WAAS Up?
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The Government Accountability Office, a Federal watchdog agency, reported on May 7th that the Global Positioning System of satellites used for navigation and many other business and scientific purposes as well as for proving that your teenage son was actually driving down the Interstate at 100 miles-per-hour last Thursday night when he claimed to be bowling, well that satellite system is in danger of becoming unusable because satellites are not being replaced quickly enough by the U.S. Air Force.
Only it isn’t true.
Right now on Google News you can find more than 400 stories all saying the same thing with varying degrees of alarm. The Air Force is three years late in launching a new generation of GPS satellites. The replacement program is over-budget by more than $700 million. The whole mess has been incompetently run and ought to be fixed. All this is true. What isn’t true is that it matters very much to the real world operation of the GPS system or its users.
The GPS system has 31 satellites in orbit right now, the oldest of which has been operating since 1990. For the system to work perfectly it must have 24 or more satellites functioning. The GAO says it is only 80 percent certain that the Air Force can maintain full coverage before replacement satellites can be launched. This lack of confidence is not based strictly on the idea that eight or more satellites will go dark over the next couple years, but that some undetermined number of satellites will go dark, the Air Force will make no progress in replacing them, and that the remaining satellites will be unable, for some reason, to be moved into new positions, filling gaps in coverage. That’s quite a combination of improbable events and makes me very suspicious of the 80 percent number.
For the GPS system to work requires that the receiver in your car, airplane or iPhone be able to simultaneously track at least three satellites (four if you require altitude information). If your receiver can show the satellites it is tracking (many can) you’ll see the number in sight is usually five to seven satellites with the rest being over the horizon and out of view.
If your GPS equipment was purchased in the last couple years it probably makes use of the Wide Area Augmentation System (WAAS), which is a system of ground stations and two geosynchronous satellites that help your receiver correct for ionospheric variations that can slightly degrade GPS performance. Without WAAS your GPS is only accurate to 7.6 meters. With WAAS accuracy is about one meter. The reason we care about this is because GPS is used now to land airplanes and the difference between 3.8 meters above the runway and 3.8 meters below the runway could ruin your whole day.
In addition to improving GPS accuracy over North America (and just North America — there are different systems for Europe and Japan), WAAS also effectively adds two virtual satellites to the GPS constellation. These are the two geosynchronous reporting satellites, which for ease of use in the system are treated by receivers like regular GPS satellites except they for some reason don’t seem to move in the sky. For WAAS-enabled GPS receivers, then, it is possible to maintain acceptable accuracy with only ONE (not three) of the regular GPS satellites in view.
The chances of the GPS system going down are very remote — FAR lower than the 20 percent suggested by the GAO. That’s because the GAO ignored completely in its analysis the implications of WAAS.
So what’s going on here? Why is this even a story?
The Air Force is late and over budget and the GAO wants to make a point of that. The best way to make that point is by putting the technical story in the worst possible light, which the GAO has done to an extreme that I think is excessive. This is just political infighting.
What’s worse, though, are those 400+ news stories that miss the point entirely. Where is a professional and questioning press? It looks to me like 400+ media outlets rewrote the GAO press release and left it at that, giving-in to the fear-mongering that has become the way government policy is promoted these days.
Some stories quoted experts saying a failure isn’t likely. Some stories said the GAO likely has a non-technical agenda. But I couldn’t find any stories that put the whole thing together and questioned whether there was any news value at all.
We need smarter, better-informed, and less gullible reporters. THAT’s the story.
While I agree with your premise on why the GAO released the report I have some doubts on some of the supporting text. The GPS accuracy of a meter with WAAS is only true for horizontal accuracy. The rule of thumb is that vertical accuracy is 2.5x worse than horizontal accuracy. The reason this doesn’t matter is that we don’t land airplanes with GPS really. We direct them down a path to the airport and then the pilot flys at minimum the last 200 feet with the runway in sight. If he can’t see it, he doesn’t land. Airliners are a different animal but they don’t use GPS for that either. There have been test trials of higher precision GPS landing systems but my understanding is that they are dead. Especially since the WAAS project was late and way over budget.
I couldn’t imagine anyone being silly enough to think that planes rely on GPS to figure out their altitude above the runway.
Well, until I hit that part of the article and my brain bluescreened on teh stupid.
WAAS-qualified avionics like Garmin’s 430W, 480W and 530W receivers are approved for precision instrument approaches based entirely on GPS. This is true for more than a thousand approved precision GPS approaches at U.S. airports. In my own plane I use a Flight Cheetah GPS receiver coupled to my Trio Avionics autopilot all the time for vertical navigation and approaches.
I don’t make this stuff up, you know, though any number of know-it-all critics seem to dismiss my work without any actual checking.
Checking? Checking!?!?! This is the internet, Bob. People cite Wikipedia as an authoritative reference!
BTW, your output seems less frequent these days. I wonder what you’re doing in your spare time. Hmmm … there’s a possible story for you. Oh, wait. Nevermind.
Bob,
Yes your fancy glass cockpit can use GPS for precision approachs; however, NOBODY actually flares and lands an airplane based on GPS altitude (the accuracy of which, as somebody pointed out, is about 2.5x horizontal accuracy). Airliners flare and land using radar altimeters with the pilot as backup, or vice versa if the pilot doesn’t want to use autoland. General aviation aircraft, even on an IFR approach, use the pilot’s senses to flare and land. So your example continues to be bogus, despite your attempts at justification.
I’m not a certified pilot but I do work in the avionics industry (Garmin is one of my clients). I calibrate the test equipment they use to certify avionics, including all the usual ILS equipment (LOC/GS, MLS, GPS, etc.).
