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Who owns GPS/Threats to the system


Guest The Bees

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Guest The Bees

I was explaining Geocaching to a colleague today when he asked a joking question, "Who do I sue if the system goes down and I'm stranded out in the woods? Microsoft? What corporation owns these things anyway?"

 

We both laughed but it got me to thinking about how much many of us really know about the GPS system. In my old job as a Senior Defense Analyst one of my responsibilities was to track the market potential for GPS equipment- from handhelds to the satellites themselves- for use by the worlds military.

 

Now, most everyone knows that our receivers receive signals from orbiting satellites, triangulate these signals, and display it as a lat/long location including an EPE from that location. Some things people don't know/forget about but should keep in mind are the following:

 

1- The GPS system and satellites are OWNED by the US Government and are under the direct control of the US military. The GPS system was designed for use by the US military with civilian use being a side problem. In all honesty, if the US military could have figured out a way to keep the signals entirely to themselves they would have, but the nature of how GPS works didn't allow for that.

 

2- The US can- at anytime- reinstitute the "dither" on the civilian channel or even shut down the signal. What one president gave us, another can take away- especially in times of crisis.

 

3- In case of war with an opponent who is also using GPS, the US military has plans to shut the system down. The system would be brought back online when US/Allied forces start a major offensive, etc. In other words, GPS signals would shut down and then come back on at seemingly random times.

 

4- GPS satellites and facilities are a viable military target. As such they can be attacked and destroyed with impunity in a war. This would obviously have the effect of severely degrading or destroying the system.

 

5- A few years ago the Russians did develop a rather small jammer capable of scrambling/blocking GPS signals. Some reports indicated that this jammer could "black out" hundreds of kilometers worth of territory at once. Arguably such a system would be used near the front lines, and I doubt many of us would venture onto a battlefield to log a cache and collect a Barney keychain. I just wanted to illustrate the types of threats that the GPS system faces now and in the future.

 

GPS manufacturers take these threats seriously enough that every single one of them, usually in there owners manual, have put in a disclaimer to the effect that it is the responsibility of the US Government to keep the system up and running (i.e. it's not their fault/problem if the system is shut down/destroyed and you can't get out of the woods/navigate the ocean/etc).

 

This is why I have stressed to anyone getting into the sport that they have some type of basic land navigation skill (i.e. being able to read a topo map and knowing the basics of compass usage). Especially if they don't have a good "direction sense" of where they came from in the woods.

 

However, I should point out that it is WAY more likely that you will lose a signal due to tree cover or having your batteries run out with no spares handy (Ok, how many on the boards have done that once? I'll be the first to sheepishly raise my hand), as opposed to some foe bursting a 20 kiloton warhead in space or sending a bunch of kinetic kill vehicles after the satellites.

 

Anyway, I hope that this little thread gives you all a little background of the GPS system, its owner and potential threats that could bring this sport and many other activities to a screeching halt.

 

Later

Mike B

 

The Bees

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Guest navdog

Yes,it is very important that everyone who relies on a GPS to still have basic map and compass skills. I think the wonder of this technology makes it too easy for finding a cache sometimes. I have spent a lot of time before gettting my GPS last year using maps and compasses for hiking and for scouting photo opps...(must have a thousand dollars worth of maps!). Thats why I enjoy the challenge of navigation.and travelling off the beaten path. The GPS makes it so much easier to wander all over the place to explore on your way to a destination or a cache... but thats where the danger of relying on the GPS comes in if you dont take a little time to check your map, compass or the position of the sun every so often... and then your GPS goes belly up!!! I am thinking of hiding some caches where you can't get a sat fix all the time so that you will have to travel part of the way to the cache usng a compass. Hopefully this will be more entertaining and challeging for those attempting it.

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Guest brokenwing

Mike, Mike, Mike.

 

Let's not forget that we are not the only users of the GPS system. The Transportation system is very dependent on GPS as well and I don't think the public would take kindly to planes falling out of the sky, or ships running aground everywhere.

 

Per the FAA:

"GPS is owned and operated by the U.S. Government as a national resource. DOD is the "steward" of GPS, and as such, is responsible to operate the system in accordance with the signal specification. The March 1996 Presidential Decision Directive, passed into law by Congress in 1998, essentially transferred "ownership" of GPS from DOD to the Interagency GPS Executive Board (IGEB). The IGEB is co-chaired by members of the Departments of Transportation and Defense, and comprised of members of the Departments of State, Agriculture, Commerce, Interior, and Justice as well as members from NASA and the Joint Chiefs of Staff. It allows for both civil and military interests to be included on all decisions related to the management of GPS.

