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#101
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On Fri, 19 Dec 2003 05:54:28 +0000, phil hunt wrote:
On Thu, 18 Dec 2003 20:53:21 GMT, Kevin Brooks wrote: "The programming for this isn't particularly hard"? Read the rest of the sentence: "...once you've written software that can identify a vehicle (or other target) in a picture" I could probably have phrased that better. Like, say, "The programming for this isn't particularly hard, once you've waved your hands and assumed all the really hard bits are already done"? [...] You have a rather optimistic view of the capabilities of most nations to handle development of truly accurate x-y-z topo data sets. And once you do have that data, you have to have a guidance system that can read it, remain compact enough to fit in your missile, You do realise, you can get hard disks small enought otfit in your hand, that store tens of gigabytes these days? Of course you can. Just because you have somewhere to put the data doesn't mean the data is easy to acquire, though. You can get detailed digital elevation data for the United States (horizontal resolution of 30 meters for the lower 48, 90 meters for Alaska), but that's because the United States Geological Survey has gone to a great deal of effort to compile it and make it available. How many other countries have done the same? Does the Royal Elbonian Survey Office even have decent 1:24,000 topographic map coverage of Elbonia to use as a starting point for compiling a digital elevation model? [...] Your LORAN system bites the dust when the curtain goes up. No, because you use multiple transmitters, which aren't all switched on at once, plus large numbers of fake transmitters there to be targets for bombs. LORAN transmitter sites are not small. Check out http://www.megapulse.com/lorsys.html for a picture of a modern solid-state transmitter -- they don't need water cooling systems any more, apparently, but you still need a large room with a HVAC system capable of handling "moderate air-conditioning loads". That's nothing compared to the size of the antennas, though. A LORAN transmitter station typically has multiple guyed antenna masts with heights ranging between 300 and 1,000 feet. You are not going to be able to build lots of them, and you definitely can't move them around. The transmitters can shift frequencies and use short transmissions, to further reduce the probability of being detected. Great -- now all you need to do is figure out how to hide a forest of immobile antenna masts that are hundreds of feet tall. Automated celestial tracking/guidance is not the purview of the amateur, and I doubt you would get the requisite accuracy from such a system mounted on such a small platform. Why is the platform size an issue? You need a stable platform for accurate celestial navigation. A small aircraft-sized HLCCM isn't it, and semi-accurate celestial navigation only tells you your position to within 5-10 miles. You also need to be able to see the stars, so using celestial navigation would mean your HLCCM would only be able to navigate to its target if it was night and the weather was clear. Automated celestial navigation is really only practical for vehicles that operate outside the Earth's atmosphere -- spacecraft and ICBMs. DR is a non-starter--again, you don't just hurl a few missiles in the general direction of the bad guys and say, "Gee, that was tough--time for a beer!" Again, why would DR not work? Because dead reckoning is the least accurate form of navigation. Do you really want your HLCCMs to miss their targets by miles because the wind changed direction after they were launched? ljd |
#103
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(George William Herbert) wrote:
The response was "Yes, but now they're working 95% of the time, rather than 55%". That lesson is hard even for well funded navies... nods And that's where the low cost frightfulness proposed elsewhere in this thread really falls down. It's pretty much a given that a decent cruise bird can be built for around $10k. However, I'd be willing to wager a bottle of beverage of choice that their reliability won't exceed 50%. That's high enough for a terror campaign, but as a useful military weapon, it's nowhere near enough. 'Cheap' weapons aren't nearly as cheap when you have to launch *four* $10k birds to ensure that *one* lands on target. Lacking assurance of a kill adds greatly to the difficulties your offense must face, and complicates your logistics chain. D. -- The STS-107 Columbia Loss FAQ can be found at the following URLs: Text-Only Version: http://www.io.com/~o_m/columbia_loss_faq.html Enhanced HTML Version: http://www.io.com/~o_m/columbia_loss_faq_x.html Corrections, comments, and additions should be e-mailed to , as well as posted to sci.space.history and sci.space.shuttle for discussion. |
#104
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"Paul F. Dietz" wrote:
George William Herbert wrote: The response was "Yes, but now they're working 95% of the time, rather than 55%". As I understand it, one of the things that motivated the invention of integrated circuits was reliability -- of naval electronics and avionics. The systems were coming up against the limits of what one could reliably do with discrete components. Reliability comes not just from increasing MTBF, but in decreasing MTTR. BITE (Built In Test Equipment), modular electronics, designing for maintenance... All these things go into increasing uptime, and IC's make them all much easier. D. -- The STS-107 Columbia Loss FAQ can be found at the following URLs: Text-Only Version: http://www.io.com/~o_m/columbia_loss_faq.html Enhanced HTML Version: http://www.io.com/~o_m/columbia_loss_faq_x.html Corrections, comments, and additions should be e-mailed to , as well as posted to sci.space.history and sci.space.shuttle for discussion. |
#105
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ess (phil hunt) wrote:
You have a rather optimistic view of the capabilities of most nations to handle development of truly accurate x-y-z topo data sets. And once you do have that data, you have to have a guidance system that can read it, remain compact enough to fit in your missile, You do realise, you can get hard disks small enought otfit in your hand, that store tens of gigabytes these days? You do realize the problem isn't *storing* the data, it's *generating and integrating it*. It's not a matter of storage, or CPU capacity, but of analysis and algorithms. (A friend of mine recently generated a 3-d topo of our county as the first step in building an integrated GIS for the local water department. Took six months.) D. -- The STS-107 Columbia Loss FAQ can be found at the following URLs: Text-Only Version: http://www.io.com/~o_m/columbia_loss_faq.html Enhanced HTML Version: http://www.io.com/~o_m/columbia_loss_faq_x.html Corrections, comments, and additions should be e-mailed to , as well as posted to sci.space.history and sci.space.shuttle for discussion. |