In your article you said “GPS is used now to land airplanes”. In your comment you clarify things a bit when you refer to “precision instrument approach”, which doesn’t sound so much like an automated landing as instrument guidance to the runway when visibility conditions don’t allow you to see it visually on approach.
I’m curious — does your GPS-coupled auto-pilot actually fly your plane on precision instrument approach all the way down to where 25 ft of altitude error could cause a crash-landing? Does it land your airplane? Either way, I’m impressed!
Then “check” on your orbital mechanics facts, nitwit. You can’t just move satellites around like you assume; *some* satellites have *limited* maneuvering capability, and I don’t think any of them are GPS satellites. Several parts of the constellation are aging and/or at higher risk, such as higher latitudes, which means if those satellites fail without replacements then there will be holes in the system, period, even if other parts work fine.
Is it “80 percent likely” that the system as a whole will fail? No. That there will be holes, potentially significant holes, in coverage? Yes, that *is* a plausible number.
Remember, this stuff *is* rocket science. And while that’s not as hard as many people think, it’s not that simple, either.
Hey Matt:
You’re a douche.
Love,
Epstein’s Mom
I appreciate the humor Bob.
There is a difference between 3.8 meters above and 3.8 meters below the runway.
Nice example that illustrates the value of WAAS, even if some of the more technical minded get caught up in the details about whether GPS could be, was, is or would be, used to land an airliner.
Um, while missing a few satellites isn’t going to horribly degrade GPS, it can cause serious problems if you are unlucky enough to have a bad configuration of satellites combined with poor reception conditions.
In essence, GPS satellites are orbiting atomic clocks which broadcast a psuedorandom sequence with a long repeat time. Using correlation techniques it is possible for a GPS reciever to determine the phase and pseudorange of the signal of each satellite. Knowing the position of the satellites you can triangulate (using 3 satellites) your 2 dimensional position or “tetra-angulate” (4 sats) your 3 dimensional position, when more than 4 satellites are available least squares techniques may be used to refine the accuracy. Of course, you have to know the precise position of the satellites precisely to do this calculation. As a result the orbits of the GPS satellite and the corresponding accuracy of the atomic clocks are carefully monitored and compensated for (even relativistic effects (velocity and gravity well) are taken into account).
Even with all this the effective accuracy of the system is effected by position and number of satellites an effect known as Geometric Dilution of Precision (GDOP). In the case of incomplete constellations (as when the system was in the process of deployment) a GDOP chimney effect can occur with through the roof degradations of accuracy (hence the name).
The WAAS system on the other hand is a set of transponders on geostationary satellites, no atomic clocks and less accuracy in position determination. As a result I’d only use the pseudorange signals as a last resort. On the other hand the primary product of the WAAS system (ionospheric correction data) is excellent and improves the accuracy of the GPS signals considerably (if they are there).
Short story, if the GPS fix is mission or life critical, I’d be praying for at least 4-6 satellites high in the sky and in a good configuration.
I’ve never seen less than six.
I’ve been in places where you couldn’t see any. Hiking in mountains, for example.
The day they shut off SA I saw 12 for a few hours in the morning. I’ve never seen 12 since. At the time I lived in Pennsylvania, a few hours from Washington DC, so I think it was a show for the movers and shakers inside the beltway.
Planes never ever ever ever land with GPS. That is done totally by radio and radar. Absolutely no GPS involved in landing a plane.
But your point is valid about the desire to be more precise in our positioning technology, if for other things besides planes landing. I heard that tanks actually need really precise position information.
Not anymore. It’s still rare for big jets to use GPS in landing, but GPS approaches have been around for some time. Now with WAAS, there are LPV approaches which use the GPS for altitude information, and the newer GPS units can fly a precision approach (down to as low as 200 feet) with only GPS. Now on a commercial jet, this is combined with the inertial navigation system and a pressure altimeter to determine altitude, but in smaller planes, the GPS is the sole source of altitude information, and the approach can be done without any radio equipment at the airport.
The Christian Science Monitor stated that reporters deserve low pay (http://www.csmonitor.com/2009/0519/p09s02-coop.html). You just proved it.
One must remember that GPS is primarily a military system. Although geosynchronous and WAAS signals may aid civilian use in the United States, the original purpose of GPS (and the primary purpose for the military, which foots the bill) is to aid in a war zone. The loss of a smaller number of satellites would degrade the ability of “smart bombs” to function or at least be targeted so precisely.
And your point is?
I think the point is that because wars, though abhorrent, must still be fought the United States military wants to limit civilian casualties through the use of precision munitions.
I hope you’re not advocating the use of precision munitions in North America!!! : )
Is there any evidence that “smart” bombs are in fact more accurate than traditional munitions? I though the jury was still out on that. BDAs never seem to validate the claims made by the peddlers of “smart” munitions.
Of course, that has never stopped the government from funding them.
You’re kidding, right? In WWII, waves of bombers (literally, thousands of them) rained millions of tons of high explosives into the heart of enemy population and industrial centers. ENTIRE cities were reduced to rubble, and if anyone cared that ancient and irreplaceable symbols of human history and culture were casualties, they weren’t saying so.
Contrast that with the Iraq War, where the U.S. military has taken great pains to deliberately exclude certain targets based upon the human or cultural toll that would be risked. That’s why, by the way, there are such things as “human shields” …
Well, it seems that no one so far has picked up on the “that” in THAT’s the story.
But I’ve been saying for years now that there is no reason to mourn the death of traditional media (newspapers etc.) when in fact they died a long time ago.
Companies, government agencies, police departments, subway authorities, and your local little league all have as part of their mission communicating with the public. It’s quite easy for them to do this now and in some ways those that used to be the conduits of this information (the press) are now like the little old lady down the street. They spread unconfirmed gossip, and when not, get the story wrong all on their own, slant it to match their own world view, or just make it up because they got stuck in traffic.
