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Subject: Re: Recalculating . . .


Author:
Buggage
[ Next Thread | Previous Thread | Next Message | Previous Message ]
Date Posted: 02:23:03 10/26/14 Sun
In reply to: Wes 's message, "Recalculating . . ." on 13:25:35 10/14/14 Tue

I run a towing company here in the Shenandoah Valley of Va. About once every two weeks or so, I get a call from someone, usually driving a big truck, who has managed to blindly follow their GPS and get stuck onone of our goat paths. The all time best one was last year, when I ended up winching a trailer (loaded of course) off an embankment, and then backing the truck & trailer out, about 2 miles to the hard surfaced road. I love folks who blindly follow the GPS, it's as if they turn the box on, and turn their brain off.

>Another column picked up from the paper. I've
>touched it up to de-emphasize the local angle a
>little, but other than that it's absolutely true.
>
>-- Wes

>
>
- - - - - - - - - - - - - - - - - -
>-

>
>Someone recently gave my wife a GPS system. She’s used
>it a little, but I haven’t very much, since I rarely
>drive anywhere these days when I don’t know where I’m
>going because I’ve been there before. Oh, once in a
>while I will go to a race track I’ve never been to
>before and I have to glance at a map, but that’s
>pretty rare.
>
>The other day I had to drive her car up to a town I'll
>call Flatburg. I was by myself, so I thought I’d give
>the GPS a fair trial. Now, I know how to get to
>Flatburg. I’ve known it for fifty years or more, so it
>wasn’t as if I really needed the help. To get to
>Flatburg, you drive north up the highway until you get
>to the interstate, go west, and wait until you get to
>the sign that says “Flatburg.” Very simple. Even a
>child could do it. Right.
>
>I managed to get the thing turned on somewhere north
>of town on the highway. That’s something I don’t
>recommend trying to do while you’re driving by
>yourself, by the way. Almost as soon as I had it on, a
>girl’s voice told me to turn right on a small dirt
>road.
>
>“You’re crazy,” I yelled at the stupid machine. “Why
>would I want to go down a dirt road a mile out of the
>way when where I’m going is right ahead of me on the
>highway?”
>
>So, I ignored it. After I passed the dirt road, in a
>rather snotty voice the machine said, “Recalculating,”
>but in a tone I took to mean, “Why didn’t you listen
>to me the first time, stupid?”
>
>In the next five miles or so it managed to keep from
>sending me down every cross road I passed, but after
>that it didn’t get a thing right. Not once. I would
>have shut the stupid thing off, except I sort of
>wanted to see just how bad it was going to be. The
>answer was “not merely bad, but downright awful.”
>
>The dumb machine tried to send me off course at every
>intersection we came to. Every one! Once it tried to
>send me down a road that was abandoned when I was a
>kid. You might have been able to get down it in a Jeep
>with four-wheel drive and a chainsaw. Another time it
>tried to get me off at an intersection that never
>existed with a road that didn’t cross.
>
>By now, I was laughing at every wrong intersection,
>sometimes shouting things like “You @#$%^&* idiot!” at
>the machine. (Yes, I talk to machines. I’ve always
>done it. Get over it.)
>
>It did get the exit from the interstate at Flatburg
>correct -- but only because the dumb machine had been
>trying to get me off the interstate at every
>intersection from the highway onward. That counts as a
>“little boy who cried wolf” problem. Even that didn’t
>count, since as soon as I was on the side road, it
>tried to get me to go back east on the interstate.
>
>It did miss trying to send me down a few wrong side
>streets once I was in Flatburg, but only a few. I
>finally hit a point at an intersection where my
>destination was clearly in sight in the block to the
>left. You guessed it: it sent me to the right.
>
>Now, my son-in-law has pointed out that the machine
>may have inadvertently been set to the wrong
>destination. I don’t think so; I had it set for a
>destination that was already on the machine and there
>weren’t a lot of choices.
>
>I will say the machine was pretty good about telling
>me where I was. Telling me how to get where I wanted
>to go, it was abysmally, hysterically wrong. So, I
>learned something from that: don’t trust GPS
>directions. I mean, I knew where I was going, so I
>knew it was wrong. But what if I didn’t know where I
>was going?
>
>I may be old-fashioned and cantankerous, but I think
>I’ll stick with paper maps, thank you.

