If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#102
|
|||
|
|||
Defense against UAV's
Keith W wrote: wrote in message ups.com... In which case they would use mines, ships are more easily sunk by letting water in the bottom than by letting air in to the top. Mines really are cheap and effective weapons. Not necesarily. You have to lay mines. Easily done by anything from a traditional dhow to a helicopter The US could blow the ship out of the water. They'd have to know you were laying mines. The straits of Hormuz are passed by dozens of Iranian vessels every day (and night). Covert mine laying is old hat. UAVs are mobile. You can launch them from deep inside Iran. Also mines being static can be swept. Not a simple task, especially if the minesweepers are subject to attack A mobile mine (a USB) would be quite a threat. Floating mines have existed for many decades Note that the Iranians are as dependent on free traffic movement through the straits as everyone else. True, but 1) They might be prepared to hurt themselves to hurt us. In a full scale war they wont care. I suspect they will when they run out of money and food 2) They will time the passage and routes of their own vessels so that they don't get attacked. And you dont think the USN would interict their ships huh ? If deterrence really did work defense policy would be a lot simpler. Keith ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- I think we have some hisory here. During Iran - Iraq Iran did indeed lay some mines. The US was in a much more difficult position legally from what would be the case were the US to be a belligenent. "Blow it out of the water" assumed US belligerent status. The US while "neural" did sink some minelayers and very nearly became a belligerent on Iraq's side. Te USN would be a lot more aggressive with a defined legal position. The US sank ships but did not mount strikes on Iranian naval facilities. |
#103
|
|||
|
|||
Defense against UAV's
Hint: Look up the accuracy specifications of GPS. In 7-10 years it will be Galileo. The specifications are a little bit eklastic as they depend on integration time. If you are talking about RELATIVE separation this will in fact be only a few centimers, the accuracy of DGPS. |
#104
|
|||
|
|||
Defense against UAV's
wrote in message ups.com... I think we have some hisory here. During Iran - Iraq Iran did indeed lay some mines. The US was in a much more difficult position legally from what would be the case were the US to be a belligenent. "Blow it out of the water" assumed US belligerent status. The US while "neural" did sink some minelayers and very nearly became a belligerent on Iraq's side. Te USN would be a lot more aggressive with a defined legal position. The US sank ships but did not mount strikes on Iranian naval facilities. Covertly laying mines is less likely to attract strikes than overt attack using drones. Keith ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#105
|
|||
|
|||
Defense against UAV's
In article ,
says... wrote in message ups.com... In which case they would use mines, ships are more easily sunk by letting water in the bottom than by letting air in to the top. Mines really are cheap and effective weapons. Not necesarily. You have to lay mines. Easily done by anything from a traditional dhow to a helicopter The US could blow the ship out of the water. They'd have to know you were laying mines. The straits of Hormuz are passed by dozens of Iranian vessels every day (and night). Covert mine laying is old hat. UAVs are mobile. You can launch them from deep inside Iran. Also mines being static can be swept. Not a simple task, especially if the minesweepers are subject to attack A mobile mine (a USB) would be quite a threat. Floating mines have existed for many decades Note that the Iranians are as dependent on free traffic movement through the straits as everyone else. True, but 1) They might be prepared to hurt themselves to hurt us. In a full scale war they wont care. I suspect they will when they run out of money and food I wouldn't hold my breath if I were you. High oil prices have allowed Iran to build up about $40Billion in foreign capital reserves. As for the hunger factor--according to the FAO, Iran is a net exporter of food. http://www.fao.org/countryprofiles/i...so3=IRN&subj=4 2) They will time the passage and routes of their own vessels so that they don't get attacked. And you dont think the USN would interict their ships huh ? Probably---but would they stop Japanese and Chinese ships loaded with Iranian oil that has already been purchased? If deterrence really did work defense policy would be a lot simpler. Keith Mark Borgerson |
#106
|
|||
|
|||
Defense against UAV's
