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Cellular Phone Forum / General / GSM / October 2004Big Brother is watching you
Big Brother is watching you FCC did it again By December 31, 2005, your cell phone company will always know exactly where you are. That's when the FCC will complete Phase II of its Enhanced 911 (E911) program, requiring all U.S. wireless carriers to provide the location-within 50 to 100 meters in most cases- http://www.pcmag.com/article2/0,1759,1463748,00.asp > Big Brother is watching you > > FCC did it again > > By December 31, 2005, your cell phone company will always know exactly where > you are. Wonder how they're going to implement that ? Here in the UK, the Vodafone GSM telco has a 'Find Me' service, and I've found it to no more accurate than a few miles at best. > That's when the FCC will complete Phase II of its Enhanced 911 > (E911) program, requiring all U.S. wireless carriers to provide the > location-within 50 to 100 meters in most cases- All new handsets must have GPS fitted ? > http://www.pcmag.com/article2/0,1759,1463748,00.asp  SignatureMichael Turner Email (ROT13) zvxr.gheare1963@grfpb.arg > > Big Brother is watching you > > [quoted text clipped - 15 lines] > > > http://www.pcmag.com/article2/0,1759,1463748,00.asp They don't need GPS -- if you measure the phone signal's time of arrival at several cell towers, you can triangulate the position. >> Big Brother is watching you >> [quoted text clipped - 4 lines] > >Wonder how they're going to implement that ? It is done by extracting more precise timing (at least on a GSM system). Normally the network only tracks timing to a few microseconds (+/- about 500 meters), however it can be tracked with much higher accuracy. If you get timings from two BTS's that are good to say .1 microsceond,. The timing data and timing advance gives you the distance from the BTS, draw the two circules, and where they intersect (2 places) are the only possible locations. Often times the second position will be impossible because of the antenna geometry (it cannot be there, because if it was, the antenna we used couldn't hear it). Worst case is a 3rd BTS timing signal, even with relativley low accuarcy will tell you where the phone has to be. >Here in the UK, the Vodafone GSM telco has a 'Find Me' service, and I've >found it to no more accurate than a few miles at best. [quoted text clipped - 6 lines] > >> http://www.pcmag.com/article2/0,1759,1463748,00.asp Why they can not find our phone when it stolen or lost ? >>> Big Brother is watching you >>> [quoted text clipped - 28 lines] >> >>> http://www.pcmag.com/article2/0,1759,1463748,00.asp >Why they can not find our phone when it stolen or lost ? Because at the moment, the operationg of the advanced timing software is tied to calling 911. >>Why they can not find our phone when it stolen or lost ? > Because at the moment, the operationg of the advanced timing software > is tied to calling 911. So for the rest of us, the location is probably determined by which cell the phone is registered on. Which could explain why my SP's(Vodafone UK) 'Find Me' feature is only accurate to a few miles at best, and is quite often more than ten miles out. SignatureMichael Turner Email (ROT13) zvxr.gheare1963@grfpb.arg >>>Why they can not find our phone when it stolen or lost ? >> Because at the moment, the operationg of the advanced timing software [quoted text clipped - 4 lines] >'Find Me' feature is only accurate to a few miles at best, and is quite >often more than ten miles out. Actually most of the time, they should be able to find you with more accuracy than that. Your distance from the BTS is known to +/- about 500 meters from the timing advance. Bearing is +/- 60 degrees. The closer you are to the BTS, the more accurate the position estimate is >Actually most of the time, they should be able to find you with more >accuracy than that. Your distance from the BTS is known to +/- about >500 meters from the timing advance. Bearing is +/- 60 degrees. The >closer you are to the BTS, the more accurate the position estimate is I have done drive testing for AT&T Wireless and they can tell where you are withing about 3 meters. Testing would indicate that they can tell you the address that you are sitting in front of and or the distance from the closest intersection. Your above explanation is incorrect. -- John S. e-mail responses to - john at kiana dot net >>Actually most of the time, they should be able to find you with more >>accuracy than that. Your distance from the BTS is known to +/- about [quoted text clipped - 7 lines] > >Your above explanation is incorrect. AT&T is obviously using signal timing, and i doubt it is +/- 3 meters. I doubt they know the position of their BTS that well! The original