Much of the printed news is in fact regurgitated press releases. After all the author of a press release isn’t likely to lodge a copyright complaint even if you copy them word for word. On complex subjects, where the reporter diverges from the pure text of the PR he is likely to be delving into Fantasyland, going from his own apocryphal knowledge of the subject. “Yeah, my GPS was acting up the other day, things must REALLY be bad!”
When it comes to Q&A where the reporters supposedly represent the interests of the public things aren’t much better. White house press conference these days are a laughing stock (and it isn’t just due to the fawning attitude of the press to the new administration).
Your assertions about regurgitation are absolutely correct. The website link I included in my post belongs to someone I know and I saw with my own eyes how the press gobbled up what he put out without fact checking and in many cases without any contact with the company at all! I saw the EXACT verbiage of his first press release repeated ad nauseum in press throughout the world. (This is not only a US problem. Irish Radio and Italian TV are guilty as well). The only reporter who did any sort of indepth questioning was from AP. The only two news organizations that seem worthy of the title are AP and Reuters.
Whenever I’ve been interviewed for a newspaper, words and facts have been twisted and/or just gotten wrong. Whenever I read a popular press article in an area where I have in-depth knowledge, it’s wrong, at least in the details.
So, I just assume that’s true all the time and go to specialists for real news reporting. I haven’t checked, but I’d assume a place like Jane’s would have a good article on this GPS thing.
How about this business model: be a journalist who’s a bona-fide expert on GPS. Write completely accurate, insightful, and helpful news articles on GPS happenings. Charge alot for them.
The last part is the trick of course. But how many GPS journalists does the world need? No more than a handful. With the Internet it should be possible to greatly reduce the number of generalist journalists and start making ‘newspapers’ much better with experts. There’s probably too much inertia at established papers but a disruptive model seems possible.
It’s not ‘mere blog aggregation’ because most bloggers aren’t writing in the form or quality required, but some scheme with writers, aggregators, and integrators could get it done. I don’t see the value in local newspapers doing anything but inserting their local stories into layout and selling ads these days – find an integrator that matches your editorial values and outsource it.
Great article Bob. I’ve been hearing the rumors of a GPS system “problem” in the popular press for a little while but chose to ignore it for the reasons you mentioned at the end of your piece. The press today exists for its entertainment or alarmist aspects. Informational, watchdog roles have totally been lost by today’s journalists.
GPS was put in place for the military and we’re able to enjoy the benefits of the systems existence (at degraded performance levels) if there truly was a problem the real owners would deal with it as too many of our smart armaments rely on the GPS network to function.
Stan
spread the word about http://www.giftcardsfordinner.com and help the unemployed
and a children’s picture book review site – http://www.theirfavoritebooks.com
First, never get into a fight with an aviator over precision approach capabilities unless your willing to bring lead to the fight. If your not an ILS signed off aviator or a GPS expert, then you’re probably in the wrong room. Bob, since your a pilot we’ll give you the benefit of the doubt here that you are ILS certified.
Second, while the current GPS and WAAS systems have been SHOWN to be accurate down to 1 meter, that’s hardly the threshold for the specification (it’s 7.6 meters BTW, both vertically and horizontally… http://gpsinformation.net/exe/waas.html). GPS with WAAS is approved for precision approaches to the runway in ILS conditions (specifically a Catagory I instrument approach). The nice thing about GPS/WAAS is you can shoot an instrument landing for a runway that has no local ILS system in place provided an approved approach for your airfield exists.
Third… most commerical aircraft with an autopilot ARE capable, and in many cases are required, to perform routine autopilot landings. Specific airports, flight crews and airlines are approved by the FAA to do autopilot landings in ILS conditions at higher than Cat 1. It’s not GPS per say, but the Flight Management System certainly utilizes GPS as an input.
Fourth, this means that 98%+ of Bob’s article is generally correct, though I agree that he could have stated the line about ‘landing airplanes’ a little better, since most laymen won’t understand what ILS is and that it’s more than GPS at work.
Fifth, if you want an actual landing using GPS, then you need a Ground Based Augmentation System (GBAS) which has been SHOWN to work by Honeywell, among others. It’s part of the FAA NextGen effort, but is still a few years away. There was a lot of screaming when GA pilots were told to buy EXPENSIVE GPS NAV units for their planes, GBAS won’t be any cheaper. The big guys will like it because it theory it will allow the airport to do away from radar almost entirely (other than transponder query) and close the spacing currently mandated by the FAA to increase airspace throughput.
As I explained above, I do GPS approaches all the time in my properly-equipped aircraft.
[...] I, Cringely » Blog Archive » WAAS Up? – Cringely on technology [...]
Nonsense. If everything was competently covered by the media, there’d be nothing to write about for bloggers. And having so many idle people with access to keyboards would be a dangerous thing. One doesn’t have to be Dick Cheney to realize this.
I thought this was just another one of those stories that the media blow out of all proportion, either in an attempt to make you live in fear or out of pure ignorance of the facts.
Here in the UK where they put fear into everything from the recession to the weather, it was reported as though your brand new Satnav will definitely be useless next summer by the mainstream press.
“These are the two geosynchronous reporting satellites, which for ease of use in the system are treated by receivers like regular GPS satellites except they for some reason don’t seem to move in the sky.”
Bob:
Geosynchronous orbit is when the orbiting satellite exactly matches the rotational speed of the earth thereby leaving the satellite above the same point on the earth. That’s why it doesn’t move in the sky. But, surely you knew that?
Geosynchronous orbit is about 22000 miles above the earth.
