You seem to forget that the Galileo constellation, while utilizing nearly the same inclination as GPS, is going to consist of 3 totally different oribital planes. Being in different orbital planes, the probablity of having a GDOP conducive to a good solution is much better with 48 satellites in 7 different planes rather than 27 in just 4.
Using more than 4 satellites does improve your position accuracy, this is generally called an "over determined solution". When SA was enabled, the benefits of this were nullified by the inaccuracies introduced by SA, but today that is not the case. Im sorry about screwing up the signal schedule, its late:). The L5 signal (what I should of said when saying L3) is going to be a long period PRN code without a data message modulated on top. Current C/A code has a period of 1ms with a 50Hz data message modulated atop of this. The unknown data message bits prevent a pre-detection integration time of 10ms, and a tracking integration time of 20ms. This limits the performance of low-level acquisition and tracking (ie indoor or space case). The L5 signal, with no data message eliminates this barrier. The new satellits going up are also going to have better atomic clocks, further improving user end accuracy. Finally C/A on L2 are going not going to be of the current Gold Code type, the details are not yet released publically.
Not to shoot you down or anything but I work specifially with GPS. The GPS C/A code broadcast on L1 (1.57542 GHz) has never been encrypted. The military simply encoded ephemerides for the GPS satellites that were inprecise (this was called "Selective Ability") onto the L1 signal. This led to a user range error of ~30 meters. After this was turned off in 2001 the error went down to ~3 meters. There has always been the PPS ("Precise Positioning Service") P-code signal on the L2 frequency (1.22760 GHz). This is actually encrypted, and is what the military uses in its. Acurracy with this service can be in the range of centimeters (low dynamics case). Working with the L2 signal requires a security clearance and a bunch of goverment red-tape. In the next 10 years there is going to be an explosion of GPS tech. First off the EU is putting up Galileo, which will double the number of SV's orbiting the earth (more satellites in view = better positioning accuracy). Althought the signal structures are not the exact same, because they will be broadcasting at similar carrier frequencies designing a dual use receiver will be a piece of cake. Also GPS is being heavily upgraded. They are adding a third signal with M-code(L3), and adding C/A code on L2. There is also talk about increasing the signal strength, which is a great boon to indoor GPS and using the GPS signal for remote sensing applications. All in all it is a great industry to be in.
I download mp3's. I download a lot of mp3's. I havent bought a CD for the past 6 years. A CD has no value for me, since every time I reformat I start my mp3 collection over. My tastes are fickle, and sounds I enjoyed when I was 13 dont quite have the same oomph for me. I am willing to pay, but for what. High speed, unlimited downloads at a good quality, for less than the price of a CD for a month. 12*16 > 0. Hopefully the RIAA will do the math, because the market is changing, no one really wants a hard copy to save forever anymore (well until the medium degrades in 15-20 years). We want the latest and greatest sounds to consume and throw away a month later, at college student prices. So I will continue to download, to expand my sonic horizons, and if the RIAA comes a knockin I'll quickly nuke my computer (magnesium is great:)), get a lawyer, and fight them tooth and nail.
I think the point is that everyone agrees that Linux beats Windows on the reliability factor, but an OS is not defined by its uptime for a large amount of the people that use computers. Installing a program should require two clicks to the user. No RPM's, no Makefiles, no gcc. If it is needed, make it invisible to the user. Changing out hardware should be as easy as it is with Windows. The majority of people dont use the command line on Windows, you should be able to do the same with Linux. All of this command line junk that is left from Unix of the 60's should at least be made transparent for the majority of tasks. Linux is behind the curve for use on a home PC, it should at least catch up before trying to out-do Windows.
Maybe it is analogous to the methods McCarthy used in his hearings. He had the FBI find out who would not stand for his shenanigans and only subpoenaed the ones who would crumble under his search for True(TM) Americans.
Actually I wouldn't trust the SDI because the physics community has overwhlemingly called it "impossible". Have you even tried to design a control system for something as simple as an inverted pendulum? Now extrapolate that to hitting a target about the size of a water-melon at Mach 10 several thousand miles away and several miles up into the atmosphere. All hail defense contractor pork!
I think a lot of this attitude has to do with perceptions involving having a large corporation dictate what you will do. Give a choice between two songs, one without DRM, one with, we would all choose the one without DRM. DRM is like having an overzealous parent standing over you shoulder all the time to make sure you dont "break the rules" arbitrarily dictated by them. None of us like being treated like children, and thus do not like dealing with DRM hindered files. It all comes down to the perception of freedom and its value when compared to higher quality files and the hassle of P2P filesharing
I live in Indianapolis, IN and have seen the effects of media consolidation. There was once two newspapers in Indy, the News and the Star. Although both were owned by the same company, they operated independantly. The News was a little left leaning, and the Star a little right leaning, and all was good. Well the corporation decided to trash the News (its readership was about 1/2 the Star), and consildate them into one paper. The sad fact is that almost none of the editors/reporters from the News were hired onto the new paper (called the Star). Thus we were left with a right leaning newspaper. Ok, this wasnt so bad, there were 3 major networks broadcasting 3 hrs of local news each a day. Ahh, but then the dominant local channel, WTHR (an NBC affiliate), joined the Indianpolis Star in a "strategic news partnership". So nowadays in Indianapolis, IN you can see the same stories, with the same angle, from two seperate mediums. All that is left is the less glitzy CBS and ABC affiliates, and a smattering of independant newspapers (Nuvo, The Recorder) which get almost no attention by the majority of the people who live in Indianapolis. I miss the days of the Indianpolis News, when I could read stories that do not get reported in the current situation.
Slashdot Mirror
Actually I work with Prof Garrison. I'm on his research team. How do you know him?
