GPS vs. Galileo; Where Are They Headed? 330
ben_ writes "This keynote speech from the recent European Navigation Conference talks about the history between the US military's GPS and the proposed EU Galileo system, as well as where they're both going. Interested in how you know where you are and what's going to happen to those satellites?"
Re:Essential to Ending US Dominance (Score:3, Interesting)
So much for "ending US strangeholds".
Maybe I missed something (Score:3, Interesting)
Does anyone know what this refers to?
makes me wonder (Score:3, Interesting)
Here's the big question: (Score:5, Interesting)
That could get VERY expensive as manufacturers of satellite navigation receivers will have to accommodate both systems for airplanes, automobiles, trucks, boats, etc.
Re:Essential to Ending US Dominance (Score:5, Interesting)
1. Someone more intelligent than Putin takes over Russia and uses Putin's communist-like infrastructure to once again impose a military state.
2. China decides that they have the most people in the world and that someone else should give up some land to support them.
While the second is more likely, either one would spell defeat for the European Union. Only the US currently has the necessary military power to stop another superpower. On the upside, China might be more inclined to take on the US first since we have more undeveloped land. It wouldn't be much of a war though. We'd fight until the Chinese start lobbing nukes. Once that happens, China can kiss their population goodbye when a few neutron bombs fall.
Re:Essential to Ending US Dominance (Score:2, Interesting)
First off, the US can't just block out who they want with GPS, that is the beauty of it, it's a one-way connectionless communication protocol, it is either OFF or ON. Second, the US would NEVER, EVER turn OFF gps, we have much more riding on GPS than anyone else. Third, our only control over GPS at this point is Selective Availability, which besides having a presidential and congressional mandate to never turn ON again, it is completely useless with today's technology. Any corruption and error caused by SA can be eliminated with L1/L2 carrier phase tracking. That is one reason SA was turned off in the first place. The other being to jump start the civilian use of GPS to increase the technology worldwide.
I know everyone likes to think that the USA is evil in every way, but I hate that no one sees the gift that was GPS. The military could have used it all for themselves, but no.. they shared with all, and turned off SA to boot. Not only that, but they didn't hide any of the implementation details. Which also makes me wonder why the GALILEO project is costing so much, much of what was done by the US won't even have to change. And the US did it cheaper than Europe is proposing.
I do not work for the GPS JPO, but I do work in the navigation field, so I hate when people spread FUD about GPS when they really don't know what they are talking about.
By the way, if you don't believe me on the L1/L2 carrier phase tracking, look up Trimble, NavCom, Ashtech, etc. etc.
Re:Where ever they are going... (Score:2, Interesting)
I understand that there would need to be some sort of receiver but it seems like this would be an issue of cost, not feasibility.
You would want these devices to be working 100% of the time, right? What if your kid has gotten stuck somewhere, is being held in someone's basement, is lost in the mall, or your car is parked in a deck/garage or is driving through tunnels.
And before the YRO posters get all riled up, the devices could be designed with some kind of passkey to protect privacy.
Re:Essential to Ending US Dominance (Score:2, Interesting)
However, know that this option hasn't been used in at least the past 3 years. (I know this because I work on GPS/Inertial navigation systems used in every commercial airplane in the world.)
Re:Essential to Ending US Dominance (Score:3, Interesting)
Why the US won't kill the signal (Score:3, Interesting)
Look at how many commerical GPS units there are, and how many military ones.
The ratio will be at least 3:1. The military GPS units, in a word, suck. They are about as big as a small boombox and fail for various reasons every 5 minutes. Ask any soldier who's had to use one in a combat environment. They will tell you that anyone who actually cares about finding out where they are will buy a Garmin.
That's why the US stopped degrading the signal and won't do it again. Even in a war zone, most of the commercial GPSes in use are those ofUS soldiers.
Re:Essential to Ending US Dominance (Score:2, Interesting)
What's the likelihood that someone hasn't scored a military unit and reverse engineered the encryption key? I'm very curious about that as it sounds like a security measure that is strong in theory, but weak in practice.
All six of the Russian-made GPS jammers fielded by Iraq were destroyed in short order, some of them by GPS guided missiles!
Indeed - by the time the guided unit was in range of the jammer, the accuracy of non-GPS measures (magnetic direction, speed, etc) is sufficient to hit the target accurately enough. Jammers would have to cover hundreds or thousands of km in all directions to really have value.
Re:Where are they going? (Score:3, Interesting)
Will it ever get built? (Score:2, Interesting)
Re:Don't forget about the Russians: GLONASS (Score:2, Interesting)
addendum (Score:2, Interesting)
Other than a healthy reference page for the interested, there's not much new information in Last's article.
A Relativity Question (Score:2, Interesting)
In modern physics, there is no "absolute" frame of reference, correct? There's no notion of something that is TRUELY stationary against which all other motion is measured, it's all relative to each other.
So say you had a hypothetical universe containing only two bodies - lets say a large moon with no atmosphere, and a spaceship. The moon is spinning, and the spaceship is in geostationary orbit around it.
What's to say that the spaceship is actually in geostationary orbit and not just STATIONARY if there is nothing else to measure their motion against? These two things are all that exist in this hypothetical universe and they are stationary relative to each other, so why aren't they 'absolutely' stationary, causing the spaceship just to fall? How do you know the moon is really even spinning?
The way I usually phrased this to physics professors was that if the spaceship, floating in space for all it knows, comes flying past the moon at near light speed, why do we assume the spaceship is moving at near lightspeed and therefore clocks on it run slower, rather than the moon is hurtling through space at near lightspeed past a stationary ship?
I can't seem to reconcile this in my mind without some notion of an absolute frame of reference, even if we can't measure what it is. I suppose we could tell what is closer to that frame of reference by seeing if, for example, the spaceship falls from it's "geostationary" orbit because the moon wasn't actually spinning, etc; or seeing which clocks dialate which way when two objects move relative to each other at high velocities...
Can someone clear this up for me?
Re:Don't forget about the Russians: GLONASS (Score:3, Interesting)
OTOH, a friend in Russia uses a Garmin!
Re:A Relativity Question (Score:3, Interesting)
Newton pondered the same question, but he used a spinning water bucket as an example. suppose you are on the inner bucket wall, you know your are spinning because you can feel your back is pressed against the wall, even if you can see any motion relative to the wall or the center pole. but when the spinning stops, the force disappears. By the same token, we can deduce the spaceship is geostationary because it does't fall, a truly stationary spaceship will fall because of gravity.
Einstein says you can see it either way, and both perspective are valid but they don't necessarily reconcile in a traditional sense. the distance and time measures differ depends on the observer's speed. In general, when you speed up and down, your space and time perspective dynamically changes. According to Einstein, it's perfectly valid for everyone on Earth to have a different time reading for the very same event, like exactly when Smarty Jones won the Kentucky Derby.