Bob, I am glad you covered this story and your conclusion was spot on. When I first heard the story — 31 satellites in orbit, all working. We need 24 for perfect service. Running on a few less would only slightly degrade service. My GPS probably would never know or care if there were 31, 24, or 20 working satellites. Anyone with a GPS can check this out for themselves by watching the display that shows the satellites being received. The system is no where near a failure.
The real story is someone in the GAO wrote a report, exaggerated the potential risk to an extreme. No one in the GAO’s management reviewed the report enough to realize it needed to be toned down.
Lets face it the USA press has become a swarm of lemmings. They march mindlessly together in any direction, just following the whim (or story) of the day. They will march into the sea, over a cliff, into a fire. It doesn’t matter. They no longer investigate stories. They no longer question stories. They just replay the reports of others.
Last summer I decided to do my own research on the USA presidential candidates. I observed several instances when a candidate said something at one time in his/her life. The comment was taken clearly taken out of context by the reporter. The news organizations replayed the story countless time, each putting their own slight spin on it. In time the comment was morphed into something completely erroneous. About then the opposing campaign would run an advertisement. They would quote countless news outlets. With many sources the story HAD to be correct, right? Guess what fellow American’s? About 85% of what you heard about a presidential candidate last year came to you this way and was definitely not factual. I quickly realized the only factual information about a candidate is what comes directly out of his/her mouth, and you have to hear the whole statement in its full context, not a few words.
Yes world, the USA press is really THIS BAD. Why do research and find the truth if it would hurt ratings?
“We need smarter, better-informed, and less gullible reporters. THAT’s the story.”
“We need smarter, better-informed, and less gullible reporters. THAT’s the story.”
I think the story is that reporters are less-informed and gullible, therefore we need an alternative.
Thanks, Mr. Cringely, for being an alternative. Also, thanks to the commenters here for contributing to the alternative.
“We need smarter, better-informed, and less gullible reporters.”
I can see you haven’t been following the Chrysler saga over the last 11 years.
The issue is not smarter reporters, or gullibility. It’s a national news media run solely for profit, whose leaders have realized that entertainment is far more important than news.
The motivation behind a story is rarely reporting reality or truth; it’s how alarming the headline is and how many people they can get to read it. Audience is garnered by any means necessary and as long as people act like gullible sheep and don’t question what they read, the problem will continue to worsen.
What we need is a public that refuses to purchase shoddy reporting.
When it pays to have better reporting, then the media industry will produce that product.
As long as shoddy reporting is acceptable to the consumer, that’s what we will get. Shoddy is less expensive than accurate reporting.
This all boils down to our populace and our level of tolerance for crap. Just like we (as a country) are now getting the government we deserve, so we are also getting the media we deserve – because we as a people have not insisted upon anything better.
We vote with our pocketbook – and we voted unwisely.
“… smarter, better-informed, and less gullible reporters.” Good luck with that. We are experiencing the Second Age of Yellow Journalism.
Dave’s comment about profit is ludicrous, however. The Soviet Union’s press had no profit motive. Our press on the other hand has always had a profit motive, yet in recent memory wasn’t so bad.
Better to look at extreme lack of ethics and professionality, which is currently affecting many disciplines.
professionality?
Having already established the status of writers, I was checking to see whether we still had good editors. Glad to see there’s still at least one!
My wife and I frequently engage in educational activities inside of and outside of the schools. I have learned over time that the very best practice is to have a neatly printed press release in hand when ever the press show up. The handout includes background information, points of interest, a detailed summary of the event, and names and contact information for those involved.
This increases the accuracy of published information, but does not guarantee it. Often, reporters still miss the point and fail to call anyone for clarification. Often, we will see up to 80% of the press release repeated verbatim. That is a best-case scenario.
I think that very few people actually go to college specifically to be a journalist. I think that the state university colleges of education and of journalism are institutions of last resort for students who are unable to meet the rigors of study programs for their chosen profession. They fall back to one of these colleges, in order to keep the credits that they already paid for and to get some sort of degree. The academic requirements are very modest. The results are far short of professional. I know for certain that the are teachers and journalists who take their chosen professions very seriously. The status quo is a terrible disservice to them, and to our society as a whole.
HOW TRUE. I live in a town that was incorporated about 10 years ago. Our town is young enough our government really doesn’t have a political “agenda.” They mostly try to do the right things for the community. A few months ago a ski-lift operator go into an argument with city hall, went to the press with a sensational story, and basically lied through his teeth. There was absolutely no coverage, or an effort to cover the city’s side of the story. Our city government was dumb founded by the event.
I met with the mayor and a couple council people over lunch and told them — ‘The press these days will make very little effort to get the complete story, they won’t even check the facts. They only will report what they are told and the more simplistic and superficial the message, the better. You (the city) need to babysit the press. Sad but true. You need to introduce yourself to a few reporters and meet with them on a regular basis. You don’t need to have any agenda, just meet them in person, buy them lunch. THEN, when another story breaks they will know who you are and will be inclined to call you. Before you talk quickly get the city council together and put together a script of the city’s position. Make sure everyone in city government has the script. Tell the press YOUR story and encourage them to call others in the government.’
This is how bad things have become.
Most reporters just parrot numbers and you can tell from the expression on their face that they are thinking “that’s a real big number”, when by percentage it may be insignificant. I suspect most people work from 1 to 100 or from 1 to 1000 and any number outside that range (except for zero) is exotic to them. We need reporters with some science or engineering training (math plus physical units capability).
The areas were this is really hurting public debate is energy (especially alternative energy) and the economy. Alternative energy sources that don’t scale are enthusiastically reported and everyone is really concerned about any amount of money, without understanding that the pre-collapse GDP of the US was around $13 trillion, the shadow banking system was handling around 50% of loans and other info like that.
