Naked Science Forum
General Science => General Science => Topic started by: moonfire on 30/05/2007 04:36:22
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I know computers can use this technology but how does it work and also, can it track where a cellphone user is?
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What do the letters stand for LO ?
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Two questions rolled into one - so I have modified the title.
Firstly, for Karen - OHP stands for OverHead Projector.
These days, it is more common that computers use special projectors to project onto screens rather than OHP units, although the principle is the same.
All a computer needs to use an OHP is an LCD screen, the same kind as in a laptop computer (the kind you break when you drop or sit on [:P]), but instead of having the screen built into a unit with its own back light, it has nothing behind it but is placed on top of the OHP unit so that the OHP unit provides the light, which is then projected up through the mirrors and lenses above, and thence on to the wall or screen where it is viewed.
The tracking of cellphones is an integral part of the cellphone design. The whole point about cell phones is that there is a network of radio masts, each responsible for a the signal over a small area (the cell), and the phone needs to be able to know which mast to talk to, and when to hand over to the next radio mast as the phone is carried from cell to cell. Thus the same technology that the network uses to identify which is the closest cell for the phone to communicate with can also be used simply to say geographically whereabouts (within which cell, and how close to the neighbouring cell) the phone is.
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The tracking of cellphones is an integral part of the cellphone design. The whole point about cell phones is that there is a network of radio masts, each responsible for a the signal over a small area (the cell), and the phone needs to be able to know which mast to talk to, and when to hand over to the next radio mast as the phone is carried from cell to cell. Thus the same technology that the network uses to identify which is the closest cell for the phone to communicate with can also be used simply to say geographically whereabouts (within which cell, and how close to the neighbouring cell) the phone is.
Additionally, your location can be pinpointed using triangulation of the cell /mobile phone towers. All phones in the USA (since 9/11) have built in GPS, to enable the government to track you - should they want.
You can also pay for a commercial company to track the phone of your child, husband...all you then do is log in to your account on the net and hay presto you can see exactly where they are, or more accurately where their phone is, in real time!
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Additionally, your location can be pinpointed using triangulation of the cell /mobile phone towers. All phones in the USA (since 9/11) have built in GPS, to enable the government to track you - should they want.
Triangulation, yes (that is inevitable since the system is trying to work out which mast is closest in order to know which you should use, and it can only do that if it tries to talk to you through all of the masts).
The GPS thing sounds suspiciously like folk lore to me. Do you have evidence of this? The cost, including battery consumption, of adding GPS to a mobile phone would be substantial; and if the technology was already incorporated, then it would make sense for the phone companies to market it as a user feature (why pay hundreds of pounds for a separate SatNav system when you have already been sold one bundled into your mobile phone?).
You can also pay for a commercial company to track the phone of your child, husband...all you then do is log in to your account on the net and hay presto you can see exactly where they are, or more accurately where their phone is, in real time!
This is certainly true, and has also been incorporated into various anti car theft devices.
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OH, that is awesome Paul and George! Sorry Karen, I just made it back here...Amazing....I was thinking about the technology and you answered it perfectly!!!
In the UK, they do not have that technology Paul?
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Additionally, your location can be pinpointed using triangulation of the cell /mobile phone towers. All phones in the USA (since 9/11) have built in GPS, to enable the government to track you - should they want.
Triangulation, yes (that is inevitable since the system is trying to work out which mast is closest in order to know which you should use, and it can only do that if it tries to talk to you through all of the masts).
The GPS thing sounds suspiciously like folk lore to me. Do you have evidence of this? The cost, including battery consumption, of adding GPS to a mobile phone would be substantial; and if the technology was already incorporated, then it would make sense for the phone companies to market it as a user feature (why pay hundreds of pounds for a separate SatNav system when you have already been sold one bundled into your mobile phone?).
You can also pay for a commercial company to track the phone of your child, husband...all you then do is log in to your account on the net and hay presto you can see exactly where they are, or more accurately where their phone is, in real time!
This is certainly true, and has also been incorporated into various anti car theft devices.
