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Global Positioning Without GPS
GadgetMike sends word of an award to Boeing for work on a Robust Positioning System that could make use of cell signals, television transmissions, and other clues to provide position information when GPS is unavailable. (Wonder if they've heard about Skyhook Wireless, which does a similar job based on Wi-Fi hotspots, for 2500 US cities and towns.) The work is being sponsored by the US military, so it's not surprising that they don't want to rely on upcoming GPS enhancers or replacements from France, China, and Russia. Here is the Boeing press release.
Reminds me of that near-field locater thingy they had in Aliens...
Hudson: This signal's weird...must be some interference or something. There's movement all over the place...
Hudson: Nine meters. Eight...!
Ripley: Can't be. That's inside the room!
Hudson: It's readin' right. Look!
Hicks: Well you're not reading it right!
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Pilots have used VOR http://en.wikipedia.org/wiki/VHF_omnidirectional_r ange for a long time. Knowing the lat/lon position of other radio beacons and being able to detect them is (IIRC) something that was experimented with for robotic vehicles.
Using geo-data and good state of the art receivers, it would be possible to locate your position reasonably accurately if you have many landmark transmitting beacons. The trouble is making those receivers small enough to be useful. Of course, this might not work too well in the middle of a desert but would function well enough for many problems.
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Before the patent wars begin, there's prior art out here: I think it is called a "map" or something.
Robust navigation? From a jumble of tv/mobile signals? I don't think so. For absolute position VOR+DME is pretty good and ILS/MLS around terminal areas. Relative collision avoidance is handled by S-mode transponders and TCAS.
Use existing systems. ATC could gather all the TCAS negotiation information via the s-mode datalinks and use that to make a more accurate picture of the traffic than the survaillance radar alone can provide and broadcast that back to the planes. All that the planes really need anyway is their relative position to other planes more accurately. Absolute geographic position is accurate enough with the existing systems for purpose of terminal procedures and terrain avoidance.
Then again I think we should develop the reliability of GPS satellite constellation and adding Galileo to that will make it very robust with dual receivers and multiple antennas on the planes. To make ADS work will need dependable GPS type vector information anyway...
We've had http://en.wikipedia.org/wiki/LORAN since WWII. It works fairly well for ships and airplanes, I'm sure it will be quite enough to guide airplanes to nearest aerodrome in case of aliens knocking off GPS satellites.
This is more a matter of removing the motive for $OTHER_COUNTRY to try to confuse the US's offensive infrastructure by destroying disabling our GPS satellites. It works both ways, obviously, if $OTHER_COUNTRY is using similar technology -- but any missile which is going to do really significant damage will be able to get close enough to where it needs to be using inertial guidance, so the example you give isn't a serious concern.
Moreover, disabling GPS is really an asymmetric threat -- it's easy to do (if you're China, for whom the necessary technology is already a sunk cost), and has an impact on your opponent far greater than its marginal cost. Avoiding unfavorable asymmetric threats is a Good Thing.
They got lost. Ships hit rocks and aircraft hit mountains. Google Earth has an interesting feature where you can overlay old maps on the current images. There you can see how inaccurate the old map makers were.
From the military point of view, GPS means less bombs hitting civilians. During WWII and the Korea war it was normal to drop hundreds of bombs, flattening several city block or even entire villages, just to hit one bridge. Today when a bomb hits anything other than the intended target it's considered a major fuck-up.
The smarter technology gets around us, the more efficient we get. We need to make sure we have a fallback system in case the new technology fails, of course, but we are still much better off with the smarter systems than with the old tech solutions.
This idea seems pretty flimsy..
If you are incorporating known, ground based beacons/signals to provide positioning data wouldn't it be easy enough for the enemy to emulate those beacons/signals from some location near to the real one to create multiple signatures and distort positioning data? Wouldn't this confuse the proposed system?
All it would require is transmitting eq that you could fit into a small, mobile (cargo van type) container. Now you have to a: track down the false signatures & have response teams to eliminate dupe signals, or b: rely solely on satellite signals which is what GPS does.
Am I making any sense?
Regards.
I actually use it several times a year when I go backpacking, but I never count on it working and always keep USGS Topo maps and/or US Forest Service maps and a compass with me so that if my GPS unit fails I don't get lost. The GPS is nice to have in the back country, but more for purposes of tracking my pace, movements, and elevation than for actual navigation. The maps available for the back country tend to be off and are missing a large amount of information on trails so all that I can use in these cases is a the lat/long or UTM info (UTM works much better with Quad maps, but with other maps latitude and longitude work just fine). I think that anyone that really relies on GPS for navigation is just short changing themselves, not know how to read a map and figure out relatively close to where you are is taking a risk.
I am also a private pilot and spend a lot of time on the water. I have never counted on GPS in these situations either, although GPS sure is handy when it comes to getting right back on top of a known fishing spot. When I got my pilot's license GPS was not an approved form of navigation so we learned dead reconing skills and how to read a chart for VFR rules (who knows what they are teching new pilots these days, I haven't flown in a long time and haven't kept myself current). I never got my IFR license so didn't spend too much time with IFR tools like Loran but they can also be quite accurate. I know I could always find an AM radio station with the direction finder (I used it to listen to talk radio more then navigation, but it was fun to know where the stations tower was located). There are plenty of ways to navigate without GPS, most of them just require finding the intersection of two lines and having an idea of where you are in the first place.
I always imagined that the GPS network must be very vulnerable to attack, any nation as industrialized as say china could probabbly fill orbit with enough shrapnel bombs to destroy the bulk of the satellites around the planet if they put the resources into it. what did people do before GPS? Well theirs a few things, but most of them don't fit in your pocket. land navigation is extreamly difficult, I spent a good part of my child hood/early teens practiceing land navigation, and I wouldn't ever want to rely on it for anything that requires great precision or speed. Also celestial navigation relies on a unubstructed horizon and clear weather obviously. from the sounds of this system it seems fairly vulnerable to tampering and interference. I wonder if you could use sound freqencys transmitted through the earth to triangulate a position.
I read somewhere that you can use the stars as well for global positioning at night. That's an interesting and novel idea. Maybe they should do some more research on that.
-- Cheers!
Bullshit.
Planes flew before GPS and they somehow managed to arrive at their destinations.
Trucks deliver goods all the time.
Walmart employees might get lost going to the toilet, but thats not actually critical.
liqbase
To be precise, the Blackbird used an astro-inertial navigation system originally developed for the Skybolt missile. This used the position of the sun or other selected stars to refine the position estimates given by the inertial nav system. A related guidance system is used in the Trident II missile.
A Shadeless room is a brighter room.
Oh come now, You must be referring to Galileo system that is being buid for the EU and ESA (European Space Agency) by European Satellite Navigation Industries. So it's basicly european system not French. Get your facts straight.
More on subject:
The EU site for the Galileo project http://ec.europa.eu/dgs/energy_transport/galileo/
The wikipedia site: http://en.wikipedia.org/wiki/Galileo_positioning_