 

DOD is required by law to "maintain a Standard Positioning Service (SPS) (as defined in the Federal Radionavigation Plan and the Standard Positioning Service Signal Specification) that will be available on a continuous, worldwide basis," and, "develop measures to prevent hostile use of GPS and its augmentations without unduly disrupting or degrading civilian uses." These strict requirements and current augmentation systems should actually make DOD use of the system transparent to the civil user. (Note: There will, necessarily, continue to be localized testing of the system by military and development teams but the testing will fall under strict notification guidelines of safety-of-life users such as Coast Guard and FAA).

 

U.S. transportation, public safety, economic, scientific, timing, and other users rely on GPS extensively. In aviation and maritime transportation, GPS is used for "safety of life" navigation and it is a critical system for these applications. DOD is the steward of the system, responsible to maintain the signal specification; the IGEB provides management oversight to assure that civil and military needs are properly balanced."

 

Could the government reinstitute SA? Yes, and they could also throw out the constitution. I'm not holding my breath that either one will ever happen.

 

Let's not worry about a really big what if.

 

Take care,

brokenwing

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Guest The Bees

LOL...

 

Sorry if I sounded like the voice of doom there Brokenwing! I completely agree with you in that I don't see SA being put back into operation. I was just trying to point out, in a brief manner, who owns the system and what could happen.

 

So many commercial enterprises rely on GPS technology worldwide that I'm sure there would be a HUGE outcry if the US were to put SA back on or even let the system decay.

 

However, I should point out that the failure of the system would not cause planes to fall from the sky, etc. While planes (I can't speak to how ships navigate/used to navigate) do use GPS to aid in navigation, the VOR/TAC system is still the primary means of how a plane gets from one place to another.

 

Respectfully

Mike B

 

The Bees

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Guest NightTide

I can give some marine info. All commercial ships use GPS information in many ways. The first and most basic is a GPS receiver, this may feed NMEA strings to many other devices such as radar, bottom machines( sonar ),VHF radios,EPERB's, chart ploters lets not forget auto pilots and the list goes on. All cable laying ships use GPS guided auto pilots to keep them on station as they lay and repair transoceanic cables and fiber optics. With all this ships still run aground, go figure.

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Guest jeremy

Regarding adding SA to all the satellites again during war times (or for any other security reason), I have some assumptions as to why this wouldn't happen -

 

1. The US Government has found a way to disrupt GPS technology during a skirmish, and has a backup geolocational tool to use in times of battle (to counter any other jamming system)

 

2. Differential GPS makes SA pointless, and technology would fix any errors introduced into the system. I believe SA was removed by the administration because inevitably it wouldn't matter.

 

3. Public outcry. The US public does not enjoy having their toys taken away.

 

I'm sure there are others, but my toaster strudel just popped out of the toaster.

 

Jeremy

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Guest The Bees

Peter,

 

Here ya go...

 

First a definition:

VOR - very high frequency omnidirectional range. A radio navigation aid operating in the 108-118 MHz band. A VOR ground station transmits a two-phase directional signal through 360ø. the aircraft's VOR receiver enables a pilot to identify his radial or bearing from/to the ground station. VOR is the most commonly used radio navigation aid in private flying. Increased accuracy is available in Doppler VORs (DVOR) which have replaced some VOR is the UK system. Also VORTAC, combined VOR and TACAN, and VOT, VOR test facility.

 

(NOTE: TAC or TACAN is the one used by the military- a completely different frequency is used. Many VOR stations are combined with TACAN stations as they are very similar.)

 

A good explanation of the system:

http://www.campbells.org/Airplanes/VOR/vor.html

 

A much more in-depth explanation:

http://www.navfltsm.addr.com/vor-appr.htm

 

A VOR station, from the air, looks like a white witches hat. Basically you fly your radial bearing by keeping you "needle" centered and a little "flag" will say "TO". AS you get close your VOR indicator will start to fluctuate. AS you pass over the station your "flag" will switch over to the "FROM" or "AWAY" tag- meaning your going away from it.

 

To get from place to place you would dial in the station you were heading to. WHen you pass over it you dial in your next station, etc. There are certain corridors designated between stations which are the "highways" of air travel. If you go to any decent airport they will have airmaps for sale. On the airmaps you can see these "highways" along with radial bearings from VOR station to VOR station.

 

This is how aircraft navigate- GPS is a nice adjunct but does not translate well into this "highway" system. It should be noted that VOR is used worldwide as a means of air navigation.

 

Hope this helps,

Mike B

 

The Bees

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Guest brokenwing

quote:
Originally posted by The Bees:

However, I should point out that the failure of the system would not cause planes to fall from the sky, etc. While planes (I can't speak to how ships navigate/used to navigate) do use GPS to aid in navigation, the VOR/TAC system is still the primary means of how a plane gets from one place to another.


