Kontsantin Kakaes wrote for The Wall Street Journal about innovation in the GPS markets:
Even the best ideas aren’t always easy to recognize. When a venture capitalist named Ed Tuck was trying to find investors for a GPS startup called Magellan in the mid-1980s, he was turned down 86 times. The military had, by that point, been using GPS and its antecedents for several decades. But Mr. Tuck was one of the first people to imagine GPS as useful for the average person. “Tuck had in mind an ideal customer called Bubba. The thing about Bubba was, he didn’t like to ask for directions,” Greg Milner writes in “Pinpoint: How GPS Is Changing Technology, Culture, and Our Minds,” one of two new accounts of GPS’s history. Mr. Tuck wanted to sell products that “would make locating one’s position as easy as glancing at a wristwatch to find the time.”
It is that easy now. Indeed, Magellan is one of many companies that make wristwatches that do just that. Cellphones, of course, also have GPS chips, as do myriad other devices. Mr. Milner estimates the total number of GPS receivers, across all gizmos, at “somewhere around 5 billion.” The “economic influence” of GPS, he wisely points out, is so pervasive that it “resists quantification.” The economic impact, along with GPS’s history, is the focus of Mr. Milner’s compactly told account. GPS’s cultural and psychological significance—arguably even more profound, though tougher to parse—is at the core of George Michelsen Foy’s “Finding North: How Navigation Makes Us Human.”The first test GPS satellite was launched in 1977. The system now comprises a constellation of 31 operational satellites. Each satellite carries a precise atomic clock and transmits the time as an encoded signal. Simply gathering the “almost impossibly faint” signal on the ground is an impressive feat, Mr. Milner writes: Picking it out of the background noise is “roughly comparable to reading a book in London by the light of a 10-watt bulb in Rome.” By comparing how long the signals from multiple satellites take to arrive, a GPS receiver infers both the current time and its own position. There are multiple complications involved in these calculations; each satellite transmits several signals, for both military and civilian use. Newer satellites transmit more sophisticated signals and have more accurate clocks. At times, as Mr. Milner recounts, the military has tried to degrade the accuracy of civilian signals, though manufacturers have in turn used clever engineering tricks to glean data from encrypted military signals. In addition, one can augment GPS satellite signals with broadcasts from nearby points on the ground, a system called differential GPS that improves precision substantially.