It is true! They have the tracking devices on the phones so if I wanted to find out where someone is....I put the information into the telephone and within seconds...I will know where you are...I know if I want to find out what song is playing, I can put the phone up to the speaker and it will text me the name of the song and who sings it
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It is true! They have the tracking devices on the phones so if I wanted to find out where someone is....I put the information into the telephone and within seconds...I will know where you are...I know if I want to find out what song is playing, I can put the phone up to the speaker and it will text me the name of the song and who sings it
Tracking, yes - I am just very, very, dubious that they use integrated GPS to do it.
They don't actually need to use GPS, since Paul mentioned they can do it using triangulation (maybe not as precise - on the other hand, high precision GPS itself requires a greater number of satellites to be used, and hence a larger unit with more battery drain).
Certainly, the police are more than capable of tracking your mobile phone (at least to within about a block), and there have been some high profile criminal cases where this has been a significant piece of evidence used.
Modern cellphones, using higher frequencies, requires smaller cells, and hence gives better tracking precision.
Incidentally, the Orion US spy plane that the Chinese brought down a few years ago was using pretty much the same idea to track Chinese military units (OK, they did not have access to the actual network cells, so maybe they could not use the total precision that might have otherwise been possible, but good enough). For this reason, the Chinese troops were subsequently forbidden from carrying cellphones, and I suspect that other military around the world, at least when they are on sensitive operations, are also prohibited from carrying mobile phones with them.
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Pretty interesting info..I had no idea!
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As far as i understand it, the GPS unit is not intended for the phone owner to use only to enable the phones location to be tracked. I agree with you George, that it does sound folk lore/ urban legend, but i got it from a reputable source...
There are many things you can do, or rather have done to your phone. As with your computer you can get viruses that allow another person to listen in to your conversation, make calls from their phone that show on your bill and many more...
this website http://www.traceamobile.co.uk/ is a major one in the uk for parents, employers to track the mobile phone of their kids, employees...
incidently, you do not need to buy most devices such as satnav. you can get them as an application for your phone.
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As far as i understand it, the GPS unit is not intended for the phone owner to use only to enable the phones location to be tracked. I agree with you George, that it does sound folk lore/ urban legend, but i got it from a reputable source...
There are many things you can do, or rather have done to your phone. As with your computer you can get viruses that allow another person to listen in to your conversation, make calls from their phone that show on your bill and many more...
this website http://www.traceamobile.co.uk/ is a major one in the uk for parents, employers to track the mobile phone of their kids, employees...
incidently, you do not need to buy most devices such as satnav. you can get them as an application for your phone.
The web site you refer to seems to indicate that it simply uses triangulation within the cell network for tracking.
It does have a separate GPS tracking hardware, but that is at £199.99, and although it uses the cell phone network to send its postion, it does not use a standard cellphone.
Nor am I ware of any GPS software only solution for most cellphones (maybe some higher end cellphones, but not the usual 'free with connection' type phones).
I am aware you were only suggesting that the GPS hardware was intended for the security services to track the phone, but if the manufacturer is forced to pay for the hardware, then in a commercial market, it would make zero commercial sense not to capitalise on that extra hardware by selling the functionality to the end user.
As for viruses on mobile phones, it really depends on the operating system used by the mobile phone (I believe that only the Symbian OS is presently vulnerable to viruses, and many mobile phones simply do not have the functionality to carry viruses).
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In june of last year I purchased a new cell phone which I tried to get turned on .. apparently they would not do it as the phone had been recalled due to the fact it contained no tracking device for emergency 911 calls . They told me that it was not ok for them to have sold this phone to me without that device added to it because new laws stated they must have that tracking ability as of whatever the date was
here in the USA. I can't remember..LOL I boxed the phone up they had a new one to me before I could mail theirs back to them! LOL This was for a tracking device! what technology do you think it uses then?
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OK, having looked up various sources, it seems I was wrong (yes, it does happen [:P])).
Firstly, the phone locatiopn capability is suppedly only sent along with 911 calls (as indicated by Karen), and even then, apparently can often be disabled.