Putting things in perspective is not what the media is about, creating a story (and panic) is the goal. As my, always calm, dad said, “when in trouble, when in doubt, run in circles, scream and shout”. He was an engineer who calmly solved serious problems day in and day out.
I use a GPS for hiking and teach the use thereof. Four good signals is all I need. How much sky is visible (am I in a canyon?) my biggest concern. The new receiver chip sets work real well under tree cover and even inside some buildings, so not much need to shift around to get signals for that.
For most people in mountains or cities, good views of the sky are likely to be a much bigger issue than only having a sat count in the low 20′s (if it were to really get that bad). The address location on the car units seems to fail within a couple of hundred feet anyway (the database is worse than the signal). I figure the units can get me to the right block or easily within a hundred feet in the mountains, then my eyeballs are my guide.
I read the report at:
http://www.gao.gov/new.items/d09670t.pdf
It says:
GLOBAL POSITIONING SYSTEM
Significant Challenges in Sustaining and Upgrading Widely Used Capabilities
Another GAO reportwritten in 2000 is here:
http://www.gao.gov/archive/2000/rc00229t.pdf
In summary it says:
Problems Plaguing the Wide Area Augmentation System and FAA’s Actions to Address Them
Having read the reports, I suggest that they are professional in their presentation of information and even handed in the documentation of facts. I suppose you could suggest the reports are extremely careful to point out the worst case scenarios, but of course they would be neglegent if they did not do that.
If there is something in the reports that are not true or they provide information that should not be made public, I cannot find it.
Here is a quote from the 2009 report:
“It is uncertain whether the Air Force will be able to acquire new satellites in time to maintain current GPS service without interruption. If not, some military operations and some civilian users could be adversely affected.”
I guess they could have followed that with something along the lines of:
“There is a greater than 80% chance that the GPS service will remain reasonably operational over the next 10 years.”
But, I think that would be an opinion with out significant facts to support it.
I’m not sure what would be the absolute best way for the GAO to cast the current situation in the most accurate light. I guess they could have stated:
“There are some problems and concerns but no action or changes need to be put in place”
Bob: Would you have liked that as a more appropriate message?
Bob you sugested the 2009 report said:
“that satellite system is in danger of becoming unusable because satellites are not being replaced quickly enough by the U.S. Air Force.”
What page and paragraph is that stated?
Thanks…
While WAAS does include two satellites that provide normal pseudorange and ephemeris information and add to the geometric diversity available to receivers, the primary reason WAAS groundstations and satellites increase accuracy is they broadcast localized corrections to pseudorange calculations to account for atmospheric and other local fluctuations not accounted for in the standard internal models.
And simply seeing three satellites doesn’t guarantee you can solve for position and time assuming altitude within acceptable error ranges. High satellite count is a statistical necessity to ensure proper geometric diversity. That is not to say I disagree with your article. This whole thing has been totally blown out of the water. Our constellation is healthy and large, not even taking into account the high likelihood that the NAVSTAR satellites long outliving their design lifespan. The widespread reliance on GPS by everyone from the FAA (who are on the way to happily phasing out VOR and other radio navigation) to pizza guys virtually guarantees public support for whatever needs to get done. And can you imagine the military happily letting the Europeans beat them with Galileo?
You are certainly right, GPS is safe, assuming this delayed solar cycle doesn’t throw us any curve balls.
Oh I see the “80%” probability data on page 5:
Figure 1: Probability of Maintaining a Constellation of at Least 24 GPS Satellites Based on Reliability Data and Launch Schedule as of March 2009
That graph bottoms out at around 80% at about 2011.
OK – I get it. The GAO significantly overstated the downside scenario. They should have had a paragraph near page 5 that better communicated the impact of having 23 or 22 or 21, etc. instead of all 24 satellites.
I admit it. Bob X is supreme. I am not worthy to read his blog
I believe the ‘net parlance is tl;dr. The GAO report was too long for a busy reporter with a word count and a deadline to read, so they just co-opted the executive summary.
Lovely, no?
The first IIIA launch is scheduled for 2014. So the following summary bullet from the GAO report about IIIA slipping its schedule by 2 years makes absolutely no sense.
3) If the Air Force does not meet its schedule goals for development of GPS IIIA satellites, there will be an increased likelihood that in 2010, as old satellites begin to fail, the overall GPS constellation will fall below the number of satellites required to provide the level of GPS service that the U.S. government commits to.
>> We need smarter, better-informed, and less gullible reporters. THAT’s the story.
But, but, but… Bob. The future of newsgathering is a gaggle of bloggers who can say anything they want, since they don’t get paid (modulo ad revs) or have to pass through any editor. Media is devolving into battling propaganda organs. Kind of like Russia in the 1920′s. Da.
This is the same media that still reports an aircraft stall as an engine problem, remember. And the same media that elected the current president too, but I digress…
Don’t be too quick to blame the media on the president. Their impact is distorting the whole process. Thanks to our gullible, clueless, lemming like, mindless press keeps our best people from running for office and ruins many of the great leaders who do chose to run. What we are left with is a choice between dumb and dumber, and people who pass the litmus test of having never taken a position or done anything controversial. These are great attributes for the leaders of our government.
Although I disagree with Rush Limbaugh on many many things, he has been making this same assertion for several years. One of the clever and entertaining things he does is compile a sizeable group of audio clips whenever a story like this breaks and all of the TV reporters use the exact same catch-phrases. Kind of funny listening to 30 to 60 seconds worth of the exact same words being spoken by a plethora of different voices. Sure doesn’t instil much confidence in our news providers.
For a non-technical reader what are the implications? Granted finding a city address with a downgraded system shouldn’t be difficult, you can usually see the address. But I use GPS for precision agriculture. Currently I’m getting about 6″ pass to pass accuracy. How much accuracy do I give up with even a single satellite gone?
