Before There Was GPS — Part 1
Before There Was GPS.
(Last updated 9 October, 2017)
Recently I came across this article about a fellow name of Stan Honey who who discussed his life and career during his keynote speech at the recent ION GNSS+ 2017 plenary.
The ION (Institute of Navigation) GNSS+ is the world’s largest technical meeting and showcase of GNSS technology, products and services.
And Stan Honey was a founding father of a company called Etak. (unlike today’s common practice of naming companies after sophisticated acronyms to form a company name, Etak is a Polynesian word meaning “navigation”. Simple.
But the technology wasn’t simple and when you consider this was a live, working, in-dash navigation system back in 1985, long before GPS was anything except a classified military “developmental” system.
A good writeup here:
Etak Was Pretty Darn Impressive
Here’s what Wikipedia has to say about the original Etak system
The original Etak Navigator was a specially-packaged Intel 8088-based system with 256K RAM, 32K EPROM, 2K SRAM, and a cassette tape drive on which digital maps and some of the operating system were stored.
The tapes could not hold much information, so for the Los Angeles area, for example, three to four tapes were required. When an edge of the map was reached, the driver needed to change cassette tapes to continue benefitting from the accuracy of map-matching.
The system had a tape drive that was designed to be installed within easy reach of the driver, so this could be done while driving. The map moved on the screen as the car was driven, but instead of the color raster graphics display of today’s systems it had a green vector display.
The Navigator had address geocoding (the ability to convert a street address to a latitude/longitude point). It worked by using a digital compass mounted somewhere in the car (typically inside the headliner) and two wheel sensors mounted on the non-driven wheels (with magnetic strips installed on the wheel rims themselves).
The system used map-matching augmented dead reckoning. The user entered the location of the car where it was first installed, and took it on a short calibration drive. From then on, the system self-corrected: error accumulated through dead reckoning could usually be reduced by checking to see if the current location and direction of movement corresponded to a street in the map data. These and other techniques developed by Etak would perhaps now be viewed as very high-end features for a car navigation system.
Very High End Features Indeed, IMO
I’ve seen several reports that the Etak system could repeatedly achieve 50 meter accuracy if the drive took care to keep it upgraded. 20 years later, in 2005, early car navigation GPS-based systems were doing well to attain a 30 meter accuracy average.
Just A Few Years Before Etak
I was doing test, development and integration work for the USAF on a new system (new to the USAF, that is) called Carousel Inertial Navigation.
Each Carousel system needed a control head the size of today’s in-dash video screens and a 75 pound “black box” located in an equipment bay below the aircraft cockpit. a complete system ran about $500,000 USD (in 1980 dollars) and could, on a good day, average about 185 meter accuracy.
I Wish I Could Have Been There For Stan’s Speech
I did read somewhere that when one publishes a blog like this s/he should have a point in mind before writing an article. So what’s my point here?
Actually I’ll make two of them:
First there were some really complex but useful navigation systems before GPS and,
Secondly, its hard to imagine the usefulness and accuracy we have available at our finger tips today via GPS.
Should I write more about the days Before There Was GPS?