inquiry involved Vodaphone, and outside the USA, the FCC rules don't count, so all they have to work with is antennae bearing (+/- 60 degrees), and basic timing advance (+/- 500 meters). >>I have done drive testing for AT&T Wireless and they can tell where you are >>withing about 3 meters. Testing would indicate that they can tell you the >>address that you are sitting in front of and or the distance from the closest >>intersection. >> >>Your above explanation is incorrect. >AT&T is obviously using signal timing, and i doubt it is +/- 3 meters. >I doubt they know the position of their BTS that well! Why not? Even a cheap consumer GPS can easily achieve that kind of accuracy. SignatureBest regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES: John Navas <http://navasgrp.home.att.net/#Cingular > [POSTED TO alt.cellular.gsm - REPLY ON USENET PLEASE] > [quoted text clipped - 9 lines] > > Why not? Even a cheap consumer GPS can easily achieve that kind of accuracy. Apparently, Matt is unaware that every BTS has it's own personal GPS receiver. Trimble seems to be the popular fashion. Signaturejer email reply - I am not a 'ten' >> [POSTED TO alt.cellular.gsm - REPLY ON USENET PLEASE] >> [quoted text clipped - 12 lines] >Apparently, Matt is unaware that every BTS has it's own personal GPS >receiver. Trimble seems to be the popular fashion. Except that the average accuarcy even with WAAS is no better than about 3 meters, and without WAAS, figure 10 meters. The GPS receiver on the BTS isn't there for positioning, it is there for timing. It is a cheap way to get atomic clock accuracy/stability. The BTS neither knows or cares where it is, but it certainly cares about network timing. >[POSTED TO alt.cellular.gsm - REPLY ON USENET PLEASE] > [quoted text clipped - 9 lines] > >Why not? Even a cheap consumer GPS can easily achieve that kind of accuracy. WRONG. A cheap GPS cannot achieve that sort of accuracy. You need WAAS to get anywhere near 3 meters. The other problem is you need a good view of the sky for a GPS work, which makes it unusable in many areas (like indoors, in parking garages, urban canyons, etc.) If what you said was true, car navigation systems would be a whole lot less expensive then they are, they could be pure GPS. The ones that work well are not! . The reality is those systems incorporate either Inertial Navigation (3 axis solid state accelerometer), or Dead reckoning (Vss input from the vehicle for distance, and a gyro for direction). >>>AT&T is obviously using signal timing, and i doubt it is +/- 3 meters. >>>I doubt they know the position of their BTS that well! >> >>Why not? Even a cheap consumer GPS can easily achieve that kind of accuracy. >WRONG. A cheap GPS cannot achieve that sort of accuracy. You need >WAAS to get anywhere near 3 meters. WAAS is available in cheap consumer GPS units; e.g., Magellan eXplorist 100, $77 at Compuplus.com >The other problem is you need a good view of the sky for a GPS work, A reasonable view. >which makes it unusable in many areas (like indoors, in parking >garages, urban canyons, etc.) My Magellan SporTrak GPS works fine under trees and in urban canyons. > If what you said was true, car navigation systems would be a whole >lot less expensive then they are, they could be pure GPS. The ones [quoted text clipped - 3 lines] >(3 axis solid state accelerometer), or Dead reckoning (Vss input from >the vehicle for distance, and a gyro for direction). A Magellan SporTrak with DirectRoute software costs as little as $300, and works great. SignatureBest regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES: John Navas <http://navasgrp.home.att.net/#Cingular If the carrier uses signal timing to determine your position, this would mean that your phone would have to be pinging the tower on a periodic basis. Is this correct? If so, how often does the phone trasmit to the tower when in standby mode? --Eric > how often does the phone >trasmit to the tower when in standby mode? The phone does not send anything unless there are several things that happen. First, if the phone is moved from one cell site to the other, it will identify itself to the new cell site so that call delivery is quicker. Second, if the phone is requested by the system to tell the system where it is. Finally, if the phone is used, it sends information to the system and is assigned a cell site to talk to. Otherwise standby is just that - standby (no transmissions of any kind). -- John S. e-mail responses to - john at kiana dot net >> how often does the phone >>trasmit to the tower when in standby mode? [quoted text clipped - 10 lines] > >Otherwise standby is just that - standby (no transmissions of any kind). CDMA devices typically register themselves every 10-20 minutes even stationary in a