wrote in message ups.com... Hint: Look up the accuracy specifications of GPS. In 7-10 years it will be Galileo. The specifications are a little bit eklastic as they depend on integration time. If you are talking about RELATIVE separation this will in fact be only a few centimers, the accuracy of DGPS. The accuracy of the GPS systems isnt the issue anyway. Its handling the problem of separattion of large numbers of drones. If they have to communicate with each other that introduces extra weight, a considerable processing issue and a vulnerability to jamming and/or spoofing. Frankly you'd probably be better off accepting a certain percentage of losses due to mid air collisions Keith ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#107
|
|||
|
|||
Defense against UAV's
Mark Borgerson wrote:
In article , says... Mark Borgerson wrote: In article , says... Jack Linthicum wrote: [snip] I think that a spread spectrum burst type transmission can be intercepted and given a rough bearing. The money to do this is miniscule in comparison with making Trident missiles into hand grenades. The command post does not move between transmissions. Spread spectrum/frequency hopping systems return to previous frequencies every few seconds. Just use several bursts to home in on the transmitter. Why are you assuming that the command post does not move? I see no reason that a mobile command post and multiple mobile transmitters could not be used. This comes down to the definition of mobile. If the command post stays in the same place for half an hour it is static. A constantly moving command post would need a vehicle the size of a bus to hold the operators and long range transmitters, possible but hard to camouflage. So you don't think the Iranians have buses or semi-trailers? Suppose there are 100 semis on the coastal road. Which one do you target? The one with the big aerial. Small aerial to small aerial on moving objects gives a short range. Spread spectrum and frequency hopping systems do use a finite number of frequencies---but the sequence of freqencies used may not repeat for many hours. That leaves you with a broadband collection problem and having to sort out multiple emitters on the same bandwidth with different hopping schedules. I suspect that is a problem handled offline and after-the-fact, and not in real time. However, the technology has probably advanced a bit in the 30 years I've been out of the sigint world. ;-) If we are trying to destroy the command post we do not need to receive the entire message we can simply wait until that frequency is reused by that transmitter. If the equipment is hopping over 100 frequencies it should be back within the next 200 transmissions. With spread-spectrum transmitters, the time spent at one particular frequency may be only a millisecond or two. If you can provide a link to a system that can accurately track a moving spread-spectrum transmitter, I'd be interested in reviewing its specifications. Try http://klabs.org/richcontent/MAPLDCon98/Papers/d3_haji.pdf For DFing you do not need to accurately track a spread-spectrum transmitter's hops. You only need to guess one of the frequencies. To intercept and decode a signal you need (almost) all the frequencies, providing it can tell the difference between static and modulated signal the above machine may be able to reconstruct the signal by listening on hundreds of frequencies simultaneously. The problem with intercepting spread-spectrum signals is that the receiver KNOWS where the next signal will arrive. It can tune it's receiver software for that frequency. The intercept receive has to be able to recieve ALL frequencies---and thus cannot use the same signal processing techniques as a receiver that knows the sequence. The computers will need programming to treat transmissions from two widely separated locations as two targets. Home in on them one at a time. How do you work with one continuously moving target transmitting on 256 different frequencies? I suppose it could be done with large enough antennas and enough processing power on a number of different ships. It's not going to be easy, cheap, or widely available, though. You can deal with frequency hopping by listening on hundreds of frequencies simultaneously. When one of the frequencies is known very accurate direction finding equipment can tune to that frequency and wait for the transmitter. Where the target is physically moving whilst transmitting something like a radar display is needed. PCs can be programmed to act in this fashion. Five years ago the army was working on things like this. Andrew Swallow |
#108
|
|||
|
|||
Defense against UAV's
In article .com,
