Who Needs GPS? The Story of Etak's 1985 Car Navigation System
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Re: Who Needs GPS? The Story of Etak's 1985 Car Navigation System
#2Interesting to read about alternative, non-centralized, forms of navigation. I wish modern cars which already have all the necessary sensors would use this method as a fallback, since GPS reception is not always available.
Re: Who Needs GPS? The Story of Etak's 1985 Car Navigation System
#3There was also Honda's Gyrocator a few years earlier:
http://world.honda.com/history/challenge/1981navigationsyste...
Re: Who Needs GPS? The Story of Etak's 1985 Car Navigation System
#4Interesting to read about alternative, non-centralized, forms of navigation. I wish modern cars which already have all the necessary sensors would use this method as a fallback, since GPS reception is not always available.
It would also be helpful in case of a hacking event: if the car's local sensors deviate from the gps data significantly, that should throw up a red flag to the car and driver.
Re: Who Needs GPS? The Story of Etak's 1985 Car Navigation System
#5Interesting to read about alternative, non-centralized, forms of navigation. I wish modern cars which already have all the necessary sensors would use this method as a fallback, since GPS reception is not always available.
I think some smartphone navigation apps do temporary dead reckoning, using the accelerometers that are built into the phone.
Dead reckoning using just acceleration data loses accuracy quickly. Using turns to reset position is a really good idea. I think I've seen my iPhone do a similar "recovery" procedure when it gets a little off track.
Re: Who Needs GPS? The Story of Etak's 1985 Car Navigation System
#6FYI, here is a part which is still relevant today:
"the system continuously ironed out accumulated errors over time by comparing actual distances driven and turns made with road shapes on the map. Honey calls the technique "augmented dead reckoning."
That means driving through a long stretch of straight highway could begin to trip up Etak's system, since there were no turns and no distinct roads for the computer to algorithmically seize upon. If that happened, the driver could manually reposition the car cursor onto a location on the map using controls on the display."
Those things work, but they are barely "good enough". The biggest problem is, it is easy to lose your position if you are in the city -- maybe you had a few sharp turns, went around the parking cars a couple of times. And once this happens, the system is unlikely to correct itself, your only way will be to manually set position, which most people will not do.
Re: Who Needs GPS? The Story of Etak's 1985 Car Navigation System
#7There was also Honda's Gyrocator a few years earlier: http://world.honda.com/history/challenge/1981navigationsyste...
I remember Alpine electronics had something very similar. I wonder if it was a joint effort?
Re: Who Needs GPS? The Story of Etak's 1985 Car Navigation System
#8Interesting to read about alternative, non-centralized, forms of navigation. I wish modern cars which already have all the necessary sensors would use this method as a fallback, since GPS reception is not always available.
Vehicle speed and steering position are available through OBDII. And inexpensive Bluetooth OBDII interfaces are available. But I don't think that navigation app developers have done anything to take advantage of that data for dead reckoning input.
Re: Who Needs GPS? The Story of Etak's 1985 Car Navigation System
#9I saw Etak back in its early days, and Stan Honey gave me a demo. I still have one of their rate gyro/2D level units, and a compass unit. There's a motor driving a spinning disk, which warps slightly when the unit is turned, and sensors to detect the warp. The level, for sensing which way is down, is a sealed cup of liquid with the liquid height sensed with four capacitor plates outside the cup. The liquid was proprietary, chosen to not slosh under automotive movement. The whole thing is the size of a soda can. The compass is a 2-axis magnetometer, about 2 inches square. It wasn't mounted on a window; it had to be mounted in the horizontal plane, preferably far from metal.
The original Etak units always had the map oriented with north at the top. That was the way sailors used maps. Honey said they'd discovered that about 20% of the population could not cope with a map that wasn't aligned with the direction they were going, which is why they started rotating the map based on vehicle travel. Now everybody does that, and that's why.
Re: Who Needs GPS? The Story of Etak's 1985 Car Navigation System
#10FYI, here is a part which is still relevant today: "the system continuously ironed out accumulated errors over time by comparing actual distances driven and turns made with road shapes on the map. Honey calls the technique "augmented dead reckoning." That means driving through a long stretch of straight highway could begin to trip up Etak's system, since there were no turns and no distinct roads for the computer to a…
No, Etak could recover position after you made a few turns, unless you were in a city with a very regular grid. The recent path would be matched against the map to find the best match. When Honey demoed the system to me, he drove around a vacant lot in Menlo Park to force it to lose position, and then it recovered after a few turns.