GPS System failure

[Auxpilot]

News has been floating around the last few days about a GAO report concerning the premature failure of GPS sats in 2010.

http://www.aopa.org/flightplanning/articles/2009/090520gpsout.html?WT.mc_id=090522epilot&WT.mc_sect=gan

Might be chicken little stuff to get more funding out of Congress. time will tell.

[Spike]

^ Actually the Air Force (who runs the GPS program) said the GAO report is crap, and not to worry!

Guess the AF has enough money already......

[Auxpilot]

^ Actually the Air Force (who runs the GPS program) said the GAO report is crap, and not to worry!

Guess the AF has enough money already......

That is good news! All I have found is the negative GAO stories out there. But that is the way the media works - print the doom and gloom and ignore the good news.

[desertengineer1]

I went to a conference a few years ago that briefed some technical details.  Two main things drove the concern at that time.

1.  Delays and stretch of the original operational lifetime cycles of the sats produce a "kneecap" of reliability risk that was not designed for.  The failure cycle becomes more dramatic than originally expected because the service life is extended beyond that defined by the original reliability curves.  IOW, instead of losing one or two here and there over a period of a few years (compansated for by a planned replacement schedule), you might lose 5 or 6 within a few months, substantially degrading overall capability.

2.  Each SVS has (I think) a set number of precision clock modules.  Only one is "prime" at a time (with maybe a backup in hot-ready - not exactly sure).  When a clock goes out of spec, it is deactivated and the next is brought on-line to replace it.  Many of the satellites are on their last clocks.  Once those go, the birds are dead.

GPS III was supposed to fix all of this, and bring additional capabilities, but unfortunately the fleet has become another victim of our short-sighted budget process.  Continuous cuts and schedule delays have pushed the envelope.

I don't think it is unmanageable, but the risk curves are a probably a little more dramatic than folks are comfortable with. 

But barring a really bad event or disaster, the fleet should continue to operate just fine - degraded, maybe, but it will be OK.

[Gunner C]

^ Actually the Air Force (who runs the GPS program) said the GAO report is crap, and not to worry!

Guess the AF has enough money already......

When a military department says "Don't worry, all is well" that's the time to duck.  Nothing is ever assured in the government and if there's a political motivation behind something, you can bet that while the talking head is giving a smiling assurance, he has one hand behind his back with his fingers crossed.

My bet is that there will be degradations of the system and the government will send up a band aid of some sort, smile, and say: "See?  No problem!"

[sardak]

^ Actually the Air Force (who runs the GPS program) said the GAO report is crap, and not to worry!

Guess the AF has enough money already......

That is good news! All I have found is the negative GAO stories out there. But that is the way the media works - print the doom and gloom and ignore the good news.

So you were concerned by all the doom and gloom reports from the media. But now you're relieved because someone here said that the Air Force said the report is a piece of crap, without providing any source or reference, thus proving that the media only reported one side of the story. Hmm. I suspect that the USAF view of the report is also one-sided and that reality is somewhere between "doom and gloom" and "good news."

The GAO page for the report is here.  The page gives the summary and recommendation, and has links to a one-page summary as well as the full, 61 page report.

Another useful non-media source for finding out about what is going on is the National Executive Committee for Space-Based Positioning, Navigation, and Timing (PNT), a U.S. Government organization established by Presidential directive to advise and coordinate federal departments and agencies on matters concerning the Global Positioning System (GPS) and related systems.

Mike

[Auxpilot]

^ Actually the Air Force (who runs the GPS program) said the GAO report is crap, and not to worry!

Guess the AF has enough money already......

That is good news! All I have found is the negative GAO stories out there. But that is the way the media works - print the doom and gloom and ignore the good news.

So you were concerned by all the doom and gloom reports from the media. But now you're relieved because someone here said that the Air Force said the report is a piece of crap, without providing any source or reference, thus proving that the media only reported one side of the story. Hmm. I suspect that the USAF view of the report is also one-sided and that reality is somewhere between "doom and gloom" and "good news."

The GAO page for the report is here.  The page gives the summary and recommendation, and has links to a one-page summary as well as the full, 61 page report.

Another useful non-media source for finding out about what is going on is the National Executive Committee for Space-Based Positioning, Navigation, and Timing (PNT), a U.S. Government organization established by Presidential directive to advise and coordinate federal departments and agencies on matters concerning the Global Positioning System (GPS) and related systems.

Mike

Not so much relieved by the fact that the AF siad it would be ok, but the fact that they did not jump in and say that it was the "worst since the great depression." With everything that they have at risk without a solid GPS system, the fact that they are not up in front of Congress asking for another trillion or two to fix this "crisis" makes me sleep a little better.

[heliodoc]

GAO reports being negative??

Got to have some oversight on all this technology...."lotta" lives depending on quality that might be given to the lowest bidder NOT to mention cost overruns on every major piece of DoD weapons yet to date

Ya think all these contractors think that Uncle SAmmy "gots" bottomless pockets??

Negative GAO reporting???  Technology like aircraft......aging issues and falling out of the sky??  Distinct possibilities...


Not to worry?? is that what the AF said??    How about that F22 project and the the Prez VIP helo??   How about that aquisition(sp) process for that equipment??

Better get back on the standard six pack and map and compasses when the MFD, PFD, and the GPS units go dim

Do not worry, tho, Congress will get to the rescue with yours and my money!!

