GPS Tracking Can’t Find Flight 477 — and Why

Few have escaped hearing the tragic story of how Air France flight 477 disappeared in to Atlantic a thousand miles or so east of Brazil on a flight to Paris.  The Brazilian military and other organizations are putting in near-heroic and not unfruitful efforts in find the remains of the passengers and plane, but as in all such tragedies their efforts seem to take too long and produce too little in the way of answers.

I’ve noticed in the past day or two a lot of activity in the general interest media regarding GPS and why GPS couldn’t just find flight 477 when it first went missing, why airline flights over the ocean aren’t routinely tracked by GPS, and today my BS detector went off when I noticed some (undoubtedly Beltway Bandit financed, in some hidden way) out and out US government propaganda using the death of the Air France passengers and crew to promote one of Washington’s most oversold and technically flawed schemes ever (friends, after you get done paying for this boondoggle, you’ll think $600 toilet seats are a bargain, believe me).  So I now expect this post will grow into several installments.  So be it, the longest journey begins with but a single step, as they say. Good example of media GPS tracking speculation here

Let’s work through some of the more common questions circulating today, working from the standpoint of most general interest to most esoteric.  This first article will certainly be of use to media types and fellow authors who want to find out a few of the basic things I virtually guarantee they currently don’t know about GPS and air commerce.

Why Can’t GPS Find Flight 477?

That one is the simplest to explain, but perhaps the most difficult for the non-techies out there to grasp.  GPS can’t find Flight 477 because GPS can’t find anything.  Yep, you read it here first, “Hey Joe, I just saw this nut on the Internet who says GPS can’t find anything.  What an idiot!”  Well nut job I may be, I’ll leave that to the shrinks.  But idiot I ain’t, at least regarding GPS.  In spite of the near universally held belief that the GPS (what most people say when the mean the NAVSTAR GPS, a GNSS (Global Navigation Satellite System), operated by the USAF and commonly described as 24 satellites circling the globe) does not track, or find anything.  Each active satellite sends out a precision timing pulse and some other navigation-related technical information, and that is that.  The satellites don’t track anyone or anything, in fact the signal between the satellites and whomever might be using their signal is purposely made one way .. the GPS satellites can’t receive any data from ‘clients’ using their signals to navigate, so even the CIA or some other fictional more secret agency can’t ‘track’ a single thing through GPS … period.  Now you may think I am mincing words or splitting hairs here, but the truth is, unless people get this basic concept in their brain and de-emphasize the fiction about GPS they routine get from TV, the movies and even certain US government officials, there are a number of important follow-on concepts here that are going to remain misunderstood.  Lives and billions of dollars, actually, ride on this concept, and I see the problem getting a lot worse rather than showing signs of improvement.

OK, so if GPD can’t track anything, why is the title of this blog GPS Tracking?  Glad you asked that, it’s the first step in understanding what is really going on here versus the common misconceptions.  Follow me through on this, it is not really too difficult.

Step One:  The GPS satellites send out a receive only (broadcast) signal.

Step Two:  A receiver sense this signal and processes the data to solve an equation.  The result of that equation is the position of the receiver in space.  (Typically on. or close above, the surface of the earth)

Step Three: The solution to the position equation is converted into something human-usable.  A display of the user’s position on an electronic map.  In simple terms this is GPS navigation in a nutshell.  The map may be on the dashboard of your car, on the screen of your cell phone, on the monitor of your laptop, on a navigational display in the cockpit of an airplane, or you name it,  but one thing is always true … up until this point in our mini-course, only you, the user, knows where you are.  No one else is tracking you or has the capability to track you … period.  The act of fixing your position or navigating with the NAVSTAR system and a “GPS Receiver” is an independent, user discrete function.  The customer knows where he is, no one else does.

Step Four:  Sometimes just knowing where you are is all you need to know.  That’s why, in fact, the vast majority of GPS products on the market are deceive/navigate only devices. They don’t get down below Step Three, above.  But there are many cases where the user wants others to know where s/he is, wants to be tracked in other words.  This is most commonly what we mean when we say “GPS Tracking”, and this is the aspect of the overall GPS utility most variable, and most misunderstood.

Let’s go back to the GPS-driven navigational display in the aircraft instrument panel we used as an example above.  This seems like the most germane example since we started out talking about the loss of Flight 477.  Did Flight 477 have such a GPS-driven navigational display?

I don’t have access to the specific equipment list of Flight 477 so the answer to the question I posed above is. yes, no or maybe.  The majority of commercial airliners flying today do not have GPS navigation aboard.  This likely will change in the future … especially if the US government succeeds in promoting and ill-advised monstrosity they call Next Gen … which the referenced GPS capability article  shows they are apparently grinding their personal axe on the bones of flight 477’s victims.  Many smaller business and private aircraft do have GPS navigation receivers/display, but the important point to wind up this install of my series on is that it matters not if Air France had GPS navigation aboard or not, because no one was in a position to track them anyway.