Secondly, the law does not actually state the technology to be used, only the average accuracy:
http://www.webopedia.com/TERM/E/E911.html
E911
Short for Enhanced 911, a location technology advanced by the FCC that will enable mobile, or cellular, phones to process 911 emergency calls and enable emergency services to locate the geographic position of the caller. When a person makes a 911 call using a traditional phone with ground wires, the call is routed to the nearest public safety answering point (PSAP) that then distributes the emergency call to the proper services. The PSAP receives the caller's phone number and the exact location of the phone from which the call was made. Prior to 1996, 911 callers using a mobile phone would have to access their service providers in order to get verification of subscription service before the call was routed to a PSAP. In 1996 the FCC ruled that a 911 call must go directly to the PSAP without receiving verification of service from a specific cellular service provider. The call must be handled by any available service carrier even if it is not the cellular phone customer's specific carrier. Under the FCC's rules, all mobile phones manufactured for sale in the United States after February 13, 2000, that are capable of operating in an analog mode must include this special method for processing 911 calls.
The FCC has rolled out E911 in two phases. In 1998, Phase I required that mobile phone carriers identify the originating call's phone number and the location of the signal tower, or cell, accurate to within a mile. In 2001, Phase II required that each mobile phone company doing business in the United States must offer either handset- or network-based location detection capability so that the caller's location is determined by the geographic location of the cellular phone within 100 meter accuracy and not the location of the tower that is transmitting its signal. The FCC refers to this as Automatic Location Identification (ALI).
http://findarticles.com/p/articles/mi_qn4188/is_20070406/ai_n19000094
The issue has become more critical as the number of 911 calls from cell phones exceeds those coming from landlines, according to public safety experts. The trend is expected to continue as more people opt to drop their landlines altogether.
CTIA, the nation's top wireless industry lobbying group, reports that 230,000 911 calls are made from cell phones each day. The group also estimates that 8.4 percent of households are "wireless only."
There is no doubt cell phones allow people to call for help from more isolated places, but public safety advocates and the wireless industry want people to understand the limits.
"People have to recognize it's not the wireline 911 system and never will be because you can only bend the laws of physics so much," said CTIA spokesman Joe Farren.
Martin's effort comes in advance of a new study from the Association of Public Safety Communications Officials that will highlight the limitations of "enhanced" 911 systems.
"It's a misconception to think that when you dial 911 on a cellular phone that the person on the other end is going to know where you are," said Bob Smith, director of emergency communications. Smith said he worries about television dramas in which police are able to locate a person in distress down to within a few feet.
"The fact is, that can't always happen in real life," he said. "The technology doesn't exist in most places to allow that to happen."
The location challenges stem from inherent limitations in how cell phones work and a decision the FCC made several years ago to allow manufacturers to use two different location technologies.
Network technology uses cell phone towers to zero in on a caller through a process known as triangulation. But to triangulate, there need to be at least three towers near the caller, which is unlikely in rural areas.
The second method uses satellite technology embedded in the phone. Rescuers use a geographical information system that guides them to the caller, often with great accuracy. While those phones are desirable in rural areas, they may be ill-suited in the urban canyons common to cities.
Federal law and FCC rules require that providers using the network method should be accurate to within 300 meters -- that's about three football fields -- for 95 percent of calls and within 100 meters for 67 percent of calls.
For the satellite method, responders must be guided to within 150 meters for 95 percent of calls and 50 meters for 67 percent of calls.
The FCC does not do any independent testing to ensure compliance, but rather acts on complaints. For assurances on accuracy, they rely on the companies themselves.
The flaw in the system is that carriers are permitted to use a large area, such as an entire state, to calculate their accuracy rate. Through averaging they may score well overall, but there may be gaps in some areas that are not addressed.
"It doesn't do any good for people in Buffalo and Albany if things are going well in New York City," Martin said.
The Association of Public Safety Communications Officials has urged the agency to require that testing be done on a community- level basis and Martin agrees. He said he will ask the full commission to issue an order granting APCO's request.
APCO also has asked that the providers share their accuracy data with rescuers, something else the chairman agrees with.