If I understand the situation… then the simplified answer is, “none”. It would take 6 concurrent failures (down to 23 satellites) to cause the service to be degraded to the point of effecting your ability to get a location with the same accuracy you have currently.
Hence Bob’s assertion that it’s a non-story. When you consider modern GPS implementations use more than just the current constellation of 31 satellites… it’s almost an anti-story.
It takes three satellites in geostationary orbit to cover the entire surface of the Earth. Two WAAS satellites might cover the U.S., but a large portion of the globe receives no benefit from them.
Depart for a moment for a political view. The GAO works directly for congress & gets paid by them. So it’s hardly “independent” and in fact tends to be partisan to whatever political party is currently in power.
So when a particular congressman/committee wants something looked at, they charter GAO to look at it and write-up a report. Unfortunately, the GAO is basically told what answer the congressman/committee wants to hear and the GAO marchs off to write a report to support that answer largely irrespective of the actual situation.
So here, it would be important to examine the house subcommittee that sponsored the report and see what vested interest they have in the subject area
[...] I, Cringely » Blog Archive » WAAS Up? – Cringely on technology. [...]
Last I checked (10 minutes ago), GPS is only an aid for landing. The accuracy claims are a little bogus for WAAS. In the New England area, on the water, WAAS accuracy is more like 10-15 meters. That, of course, is more than enough for maritime use. I seriously doubt however that vertical accuracy is better than a pilot’s eyes-on.
“These are the two geosynchronous reporting satellites, which for ease of use in the system are treated by receivers like regular GPS satellites except they for some reason don’t seem to move in the sky. ”
Umm, for the reason they’re geosynchronous?
I agree with your overall point that the reports of the demise of GPS are exaggerated But the 80% number seems about right to me if you consider they are talking about the potential of losing world wide, *continuous* coverage if they go to below 24. There still will be likely 24/7 coverage of the ‘civilized’ world, and anywhere the military has ongoing ops, but really remote areas may be intermittent.
Bob wrote…
It looks to me like 400+ media outlets rewrote the GAO press release and left it at that…
Got that one right. I have several Google and Yahoo searches set up to report daily on various topics. Day after day (after day…) I get lists of articles that are just cut’n'paste of each other, sourced from news organizations, market analysts, company press releases, etc.
And it is cut’n'paste: in most cases the words don’t change. The same thing happens with Google News: 4,301 stories on some topic, and 90% of them are duplicates or excerpts of each other. Doesn’t matter if the subject’s GPS satellites or the pop diva of the week.
Sometimes I doubt just how much new information these interwebitubes are really bringing us compared to the old ways.
Dick Grune (author of CVS) wrote a software (and text) similarity tester to detect fraud on the part of students copying (excerpts of) their (software) assignment from other students.
Maybe Google should integrate this into Google News and rank the news articles according to how unique the articles are.
Then again, maybe Google News (algorithm) can’t group articles if they’re too dissimilar from each other and the one (or few) articles that actually cover a story based on the story (and not other articles) might not even be considered to be a related story and subsequently won’t appear as a related story.
http://www.cs.vu.nl/~dick/sim.html
The real story here is why the program is $700M over budget.
Why can’t we deliver projects on time and under budget anymore?
Time to name names and get the incompetents out whether they are in goverment, military or private sector contractors.
[...] 2: This may well not be true. Categories: tech Tags: tech Comments (0) Trackbacks (0) Leave a comment [...]
Don’t surveyors use GPS to tell you where your property lines are these days? Maybe 6″ is accurate enough for that, but you certainly can’t use a system that is accurate only to a meter!
I’ve puzzled over this for several years, it seems like there are probably people in this discussion who understand what’s going on with this.
My understanding is that when the receiver is stationary, you can take multiple readings, and the average of these will converge on the true location. This was possible even when the deliberate error was added to the civilian signal. I remember reading that people could get accuracy down to one or two centimeters using this method.
Surveying applications usually use a local fixed GPS and survey with another GPS linked via radio. The delta distances between this fixed base and the rover GPS are accurate to about a cm horizontally and 2 cm vertically. The caveat with all this is that you don’t get that quality of result typically with less than five satellites and more are needed to reliably stay in a fixed (high quality state). The geometry of the satellites you do have also makes a difference but with more your likelyhood of good geometry is higher. Even with the current number of satellites, tree cover and other obstructions often cause periods where a fixed solution is not possible. The latest RTK GPS receivers support multiple constellations (GPS, Glonass, and someday Galileo) to minimize downtime due to cover and bad geometry.
[...] be forced to circle the equator until they run out of fuel and kill all known pandas in existence? Turns out it probably won’t (via @brianw.) 400 so called journalists copied the GAO press-release and it took a blogger to [...]
Here here! The media in this country is incompetant and lazy. There has been very little in the way of investigative reporting lately. Hundreds of media sources are motivated only by the desire to get something on the screen, ignoring the secondary objective of actually verifying that the facts they report are accurate.
We can probably thank the Internet for that.
Not true. Simply observe how much money CNN, the network “news” programs and Fox “News” waste on shouting heads, worthless graphics and their so-called “experts”. The New York Times Judith Miller fiasco showed that even the country’s ostensibly top newspaper is perfectly content rubber stamping whatever government sources put in front of them.
Any reporter could spend an hour and consult, say, someone at Garmin to see if the system is really in trouble. But, no, just like John says, they just rephrase the press release and publish it as a “report”.
