Brad Parkinson, who led the original 1970s team that created the Global Positioning System, talks to Martin Cooper MBCS, about how the technology came to be and what it means to be an engineer.

It’s hard to imagine another technology that is so deeply woven into the weft and warp of our lives than the Global Positioning System or GPS. From getting you home on a dark night, to keeping planes in the sky and boats safe at sea, the ability to pinpoint a location exactly - in space and in time - has been nothing short of revolutionary. It really has made our lives that bit better.

Such is GPS’s importance, the team that created it - Richard Schwartz, Brad Parkinson, James Spilker Jr and Hugo Fruehauf - were recently awarded the Queen Elizabeth Engineering prize. ITNOW caught up with Brad Parkinson, a man regarded by many as the father of GPS.

Back to the 1970s

Back in 1973, the year that the Vietnam war ended and Pink Floyd released 'The Dark Side of the Moon', GPS began to take shape. Parkinson created the initial specification and pitched it to the Department of Defense - who initially rejected it. ‘I spent months travelling up to the Pentagon from LA - which is a long journey. And I got beat up by people who said “no”,’ Parkinson recalls. I called a small meeting to redesign our offering over three days in September.’

He spent the next three months persuading the Defence Department Officials to fund a full-scale demonstration of the revamped design. By the end of the year, the American government relented and the GPS story began in earnest. By 1978, the system had been designed, launched and entered prototype operation. It met every capability that Parkinson had claimed four years earlier.

GPS' initial driver was, of course, military precision. ‘Frankly, World War Two was a travesty - to take out a factory in Germany we sacrificed many aeroplanes and dropped a lot of bombs,’ Parkinson says. ‘We hit a lot of things that we didn’t want to hit... It wasn’t good.’ Today, of course, targets can be hit with very high degrees of accuracy.

GPS’ other driver was economic. The Department of Defence had, at the time, over 60 positioning and navigation systems. The GPS team believed this number could be reduced to two.

Civilian and military systems

Despite GPS’s focus on being a tool for the military, Parkinson is keen to dispel a common misconception: 'From day one, I said, there will be a civil navigation capability. Part of the signal would be free and open. Testifying before congress in 1975, from the get-go, I said that GPS was a dual-purpose system - civil and military.’

To drive that point home, Parkinson released the complete signal specifications. And the first team to lock on to the civil signal was a group of students from the University of Leeds. ‘They hand crafted a receiver and locked on to the signal in the first day.’

Imagine the future

This leads to a tantalising question... Did Parkinson and his team ever imagine, back in the 1970s, that their creation would go on to change the world so profoundly? The problem with answering the question, he explains, is technology has changed so profoundly since the days of vacuum tubes.

‘You have to remember that the integrated circuit didn’t exist. It does now.’ He says. ‘Today, a receiver costs two dollars. Back in the seventies, it cost us a quarter of a million dollars - and that’s when the dollar was worth something. That’s astonishing. It completely changed where and how this capability can be used.’

Defining challenges

Despite having access to, by today’s standards, limited technology, the team forged ahead. With a budget of around $200m they built and deployed four satellites and carried out a test programme.

And though the Pentagon and politics might have been big challenges, GPS’ biggest test lay in space. ‘We had to solve some huge challenges,’ Parkinson explains. ‘We had to build an atomic clock that would survive the upper Van Allen belt.’

In this area of space, the Earth’s magnetic field captures and holds charged particles from the sun. The level of radiation in the Van Allen belt is so strong it would deliver a fatal dose to an unshielded human in under ten seconds. Along with withstanding these hostilities, the atomic clock had to be able to survive the vibrations and forces a rocket launch imposes. The clocks also needed to last for at least three years. And they did. Some, Parkinson says, lasted for over 25 years.

‘We also had to solve the problem of how to design receivers for an extremely weak signal,’ he recalls. ‘The signal that arrives at your cell phone is a tenth of a millionth of a billionth of a Watt. It is an extremely tiny signal. And we had to devise a technique that would let you take that signal out of the ambient noise. It’s a hundred times below ambient noise.’

