Re: Using mobile phone masts to track things
Steve Schear wrote: At 06:33 PM 10/15/2002 +1300, [EMAIL PROTECTED] (Peter Gutmann) wrote: Scribe [EMAIL PROTECTED] writes: The technology 'sees' the shapes made when radio waves emitted by mobile phone masts meet an obstruction. Signals bounced back by immobile objects, such as walls or trees, are filtered out by the receiver. This allows anything moving, such as cars or people, to be tracked. [snip] Isn't this what CDMA already does using RAKE receivers (different fingers track multiple signals, so it uses multipath as a feature rather than a problem). [snip] Yes, this is very similar to a RAKE receiver. Its also similar to the passive radar systems the U.S. recently accused a former Soviet republic of selling to Iraq. Passive radars are particularly good at spotting current generation stealth aircraft. Being passive, typically using distant powerful shortwave broadcast signals, means its much harder to spot the receiving sites. Nice explanatory picture at... http://www.pcquest.com/content/technology/101081001.asp The (over-a-year-old) article also states: The downside is that you cant make out whether the plane is a spy plane or not. However various companies are working on making it viable for detecting stealth aircraft. For instance, Roke Manor Research (www.roke.co.uk), UK-based has developed sensor technologies which can work with cellphone base stations to detect stealth aircraft. Detecting moving objects is one (simple) thing. Tracking them while identifying the type of object (stealth plane vs civilian, motorbike vs car, etc) is a different issue, naturally. What kind of resolution can be obtained from a few hundred meters (say, for mass-public-monitoring-services) if grounded base stations can make out high-altitude aircraft? Further, are there any known defenses against this kind of passive technology yet? Solitary surveillance aircrafts would surely have a harder time achieving countermeasures than a person on a cellphone amongst a crowd of bystanders. Intereference? Decoys?
Re: Using mobile phone masts to track things
Steve Schear wrote: At 06:33 PM 10/15/2002 +1300, [EMAIL PROTECTED] (Peter Gutmann) wrote: Scribe [EMAIL PROTECTED] writes: The technology 'sees' the shapes made when radio waves emitted by mobile phone masts meet an obstruction. Signals bounced back by immobile objects, such as walls or trees, are filtered out by the receiver. This allows anything moving, such as cars or people, to be tracked. [snip] Isn't this what CDMA already does using RAKE receivers (different fingers track multiple signals, so it uses multipath as a feature rather than a problem). [snip] Yes, this is very similar to a RAKE receiver. Its also similar to the passive radar systems the U.S. recently accused a former Soviet republic of selling to Iraq. Passive radars are particularly good at spotting current generation stealth aircraft. Being passive, typically using distant powerful shortwave broadcast signals, means its much harder to spot the receiving sites. Nice explanatory picture at... http://www.pcquest.com/content/technology/101081001.asp The (over-a-year-old) article also states: The downside is that you cant make out whether the plane is a spy plane or not. However various companies are working on making it viable for detecting stealth aircraft. For instance, Roke Manor Research (www.roke.co.uk), UK-based has developed sensor technologies which can work with cellphone base stations to detect stealth aircraft. Detecting moving objects is one (simple) thing. Tracking them while identifying the type of object (stealth plane vs civilian, motorbike vs car, etc) is a different issue, naturally. What kind of resolution can be obtained from a few hundred meters (say, for mass-public-monitoring-services) if grounded base stations can make out high-altitude aircraft? Further, are there any known defenses against this kind of passive technology yet? Solitary surveillance aircrafts would surely have a harder time achieving countermeasures than a person on a cellphone amongst a crowd of bystanders. Intereference? Decoys?
More on cash through mobile phones...
Don't remember anyone mentioning Korea in the recent talk of cash+phones, but this is from a BBC article (regarding broadband content access), might be of interest: By far the most popular way of paying for content in Korea is a simple system which gives surfers a pre-paid cyber-wallet to spend. Users buy currency in advance via a text message and are sent an authorisation code which is typed into the website and debited from their mobile phone bill. ok, so it's not full on digicash exchange through a portable device, but it's a step in that direction. Article says Europeans are unlikely to embrace it (now there's a surprise...). Doesn't mention what kind of system is being used, or if they've got anything else planned. http://news.bbc.co.uk/1/hi/technology/2326253.stm
Using mobile phone masts to track things
The technology 'sees' the shapes made when radio waves emitted by mobile phone masts meet an obstruction. Signals bounced back by immobile objects, such as walls or trees, are filtered out by the receiver. This allows anything moving, such as cars or people, to be tracked. Previously, radar needed massive fixed equipment to work and transmissions from mobile phone masts were thought too weak to be useful. Not enough detail in there to answer many questions - anyone have any more info on this? http://www.observer.co.uk/uk_news/story/0,6903,811027,00.html
Using mobile phone masts to track things
The technology 'sees' the shapes made when radio waves emitted by mobile phone masts meet an obstruction. Signals bounced back by immobile objects, such as walls or trees, are filtered out by the receiver. This allows anything moving, such as cars or people, to be tracked. Previously, radar needed massive fixed equipment to work and transmissions from mobile phone masts were thought too weak to be useful. Not enough detail in there to answer many questions - anyone have any more info on this? http://www.observer.co.uk/uk_news/story/0,6903,811027,00.html
