LEGACY VOR's
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Vinny
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There's going to be a lot more than 24 VORs left when the FAA finishes the Minimum Operational Network (MON) by 2020 - at that point there will still be about 500 VORs active.
http://www.faa.gov/about/office_org...echops/navservices/gnss/mobileAll/VOR_MON.pdf
http://www.faa.gov/about/office_org...echops/navservices/gnss/mobileAll/VOR_MON.pdf
MAKG1
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Only for those people who completely trust GPS.
It's no worse than any other single instrument failure if you have appropriate redundancy. But, another GPS is not redundant.
Am I wrong ? I thought I had seen several references to an eventual sytem design which would leave the US with only this set of 24 ? " LEGACY VORS ". I'm sure there will be other Stages where there are many more than 24 VORS left. But, my question is - have the final 24 been identified and if so, will they have different capability when they are the only VORS left ?
Dale
Dale
weirdjim
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I have said, repeatedly, given about $10k in equipment, anybody with the remotest knowledge of microwave could sterilize a GPS area the size of Utah from 10k' in a 172. And given a brain cell the size of an FAA inspector's could get away with it nearly forever.
We have a fairly secure system in VOR, and we decommissioned the ultimate unjammable system in LORAN a few years ago.
Sometimes I think the C- students are running the show.
Jim
dans2992
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I am thinking it would be crazy because once many VORs are decommissioned, and ATC is used to separating traffic with ADS-B, arrival rates would slow quite a bit.
Let's face it, I don't see the FAA maintaining the ADS-B network and traditional radar forever.
MAKG1
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I do.
The government has come to the realization over the past few years that depending exclusively on one solution is not a robust strategy.
Radar won't go away based upon GPS alone. It might with another, alternative, solution, perhaps something like (but not identical to) LAAS.
Efficiency arguments only go so far. Redundancy is inherently inefficient. But designing a system that is not allowed to fail is a fool's errand.
Vinny
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I don't think so. I've seen a list of 30 airports that will have VOR coverage maintained, but not 24 VORs. Not sure where you're getting that number from. There are 29 VORs in the current system that are just plain jane VORs (i.e., no DME or TACAN capability), but other than that, I have no idea what you're referring to. The FAA has started very preliminary investigations of what would come after the MON (say after 2030), but it's all theoretical at this point.
Here's the core 30 airport list:
http://aspmhelp.faa.gov/index.php/Core_30
LifeInverted
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I'll take a VOR over GPS dependency any day
JHW
En-Route
its silly to talk about independance from gps. Thats akin to preppers with backward bomb shelters.
If you use electricity or natural gas or public water or petroleum or goods shipped in containers, then you have gps dependancy.
Pipeline pumping stations, railroad signals, elements of the electric grid, all depend on gps for timing if not for position.
If the gps constellation were wiped out tonight, the world economy would tank. Whether or not you can find gastons in your cessna is the last of your worries.
If you use electricity or natural gas or public water or petroleum or goods shipped in containers, then you have gps dependancy.
Pipeline pumping stations, railroad signals, elements of the electric grid, all depend on gps for timing if not for position.
If the gps constellation were wiped out tonight, the world economy would tank. Whether or not you can find gastons in your cessna is the last of your worries.
Dr. O
Pattern Altitude
Jeff, while I do not dispute your contention that losing GPS would have world wide consequences, I do dispute your conclusion that "therefore" GPS will not be allowed to fail.
The Iranians made a quite convincing demonstration that spoofing GPS is easy - and fun.
A hostile with the resources of, oh let's say Vlad the Super Slav for example, could simply wipe out GPS over the USA by using satellites - until we do what he says.
Let the Sun hack up a hairball in our direction and you could easily find half or two thirds of GPS birds offline. Being that we have only been tracking coronal mass ejections for roughly 150 years, and only since the 1940's on the effects on the power grid and for less than 40 years for electronic/satellite systems. We do not have a handle on how often the Sun spits out The Big One, like 1859. I remember the one in the winter of 1958. You could read the print on a page at midnight by the glow of the Northern Lights. My ham radio was completely down. Not even static was heard.
I am one of those who have come to the conclusion that shutting down LORAN (an almost infinitesimal slice of the national budget to keep operating) will come back to bite us.
With the shut down of Loran, a loss of GPS will shut down commercial maritime shipping - both entering and leaving the USA. You want to calculate the cost of that?
Likewise, having a robust VOR/DME system is in our best interests.
Take a look at:
http://www.solarstorms.org/SRefStorms.html
Haoving all your critical eggs on one basket is nothing short of insanity.
The Iranians made a quite convincing demonstration that spoofing GPS is easy - and fun.
A hostile with the resources of, oh let's say Vlad the Super Slav for example, could simply wipe out GPS over the USA by using satellites - until we do what he says.
Let the Sun hack up a hairball in our direction and you could easily find half or two thirds of GPS birds offline. Being that we have only been tracking coronal mass ejections for roughly 150 years, and only since the 1940's on the effects on the power grid and for less than 40 years for electronic/satellite systems. We do not have a handle on how often the Sun spits out The Big One, like 1859. I remember the one in the winter of 1958. You could read the print on a page at midnight by the glow of the Northern Lights. My ham radio was completely down. Not even static was heard.
