interference has been experienced elsewhere at different times.

Intentional jamming of GPS signals was utilized sporadically by the by Iraqi forces during the Iraq War. There is now concern that terrorists might use GPS jamming to disrupt shipping and possibly induce collisions and groundings. Trinity House in the United Kingdom has commenced tests to determine the susceptibility of ships to such GPS errors.

The take-away is: Don’t yet throw out your sextant.


Posted by Dennis Bryant on 10/23/2009 7:00:00 AM

[Carl]

The mentality of everyone seems to be sinking.

[amuh60]

Always maintain situational awareness! And always know where you are on the MAP!!!!

-ANDY

[PaulJ]

Bruce...
I'm in this business. Outlook for GPS is grim....
http://www.engadget.com/2009/05/19/gps- ... unting-of/
http://www.drudge.com/archive/121177/gp ... -breakdown

Even if they can get the satellites built in time, there is a waiting list for launch.

Paul J.

[Carl]

I'm not worried...Everyone Always Tells me Where To Go!!! ;-)

[IRGuy]

Having been watch captain and navigator/backup navigator on ocean racing sailboats for over 30 years I have used Radio Direction Finders, Loran A, Loran C, Satnav and now GPS. I have seen all of them fail at one time or another for a variety of reasons.

We always plotted our positions on paper charts every half hour when offshore. We also kept notes on wind, current, wave direction, and anything else that would be helpful in estimating our position if we lost any of our electronics.

Never trust any navigation system 100%.. always have backup systems available, and use paper charts to plot your position regularly. And know at least how to use dead reckoning and be able to plot your estimated position. You probably will find that usually the times your electronic systems fail you is when you need them the most!