Not Loran but eLoran

[ricardian]

BBC report (http://www.bbc.co.uk/news/science-environment-29758872) Technology developed during World War Two is to be used as a back-up for GPS.
The General Lighthouse Authorities (GLA) have announced that they have installed a system called eLoran in seven ports across Britain.

[4Greens]

A very good idea. It is often forgotten that the satellites running GPS are all controlled by the US military. There is no back up - in safety terms a 'single point failure.

[Heathrow Harry]

welllllllllll - the Russians have a system in use and the Europeans are putting one in place as well so it's not all US controlled

However they are dependent on satellites and there are a number of scenarios (some natural so man made) that would see the network seriously degraded.

GPS has quite a few issues from a survey point of view that the average guy has no idea about as well

Having a back-up in place is a really good idea

[effortless]

I guess that it is less vulnerable to jamming.

[Pontius Navigator]

And Chinese:
BeiDou Navigation Satellite System - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/BeiDou_Navigation_Satellite_System)

[4Greens]

Chinese only available to China and neighbours. Europe not yet operational. Russian only available if you ask Putin.

[Pontius Navigator]

At least Galileo is said to be 10x more accurate than the Chinese one.

I see also that new GPS satellites do not have a SA capability (they say)'
.

[sandozer]

You do realise we have all been using Glonass since 2011? :cool:

GPS Test app on Android differentiates between Glonass satellites and GPS satellites if you want to see what you are locked into.

[Courtney Mil]

PN, they turned SA off best part of 15 years ago, although not much publicized ahead of time. They haven't even been building the facility into the birds for five years or more. Mind you, my car still can't find its way home.

[Exnomad]

There was something called Loran available over the North Atlantic Whwn I was serving in the early 1950.

[4Greens]

Exnomad , I used it to fix a position in a frigate on the way to Halifax Nova Scotia.

[Tankertrashnav]

There was something called Loran available over the North Atlantic Whwn I was serving in the early 1950.

Loran? We dreamt of Loran! Slaving over an 'ot sextant half way across the pond!

Loran? Luxury!

[Pontius Navigator]

4Greens, or did you mean a weather ship? Marvellous job is you liked the ocean life and had a strong stomach. IIRC the kipper fleet did a Christmas mail drop.
http://m.youtube.com/watch?v=W2DBtuUA86s

[4Greens]

It was definitely a frigate. Very bad weather and ice froze all the aerials including Loran. Got a sun position line four days later. We found our way in at last.

[ian16th]

LORAN was an American version of the UK Gee system.

It worked at a lower frequency, this gave it a longer range and was used over the Atlantic and by ships, whereas Gee was 'Eurocentric' and built as a bombing aid aimed at the continent.

For bombing use, Gee evolved into Gee-H and the existing Gee transmitters were retained became a general navaid.

In the 50's and 60's most RAF 'navigator equipped' a/c had a 'Gee box' of one sort or another. An odd version in the Valiant was Gee-H with the 'H' parts not fitted.

To my knowledge, Gee II was fitted to Hastings and Gee III to Beverley's, some Hastings at Dishforth in 1959 also had LORAN.

I was never involved with Coastal Command, but I would have expected that the Shackleton's of the time would have used LORAN.

[Heathrow Harry]

Problem was that coverage was not worldwide IIRC - if you wanted something in teh middle of no-where you had to set up your own system

[HTB]

We had Loran C fitted into 27 Sqn Vulcans in the MRR role, which apparently gave rise to the designation B2(MRR), a though sometimes without the brackets. It worked pretty much world-wide, with some areas that were a bit flaky, but suited our needs over the Pacific in the other sqn role. Still a lot of swing from the sextants, though to validate signal integrity (or was it the other way round...)

Mister B

[finncapt]

Twas also used in commercial aviation.

As a VC10 pilot /nav with BOAC, I remember it well.

We used consol too and of course a sextant.

The weather ships also had radar and would give one a range and bearing.

Oh the "good old days".

[Herod]

What I find disconcerting is the bit in the article where he pulls the plug and everything goes dark. OK, the plot goes, but radar (raw data anyone?), steering, comms and even the clock. Too much reliance on a single point. In my last aircraft (737NG) loss of GPS was not a major failure. VOR, DME, ADF, the good old E2B compass would still get you home.

