Our recent “Retrotechtacular” feature on an early 1970s dead-reckoning car navigation system stirred a memory of another pre-GPS solution for the question that had vexed the motoring public on road trips into unfamiliar areas for decades: “Where the heck are we?” In an age when the tattered remains of long-outdated paper roadmaps were often the best navigational aid a driver had, the dream of an in-dash scrolling map seemed like something Q would build for James Bond to destroy.
And yet, in the mid-1980s, just such a device was designed and made available to the public. Dubbed Etak, the system was simultaneously far ahead of its time and doomed to failure by the constellation of global positioning satellites being assembled overhead as it was being rolled out. Given the constraints it was operating under, Etak worked very well, and even managed to introduce some of the features of modern GPS that we take for granted, such as searching for services and businesses. Here’s a little bit about how the system came to be and how it worked.
Dead Reckoning Revived
Etak’s story begins on a racing yacht off the coast of California in 1983. The yacht’s owner was serial Silicon Valey entrepreneur Nolan Bushnell, who along with Ted Dabney founded Atari and introduced the world to Pong. Along for the race was Stan Honey, an engineer and seasoned yachtsman signed on as navigator. Bushnell and Honey began brainstorming how to turn the navigation system Honey had built for the yacht into a land-based system. By the end of the race, Honey had the rough design for a system and a promise from Bushnell to bankroll its development.
From his navigation experience, Honey knew the challenges of dead-reckoning, the navigational technique that depends on keeping track of the distance and direction traveled from known positions, or fixes. Small errors in measuring either distance or direction of travel would accumulate until position couldn’t be determined with any reliability. Honey figured that correcting for dead reckoning errors in a car navigation would be easy because drivers are generally constrained to roads; correlating the current assumed position to the nearest roadway would provide a constant series of fixes and keep the system on track.
The company Honey formed to commercialize this idea was called Etak, after a term used by aboriginal Polynesian mariners for moving navigational reference points. The task faced by Honey and his team was formidable. Not only was the computer hardware of the day limited, the map database needed for his “augmented dead reckoning” system didn’t exist. The computer problem would turn out to be less of an issue than the maps.
An 8088-based machine running at 4.77 MHz with 128 kB of RAM was stuffed into a shoebox-sized case for the vehicle’s trunk. The team found that traditional raster CRTs didn’t have the resolution needed to show map details, so they built a vector-based display like the one used on Atari’s Asteroids video game.
Keeping track of the vehicle’s direction and distance traveled was the job a pair of sensors. A fluxgate compass mounted on the vehicle’s rear windshield kept track of heading relative to magnetic north, while a pair of Hall-effect sensors mounted to the non-driven wheels counted off the miles. The wheel sensors also provided additional vector data by keeping track of the difference in rotational speed as the vehicle cornered.
Mass storage for the map data was another matter entirely. Hard drives of the day were expensive and bulky and singularly unsuited for life in the trunk of a car. CD-ROMs were years in the future, and floppy drives didn’t have the capacity needed to hold a usably large block of map data. After much experimentation, Honey’s team settled on a modified version of the standard audio cassette tape drive. A high-speed, random access drive using ruggedized cassettes was placed within reach of the driver, who would need to swap tapes when the limits of a particular map block were reached. Each cassette held 3.5 megabytes, which was pretty impressive at the time.
The Topology of Tapes
But exactly how to populate those tapes with maps was by far the thornier problem. Honey had an acquaintance working at the United States Census Bureau on digital mapping, Marvin White, and persuaded him to join the team. Together with teams of digitizers, they turned public domain paper maps into digital models, using scanners and custom digitizing software. They started with the area around the company’s Silicon Valley headquarters and expanded to major metropolitan areas around the U.S.
Storing the data on the tapes turned out to be a major challenge, and a breakthrough in storage technology. White’s knowledge of digital mapping and the mathematical field of topology led to a hierarchical approach to storing the map data, where the physical location of the data needed for the next turn or waypoint was most likely stored very close to the current tape position. This made Etak’s geocoding algorithms much more efficient than anything that had come before, and would be the key to the long-term success of the company after the GPS revolution.
Etak’s first product, the Navigator, came in two flavors. Model 450 had a small 4.5″ vector display and retailed for $1,395, while the Model 700 sported a spacious 7″ screen and a $200 premium. Each map cassette went for $35. Given that six tapes were needed just for the Bay Area map, the Etak was not exactly consumer-friendly. Still, it had a number of deep-pocketed early adopters, including Michael Jackson and former child star Gary Coleman. In the end, though, the consumer market didn’t create nearly the demand as the public service and commercial transportation markets, which were attracted to street-level detail provided by Etak’s geocoding system.
With something like 5,000 units sold by the late 80s, the days were numbered for Etak’s Navigator. As the U.S. government continued to build out the NAVSTAR global positioning system, it was clear that what was once a closely held military secret would one day be opened up to public use, and Etak saw the writing on the wall. They realized that the true value in their company was the digital map data, and in a move many companies would not have had the guts to take, they got out of the hardware business altogether and focused on their digital maps.
Certain readers will likely remember that early Mapquest maps bore a small Etak copyright, and with the eventual sale of the company to TomTom, their mapping technology lives on to this day. Etak Navigators may look quaint by today’s standards, but the technology Stan Honey developed unlocked digital mapping and set the stage for the GPS revolution that soon followed.