#106
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"Paul J. Adam" wrote in message
... Done thirty years ago with assorted single launchers (basically just a rail and a stand) to point a 107mm or 122mm rocket targetwards, and a countdown timer to fire it minutes or hours after the guerilla has departed. If you're lucky then you can plant it on the hospital roof, across the street from the orphanage and next door to the elementary school, and tip off the news crews so that any enemy counterbattery fire is widely reported. Of course, how hard would it be to add GPS guidance to a Katyusha rocket? If you could bring the CEP down to 10m or so and still have a warhead of 10kg (the 122mm Katyusha has a 20kg warhead so this is at least plausible), you'd have a very, very nasty weapon for insurgents (target checkpoints, the people trying to evac the victims of the latest road-side bomb, etc.) or terrorists (target parked commercial aircraft at a gate, the 50-yard line at the Super bowl, etc.). The Katyusha has a range of around 20km so the only defense would be hard cover (tough to arrange everywhere), active defenses (which have yet to be fielded), or GPS-spoofing. The last is possible but it diminishes the usefulness of GPS for your side as well. |
#107
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ess (phil hunt) wrote:
Otherwise, there are other methods of nagivation: dead reckoning, celestial, a LORAN-like system could be set up. Your LORAN system bites the dust when the curtain goes up. No, because you use multiple transmitters, which aren't all switched on at once, plus large numbers of fake transmitters there to be targets for bombs. The transmitters can shift frequencies and use short transmissions, to further reduce the probability of being detected. All of which increases the cost and complexity of your missile guidance system. It has to; store *all* possible stations,be able to determine which master/slave complex is currently active, and determine which frequencies to use. Not easy, not easy at all. (Setting aside the difficulties of setting up such a system.) Automated celestial tracking/guidance is not the purview of the amateur, LORAN was around 40 years ago; therefore any country with 1960s-equivalent tech should be able to build one. Nice dodge there, failing to address the issue of celestial navigation. And sorry, the assumption that anyone can easily do something that was done forty years ago is invalid on it's face. A LORAN system requires complex electronics, accurate surveying, guaranteed power, good sized antenna... All non-trivial, none cheap, and none 'garage' compatible. DR is a non-starter--again, you don't just hurl a few missiles in the general direction of the bad guys and say, "Gee, that was tough--time for a beer!" Again, why would DR not work? Because all navigation system accumulate inaccuracy as time-of-flight increases. Without periodic updates, you are almost ensured of failing to hit your target. D. -- The STS-107 Columbia Loss FAQ can be found at the following URLs: Text-Only Version: http://www.io.com/~o_m/columbia_loss_faq.html Enhanced HTML Version: http://www.io.com/~o_m/columbia_loss_faq_x.html Corrections, comments, and additions should be e-mailed to , as well as posted to sci.space.history and sci.space.shuttle for discussion. |
#108
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"phil hunt" wrote in
What would be sensible strategies/weapons for a middle-ranking country to employ if it thought it is likely to be involved in a war against the USA or other Western countries, say in the next 10 years? To deal with the US Army... Use SUVs with anti-tank rockets and a millimetric radar mounted on the back. In iraq US gunners opened fire at 5miles. Since the rounds travel at a mile/second, this would give an SUV 5 seconds to dudge, which would be simple with guidence from the radar. Meanwhile the top-attack missiles tear through the thin turret roofs. Buy a few otto-76mm armed tanks with dual use surface/air to deal with incomming aircraft/missiles/bombs/helicopters and to rip enemy soldiers to pieces. To deal with the US Air Force... Buy old airliners and fit with reloadable missile launchers and modern AA radar, counter measures, and refueling probe. Take old fighter designs, and hang them fully fueled and armed from ballons. That'll multiply thier endurance by a factor of ten at least. Fit search-radar in envelope and have them patrol your boarder. Network them together and you'll have an end to surprise US attacks. To deal with the US Navy... Buy old torpedos and fit to larch home made rockets (see X-prize entries) with 50-100 mile range. Get the rockets to dump the torpedos within a few miles of a nimitz carrier groups and you're garanteed to blow up something *really* expensive! Alternatively buy the following: 1 million RPG-7s 5 million RPG-7 rounds 10 million AK-74s 1 billion bullets Distribute evenly through out your population, train them, set up a Swiss-style monitoring system, and let the Americans invade. Then blow up everything of value they own the second they let their guard down. They'll leave in a few months and you can go back to normal. Alternatively fly a few airliners into american nuclear power stations. The aftermath of multiple chernobles will destroy America as an effective strategic power. ANTIcarrot. |
#109
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On Fri, 19 Dec 2003 01:30:28 GMT, "Anthony Garcia"
wrote: If it were easy to hit troops with self-targeting systems don't you think the U.S. would be doing it already? I think the hard thing to do is to avoid incidental civilian casualties with self-targetting systems. This is probably enough to scrap the idea in the US, which is public ally committed to the idea of avoiding avoidable harm to non-combatants. I'm a little bit cynical as to how this works out in practice, but I do think that most of the high-ranking staff officers do try to make battle plans that will minimize civilian casualties. Probably the main difficulty is that battles don't always follow the battle plans.... How did I get off on that topic? Anyway, I really don't know how well the idea would work if bystander casualties were not a concern. It seems to me that we would not actually know until the idea was built and tested, and we probably would not really know until it was used in the field. I think that the intimal development of such weapons would be prohibitively expensive if it were carried out by a government. It's possible that some private companies might be able to develop such weapons at a reasonable cost (and a significant risk that they would not work after being developed), but it's unclear if they would perceive the market demand for them to justify the cost and the risk. |
#110
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