[ian16th]

Problem was that coverage was not worldwide IIRCHH

This will always be so with any 'secondary' radar. The definition of secondary radar means that it is dependent upon a second piece of kit. In some cases on the ground, in others in the a/c.

Look at the MH370 thread, many people have been educated as to how the civil authorities are almost totally dependent upon the a/c side of these systems being serviceable and used correctly. No 'squawk' and the a/c was invisible!

Just about all of the primary ground based radars are in the hands of the military.

[Pontius Navigator]

The early Loran was later termed Loran A, so the later kit was Loran A/C capable of receiving both types.

Later, late 70s, Omega was introduced at VLF and with microprocessors could correct of changes in transmission speeds over different terrain and present your position as lat and long, real time position and no plotting on lattice charts.

[pmills575]

Costal used Loran A on Shacklebombers and Loran A/C on the Nimrod, Mk1's anyway.

Also Shacks fitted with GEE III. Last GEE/AMES 7000 ground stations were switched off in 1971 I believe.


pm575

[Mal Drop]

The Apollo ADL604 LORAN bolted beneath the Nav's radar was a very accurate system in GW1 but as we got the cheap version it tended to have fits of the vapours above 150 kts.

And there was no pilot display.

And all the information was displayed on a couple of lines of green LED dots.

And there was no training other than the Nav reading the 400 page manual.

And it was an utter bastard to use...

But apart from that, what have the Romans ever done for us?

[Willard Whyte]

I was a little late to the GW1 party; I seem to recall the primary purpose of Apollo when I was on 'ercs was to leave rude messages for the next nav on mct/cpt sorties.

Never got the hang of that either.

I could play a good game of 'find the fish' though. Still remember my first pond crossing; not realising nav screen had gone off somewhere I proceded to change chains. Having (successfully) done so said screen returned to flight deck and instructed me to change back to the original chains and then to the new ones as he hadn't observed me doing it previously. Arse.

[Party Animal]

Loran continued in use on the Nimrod MR2 up until - eerm mid 90's? Gave the route nav a toy to play with and tweak during those quiet momemts of boredom. On its day, it could be very good.

[ricardian]

e-Loran Signal Tests Start, Could Demonstrate GPS Backup Alternative. 12 month test starts (http://www.insidegnss.com/node/4539)

[Phalconphixer]

@ian16th...

Problem was that coverage was not worldwide IIRC
HH

This will always be so with any 'secondary' radar. The definition of secondary radar means that it is dependent upon a second piece of kit. In some cases on the ground, in others in the a/c.

Look at the MH370 thread, many people have been educated as to how the civil authorities are almost totally dependent upon the a/c side of these systems being serviceable and used correctly. No 'squawk' and the a/c was invisible!

Just about all of the primary ground based radars are in the hands of the military.

Sorry but Loran? Secondary Radar?? Hardly!
Loran in either its A or C variants was / is a LF Hyperbolic Radio System. Primary or secondary it had absolutely nothing to do with radar.
Prior to rejoining the civvy world it was my dubious pleasure to be one of the very few trained 2nd / 3rd line techs at RAF Sealand 30MU responsible for the servicing and repair of the ADL-21 Airborne receivers... when it was good, it was very very good... but a rogue receiver (and s/n 222 comes to mind... temperature sensitive motherboard) could be a real pig.
More info about Loran A and C available here...
http://en.wikipedia.org/wiki/Radio_navigation#LORAN-C
Superceded generally by Omega and then later by GPS...

[Dan Winterland]

The decommissioning of Loran started in the US and Canada from about 2009 with many of the transmitters being turned off. However, the Europeans being a bit suspicious of the US control of GPS upgraded their chains to eLORAN. The Americans thought this was a good idea and have started to convert their existing chains to eLoran.

The advantage of eLoran over SATNAV is that the transmissions are much more powerful and less susceptible to jamming. And SATNAV GBAS enhancement can be transmitted on the eLoran signal.

Combine eLoran and GPS receivers have been available for marine use for a couple of years, and now the US Army want to buy 50,000 eLoran sets.

Loran is not dead!