I am one of those who have come to the conclusion that shutting down LORAN (an almost infinitesimal slice of the national budget to keep operating) will come back to bite us.
With the shut down of Loran, a loss of GPS will shut down commercial maritime shipping - both entering and leaving the USA. You want to calculate the cost of that?
Likewise, having a robust VOR/DME system is in our best interests.
Take a look at:
http://www.solarstorms.org/SRefStorms.html
Haoving all your critical eggs on one basket is nothing short of insanity.
JHW
En-Route
I said no such thing. I merely stated that the aviation worst case scenarios are pointless. There are much bigger issues.
denverpilot
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Jim,
I can think of a number of ways to jam both LORAN and VOR. LORAN being limited by antenna size... Be pretty easy to find you. VOR? Much easier to hide.
Or at least make them unreliable enough the receiver would say, "not going to use that signal".
What makes you say LORAN was "the ultimate unjammable system"?
Derek Zeanah
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The comment was probably directed at the low strength of GPS signals and the occasional stories of "truck driver wants to make bootie call during work hours, buys $70 cigarette-lighter-GPS jammer to trick his employer and causes GPS to fail for all aircraft in a 70 mile radius." It *seems* (and I haven't done the research or the math) that a single 100W transmitter at 10,000' could be built to take down GPS for a wide area. Maybe you string together some weather balloons and allow a homemade transmitter to float into the flight levels at a heavy traffic time...
Now, what would you need to do to get the same effect with Loran? How widespread would the disruption be? VORs are good for a 40NM range, right?
weirdjim
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VORs run about 100 watts and have a normal range of 120 miles or line of sight, whichever is less. You can jam a single VOR with a single jammer transmitter, but in the USA you've almost always got three or four VORs within range to use. Unless you are going to broadcast random noise over the whole bandwidth and then you've got to have a hell of a lot of power to give each slice of the spectrum enough oomph (that's a technical term, you'll get used to it) to frap each individual receiver.
LORAN was running MEGAwatts of power but on a single frequency. Sure, given a little sparky noise at 100 kHz. you could jam a very small area, but any aircraft would soon get out of that little tiny area. Megawatt jammers are pretty easy to home on and I doubt you'd get much time before Sammy Unkle came a'callin'.
To the feller that said he'd need a hundred watts to jam the GPS, do the calculation again. A watt or two at balloon height will do the job quite nicely and most of us microwavers can generate that amount of poo quite easily. T'ain't rocket science. MOre like balloon science.
Jim
Dr. O
Pattern Altitude
At this point resurrecting Loran will cost.
They were so desperate to make sure it could not come back they cut the guy wires on the towers and let them fall.
I have heard rumors that they even crushed the transmitters to be sure. (I do not know that for fact)
Someone had a very big hard on for the Loran system.
Can it be resurrected? For sure - and for a tiny fraction of the cost of launching GPS sats. But someone very big is determined that will never happen.
Motive?
They were so desperate to make sure it could not come back they cut the guy wires on the towers and let them fall.
I have heard rumors that they even crushed the transmitters to be sure. (I do not know that for fact)
Someone had a very big hard on for the Loran system.
Can it be resurrected? For sure - and for a tiny fraction of the cost of launching GPS sats. But someone very big is determined that will never happen.
Motive?
NoHeat
En-Route
Is marine navigation more dependent on GPS than aviation?
I was just thinking this might be so, since marine doesn't have VORs. And no pilotage, either, when far from land.
I was just thinking this might be so, since marine doesn't have VORs. And no pilotage, either, when far from land.
NoHeat
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A video from 2010 of a tower in Alaska being demolished.
http://m.youtube.com/watch?v=7zqj1hy9NS8
Different camera angles are interesting -- there's one at about 2:00 where the tower almost hits the camera, and that seems a bit scary.
John Collins
En-Route
Your information source is very wrong. The FAA plan is to eliminate roughly half of the VOR's and virtually none in the Western US. The plan is to always be within 77 NM of a VOR at 5000 feet anywhere in the NAS.
MBDiagMan
Final Approach
John Collins
En-Route
LORAN may not be jammable, but no one let mother nature know. Even with a dozen new static wicks, I almost always lost LORAN in the rain in IMC. My KLN88 was certified for IFR enroute and terminal operations, but I couldn't count on it. GPS has been much more reliable.
That's pretty cool. Amazing how fragile those towers are sans guy wires.
denverpilot
Tied Down
Interesting point about the geographic diversity, Jim. There are some places where three VORs in range means they're way off a long way away, though. Wouldn't take much to hit them with targeted frequency jamming. Just more gear than needed to jam GPS, agreed.
FedGov around here jams GPS regularly.
See top NOTAM. 335 nm radius from the GPS test area.
denverpilot
Tied Down
Without the guy wires they often aren't built to handle side loads beyond a very small one. The guys have to be checked for tension annually and anchors have to be checked for erosion or improper installation. Many are just dead-man style concrete blocks buried. The amount of concrete and rebar underneath as a counterweight is also prescribed by the manufacturer.