"The technology’s there — we’ve had this stuff for 15 years and little’s happened," said Michael Boyd, a Colorado-based airline analyst. "My BlackBerry can be used to track me, so why can’t we do it with planes?"

Not quite, Mr. Boyd, you’re on the right track, believe me, but your “analysis” has a few holes in it.  In order to make a GPS Tracking system out of a “common GPS”, you need two important components we haven’t mentioned yet and which no one, including the Next gen spin-meisters has really considered.  I’ll return to those issues next installment, meanwhile just remember this key point:

GPS can’t find Flight 477 because “GPS’ does not track commercial airliners in general and over the oceans and polar regions in particular.  “Common GPS” can not do so, period, the mechanisms and physics aren’t there.  Commercial airlines could be tracked with varying degrees of effort and expense, and next installment we’ll consider some of the pros and cons and costs.

GPS Tracking — Is The Sky Really Falling?

I’ve been meaning to post on this current issue for a few days now.  I came across this excellent summary from my blogging colleague John Ewing, the Aviation Mentor, so I might as well point it out to you and avoid covering a lot of the ground that John has already written informatively and sensibly on.

Constellation GPS I particularly like John’s blog as he is one of a select few who actually writes about some of the real-world uses of GPS rather than the toy aspects so many focus on.  GPS is so much more than a dashboard car navigator or a pocket caching device, and it’s hard to explain things so that the average person gets the picture.

John is a professional pilot and Gold Seal flight instructor and he specializes in modern aircraft “glass dashes” which typically include integrated GPS systems.  Usually worth a read even if you don’t have wings.

The issue at hand is that the US General Accounting Office (GAO) has recently released a report Global Positioning System: Significant Challenges in Sustaining and Upgrading Widely Used Capabilities that is pretty critical of the USAF (the folks who actual build and run the GPS for the world) and in particular their efforts in getting the IIF (Block I Follow-on) birds built, tested and launched.

As a former USAF employee, directly involved with the GPS program since the days there was only one satellite on orbit, I’m a bit troubled too.  I’m disappointed by two things, two issues that are in some ways diametrically opposed to each other.

First I have been troubled for years by the way senior levels of US government have treated the NAVSTAR program.  I am a firm believer that my former USAF colleagues can accomplish most any reasonable task, but the mission of the USAF is to fly and fight.  The GPS is a national, nay, world public utility, and it’s contrary to logic and good leadership practices to just tell the USAF, “Okay general, while you are at it, promoting political change in SW Asia, providing the only space object catalog orbital control utility for the world and keeping those 50 year old KC-135 tankers in the air, take care of this little GPS project too.” 

The GPS, like the Internet, is another US military project that has expanded beyond all rational expectations and is being left to run as best it can.  Where is the higher level national interest and the world interest in these now essential international systems.  The European Union over the past few years have shown true “raised middle finger” leadership by wasting billions of Euros on their competitive and ill-advised Galileo program, essential just so they can be ‘different’.  What is needed her is cooperative leadership, not national pride and flag waving.  This deserves attention at much higher levels than the GAO.

As an aside I get a bit of a chuckle out of John’s concerns about the age of the current GPS constellation … “That means about a third of the GPS satellites are between 12 and 19 years old; a sobering thought” … valid concern, but how much more sobering to consider the age of the existing USAF aircraft and missile combat forces .. the GPS turns out to be one of the youngest and most technology ‘fresh’ systems out there.

The second issue that concerns me that the GAO report draws attention to at the intellectual level is faulty expectations.  The GPS today is exceeding expectations in virtually all aspects.  The life of the satellites has been prolonged far beyond the dreams of the original designers … to a large degree by the ingenuity and dedication of the folks in the 2 SOPS out there on the barren eastern plains of Colorado.  As an example, technicians in the 2 SOPS developed a technique years ago to ‘recondition’ batteries aboard the satellites remotely … one significant factor in the record levels of longevity. 

Also, since the first Gulf war, the accuracy of the navigation solution in the areas of combat has been greatly enhanced by ‘touching’ each bird (making more frequent ground to space contacts to enhance clock accuracy) bringing the overall accuracy in the area of interest up to better than 5 times the system specified figure.  A side effect from this work has been a sort of artificial world-wide increase in observed performance, leading to greater and greater expectations. 

USAF 2 SOPS logo How would anyone actually codify these efforts much less write them into a contract to operate the system?  My fear is, at some date that may be closer than we think, the Air Force is going to be forced to cut back on this labor-intensive ‘hand tuning’ and the system overall will revert to a level of performance far closer to its design document specifications.  The USAF will still be doing a highly creditable job … they always do .. but there may be a lot of customers who have grown used to getting a lot of extra performance for free that may become quite disappointed.

Here’s a great resource that shows a lot of data about the age of the GPS fleet.  Some areas for concern?  Indeed, but fear not, I think the system will stay healthy through the foreseeable future … there are a lot of my former colleagues, Civil Service, officer, enlisted and contractor personnel who are well aware of how critical the GPS is, even though it is actually so far outside their “job description”.  Hat’s off, guys, sometimes I wish I was still there.