Detroit maps the way to never getting lost again

Will cars of the future come with video games?

Don't count on it. But electronic engineers in both the United States and Japan are already hard at work developing navigational systems that may be as much fun as a video game, with the functional value of helping motorists find unfamiliar destinations without getting lost.

Toyota, Nissan, and Honda are already marketing cars in Japan with relatively simple navigational equipment, while Ford Motor Company and General Motors are demonstrating experimental systems that are considerably more sophisticated.

What the motorist generally sees with these systems is a small TV-like screen on the instrument panel or console which shows an illuminated map of the areas he's traveling through, plus three prominent dots indicating his point of departure, current location, and destination.

Further, there will probably be digital readouts telling the distance remaining on the trip and percentage of route yet to be covered.

Partly because of the relatively small size of Japan, the Japanese companies have elected to produce self-contained or ''dead reckoning'' systems which rely entirely on internal components and simply keep the driver informed of the directions and distance he has traveled.

The experimental US systems, by contrast, combine this self-contained equipment with some external locator, either a satellite or an earth-based transmitting station, which periodically locates the vehicle more precisely.

The externally oriented systems cost more money, but they're much more suited to the US and are less subject to ''drift,'' the gradual loss of accurate positioning. But all the systems have their limitations and all have ''black boxes'' that could probably be repaired only by returning them to the factory.

Toyota's Navicom system was introduced on Celicas sold in Japan in mid-1981 and has since been made optional on the Crown and Corona. Designed to facilitate driving in unfamiliar locales, Navicom presents data continuously on the direction, distance, and percentage of straight-line distance attained.

When navigating by Navicom, the driver first puts in east-west and north-south distances to the destination point. Along the route, 16 luminous diodes act as compass-needle points, providing a continuous display of the gap between present vehicle position and destination.

Distance to destination and percentage of trip remaining are also supplied digitally.

To start a trip, the driver uses a map to measure the east-west and north-south distances, feeding this information into the microprocessor. The computer then calculates the straight-line distance between departure point and destination, as well as the direction of the destination.

A terrestrial magnetic sensor determines and reports continuously the direction the vehicle is traveling.

Honda's system is quite similar to Toyota's, except that it uses a helium gyroscope to keep track of the direction the vehicle is moving. This device employs a stream of ions which cools a heated wire. When the vehicle changes direction, the momentary inertia of the helium ions causes the hot wires to cool at different rates, thus indicating changes in direction.

Nissan's Skyline, a car not sold in the US, has a Driver Guide navigation system. The key components are the directional sensor, which determines the vehicle's direction, and a speed sensor, which reports the distance covered.

After the latitude and longitude of the starting location and the destination are put into the Driver Guide, the directional and speed sensors enable the system to keep track of and report the remaining distance and direction to the destination.

An automotive navigation system for use in the US is much more difficult to develop, because the US is so much wider than Japan. As a result, it's much more difficult to correct directional readings because compass variation - the difference between true north and magnetic north - differs so much from the East Coast to the West Coast.

Ford electronic engineers elected to solve this problem by developing a navigation system based on US Navy transit satellites that circle the earth on a polar orbit. Five of these satellites continually circle overhead in a sort of ''birdcage'' arrangement, sending navigational signals to all ships and vehicles about every 90 minutes.

The Navy launched these satellites in 1964 for the Polaris missile system. In 1967 they were released for civilian use. Many thousand commercial and pleasure ships now use the satellites for navigating.

Joseph Gormley, who took part in this early work as an employee of a Washington firm that assisted Johns Hopkins University in the program, now heads a group that's developing the satellite navigation system at Ford.

Gormley says the satellites continually transmit their positions, which the ships and the cars pick up. Using this information and a set of complicated equations, they can precisely locate themselves.

Ford's system consists of a 7-inch antenna, currently located in the middle of the roof, a distance sensor, an angular or directional sensor, and an electronic unit.

Down the road Gormley expects the Ford system to have some kind of a standby power unit that would permit the computational electronics to be done without engine power.

Asked who would use these systems, Gormley says they could be especially worthwhile for drivers of taxis and delivery trucks operating in large cities or anyone else who did considerable traveling in unfamiliar areas.

For cross-country travel, he envisions using some sort of a cassette containing the maps of local areas which would be displayed on the screen after being plugged into the electronic system.

While asserting it was too early to put a cost on the Ford navigation equipment, Gormley estimated that it might cost about as much as an automobile air conditioner.

General Motors is working on a variety of navigational systems. Its most promising unit keys on the government's Loran navigational system, which is used by the US Coast Guard for navigation.

Edward Mertz, Buick's chief engineer, says: ''Our experimental unit has a colored CRT (cathode ray tube) and a digital map of the surrounding territory in the car. As you drive along, a little dot on the CRT shows the car on the map, enabling the driver to know where he's located and which roads he wants to use.''

Mr. Mertz adds that an important element of the system is a ''memory'' in the microprocessor to record information about where the driver wants to go and where the vehicle actually is. This permits comparisons, enabling the minicomputer to determine distance and direction to the final destination.

GM also is exploring the satellite-based navigation system as well as systems that do not rely on external signals.

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