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widgeon
22nd Jan 2007, 21:23
Some not convinced to shelve LORAN
January 16,2007
PATRICIA SMITH
DAILY NEWS STAFF
Federal authorities are considering decommissioning the Long Range Aids to Navigation (LORAN-C) system.

And at least one local boater thinks that would be a mistake.

"I think it would be very foolish, otherwise we'll end up with all our eggs in one basket," said Bill Brogdon, a retired U.S. Coast Guard captain who lives in Cape Carteret.

LORAN-C is a radio navigation system based on technology developed in the 1960s that uses land-based radio transmitters to allow mariners and aviators to determine their position. It is accurate to within a 500-yard diameter, said U.S. Coast Guard Petty Officer Jonathan Cilley, of District 11 public affairs.

Global Positioning System (GPS) is a satellite-based radio navigation system that is much more accurate.

"That's exact, that will give you exact coordinates of where you are in the water," Cilley said.

Last week, the U.S. Coast Guard, under the Department of Homeland Security and the U.S. Department of Transportation, posted a notice in the Federal Register requesting public comments on whether or not GPS renders LORAN-C obsolete.

The government is asking the public if the nation still needs LORAN-C given that many now use GPS or if we should continue investment in upgrading to Enhanced LORAN (eLORAN).

"GPS is more of a reliable system where LORAN-C is getting to the point where it's outdated," Cilley said.

"Most mariners don't even use it anymore."

Those that do are mainly the old fishing boats, Cilley said.

Brogdon said many of the fishermen do still use LORAN-C to get back to fishing holes they logged years ago. But the main reason Brogdon thinks the nation should keep LORAN-C is because GPS is vulnerable to interference.

"It's a great system, but like anything else, it's manmade. It's not perfect," Brogdon said.

Sunspots can cause temporary blackouts, as can testing of military communications jamming equipment, Brogdon said. There have even been cases where TV and radio antennas from one vessel interfered with GPS signals for nearby boats, he said.

If a fisherman out on the water loses GPS for 15 minutes, he may not notice it. But for a ship coming into port, it could be disastrous without some backup system, Brogdon said.

The government is accepting public comments until Feb. 7.

They should be identified by Coast Guard docket number USCG-2006-24685 and sent to the Docket Management Facility of the U.S. Department of Transporation by mail to 400 Seventh St., SW., Washington, D.C. 20590-0001; by fax to (202) 493-2251; or by logging on to the web at http://dms.dot.gov.

http://www.jdnews.com/SiteProcessor.cfm?Template=/GlobalTemplates/Details.cfm&StoryID=47850&Section=News

ShyTorque
22nd Jan 2007, 22:10
Good question - so soon after it was announced that China has proved a capability to shoot down a satellite. :ok:

SASless
22nd Jan 2007, 22:40
"It's a great system, but like anything else, it's manmade. It's not perfect," Brogdon said.

Now who does Brogdon think made LORAN?

What did folks do before electronic navaids anyway?

(This smartassed comment coming from a guy who has two GPS receivers in his car, mind you!:( )

Shawn Coyle
22nd Jan 2007, 23:38
One of the things that isn't often said about the use of LORAN is that it could be combined with GPS to make a very good, redundant precision navigation system.
LORAN would carry corrections to GPS signals (like WAAS or LAAS) and GPS could carry corrections to the LORAN signal.
No more VORs, DME, etc. - just your correct position.

Brilliant Stuff
23rd Jan 2007, 00:32
That would be common sense. Under no circumstances can we have that.:ugh:

Doc Cameron
23rd Jan 2007, 01:27
Surely DGPS is the way to go if you need redundancy and corrections to your Sat based system...

And no SAS the two GPS receivers in your car don't count as 'differential'.

Thridle Op Des
23rd Jan 2007, 05:50
Hmm this sounds a 'Good Idea'; lets keep an antiquated Hyperbolic navigation system around and use it as a back up for the GPS constellation. Ohh look no one else in the world has LORAN except us so we will tell everyone else to go out and knock up several hundred Master/Slave ground stations since we think it will make our lives safer - we will ignore Glonass and the up and coming Galileo which we don't have control over since it is NIH.

Oh I almost forgot - it is so much easier to jam/disrupt GPS than LORAN since LORAN is such a wonderful hardend piece of 1940's equipment.

BTW have you seen the difference in orbital altitudes between a GPS SV and a tired old 'Great Wall Industries' clapped out satellite?

Excuse the excessive sarcasm Gentlemen, but please just pull the plug on LORAN, it's not required anymore.

TOD

NickLappos
23rd Jan 2007, 05:55
I am reminded of the simple law of design:

Everything is nice and desirable for you to have, until YOU have to pay for it.

If a 28 to 32 satellite GPS ephemorous is not redundant enough, you have a REAL nav problem!


http://www.garmin.com/graphics/24satellite.jpg

widgeon
23rd Jan 2007, 21:18
Was there ever Loran a and Loran b ?. I recall the Canajun COast guard helicopters had some Decca system in em , is that still working ?.

http://www.prnewswire.co.uk/cgi/news/release?id=19360

oops missed that end of an era anouncement,

MarcK
24th Jan 2007, 20:04
Loran A: http://www.jproc.ca/hyperbolic/loran_a.html

MarcK
24th Jan 2007, 20:07
Lorans B, D, F (http://www.jproc.ca/hyperbolic/loran_b_d.html)

outhouse
25th Jan 2007, 11:50
I remember the Decca system on the North Sea, a rather nice paper moving map and a squeaky pen that indicated a position, not necessarily the correct one? If the map got wet (leaky roof in the old 61 when it rained) the map refused to drive over the rollers and went soggy, and the squeaky pen tangled in the wet paper.
Thank goodness for modern technology, lovely GPS in the car but the lady who talks sometimes reminds me of the wet map and squeaky pen, bloody infuriating.

outhouse
:cool:

MBJ
26th Jan 2007, 10:37
Yes, Outhouse, loved the way we twisted the earth to fit the hyperbolic signal on those paper maps. Loved the way when the weather was dank the nav stopped working. Character building!

The Europeans and the Russians are producing satellite nav soon so we could have triple redundant systems in due course. When we do we can unplug Loran with a sigh of relief.

outhouse
26th Jan 2007, 12:27
Yes BBJ, what happened to those Character Building times, it all seems so Boringly? Dull these days.
outhouse
:)