Martin also said he will address the network-versus-handset technology issue, something that may have a profound effect on the makers of the nation's 200 million-plus cell phones.
http://en.wikipedia.org/wiki/9-1-1#Locating_callers_automatically
In 2000 the FCC issued an order requiring wireless carriers to determine and transmit the location of callers who dial 9-1-1. They set up a phased program: Phase I transmitted the location of the receiving antenna for 9-1-1 calls, while Phase II transmitted the location of the calling telephone. The order set up certain accuracy requirements and other technical details, and milestones for completing the implementation of wireless location services. Subsequent to the FCC's order, many wireless carriers requested waivers of the milestones, and the FCC granted many of them. As of mid-2005, the process of Phase II implementation is generally underway, but limited by the complexity of coordination required between wireless carriers, PSAPs, local telephone companies and other affected government agencies, and the limited funding available to local agencies for the conversion of PSAP equipment to display the location data (usually on computerized maps).
These FCC rules require new mobile phones to provide their latitude and longitude to emergency operators in the event of a 911 call. Carriers may choose whether to implement this via GPS chips in each phone, or via triangulation between cell towers. In addition, the rules require carriers to connect 911 calls from any mobile phone, regardless of whether that phone is currently active. Due to limitations in technology (of the mobile phone, cell phone towers, and PSAP equipment), a mobile caller's geographical information may not always be available to the local PSAP. Although there are other ways, in addition to those previously stated, in which to obtain the geographical location of the caller, the caller should try to be aware of the location of the incident for which they are calling.
In the U.S., FCC rules require every telephone that can physically access the network to be able to dial 911, regardless of any reason that normal service may have been disconnected (including non-payment). On wired (land line) phones, this usually is accomplished by a "soft" dial tone, which sounds normal, but will only allow emergency calls. Often, an unused and unpublished phone number will be issued to the line so that it will work properly.
If 911 is dialed from a commercial VoIP service, depending on how the provider handles such calls, the call may not go anywhere at all, or it may go to a non-emergency number at the public safety answering point associated with the billing or service address of the caller. Because a VoIP adapter can be plugged into any broadband internet connection, the caller could actually be hundreds or even thousands of miles away from home, yet if the call goes to an answering point at all, it would be the one associated with the caller's address and not the actual location. It may never be possible to accurately pinpoint the exact location of a VoIP user (even if a GPS receiver is installed in the VoIP adapter, it will likely be indoors, and may not be able to get a signal), so users should be aware of this limitation and make other arrangements for summoning assistance in an emergency.
In March 2005, commercial Internet telephony provider Vonage was sued by the Texas attorney general, who alleged that their website and other sales and service documentation did not make clear enough that Vonage's provision of 911 service was not done in the traditional manner.
In May 2005 the FCC issued an Order requiring VoIP providers to offer 9-1-1 service to all their subscribers within 120 days of the Order being published. The order has set off anxiety among many VoIP providers, who feel it will be too expensive and require them to adopt solutions that won't support future VoIP products.
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OK, having looked up various sources, it seems I was wrong (yes, it does happen [:P])).
Hold on, does that mean i was right about something! Please recheck your data George, or i may have to chage my signature. [;)]
Firstly, the phone locatiopn capability is suppedly only sent along with 911 calls (as indicated by Karen), and even then, apparently can often be disabled.
I know i run the risk of sounding like a conspicary nut, but i like the word "supposidly". I have my own feelings about this, but would hate to have another conspiracy topic going.
Just a few other quick points:
1. In the write up for the link i gave earlier, they hinted that the tracking service could only be used when the phone was turned on and i don't think their level of accuracy was all that good. This would lead me to think that their service is not top notch. "I believe" your phone can still be tracked or traced even when turned off as long as your sim card is still in the phone, if you want you phone to be untrackable you do have to remove the sim and battery.
2. Yes the major problem with phones and viruses are related to those using the Symbian OS, but they have also been around for the microsoft mobile OS for a number of years. You can buy (no real free option) anti virus software for your phone buti have not found this to be too good when running simple tests.
You also have the added problem of flash messages. I have no proof for this but "think", flash messaging is an easy way to transmit a virus and have found no may of rejecting or restricting incoming flash messages.