says... wrote: This implies 1000 km of constant wind and cloud. Not necessarily. They could be further apart in good weather and closer toghether in bad. As far as wind is concerned COTS provides cheap (1m or less) GPS. They could stay in formation unless the wind speed exceeded forward speed. Unlikely. Wind is never homogenous and never from the same direction, especially over 1000klicks, all the 100 or 500 or whatever comms checks on position would certainly excite someone on the Elint watch. Those people are good, by the way, and have a real ear for the rare and unusual. Do you have a range (distance) for communications in this manner by the way? The $179, spread-spectrum, 1W, 900Mhz radios we use for telemetry have line-of sight ranges up to 40 miles. You can check out the state of the art in commercial products at http://www.maxstream.net/products/ That would be fine for covering the Straits of Hormuz. For that you don't need a 1000km swarm in any case. Mark Borgerson |
#109
|
|||
|
|||
Defense against UAV's
In article ,
says... wrote: :Not necessarily. They could be further apart in good weather and closer :toghether in bad. As far as wind is concerned COTS provides cheap (1m r less) GPS. Hint: Look up the accuracy specifications of GPS. Hint #2; consider that the improvements due to WAAS are not available outside North America. Hit #3: Consider the difference between accuracy and relative precision. The accuracy needed to transmit a target location is different from the relative precision you need to keep from colliding with other UAVs in the swarm. Mark Borgerson |
#110
|
|||
|
|||
Defense against UAV's
Keith W wrote: wrote in message ups.com... Hint: Look up the accuracy specifications of GPS. In 7-10 years it will be Galileo. The specifications are a little bit eklastic as they depend on integration time. If you are talking about RELATIVE separation this will in fact be only a few centimers, the accuracy of DGPS. The accuracy of the GPS systems isnt the issue anyway. Its handling the problem of separattion of large numbers of drones. If they have to communicate with each other that introduces extra weight, a considerable processing issue and a vulnerability to jamming and/or spoofing. Frankly you'd probably be better off accepting a certain percentage of losses due to mid air collisions Keith ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- The issue of transmission is the ability of a controller to take action. Also you need some degree of defense in depth. If an enemy swarm approached you, you would need the ability to direct resources to that are. One UAV with a LMG is not going to stop a swarm. If however it had communication technoilogy it might. Acceptance of losses due to mid air collisions - OK there will be heavy losses from a variety of causes. This is, of course, acceptable in a cheap unmanned system. To me the amazing thing is the sophistication of COTS. You talk about weight and cost, but I can put a mobile in my shirt pocket which can do the most amazing things. Spoofing - all converstaions are routinely encrypted. Jamming - yes OK but if you are the US you simply put the jammers out of action. In point of fact use of an error correcting code, such as Reed Soloman, will go a long way to soving the problem of jamming. You transmit in bursts, the jammers have be on all the time. If you were to have a swarm of UAVs with slightly modified mobile phones with some aircraft being base stations and commumicating via satellite you would have gone a fair way to building your system without too much reaearch. To do peer-peer communication is something which has been considered, a lot of development would be needed. What I think is amazing is the pace of COTS development. It provides a very good arument against secret projects. What in fact I had in mind was the provisions of contracts to the perveyors of COTS to advance their act in military directions. The military could make the new generation of Internet appear faster. The experts talk about 1) Specificicity. This will involve linguistic research. If you put in "lock" it will know whether you mean "eclusia" or "cerradura". 2) This is relevant here. The ability of a mobile phone to read a nearby screen. This is the whole concept of connectivity. Why not provide funds to get this done? No secrecy required. Tell Al Qaeda about the strength and breaking strain of the rope. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
GAO: Electronic Warfa Comprehensive Strategy Needed for Suppressing Enemy | Mike | Naval Aviation | 0 | December 27th 05 06:23 PM |
CRS: V-22 Osprey Tilt-Rotor Aircraft | Mike | Naval Aviation | 0 | October 14th 05 08:14 PM |
Air defense (naval and air force) | Mike | Military Aviation | 0 | September 18th 04 04:42 PM |
Naval air defense | Mike | Naval Aviation | 0 | September 18th 04 04:42 PM |
Showstoppers (long, but interesting questions raised) | Anonymous Spamless | Military Aviation | 0 | April 21st 04 05:09 AM |