[Short Field]

With everything that they have at risk without a solid GPS system, the fact that they are not up in front of Congress asking for another trillion or two to fix this "crisis" makes me sleep a little better.

+1 

[Spike]

But now you're relieved because someone here said that the Air Force said the report is a piece of crap, without providing any source or reference, thus proving that the media only reported one side of the story. Hmm.

HERE YA GO!!!!!!!!!!!!!!!!!!!!!!

http://www.pcworld.com/businesscenter/article/165305/air_force_responds_to_gps_outage_concerns.html

http://www.af.mil/news/story.asp?id=123150625

[desertengineer1]

Folks, I don't intend to be mean here, but the armchair engineering factor is reaching an annoying level.

It's obvious you don't understand the technical role of GPS (based on what I'm reading) - or your training is really deficient (Which I see way too much in aviation) 

So, hate to burst a bubble here..

GPS IS NOT a primary navigation system that is safety critical. 

Let me explain a little before the flames start.

In most navigation systems, especially weapons or defense aircraft, GPS is only another input to the Navigation solution, commonly referred to as a DAMPING source.  Raw GPS data is extremely noisy.  It might be OK for your Tom Tom, but it is a detriment to systems requiring wide-spectrum precision.  Those systems employ Kalman filters of many inputs.  GPS position and velocity inputs reduce the error through integrated, weighted averaging.

It's not the center of the universe, just another navigation input to keep accuracy tight. 

If you want to argue otherwise, try this...  Pull the circuit breaker for the GPS receiver (if there is one) in the G1000 next time you fly.  It will not crash.  You'll still have VOR and ILS.  Altitude hold will still work (pressure).  GPS just gives you a pretty screen and tools to do a more efficient job.  Gyros and the ADC are your primary flight sensors - not the GPS.

[Spike]

^ Since most of the world has no idea how to use a map or compass anymore, GPS failure is a concern for those so accustomed to it.

Ask a 16 year old kid how to get from his house to your house using a map.  I bet most can not do it.  Biggest question I hear....."do even or odd numbered interstates run north and south?"

I don't think this was about flying!  All pilots know (or should know) how to use dials, gyros, vfr, vor....etc.etc.etc.

[Ricochet13]

^ Since most of the world has no idea how to use a map or compass anymore, GPS failure is a concern for those so accustomed to it.

Ask a 16 year old kid how to get from his house to your house using a map.  I bet most can not do it.  Biggest question I hear....."do even or odd numbered interstates run north and south?"

I don't think this was about flying!  All pilots know (or should know) how to use dials, gyros, vfr, vor....etc.etc.etc.

Still using LORAN here.  I make a point of integrating LORAN into VOR, ADF, DME, and a good old chart with course line and check points, especially when flying long distances.  Redundancy is safety.  Will break down one day when LORAN stations go completely silent and purchase an aircraft GPS, but it will remain part of a system of navigational devices, not the sole one.

[Major Lord]

There are two other similar fall back systems, GLONASS, the Russian system, and a Chinese system whos crepuscular acronym escapes me. You won't be able to use your current gear, but if the Air Force source is....well....inaccurate......(perish the thought!) there is a work-around. My business is manufacturing APRS transmitters that rely on GPS, so I will be looking at using dual- standard positioning receivers.

Major Lord

[Auxpilot]

^ Since most of the world has no idea how to use a map or compass anymore, GPS failure is a concern for those so accustomed to it.

Ask a 16 year old kid how to get from his house to your house using a map.  I bet most can not do it.  Biggest question I hear....."do even or odd numbered interstates run north and south?"

I don't think this was about flying!  All pilots know (or should know) how to use dials, gyros, vfr, vor....etc.etc.etc.

Still using LORAN here.  I make a point of integrating LORAN into VOR, ADF, DME, and a good old chart with course line and check points, especially when flying long distances.  Redundancy is safety.  Will break down one day when LORAN stations go completely silent and purchase an aircraft GPS, but it will remain part of a system of navigational devices, not the sole one.

Better start shopping for a GPS. Our Presidents budget calls for killing loran. Says it will save like $100 mill.

[Spike]

^ WOW!  I missed that. 

[Short Field]

How many airplanes still have Loran?  Current installed Loran base versus installed base of GPS equiped aircraft (portable included)?

[desertengineer1]

GPS is going to be fine.  All the report does is identify areas of higher risk (in the category of program risk - impacts to schedule, cost, and the higher levels of optimum performance), and recommend systemic adjutments for mitigation.

Again, none of our weapon systems will be shelved if GPS is lost.  It is a precision enhancer, i.e. not a single-core element.  You don't design such systems with single points of failure, especially the multimillion dollar / high effectivity ones.

For GPS istelf, there are many modes of degraded operation that will kick in if a substantial reduction in infrastructure or satellites occur. 

This is a program execution concern.  The operational capability will be fine.  Numerous layers of redundancy and design are embedded as well.

The other side of the coin is the commercial use.  American planes and GPS technology are sought because of the high quality and reliability.  Loss of capability would mean loss of billions to our economy.  Would hate to see a day the world says "American GPS has fallen into disrepair so much, we are forced to design for GLONASS from now on".  This would impact multiple facets of our technology industry.  Companies like Lowrance, Garmin, Boeing, and General Dynamics (to name a few) would lose billions.

[PHall]

Funny you should mention Boeing, they're the one's who are building the new GPS satellites and it's their delays (some their fault, some not) that generated the GAO report.