I'm gathering info to put my tower up. Can you tell?
Still hunting for a deal on good sections of Rohn 45. The typical winds out here are going to push the engineering requirements up. Even just 10 sq ft of wind load with 100 MPH gusts exerts a significant force trying to push the tower over from the top. The guys have to stop the tower from getting too far past vertical or bad things start to happen.
Interestingly, most code requires towers falling from a failure at the base must fall completely on your property. They differ on whether the tower can fall on structures on the property. And base failures are really rare. Usually you come home to find the mast snapped at the top and the antenna system dangling from the crushed piece of pipe or the top section failed and a leg buckled and folded over and the whole section is dangling from the top.
Unrelated to he tower, the even more common failure is pieces and parts blowing off the antennas themselves.
And of course, there's always lightning and grounding to take into account. A friend put what was left of the pieces of a 20' tall vertical collinear fiberglass encased antenna in a kitchen trash bag after a lightning strike blew it to smithereens on a mountaintop.
bnt83
Final Approach
Basically the moral of the story is buy a used inertial system out of a retired airliner and rig that puppy up the cigarette lighter and strap it to a couple two by fours in the airplane.
OK John,
Where is this plan to "eliminate roughly half of the VORS " specified in a document available to the public ? I am interested in finding official intent on this issue and it's' justification as a part of NEXTGEN or as a bridge to it. I have seen the idea of 24 VORS as a remnant in a few AvMag articles which may simply have been some aviation writers' wild dream. Let that be as it may be and since no one else seems to have heard of 24, I'll just accept that is wrong. However, there seems to be little disagreement that will be many fewer than we currently have and I believe knowledge of what the plan is and where the shutdowns will be is an important factor for the pilots on this forum.
Dale
Vinny
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Cousin Vinny
Post #2. Also,
http://www.faa.gov/air_traffic/flig...ns/12-02-Discon_of_VOR_Srvcs_presentation.pdf
Also,
http://www.rtca.org/Files/Miscellaneous Files/VOR_MON_Prioritization_final.pdf (Interim Report of VOR MON Selection Criteria in Response to Tasking from the Federal Aviation Administration)
Also,
http://www.rtca.org/Files/Miscellaneous Files/VOR MON Criteria Prioritization Feb 2014 TOC final.pdf (VOR MON Criteria Prioritization)
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John Collins
En-Route
The plan was published in the Federal Register by the FAA to solicit comments from the public back in 2011. Here is a link to the federal register posting. https://www.federalregister.gov/art...ration-air-transportation-system-nextgen#h-11
There are other resources you can find on the web that describe the MON or Minimum Operational Network. The specific VOR's that will be decommissioned has not yet been decided and there will be a process that undoubtedly will get political involvement before it is all over.
drotto
Cleared for Takeoff
I thought the two main determining factors were going to be cost to repair/replace and "populatity" of the VOR. The biggest reason this VOR thing has become an issue is we have 40 plus year old towers that are at the end of their lifespan, and the feds are esimating 100's of millionsof dollars if not higher, if we attempted to replace all the existing transmitters.
I do not think that shutting down the VOR is wise, but really taking a look at which ones need to be maintained can't be a bad thing.
MAKG1
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And for comparison, the cost of ONE GPS satellite launch is more than that.
$100 million isn't much money for infrastructure, especially when you're talking about nationwide infrastructure.
$100 million isn't much money for infrastructure, especially when you're talking about nationwide infrastructure.
denverpilot
Tied Down
Towers huh? Cool. I didn't know that they started installing these on top of towers.
Does ADS-B use towers? Do they require maintenance? How many? What's the cost estimate?
Is it 100's of millions in devalued inflated dollars or today's?
(I'm letting you think about it. I already know the answers to the above in general numbers. Here's a hint: a VOR can cover X amount of sky. How much can an ADS-B site cover? Can the same number of staff cover the reduced VOR workload and the ADS-B sites without an increase in staff, vehicles, test equipment, training...)
weirdjim
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And you and I both know that a simple VOR without all the crap the FAA demands that it have, accurate to half a degree in the electronics, can be fabbed and built for the high tens of thousands of $$ or perhaps dipping into the low hundreds of K. And a HELL of a lot more reliable than those old creakers that are sitting out in the bean fields.
Jim
denverpilot
Tied Down
Yep. Never happen with FAA though.
And even so, it'd be another reason not to deploy ADS-B. They NEED the VOR network to look old and outdated to pull off the Marketing spin that's getting us a low speed data network for GPS coordinates and blocky weather radar pictures from the 90s.
That still needs radar to back it up.
Wide scale deployment of wide area multilateralization would have been really really cheap and could have replaced most of the radar.
NoHeat
En-Route
Will it become harder to reach FSS on the radio, by voice, when they decommission most of the VORs?
JHW
En-Route
when was the last time you called flight watch ? in the usa I still listen to the frequency out of habit but it is dead silence these days