You seem to forget that the Galileo constellation, while utilizing nearly the same inclination as GPS, is going to consist of 3 totally different oribital planes. Being in different orbital planes, the probablity of having a GDOP conducive to a good solution is much better with 48 satellites in 7 different planes rather than 27 in just 4.
Using more than 4 satellites does improve your position accuracy, this is generally called an "over determined solution". When SA was enabled, the benefits of this were nullified by the inaccuracies introduced by SA, but today that is not the case. Im sorry about screwing up the signal schedule, its late :). The L5 signal (what I should of said when saying L3) is going to be a long period PRN code without a data message modulated on top. Current C/A code has a period of 1ms with a 50Hz data message modulated atop of this. The unknown data message bits prevent a pre-detection integration time of 10ms, and a tracking integration time of 20ms. This limits the performance of low-level acquisition and tracking (ie indoor or space case). The L5 signal, with no data message eliminates this barrier. The new satellits going up are also going to have better atomic clocks, further improving user end accuracy. Finally C/A on L2 are going not going to be of the current Gold Code type, the details are not yet released publically.
NASA GSFC & Purdue University
Not to shoot you down or anything but I work specifially with GPS. The GPS C/A code broadcast on L1 (1.57542 GHz) has never been encrypted. The military simply encoded ephemerides for the GPS satellites that were inprecise (this was called "Selective Ability") onto the L1 signal. This led to a user range error of ~30 meters. After this was turned off in 2001 the error went down to ~3 meters. There has always been the PPS ("Precise Positioning Service") P-code signal on the L2 frequency (1.22760 GHz). This is actually encrypted, and is what the military uses in its. Acurracy with this service can be in the range of centimeters (low dynamics case). Working with the L2 signal requires a security clearance and a bunch of goverment red-tape. In the next 10 years there is going to be an explosion of GPS tech. First off the EU is putting up Galileo, which will double the number of SV's orbiting the earth (more satellites in view = better positioning accuracy). Althought the signal structures are not the exact same, because they will be broadcasting at similar carrier frequencies designing a dual use receiver will be a piece of cake. Also GPS is being heavily upgraded. They are adding a third signal with M-code(L3), and adding C/A code on L2. There is also talk about increasing the signal strength, which is a great boon to indoor GPS and using the GPS signal for remote sensing applications. All in all it is a great industry to be in.
I download mp3's. I download a lot of mp3's. :)), get a lawyer, and fight them tooth and nail.
I havent bought a CD for the past 6 years.
A CD has no value for me, since every time I reformat I start my mp3 collection over. My tastes are fickle, and sounds I enjoyed when I was 13 dont quite have the same oomph for me. I am willing to pay, but for what. High speed, unlimited downloads at a good quality, for less than the price of a CD for a month. 12*16 > 0. Hopefully the RIAA will do the math, because the market is changing, no one really wants a hard copy to save forever anymore (well until the medium degrades in 15-20 years). We want the latest and greatest sounds to consume and throw away a month later, at college student prices. So I will continue to download, to expand my sonic horizons, and if the RIAA comes a knockin I'll quickly nuke my computer (magnesium is great
I think the point is that everyone agrees that Linux beats Windows on the reliability factor, but an OS is not defined by its uptime for a large amount of the people that use computers. Installing a program should require two clicks to the user. No RPM's, no Makefiles, no gcc. If it is needed, make it invisible to the user. Changing out hardware should be as easy as it is with Windows. The majority of people dont use the command line on Windows, you should be able to do the same with Linux. All of this command line junk that is left from Unix of the 60's should at least be made transparent for the majority of tasks. Linux is behind the curve for use on a home PC, it should at least catch up before trying to out-do Windows.
Maybe it is analogous to the methods McCarthy used in his hearings. He had the FBI find out who would not stand for his shenanigans and only subpoenaed the ones who would crumble under his search for True(TM) Americans.
Actually I wouldn't trust the SDI because the physics community has overwhlemingly called it "impossible". Have you even tried to design a control system for something as simple as an inverted pendulum? Now extrapolate that to hitting a target about the size of a water-melon at Mach 10 several thousand miles away and several miles up into the atmosphere. All hail defense contractor pork!
I think a lot of this attitude has to do with perceptions involving having a large corporation dictate what you will do. Give a choice between two songs, one without DRM, one with, we would all choose the one without DRM. DRM is like having an overzealous parent standing over you shoulder all the time to make sure you dont "break the rules" arbitrarily dictated by them. None of us like being treated like children, and thus do not like dealing with DRM hindered files. It all comes down to the perception of freedom and its value when compared to higher quality files and the hassle of P2P filesharing
Just my two cents:
I live in Indianapolis, IN and have seen the effects of media consolidation. There was once two newspapers in Indy, the News and the Star. Although both were owned by the same company, they operated independantly. The News was a little left leaning, and the Star a little right leaning, and all was good. Well the corporation decided to trash the News (its readership was about 1/2 the Star), and consildate them into one paper. The sad fact is that almost none of the editors/reporters from the News were hired onto the new paper (called the Star). Thus we were left with a right leaning newspaper. Ok, this wasnt so bad, there were 3 major networks broadcasting 3 hrs of local news each a day. Ahh, but then the dominant local channel, WTHR (an NBC affiliate), joined the Indianpolis Star in a "strategic news partnership". So nowadays in Indianapolis, IN you can see the same stories, with the same angle, from two seperate mediums. All that is left is the less glitzy CBS and ABC affiliates, and a smattering of independant newspapers (Nuvo, The Recorder) which get almost no attention by the majority of the people who live in Indianapolis. I miss the days of the Indianpolis News, when I could read stories that do not get reported in the current situation.