[ Next Thread | Previous Thread | Next Message | Previous Message ]

Replies:
[> Subject: Re: Recalculating . . .


Author:
Kirby Lambert
[ Edit | View ]

Date Posted: 16:04:01 10/28/14 Tue

I remember back in 2002 I was in New Jersey for the first time. It was after dark and I was going from the Newark airport to Berkley Heights. I had printed maps be fore I left so I was covered. I tried the Hertz Neverlost system just for grins. It showed that I was driving in the river not on the highway. Although I did use the system succesfully over a number of years from that point on I called it Everlost!

Kirby


>Another column picked up from the paper. I've
>touched it up to de-emphasize the local angle a
>little, but other than that it's absolutely true.
>
>-- Wes

[> [> Subject: Re: Recalculating . . .


Author:
Mikey
[ Edit | View ]

Date Posted: 01:21:48 10/30/14 Thu

>I remember back in 2002 I was in New Jersey for the
>first time. It was after dark and I was going from the
>Newark airport to Berkley Heights. I had printed maps
>before I left so I was covered. I tried the Hertz
>Neverlost system just for grins. It showed that I was
>driving in the river not on the highway. Although I
>did use the system succesfully over a number of years
>from that point on I called it Everlost!
>
>Kirby


You were driving in the river due to a feature called "selective availability" or just "SA".

"Selective availability" was an intentional degradation of public GPS signal accuracy supposedly included in the design for national security reasons.

When switched on, SA allowed the system controllers to offset the displayed location by a selectable amount in a selected direction, usually either east or west.

My first personal experience in using GPS was in a Hertz rental in 1999 or 2000, in the San Francisco Bay area. My passenger said that we were "driving in the weeds" that paralleled the highways.

SA was switched off in September 2007. A friend of mine told me that he was driving on highway 15 between Los Angeles and Las Vegas at the moment when it was actually switched off and the icon representing his car on his Magellan receiver screen "swept" from 500 feet east in the weeds to about 1000 feet west into the desert, then "jumped" to the exact lane he was in and stayed there.

More info:
http://www.cs.cmu.edu/~sensing-sensors/readings/GPS_History-MR614.appb.pdf

A bit of history:
My first exposure to what is now called GPS was at an amateur radio club meeting in the mid 1980s, where the speaker was one of the engineers that developed the system (and who was also a licensed ham). The presenter mentioned that there was a poster on the wall of their R&D lab showing the Q-developed locator screen in center console of James Bond's Aston Martin (as shown in the 1964 movie Goldfinger).

A number of photos were shown in the ham radio club presentation. One was of the first usable vehicular receiver - all it displayed was latitude and longitude on a set of numeric displays.

Another of the more interesting photos was of a mobile GPS mapping display receiver demonstration vehicle - a large van with three racks of equipment containing a CRT-based graphics display terminal, it's supporting hardware, a couple of rack-mount disk drives, a minicomputer system to do the GPS location calculations, and an attached external floating point processor to help it do that. The third rack held nothing but satellite radio receivers.

There was a satellite receiving antenna mounted on an attached trailer - and under the antenna was mounted a 15kw 240v generator to power the equipment racks, the disk drives plus the three RV air conditioners (installed in the roof of the van).

The fragility of the disk drives of the day precluded the unit from being used while in motion - any vertical movement, including rough asphalt or even bad tire vibration would crash the disk heads into the spinning platters.

From the time the van came to a stop to the time the operator could generate a location was about 15-20 minutes - assuming the generator actually started, and there were no computer or satellite receiver glitches.

Mike
[> [> [> Subject: Re: Recalculating . . .


Author:
Dmitri
[ Edit | View ]

Date Posted: 09:01:27 10/30/14 Thu

My research indicates that Selective Availability was actually turned off in May of 2000 (the end of Slick Willy Clinton's administration). My own experimentation with it (for wilderness canoeing and hiking) before and after that time period, showed it had settled down a lot during accuracy checks with my own little hand-held unit (not for automobile navigation). I could paddle my canoe away from a beach and then follow a track back and take out on my footprints made when leaving the beach. Before that, I could be as much as a quarter mile off or more (several hundred yards away), though it was often much less than that extreme.

