THE INSTITUTEWith smartphones and built-in GPS, many drivers now take in-car navigation for granted. But Honda developed a navigation system in 1981—14 years before GPS was fully operational. The company’s Electro Gyrocator [above] was the world’s first map-based automotive navigation system.
The system has been named an IEEE Milestone. Administered by the IEEE History Center and supported by donors, the milestone program recognizes outstanding technical developments around the world.
Sold as an option for the 1981 Honda Accord and Honda Vigor vehicles, the Electro Gyrocator was based on inertial navigation technology using gyro and mileage sensors.
The vehicle’s location was represented by a moving dot on a 15-centimeter cathode-ray-tube display, with transparent road-map sheets overlaying the screen to show the driver where the car was on the road. The CRT display was mounted on the dashboard.
The route was displayed on the green screen; the vehicle position (a large round mark) and vehicle direction (a cross) were displayed at the edge.
Honda developed a number of devices to make the Electro Gyrocator work, including a gyroscope that had two wires in a stream of circulating helium. When the vehicle moved straight ahead, helium hit both wires equally, keeping them at the same temperature. When the vehicle turned, the flow of helium deviated to produce a temperature difference between the two wires. An onboard computer could detect that difference and translate it into directional information. Engineers at Honda designed and built the computer as well as its operating system.
Using the data plus mileage data from a sensor attached to the transmission, the 16-bit computer calculated the car’s position and direction of travel, with brief intervals between calculations. Calculated results were written in a data table, enabling the display to enlarge, reduce, and rotate pictures of traveled courses shown on the screen at the touch of a button.
At the time, it was impractical for the onboard computer to store all the data needed for digitized maps, so Honda worked with a mapmaker to produce transparent overlays for the system. When the route traveled reached the edge of a map overlay, the driver or passenger could switch it out for another. Inertial navigation is not as accurate as GPS, but the driver could manually adjust the map’s position and angle, and the position of the dot, to keep the dot on the map.
The helium gas-rate gyroscope and other technologies developed for the Gyrocator led to several patents. In addition, IEEE Member Tsuneo Takahashi, a researcher at Honda during the system’s development, received the 2013 IEEE Medal for Environmental and Safety Technologies “for pioneering the development of navigation technology in automobiles.”
The Electro Gyrocator was offered as an upgrade for late-1981 models. The feature cost US $2,746 (more than $7,000 in today’s money)—almost a quarter of the car’s total price.
The Honda Electro Gyrocator was honored on 2 March during a ceremony at the Honda Collection Hall, in Motegi, Japan. A plaque mounted in an exhibition room reads:
The world’s first map-based automotive navigation system, ‘Honda Electro Gyrocator,’ was released in 1981. This system was based on inertial navigation technology using mileage and gyro sensors. It pioneered the on-board display of the destination path of a moving vehicle on overlaying transparent road-map sheets, and contributed to the advancement of automotive navigation systems.
This article was written with assistance from the IEEE History Center, which is partially funded by donations to the IEEE Foundation.