You then have the problem of bluetooth. This is how most scammers work, leaving your bluetooth turned on is a serious security risk to your phone. there is plenty of free software that will alow you to access another phone via bluetooth, giving you access to their phone book and calls. where the service is avaliable (the USA predominately) push to talk is far easier, more convenient and secure.
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Firstly, the phone locatiopn capability is suppedly only sent along with 911 calls (as indicated by Karen), and even then, apparently can often be disabled.
I know i run the risk of sounding like a conspicary nut, but i like the word "supposidly". I have my own feelings about this, but would hate to have another conspiracy topic going.
The word supposedly is deliberate, because there is no technical reason it could not be sent at other times. Phone tracking using triangulation is available as long as your phone is switched on, and is an integral part of the network, so cannot be switched off (the main issue regarding E911 was that the information should be passed to the emergency services automatically without needing the active cooperation of the network providers).
In theory, phones could be designed to disable GPS data from being sent except when 911 is dialed (and it seems that not all network providers even use GPS for location, given its unreliability in urban environments). Whether the phones actually do or do not disable GPS at other times is anybody's speculation. Nonetheless, whether GPS or triangulation, it cannot be done without battery power, and so would seem unlikely to be done with the phone switched off, since that would imply a significant drain on batteries, and that would lead to serious usability issues if users were finding no difference in battery drain between the phone being switched on or the phone being switched off.
If you really wanted to be 100% certain about not being able to be tracked through your mobile phone, then remove the battery; but I do think it very implausible that the off switch on the phone would still be acting in such a way as to not substantially isolate the battery (enough that it could not power any of the radio transmitters in the phone).
Ofcourse, the real debate about tracking people, without battery usage, is by use of RFID tags - they may be short range, but they are passive devices (i.e. require no battery), so cannot be switched off.
The issue about GPS is that while they will be more accurate than triangulation, but the GPS signal can even be obscured by a tree (OK, one tree may block one GPS signal, but you can have potentially anywhere up to 12 of them within your horizon at one time); and GPS is totally unusable within a building (you need a clear view of at least some patch of sky, and it has to be a patch of sky with at least two satellites - maybe even 3, not sure - within it at the time); whereas many buildings still allow effective use of the mobile phone, and so allow triangulation of network signal to work to some degree (at least if you have access to at least 2, and preferably 3, radio masts - and this is not necessarily the case if you are in a reinforced steel building with windows only in one direction, facing only one transmitter).
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And with GPS satellite system, real time vehicle tracking (http://www.topvehicletracking.com/Real+Time+Vehicle+Tracking+As+State-Of-The-Art+Modern+Day+Technology.10287.htm) became a reality.
We must be thankful with this new technology coz' it will help in the decrease of car jacking.
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Triangulation?
That would rely on accurate direction finding antennae in each cell - to get the 'angles'.
It is much more likely that the position of the phone is found by
1. Finding the cell with the strongest signal.
2. Comparing the signal strengths for the surrounding cells and the primary cell and using that info to find, to a greater or lesser extent, which side of the primary base station you are and, roughly, your likely relative distances from the base stations.
3. Phase / timing comparison could be made, for much greater accuracy but this would involve more complex equipment and I have not heard of its use for mobile networks; large area nav systems, like Decca Navigator use(d) this method.
Local terrain will have a huge effect on measurement of relative signal levels but it is easy to 'calibrate' an area to compensate, somewhat, for this.
We have all seen far too many spy films and the popular conception is that 'they' can see you as a moving spot on a map or within a building. The truth is probably a lot more mundane and subject to a lot of error.
Have you seen films of naturalists trying to find tagged wild animals by waving an antenna around and chasing through the undergrowth? I think that is a more realistic picture. It is interesting to note that, on such films, they tend to use a directional (yagi - type) of antenna and locate a signal maximum. This is very approximate because of the broad beam pattern. The best DF method (used by all Second World War Nazis when trying to find secret agents in films) is to use a crossed loop - type antenna (or equivalent) which has a very sharp 'null' and can determine direction to within a degree or two by nulling our the wanted signal. Of course, two or more receiving positions are needed to produce true triangulation once you have found the null bearing.