Dmitri

>>I remember back in 2002 I was in New Jersey for the
>>first time. It was after dark and I was going from the
>>Newark airport to Berkley Heights. I had printed maps
>>before I left so I was covered. I tried the Hertz
>>Neverlost system just for grins. It showed that I was
>>driving in the river not on the highway. Although I
>>did use the system succesfully over a number of years
>>from that point on I called it Everlost!
>>
>>Kirby
>
>
>You were driving in the river due to a feature called
>"selective availability" or just "SA".
>
>"Selective availability" was an intentional
>degradation of public GPS signal accuracy supposedly
>included in the design for national security reasons.
>
>When switched on, SA allowed the system controllers to
>offset the displayed location by a selectable amount
>in a selected direction, usually either east or west.
>
>My first personal experience in using GPS was in a
>Hertz rental in 1999 or 2000, in the San Francisco Bay
>area. My passenger said that we were "driving in the
>weeds" that paralleled the highways.
>
>SA was switched off in September 2007. A friend of
>mine told me that he was driving on highway 15 between
>Los Angeles and Las Vegas at the moment when it was
>actually switched off and the icon representing his
>car on his Magellan receiver screen "swept" from 500
>feet east in the weeds to about 1000 feet west into
>the desert, then "jumped" to the exact lane he was in
>and stayed there.
>
>More info:
> >href="http://www.cs.cmu.edu/~sensing-sensors/readings/G
>PS_History-MR614.appb.pdf">http://www.cs.cmu.edu/~sensi
>ng-sensors/readings/GPS_History-MR614.appb.pdf

>
>A bit of history:
>My first exposure to what is now called GPS was at an
>amateur radio club meeting in the mid 1980s, where the
>speaker was one of the engineers that developed the
>system (and who was also a licensed ham). The
>presenter mentioned that there was a poster on the
>wall of their R&D lab showing the Q-developed locator
>screen in center console of James Bond's Aston Martin
>(as shown in the 1964 movie Goldfinger).
>
>A number of photos were shown in the ham radio club
>presentation. One was of the first usable vehicular
>receiver - all it displayed was latitude and longitude
>on a set of numeric displays.
>
>Another of the more interesting photos was of a mobile
>GPS mapping display receiver demonstration vehicle - a
>large van with three racks of equipment containing a
>CRT-based graphics display terminal, it's supporting
>hardware, a couple of rack-mount disk drives, a
>minicomputer system to do the GPS location
>calculations, and an attached external floating point
>processor to help it do that. The third rack held
>nothing but satellite radio receivers.
>
>There was a satellite receiving antenna mounted on an
>attached trailer - and under the antenna was mounted a
>15kw 240v generator to power the equipment racks, the
>disk drives plus the three RV air conditioners
>(installed in the roof of the van).
>
>The fragility of the disk drives of the day precluded
>the unit from being used while in motion - any
>vertical movement, including rough asphalt or even bad
>tire vibration would crash the disk heads into the
>spinning platters.
>
>From the time the van came to a stop to the time the
>operator could generate a location was about 15-20
>minutes - assuming the generator actually started, and
>there were no computer or satellite receiver glitches.
>
>Mike
[> [> Subject: Re: Recalculating . . .


Author:
IanS
[ Edit | View ]

Date Posted: 17:01:55 11/03/14 Mon

A group of then diving enthusiasts we combined to buy an early GPS receiver that had an interface port. Whilst tied up in port we connected it to a plotter and the plotter plotted a near perfect circle with random dots with our actual position at the centre.
As we normally set off from the same location we found that when the USA had problems abroad SA was switched off our position was correct. Presumably it was switched off so that its forces could use many cheep commercial sets instead of the few milspec sets in high value vehicals.

>I remember back in 2002 I was in New Jersey for the
>first time. It was after dark and I was going from the
>Newark airport to Berkley Heights. I had printed maps
>be fore I left so I was covered. I tried the Hertz
>Neverlost system just for grins. It showed that I was
>driving in the river not on the highway. Although I
>did use the system succesfully over a number of years
>from that point on I called it Everlost!
>
>Kirby
>
>
>>Another column picked up from the paper. I've
>>touched it up to de-emphasize the local angle a
>>little, but other than that it's absolutely true.
>>
>>-- Wes


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