Again, working with such a signal is made easier with today’s technology. ‘On my smartphone, we have storage and computing speed and software that dwarfs anything we had back then by factors of a million,’ Parkinson recalls.

Back in the seventies, it was a different story. ‘We had to build our receivers using discrete parts - individual transistors to do specific jobs. A modern GPS chip has millions of parts in it,’ he explains. ‘During our initial development, the discrete parts had to go on discrete boards. Printed circuit boards did exist, but they all had to be built up.’

When completed, an original receiver stood six feet tall and around four feet wide. It could receive four channels and cost around $5m to build. ‘In your cell phone you’ll find a tiny chip that cost two dollars and it can receive 200 channels. And it can do it with much more precision and accuracy than that old system,’ Parkinson says.  

Despite the huge leaps in technology that we’ve experienced between the 1970s and today, much of GPS’ defining specifications and ideas remain largely unchanged. ‘The signal structure we invented in the early 70s is still the underlying structure for all US systems... if you had a set from 1985 it would still work today.’

Korean airline KAL007

The first of September 1983 was a watershed moment for GPS. On that day, Korean Airlines flight 007 - KAL007 was shot down by a Soviet supersonic jet fighter. The Boeing 747 was carrying 269 passengers and was on route from Anchorage to Seoul. Tragically, it transpired, the plane made a navigation error, deviated from its original flight path and flew through controlled Soviet airspace. In response, the Russians shot the plane down. Along with the loss of life, the KAL007 elevated Cold War tensions to dangerous levels.  

As a direct response to the incident, President Reagan guaranteed worldwide access to the United States’ GPS system - in an effort to prevent such incidents happening again. 

Remembering Reagan as the reason for GPS becoming a public service isn’t, however, quite correct. Parkinson explains: ‘Right from the beginning, as we’ve seen, GPS was created as both a military and civilian system. The problem was, prior to Reagan’s announcement, the civilian signal wasn’t a guaranteed service. Following KAL007 however, the President changed that. GPS would be guaranteed on a rolling 10-year basis - if the US government changes its mind it’ll have to give the world ten years’ notice.

‘Back then, the military could still wiggle the signal and induce an error of 30-40 metres in a civil set,’ Parkinson says. ‘This was a modest corruption of the accuracy. But President Clinton announced that it wasn’t in the best interests of the world. He announced the US would cease degrading the signal and would no longer design that [wiggle] into satellites. We’d give the same underlying accuracy to civilians as the military but retaining a military encrypted signal.’

Navigating today

Cumulatively the world changed, politics shifted and technology charged forward as GPS aged, matured and became far more accurate. ‘The implications of all this was huge,’ Parkinson enthuses. ‘Suddenly engineers were thinking: “What can we build with it?” Creative minds here in the US, in Europe and around the world went to work to try to figure out what could be done with GPS.’

And of all the jobs that these creative minds and GPS helps us do today, which gives Parkinson most satisfaction? ‘The most satisfying has been farming. It benefits humanity in ways the public doesn’t even know. Less herbicide is sprayed because of the precision of spraying. There’s less cost. You lay down less fertiliser. There’s less pollution... You also make food better and less expensive.’

Finishing his point, he says: ‘Landing airplanes precisely? That’s important. But farming, that’s the one I would hold out. At Stanford, I had such a talented team of engineering students. And society doesn’t know them... It has no idea. And that’s the way of engineering.’

As a closing note, he says: ‘What reunites [the GPS team today] is the joy of knowing we have made life on this planet just a little better. Maybe a lot better. We could all take pride in it. The greatest compliment for GPS now is that it’s taken for granted. If you can put in place the engineering technology that helps the world and is so subtle and so pervasive that it’s taken for granted, you know, that’s pretty good… That’s the joy.’