The Plane Crash That Gave Us GPS

HughPickens.com writes: Sarah Laskow reports at The Atlantic about the aftereffects of the KAL 007 incident, where the Soviet Union shot down a passenger plane on September 1, 1983. All 269 passengers were killed, including a U.S. Congressman en route from New York City to Seoul via Anchorage. At first, the Soviet Union wouldn't even admit its military had shot the plane down, but the Reagan administration immediately started pushing to establish what had happened and stymie the operations of the Soviet Aeroflot airline. It is widely believed that Korean Air Lines Flight 007 was already well off course when the crew routinely radioed that it was over its proper ''way point,'' or checkpoint, at a 90-degree angle to Shemya Island in the West Aleutian chain. Ultimately, the Boeing 747 jumbo jet cut across the lower tip of the Kamchatka Peninsula and the southern tip of Sakhalin Island, where it was shot down by a Soviet fighter.

This resulted in President Reagan making a notable choice. While this choice was reported at the time, it was not the biggest news to come out of this event: Reagan decided to speed up the timeline for civilian use of GPS. The U.S. had already launched almost a dozen satellites into orbit that could help locate its military craft, on land, in the air, or on the sea. But the use of the system was restricted. Now, Reagan said, as soon as the next iteration of the GPS system was working, it would be available for free. It took more than $10 billion and over 10 years for the second version of the U.S.'s GPS system to come fully online. But in 1995, as promised, it was available to private companies for consumer applications. It didn't take long, though, for commercial providers of GPS services to start complaining about the system's "selective availability" which reserved access to the best, most precise signals for the U.S. military. In 2000, not that long before he left office, President Clinton got rid of selective availability and freed the world from ever depending on paper maps or confusing directions from relatives again.

Comments

Thank you, Presidents Reagan and Clinton.

[jeffb (2.718)]

I'm sure any Slashdot post invoking both of these political figures will attract only the most calm and well-reasoned discussion.

Re:Thank you, Presidents Reagan and Clinton.

[ArcadeMan]

These guys are just an actor and a saxophone player, what's there to talk about?

Re:Thank you, Presidents Reagan and Clinton.

[cold fjord]

The actor was actually a union boss that took on the studios for the benefit of the actors, and won.
   

Re:Thank you, Presidents Reagan and Clinton.

[SJHillman]

I have no doubt that one of them was a great actor, but I'm not so sure about the other one's saxophone skills - did Reagan ever even touch a sax?

Re:Thank you, Presidents Reagan and Clinton.

[gstoddart]

No, but Clinton definitely did not have sax with Monica Lewinsky. ;-)

She helped him change his reed, and wiped off end.

It was all a misunderstanding.

timeline

[afidel]

But in 1995, as promised, it was available to private companies for consumer applications

Say what? There were consumer GPS receivers in the late 1980's, in fact in the first Gulf War (2 August 1990 – 28 February 1991) many soldiers used commercial units purchased from US retailers because the crypto hardened milspec units were in such short supply. In fact I'm not sure what they're referring to with the 1995 date, since the biggest change wrt consumer use was Clinton's order to permanently disable selective availability, but that wasn't until 2000.

Re:timeline

[dj245]

But in 1995, as promised, it was available to private companies for consumer applications

Say what? There were consumer GPS receivers in the late 1980's, in fact in the first Gulf War (2 August 1990 – 28 February 1991) many soldiers used commercial units purchased from US retailers because the crypto hardened milspec units were in such short supply. In fact I'm not sure what they're referring to with the 1995 date, since the biggest change wrt consumer use was Clinton's order to permanently disable selective availability, but that wasn't until 2000.

I believe the 1995 date refers to the date at which the GPS satellite constellation was completed, in other words when the full set of 24 satellites was operational. You need just 4 signals to get a cold location fix without making assumptions, but prior to 1995 it is probable that in some parts of the world, 4 satellites were not visible at certain times. Prior to 1995 the system wasn't complete.

I can't find any information in 1980s GPS units, but given the nature of the calculations required to obtain a locational fix, and the processing power available in that era, they must have been excitingly expensive.

Re:timeline

[tlhIngan]

. During the gulf war public use was actually turned off so the military could have better access. So I don't know how well those commercial ones you speak of worked. Then in 1993 it was back on

No, public access was never turned off. You need the "public" (C/A for Coarse Acquisition) signal even to get the P (precision?) military signal.

A military receiver first acquires the C/A signal, like a civilian receiver. it needs this in order to get all the timing locked up so it can then acquire the P signal to get the necessary correction information.