Of course, sometimes the press is too dumb to be bothered with the government reports. Since about 2005, the CBO has published numerous reports putting the cost of the Iraq war at $1 trillion plus, a figure much higher than any number claimed by any Republican, but nobody in the press ever reported on these numbers. All they had to do was go to http://www.cbo.gov, click on the pdf link and read the cost estimates, which are the most accurate anywhere. But, no, they were just too happy rephrasing various press releases and publishing them as “news”.
The press in the US is in a truly wretched state. Just look at all the stupidity around the Supreme Court nomination that was announced today. “Is she liberal?” “Is she activist?” The American press is, indisputably, dominated by morons.
[...] WAAS Up? – “The Government Accountability Office, a Federal watchdog agency, reported on May 7th that the Global Positioning System of satellites used for navigation and many other business and scientific purposes as well as for proving that your teenage son was actually driving down the Interstate at 100 miles-per-hour last Thursday night when he claimed to be bowling, well that satellite system is in danger of becoming unusable because satellites are not being replaced quickly enough by the U.S. Air Force. Only it isn’t true.“ [...]
To skip the technical hammering, and go for the point you were really trying to make…
A few years back, I took the family to see John Dean speak. Yes, that John Dean, the Watergate guy. This was in the “middle days” of the Iraq war – when we knew there were no WMD, but most people weren’t upset about it. During the Q&A my wife asked if the lack of critical coverage in the press had something to do with any sort of “right-wing conspiracy,” based on the idea that the press favors an administration with a hands-off stance towards their mergers, consolidations, etc.
John Dean said that he and his team had looked into that, thinking they might find something fo the sort. They didn’t. What they found instead was extreme cost-cutting. The press simply takes press releases and prints them, because they have little time to do anything else, and practically no time for investigative reporting. In today’s environment, nobody could have afforded the 6 months “down time” Woodward and Bernstein took to unravel Watergate. Nixon would have finished out his term.
To broaden this just a little, because such broadening is necessary, this is an example where a necessary and vital service is hidden in the apparent cost of a different service. For this example, we have become accustomed to think of true journalism as free, and the things that cost are the dead trees we hold in our hands. That isn’t so, and unfortunately as electronic communications (Internet, for instance) take down the dead tree, journalism becomes a collateral casualty. At the moment, we don’t have any sort of separate way to pay for journalism well worked, out, either. I firmly hope we find one.
In a similar vein, consider the recording industry. For sake of argument, they have 5 missions: talent search, studio recording, editorial control, promotion, and duplication/distribution. However, mentally we tend to lump the cost of music into that last category. At the same time, modern electronics and communications have completely changed the game on every facet of that industry except editorial control. Yet they’re still trying to force-fit it all into the old business model, and doing everything they can to destroy the end-to-end concept/nature of the internet in the bargain. At the same time, they’re falling short on the one surviving concept – editorial control. If they were doing THAT job correctly, we wouldn’t complain so hard about new music being junk.
Thanks Dave. That was very good information and analysis. Thanks.
Interesting site, but much advertisments on him. Shall read as subscription, rss.
A couple of things pertaining to GPS:
a. GPS was originally designed strictly for military use.
b. GPS can still be pulled from civilian use in a matter of minutes (encrypted signal).
c. There is no civilian requirement for GPS — period (compass, sextant, map work just fine).
Hence, who cares if GPS isn’t available to civilians? Twas never meant for civilian use to begin with.
krp
The Internet was developed by the military. In time the government realized its value to society and opened it up. The same is true for GPS. Society now uses and is dependent on the GPS system. So every effort will be made to keep it in good working condition.
Something we, and the GAO forgot. The original GPS system ASSUMED one would access 3 or 4 satellites to obtain position information. Then someone decided to build a receiver that could accept signals from 12 satellites at a time. Even with induced randomized error in the system, when you average the data of 12 satellites you can still get very good position accuracy. This was one of the factors that led the Clinton administration to the decision to turn off the induced random error. The new and improved 12 satellite receivers pretty much negated efforts to degrade the accuracy of the system.
I haven’t done the statistics, but if my receiver is regularly tracking 6-8 satellites and it needs only 4 to operate, then my guess is we can get by with many satellites less than 24. The GPS sky is not falling. The chicken little GAO can be ignored this time.
[...] be forced to circle the equator until they run out of fuel and kill all known pandas in existence? Turns out it probably won’t (via @brianw.) 400 so called journalists copied the GAO press-release and it took a blogger to [...]
Bob,
I can imagine that you don’t follow the slings of political arrows that fly between GAO and the Air Force, but since I work as an AF contractor, I’ve seen it first-hand. This report by the GAO is only the latest panties-in-a-wad snit in a long line of them.
The GAO report isn’t really about GPS at all — its about the AF’s apparent lack of discipline (in GAO’s view) in acquiring systems (including weapons) and technology. On Page 1 of the report under “Highlights”, GAO notes that a review of the acquisition process spurred the reports creation.
Think back over the past several years, and you’ll no doubt recall several AF source selection decisions (and the processes that led to them) that have been over-turned by GAO. This includes, very recently, the widely reported cancellation of the award for a new aerial refueling tanker to Airbus/Northrop. This came on the heals of the overturned award for combat search-and-rescue helicopters, which followed AF embarrassment over the Darlene Druyun (who had been head of AF procurement) scandal. Druyun, you may recall, all but sent Boeing an engraved contract for aerial tankers in exchange for lucrative employment opportunities for herself and others.
The final “proof”, however, is that the GAO points out that the program for acquiring new satellites is over-budget and behind schedule, and goes into exhaustive detail the reasons for the current situation. The fact that satellites will begin to fail is only included to illustrate the potential consequences if the AF doesn’t get its act together.
SED, thanks. This is wonderful.
If anyone in the press had spent 30 minutes and done some Google searches on the Air Force and GAO, they would probably have found a much better story. You put this story in the right context. It is amazing the press is unable or unwilling to figure this stuff out these days.