GPS can be hopeless around high buildings and, of course, consumes battery power. Not too good for tracking people but, for cars on the move, that wouldn't matter (sat nave works ok, mostly). We're not actually suggesting GPS is included in all phones, are we? If it were, they would advertise it and charge for it.
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Firstly, one has to look at what is possible with a 1GHz signal, as against something in the HF band that would have historically been relevant.
Yes, when I was referring to triangulation, I was referring as much to relative signal strength as signal direction; although modern cell phone base stations (particularly in crowded urban areas) tend to segment up the cells by using directional aerials anyway, so at least some degree of directionality is possible. Also, since you are dealing with a grid of cells, if you are dealing with a moving target, you can also get some degree of speed and direction of movement (by judging when the target crosses cell boundaries), and so make a better projection of current location.
Ofcourse, all of this means the exact precision you get is highly variable, but in some circumstances can be quite good.
I believe satnav is now included in many phones as standard. I am not sure why it is not marketed more vigorously, but it might be because the phone manufacturers don't believe the implementation of it is good enough to be able to make it a marketable feature, so rather than cause consumer disappointment, they just keep quite about it.
In any case, I think the phone manufacturers are more concerned about marketing applications than technologies (probably rightly so), so they market features such as listing restaurants near your present location, rather than marketing GPS as an underlying technology. They are not marketing GPS map following because they have not implemented the application (as I said, they may not trust their implementation of the technology to deliver that application, or it may simply be they lack the processing power in the phone to deliver that application).
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although modern cell phone base stations (particularly in crowded urban areas) tend to segment up the cells by using directional aerials anyway, so at least some degree of directionality is possible.
Yes, of course you can make them directive - but the aperture is hardly more than a wavelength or so and this produces a beam which probably covers tens of degrees. In any case, the beam can't be subdivided if you wanted to find the direction of your phone.
I just don't believe that any of the arrays I have seen could do any amount of 'De efFing'. They certainly don't have steering up there!
There are phones on the market with gps but I can't imagine it not being an advertised feature.
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The network can tell which base station you are using and there may be a record of previous base stations but that is it. Anything else is fantasy. In my case here at home my phone shows not the local phone code, not even the adjecent code but the one beyond that. I must be getting a better signal from a hilltop base station than local stations so I might be thought to be 20km further south.
It may be that as you move out of your local area the phone goes to transmit to tell the network where you are so you are ready to take a call but certainly when you switch a phone on it goes to transmit briefly so if don't want to be tracked keep the phone 100% off.
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It amazes me that criminals are daft enough to use the same phone all the time. You can buy a new phone every day for not many quids and no one would ever trace you on pay as you go.
Not a bad investment for a multi million pound scam.
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I know computers can use this technology but how does it work and also, can it track where a cellphone user is?
Ok, dear, I won't keep tracking your phone anylonger! [:)]
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It amazes me that criminals are daft enough to use the same phone all the time. You can buy a new phone every day for not many quids and no one would ever trace you on pay as you go.
Not a bad investment for a multi million pound scam.
Andrew, try downloading this to your pda
http://www.google.com/mobile/gmm/index.html
try it out, and lets us/me know what you think.
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It amazes me that criminals are daft enough to use the same phone all the time. You can buy a new phone every day for not many quids and no one would ever trace you on pay as you go.
Not a bad investment for a multi million pound scam.
Which is why the UK government now insists you show ID when you buy a mobile phone (part of their anti-terrorist legislation).
Ofcourse, that does not stop you from buying phones on the black market (probably stolen phones).
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"Triangulation?
That would rely on accurate direction finding antennae in each cell - to get the 'angles'."
No you can do without the angle data if you know the distances. You can gaet that (badly) from signal strength or quite accurately from timing data (which is how GPS works).
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Maybe but do they actually do it?
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Anyone can request spare sim cards, in the UK. All you need do if contact say t-mobile and ask for payg sims to be sent to your home.
they will then send you two, and not bother to check that the person they are addressed to lives at that address, i know i have just done it.
http://www.t-mobilesimgiveaway.co.uk/?WT.mc_id=ON-TM-W-Home