During the first Gulf War, military GPS units were hard to get, so they turned off selective availability so soldiers could use the civilian GPS units they brought with them. Then once the war was over, they turned selective availability back on to make the results imprecise.

All GPS units need the public (C/A) signal first before they can do anything.

Re:timeline

[dbc]

You are right about GPS being available, but with a limited constellation. But the prices weren't awful -- in the sailing world they were comparable with other navigation electronics. I learned to sail during the transition -- people still had LORAN receivers, and long-haul sailors still needed to know celestial navigation, but a GPS was certainly a gizmo you could afford for you boat. But sailors crossing the Pacific might go hours without a GPS fix, because not enough birds were in view.

Original Article?

[IMarvinTPA]

So, which of these links is the original article the large excerpt is from?

I really wish OA was linked separately at the top or something. Why was it the 3rd link? Why not anchor it on "The Atlantic" in the first line?

http://www.theatlantic.com/tec...

Thanks...

Re:Paper maps and confusing directions?

[Russ1642]

GPS doesn't work in caves either. GPS sucks and should be abandoned. What a waste of resources getting those stupid satellites up there.

Re:Paper maps and confusing directions?

[Richard_at_work]

GPS isn't a substitute for actually thinking about stuff as you do it.

Re:If only that were enough...

[mi]

Or the shooting down of airliners by Americans...

That was in 1988 — before Reagan-intensified initiative was completed and GPS came into common usage.

Or the Ukrainians - http://en.wikipedia.org/wiki/S...

Interestingly enough, the Ukrainians responsible for that disaster are currently Russians — the missile came from Crimea...

Re:Paper maps and confusing directions?

[gstoddart]

As far as confusing directions go talk to the people, if they are still alive, who got stuck or drove their car over cliffs etc

You know, you're still operating the damned car, and you're still responsible for where it goes.

If you drove your car off a cliff because your GPS told you to go straight off a cliff, you would have driven off a cliff sooner or later anyway.

Because apparently you don't think things through very well.

Re:Paper Maps

[Russ1642]

GPS doesn't tell you how to get anywhere. It tells you where you are and that's it.

Not how I remember it

[mbone]

And I was there.

Reagan may have sped up this or that, but

- GPS was designed as a mixed civilian / military system. That's why there WAS selective availability (AKA SA - fuzzing of civilian accuracy). SA was designed to give 30 meter accuracy, and lots of civilian needs could still be met with that accuracy.
- Lots of us wondered why KAL 007 didn't have GPS - a 30 meter error was tiny compared to their actual error.
- There was intense commercial interest in GPS in 1983.
- Use of GPS has always been free - even under SA, you either had the keys to decrypt it, or not.
- The real big push for commercial development came during the first Gulf War, when we didn't have nearly enough military units, and so Charley Trimble (Trimble Navigation - and others) got a huge order to send outdoor units to the Persian Gulf ASAP - AND they turned off Selective Availability (globally, for the duration).

The part about Clinton and SA was accurate. However, by the 90's. a lot of people were working on work-arounds for SA. SA implemented by making each satellite's clock go fast and slow deliberately, so you could fix it by having a ground station with a good clock looking at the same satellite, and sending corrections, so removing SA wasn't as big a deal as it would have been in 1985.

And all it took was a dead Congressman

[Opportunist]

Just think what wonders we could have if we shot them all.

Re:If only that were enough...

[Shakrai]

Not that I normally defend US military action... but come on.

Why was the US warship there in the first place? Iran was at war with Iraq, and had started to attack US oil tankers off shore. The US Military sent US Naval ships as escorts. Then Iran started actively attacking US warships. That ship had been under attack by Iranian gun boats just and hour earlier and that plane had taken off from a based that F14 attack craft were routinely operated out of.

I do normally defend US military action but I will not defend the shoot down of the Iranian airliner. Captain Rogers was a trigger happy asshole, with a poorly trained crew that was oblivious to what their instruments were reporting. The instruments aboard the USS Vincennes reported a climbing aircraft that was squawking Mode III (Civilian) IFF; the crew somehow interpreted this as a descending aircraft squawking a military code, which would actually be a legitimate threat to the ship, but that was not what was reported by their instruments.

If you want to be generous to Captain Rogers you can call it an example of scenario fulfillment but I'm not willing to give him that much benefit of the doubt. The Commanding Officer of at least one neighboring ship thought he was reckless and trigger happy (*) and his crew's failure to properly operate their ship represents a gross failure of training and accountability that the Captain of said ship is ultimately responsible for.

(*) See the various media interviews of Commander Carlson, Captain of the USS Sides, which was assigned to the same mission and tracked Iran Air Flight 655 on her own radar prior to the shootdown.