The origins of GPS

Today we take our navigation for granted. Just a few moments using our phone and we’ve got our quickest route home, the scenic drive to work, and directions to the nearest coffee shop. But have you ever stopped to wonder how it actually works, or who made it?

For a special sixth episode of the Create the Future podcast, we spoke to the winners of the 2019 Queen Elizabeth Prize for Engineering after they received the award from HRH The Prince of Wales, about their work developing the Global Positioning System – GPS.

Today, it is estimated that four billion people around the world use GPS. It provides an accessible service for all and a powerful tool that engineers can integrate with their applications for free. It can help to track disease outbreaks, guide self-driving tractors, prevent shark attacks, and even improve the performance of sports teams. New applications for GPS continue to revolutionise entire industries, and its annual economic value has been estimated to be $80 billion for the USA alone.

In this episode, Dr Bradford Parkinson, Richard Schwartz, Hugo Fruehauf, and Anna Marie Spilker, on behalf of her late husband, Professor James Spilker, Jr, recount stories of how they started working on GPS, their contributions to the project, the highlights and challenges of the colossal innovation, as well as their thoughts on its future applications.

About the guests

Dr Bradford Parkinson

Born in Wisconsin, USA, on 16 February 1935, Bradford Parkinson is often called the ‘father of GPS’. He gained a degree in engineering from the US Naval Academy and immediately joined the US Air Force, where he helped develop a modernised AC-130 Spectre Gunship and flew more than 170 combat hours

He became the first Director of the NAVSTAR GPS Joint Program Office in 1973, which led to the development of the GPS spacecraft, Master Control Station, and eight types of user equipment. He developed GPS applications such as the first automatic landing of a commercial aircraft and the first fully automatic control of farm tractors on a field to an accuracy of 5cm.

Highlights

• "From beginning to end, it was an open teamwork environment and I think that's what led to success. Having four first-of-a-kind satellites all operate virtually flawlessly is almost unheard of."
• "Engineers are an interesting lot. By and large, I believe they're driven by achievement, by making something work. That excites them more than the fact that everyone knows they did it. If they know they did it, there's a deep inner satisfaction. So, engineers as a group tend to be anonymous, but at the same time they don't necessarily invent things; they take little pieces of invention and combine them in creative new ways. They make them robust, reliable, and useful, and as a result, the engineer turns around and gets his derived satisfaction from seeing that something is working and benefiting humanity."

Richard Schwartz

Richard Schwartz graduated in engineering from The Cooper Union for the Advancement of Science and Art in New York and has an MBA from Pepperdine University. He joined Rockwell in 1957 and led many of its most successful space and satellite programs, including the first flights of GPS and the NASA Space Shuttle.

He was Rockwell’s GPS Satellite Program Manager and commissioned his chief engineer, Hugo Fruehauf, to work with Efratom engineers to produce a satellite design that could withstand intense radiation. It also had antennas that ensured uniform power.

Highlights

• "We had to recognize that we were working in the Van Allen belt, and so we had to protect the components, and I think the most difficult thing – or maybe the most fun thing – is setting a very high standard for the people, for whom perfection was the name of the game."
• [On Galileo, GLONASS, and other alternatives] "The more satellites up there the better. You build the receiver, and you can receive their signals. Instead of thirty-some satellites that we've got up, suddenly you've got fifty. It gives you better navigation as long as you're not picky who you're using."

Anna Marie Spilker

Anna Marie Spilker graduated from the University of California, Santa Cruz with a degree in Theoretical Economics and pursued careers in both finance and real estate. She and Professor Spilker were married for nearly 50 years, and Anna is currently working on the completion of Professor Spilker’s autobiography.

Highlights

• "The emphasis for Jim was to get the work done – to do the work of engineering and to do it to the best of his abilities. That was his satisfaction."
• "Half of the employees approximately were PhD graduates; the other half were the support team. He mentored everyone, and many of his employees said that working at Stanford telecommunications was the best job they ever had. Others said that it was like getting another PhD – Jim challenged them."

Hugo Fruehauf

Hugo Fruehauf gained his degree in electronic engineering technology from DeVry University, Illinois. He joined Rockwell International as an electrical systems manager and became Rockwell’s Chief Engineer and Systems Manager for the design and development of the GPS Satellite.

He was also Chief Engineer for the design and development of NASA's TDRS (Tracking and Data Relay Satellite) and helped develop the first fully radiation-hardened rubidium vapour atomic clock alongside Dick Schwartz.

Highlights

• "The satellite, by the time you have another kick motor to put it into this 20,000 orbit, can only weigh 850 pounds. Today they weigh 4000 pounds so you can put anything you want on there today, but then, you know, three 50 pound clocks? That took about 20% of my weight."
• "Everyone wants their own system, rather than just using an American system. In that instance, everybody uses different codes. Most of the time it's 1023 bits, and it's like raindrops that fall; every satellite system has different raindrops falling on different places, so everybody can navigate from this clear signal. A receiver just picks the ones that that are closest in time and the best position to receive. It does all the work, and it's all you really need. It ends up with a solution with only four satellites, although it has a choice of, as Dick said, maybe 20 nearby."

For more information on the 2019 Prize winners, click here or visit: https://qeprize.org/winners/the-global-positioning-system

About Professor James Spilker, Jr.

James Spilker gained a degree, masters and PhD in electrical engineering from Stanford University. He joined the Lockheed Research Labs and during the 1960s wrote a number of papers on signal timing technology. These made the precision tracking of satellites, which is necessary for GPS, possible.

Brad Parkinson asked Spilker to join him at Stanford in the 1970s, where he contributed to the original GPS architecture and designed the GPS civil signal. In 1973 Spilker co-founded Stanford Telecommunications Inc., which was selected by Parkinson to recommend the GPS signal structure for CDMA (code division multiple access). This became the civilian signal that is now used by 4 billion receivers.

Spilker’s delay lock loop process for tracking CDMA signals was the key component that enabled the system and is essential to GPS accuracy and vector tracking will be critical to handling GPS satellite navigation expansion in the future.

Professor Spilker died in September 2019, aged 86.