Review: GPS Declassified: From Smart Bombs to Smartphones
by William F. Mellberg
|Space enthusiasts will enjoy reading about some little-known chapters in space history: episodes that were once shrouded in Pentagon secrecy, but which eventually led to things that most of us now take for granted, like the GPS units in today’s cars.
Today’s drivers don’t have to worry about cloudy skies or locating the North Star to guide their path. A whole new constellation of man-made “stars” now orbits our Earth, providing travelers with precise locations and directions through the revolutionary Global Positioning System (GPS). GPS Declassified describes in fascinating detail some of the navigation techniques that were employed prior to GPS, the Space Age events that paved the way to GPS, the development of GPS, and the assorted applications of GPS in today’s society. It also tells the inside stories of the people who created GPS, including Roger Easton, the father of co-author Richard Easton.
Despite the highly technical nature of the subject matter, GPS Declassified is totally accessible to any reader with a modest interest in science, technology, history, and culture. The authors use plain English and employ a largely chronological approach that is easy to follow. Space enthusiasts will enjoy reading about some little-known chapters in space history: episodes that were once shrouded in Pentagon secrecy, but which eventually led to things that most of us now take for granted, like the GPS units in today’s cars.
Ten chapters guide the reader from the ancient Greeks and 18th Century mariners to early Space Age pioneers and (as the subtitle suggests) modern smartphones. The authors repeat themselves in a few places. This is not a criticism. Easton and Frazier simply remind us of some things mentioned earlier in the book, reminders which I found very useful. There is a lot of material packed between the covers of this tome, and there could have been even more. Again, this is not a criticism. So many interesting tidbits are included that I frequently found myself going to my bookshelf or searching the Internet for additional information. Here are three examples:
One: Captain James Cook was able to determine his longitude while exploring Pacific islands by observing and timing the motions of Jupiter’s Galilean satellites. (And to think that I always thought those tables were published in nautical almanacs simply for the benefit of amateur astronomers like myself!)
Two: The downing of Korean Air Lines Flight 007 in 1983 precipitated the civil use of GPS. Had that Boeing 747 been equipped with GPS instead of INS, it is unlikely the crew would have strayed over restricted Soviet airspace, which is why President Reagan approved the use of the Pentagon’s GPS for civilian airliners and other commercial applications.
Three: Actress Hedy Lamarr and pianist-composer George Antheil invented the spread-spectrum signal structure during World War II. As the authors note, “They deserve at least some of the credit for the signal used by GPS.”
The invention of GPS takes up a good portion of the book, and co-author Richard Easton is in an excellent position to tell his father’s story. He was a youngster when Roger Easton, a scientist at the Naval Research Laboratory, helped develop the Vanguard satellites and invented the Minitrack tracking system, which determined their orbits. That work led to Easton’s invention of the Naval Space Surveillance System (NAVPASUR) to detect Soviet spy satellites. That system, in turn, led to Roger Easton’s invention of GPS.
|The path from Vanguard I to Timation I—an experimental satellite designed by Easton and launched in 1967 to test his ideas for a Global Positioning System—was a long one. Inter-service rivalries between the Navy and Air Force made the effort even more difficult.
Being a space historian myself, the authors really held my attention through the first half of the book as they recounted those early years of the Space Age. Project Vanguard is often depicted as a failure because of the launch pad explosion that took place on December 6, 1957, two months after the Soviet Union put the world’s first artificial Earth satellite into space. But, Vanguard was really a great success, and it represented an innovative approach to designing and tracking scientific satellites. Vanguard I, as the authors note, is still in orbit today. A mere fifteen years separated the launch of the “grapefruit-sized” Vanguard I and Apollo 17—the last human voyage to the Moon. What a remarkable fifteen years that was.
The path from Vanguard I to Timation I—an experimental satellite designed by Easton and launched in 1967 to test his ideas for a Global Positioning System—was a long one. Inter-service rivalries between the Navy and Air Force made the effort even more difficult, as the authors describe in detail. The second half of the book recalls the evolution from military to commercial use of GPS. It also describes the constellation of satellites required to make GPS work. At least four satellites must cover every spot on Earth, 24 hours a day. Currently, a network of 30 satellites makes that possible. Each of the satellites is equipped with an atomic clock (another Roger Easton innovation) because the system depends on extreme accuracy in measuring time and distance. The first civilian application of GPS was for land surveying—something Easton envisioned during the Vanguard era when he talked about using satellites for geodetic purposes.
The 1991 Gulf War provided the first real test of GPS for guiding smart bombs. The same technology that was used to accurately find targets could also be used to locate troops caught behind enemy lines. The authors recall the dramatic story of downed F-16 pilot Scott O’Grady’s daring rescue from Bosnia in 1995. GPS was also being used for commercial aviation by that time, as well as in agriculture and highway navigation. Just as GPS was employed to locate Captain O’Grady, it is now used to find lost hikers. Of course, smartphones have become commonplace, too—thanks to GPS.
GPS Declassified is a carefully researched, well written, fast-paced, and thoroughly enjoyable book. It offers an excellent mix of science, technology, history and culture. Kudos to co-authors Richard Easton and Eric Frazier for their outstanding contribution to space history. This book is highly recommended.