 

Well, I admit that I was embellishing somewhat. I am aware that planes would not come crashing out of the sky without GPS. I do think the FAA?s plans for the future of GPS and WAAS will make aerial navigation much more dependent on GPS. Have you heard anything about that, and what do you think this means for the rest of us?

 

Thanks,

brokenwing

 

[This message has been edited by brokenwing (edited 28 July 2001).]

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Guest The Bees

Hiya Brokenwing!

 

I only know a little on WAAS. If/when it gets working it will be an excellent nav aid and it will have the ability to maybe, in time, supplant VOR.

 

However, a WAAS receiver would be prohibitively expensive and too bulky for general aviation for the foreseeable future. WAAS is also a US initiative although I understand Europe is interested in the concept. The only way WAAS will take hold is if the US and/or Europe will require flights into/out of the US and/or Europe to be WAAS capable. Then, over time, the rest of the world would catch up. My best guess for worldwide WAAS would be the 2040-2050 range.

 

As too how it will affect us, I *think* it will have little to no impact for us dirt grubbers. The WAAS stations will be designed to broadcast the "cleaned up" GPS signal to certain frequencies that will be used by aircraft. The current plan is for 25 WAAS stations around the US. Terrain and curvature of the earth would block the vast majority of these signals from us. However, nothing surprises me more than human ingenuity so it is quite possible that in 5-10 years we could see handheld accuracies of less than 5 feet using derivative WAAS technology.

 

For more info on WAAS here is the official FAA site:

 

http://gps.faa.gov/Programs/WAAS/waas.htm

 

Later

Mike B

 

The Bees

 

[This message has been edited by The Bees (edited 28 July 2001).]

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Guest peter

quote:
Originally posted by The Bees:

However, a WAAS receiver would be prohibitively expensive and too bulky for general aviation for the foreseeable future. WAAS is also a US initiative although I understand Europe is interested in the concept. ...

The WAAS stations will be designed to broadcast the "cleaned up" GPS signal to certain frequencies that will be used by aircraft. The current plan is for 25 WAAS stations around the US. Terrain and curvature of the earth would block the vast majority of these signals from us.


 

WAAS is available now in quite a few handheld GPSRs, including the Garmin Venture, Legend, Vista, 76, 295, and Magellan 330. Usable WAAS correction signals are currently available in both the US and Europe (although Garmin GPSRs don't accept the European ones since they are labelled as test signals). WAAS correction data are broadcast on the same frequency as the regular civilian GPS signals to minimize the complexity and cost of the GPSRs.

You are correct that there are 25 WAAS ground stations in the US, but the user doesn't receive data from them directly, so this doesn't create any issue with 'terrain and curvature'. Instead, the data gathered by the WAAS ground stations is analyzed and correction data is broadcast by geosynchronous satellites. These do have a visibility problem for ground-based users since there are currently only two of these satellites covering the US and they are low in the sky for most of the country.

However, for many boaters, aviators, and others with fairly unobstructed southern horizons, the improved accuracy of WAAS is available now.

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Guest The Bees

my... you know...

 

OK, everyone ignore the ignorant ones post (i.e. mine) just above Pete's reply (though the link is still good!). icon_smile.gif

 

Later

Mike B

 

The Bees

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Guest The Bees

my... you know...

 

OK, everyone ignore the ignorant ones post (i.e. mine) just above Pete's reply (though the link is still good!). icon_smile.gif

 

Later

Mike B

 

The Bees

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Guest jimmyt5

Hi:

Just would like to say a few things about GPS.

I am retired US Navy 26 Yrs, spent some of my time in the US Navy Astronatics Group. We were doing the R & D on what is now the GPS System.

I guess that some of this can now be told.

The Navy was looking at a reliable system to tell were their Boomer Subs were at, you can not shoot at something and hit it if you don't know were you are shooting from.

Anyhow a fellow was listening to the Russian

Spudnick go by and noticed that there was a Doppler shift (like when a train goes by) when it passed the closest point to him and he and some of his guys came up with the birth of The Navy Navigation Satellite System.

At the time 1962 we were not allowed to tell what we did and the name of our outfit lead to a lot of confusion.

The first Sat put up was called ANNA and it was in a polar orbit, this way you didn't need as many SAT?s.

The Navy had three tracking stations, one in Hawaii, Minn, Maine, and headquarters at Pt Mugu Calif.

I am real proud of the system and all the things you can see it being used for playing golf, to saving lives.

Many other stories put thats an other time.

 

Good luck and happy hunting.

 

MasterChief USN Ret

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