John, thanks. But, if you think this is looking past the trees to find the forest, trying reading the UN’s Intergovernmental Panel on Climate Change reports sometime. Don’t stop at the summary, (which is all the press – and most so-called “greens” – ever read, if they get that far). Read an entire report. You’ll find it illuminating, and “Exhibit A” in the case against the alarmists.
Do you have a link to the UN report?
There was an environmentalist on CNBC yesterday who genuinely believed we could repeal the laws of thermodynamics.
The real issue here is the press is run by profit motive and today truth or getting the story right are not important. Getting the most sensational headline that sells newspapers or gets ratings during sweeps or generates page hits is much more important than getting the whole story or even part of the story. The public eats this S**t up and obviously doesn’t care about accuracy or else the NY Post would be out of business and the Times would have 10 times the circulation it does. In a capitalist society, the public gets what it wants.
On actual landing systems, I believe WAAS enhanced GPS enables RNAV approaches — not landings, just like its predecessor ILS allowed Category I approaches or Category III approaches. Some of the small minded people…
Also, I believe all instrument rated planes have altimeters, and a local ASI pressure is observed at least hourly and disseminated on ATIS or ASOS to pilots to use to calibrate their altimeters. Lack of ASI has been known to shut down approaches to airports.
The task of acquiring, synthesizing, and disseminating accurate information has become an epistemological crisis in the Internet age. How’s that for an opaque opening?
Epistemology attempts to answer the question “How do we know what we know?” In today’s world, there is too much knowledge for anyone to be an expert in more than a small fraction of subjects, so even experts are ignoramuses in other areas.
In the old days a city beat reporter could have a news photographer on the scene, look at the chalk outline himself, and interview the officers involved, just like all those great old movies. Today, if we want to know something, our attempts to know are mediated by some combination of Google, Wikipedia, CNN, MSNBC, and Fox. All these mediators have agendas of their own and their own set of flaws. The best we can do is to learn the strengths and weaknesses of each information provider, and arrive at our own means of finding “truth”.
Couple that with the fact that good investigative reporting costs money. When Jon Stewart has someone do a “live” report from Baghdad in front of a green screen, it’s a joke. But he’s not the only one doing it. News providers are cutting costs, which means more rewritten press releases and Google-based journalism, and fewer interviews with primary sources.
So we’re fubared, except for those things we can know directly. If you can smell it and rub up against it yourself, it’s true. Anything else you have to take on faith from those who regularly show themselves to be faithless. Perhaps we should just cultivate our garden, in this the best of all possible worlds.
At least I’m on topic. Screw GPS; this is about TRUTH, baby.
Bob,
I think that an additional reason that this is a story, is to sell data / GPS enabled Cell phone plans. My son has one of these plans and a small part of his rational is that a separate GPS will be obsolete because the GPS satellite system being phased out in the future.
Thank you,
Greg
There’s lots of griping and complaining from Cringely and commenters about the quality of journalism, but no real solutions (aside from “do better!”). General journalism has never been good on tech, because most people who know about technology do better working in the field than writing about it. Print journalism is a rapidly shrinking while television journalism is increasingly focusing on lowest-common-denominator sensationalism.
Everyone would agree that we need better journalists. Who’s going to pay for them, and where are they going to come from? How do we convince the popular press to syndicate better quality material than what appears on the AP wire?
The first step in fixing a problem is to recognize one has a problem. I would characterize the comments here less as griping, and more of agreement and acceptance a problem exists.
The next step in fixing a problem is to understand the core of the problem, what is not working. It is easy to blame the Internet or Television for the demise of print journalism. In my real opinion these are a part of change, but not the real problem. The real problem in my opinion is print journalism has lost its connection to the market, its readers.
We still have a newspaper subscription. When the paper arrives we use two sections — sports and the weekend advertising. There is no real local news coverage. One of our major local highways is closed for construction. It would be nice if there was a regular report on its status. There is NOTHING. There are events all over our region. You’ll never find out about them in our newspapers.
When I was a kid and teenager I used to read a few magazines on a regular basis. My kids don’t read magazines, do not have any subscriptions, do not even care about magazines. Why? To start, magazines are now too expensive. There has to be a REALLY good issue for me to personally shell out $5+. At that price magazines are completely out of a kids budget.
The core of the problem starts with a basic product problem. Too many firms are not producing publications with content people need or want. The key in fixing the problems in the print media is for them to reconnect with their customers, their subscribers.
Whether I read an article or issue in print or on the internet is irrelevant. If good content is provided, people will read it.
The next challenge is for publications to learn how to make money with the Internet. It IS possible and there are a few examples of good and successful websites. As an example, consider: http://www.news-leader.com/ Look at the amount of advertising on this paper’s site! Does your town’s paper have this much advertising? Look at the local nature of the advertising. If I lived in Springfield (and I don’t) I could actually use this website to help me with my local shopping. Look at the smooth connection between this website and other sites. I can find a movie, read a review, find a theater and showtime, and even buy a ticket. If you tried this with my local newspaper, you’d give up and total frustration. My community is a good 25x bigger than Springfield.
Most of a newspaper’s customers are LOCAL. Most of their customers spend most of their money LOCALLY. Show me a newspaper with little or no local advertisements and I’ll show you an idiot. Companies exist to do business. This applies to print media too. A newspaper is in a unique position to connect local consumers to local business. If the newspaper will recognize this and facilitate it, the advertising money will be there.
One of the many capabilities of the Internet is the ability to do survey’s, solicit feedback, to do market research. Once a newspaper or magazine starts reconnecting to its customers, start listening to them! They will be an incredible source of ideas, of input, of value.
John