given zone. GSM typically does this as well, to guard against location database failure. SignatureBest regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES: John Navas <http://navasgrp.home.att.net/#Cingular >> how often does the phone >>trasmit to the tower when in standby mode? [quoted text clipped - 5 lines] > it will identify itself to the new cell site so that call > delivery is quicker. Only if the next cell has a different LAC (Location Area Code) from the on already camped on. Registration is to an LAC, not to an individual cell. This makes sense when you consider that the paging for an incoming call is done over all cells within an LAC. Registration with the correct LAC is absolutely essential to the routing of incoming calls - it's not just a matter of quicker delivery. John >Only if the next cell has a different LAC (Location Area Code) >from the on already camped on. This used to be the case, however the cell phone's location is accounted for to the cell site now for faster call delivery. -- John S. e-mail responses to - john at kiana dot net >>Only if the next cell has a different LAC (Location Area Code) >>from the on already camped on. > > This used to be the case, however the cell phone's location is > accounted for to the cell site now for faster call delivery. I can't believe that, unless each cell has its own unique LAC. But then battery life would be absolutely atrocious with so many location updates. What's potentially slow about being paged by every cell in an LAC? There are often hundreds of cells within each LAC where I live. There's no location update done when switching cells within an LAC, and paging takes a couple of seconds at most. John >If the carrier uses signal timing to determine your position, this >would mean that your phone would have to be pinging the tower on a >periodic basis. Is this correct? If so, how often does the phone >trasmit to the tower when in standby mode? > >--Eric The requirement to locate the phone only exists while it is active, i.e. a call to 911. As a practical matter, GSM networks poll phones periodically to see where they are in relatively general times, and if they are still on the network, happens 2-4 times in 24 hours, depending upon the carrier. The FCC regulations in the US make most devices relative immune, but outside the USA, often the radio or TV will let loose with the 217 Hz buzz when it happens. When you hear it, it means either your phone is about to ring, or it was just polled. >>If the carrier uses signal timing to determine your position, this >>would mean that your phone would have to be pinging the tower on a [quoted text clipped - 13 lines] > the 217 Hz buzz when it happens. When you hear it, it means either > your phone is about to ring, or it was just polled. I must have one of those cheap radios in my car, I hear it regularly. There's even one place where I hear it every time I drive through - must be a weak spot in network coverage. Signaturejer email reply - I am not a 'ten' >>>If the carrier uses signal timing to determine your position, this >>>would mean that your phone would have to be pinging the tower on a [quoted text clipped - 17 lines] >There's even one place where I hear it every time I drive through - must >be a weak spot in network coverage. No, devices intended for Mobil use are exempt from the relevant FCC regulation regarding conducted and radiated emissions. The result is a Car radio is exempt, a table radio is not. >>>>If the carrier uses signal timing to determine your position, this >>>>would mean that your phone would have to be pinging the tower on a [quoted text clipped - 21 lines] > regulation regarding conducted and radiated emissions. The result is a > Car radio is exempt, a table radio is not. Funny that you mention table radios, because I've heard the 217 phantom on many of those as well. It's really not a problem for me as it's more a precursor to another call going to vmail. Signaturejer email reply - I am not a 'ten' >AT&T is obviously using signal timing, and i doubt it is +/- 3 meters. >I doubt they know the position of their BTS that well! Well, they know within 3" where the BTS is. The GPS positioning system is very good. -- John S. e-mail responses to - john at kiana dot net >>AT&T is obviously using signal timing, and i doubt it is +/- 3 meters. >>I doubt they know the position of their BTS that well! > >Well, they know within 3" where the BTS is. The GPS positioning system is very >good. GPS is indeed very good, but not that good: With WAAS, 1-2 meter accuracy Even with LAAS, 0.5 meter accuracy SignatureBest regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES: John Navas <http://navasgrp.home.att.net/#Cingular > Why they can not find our phone when it stolen or lost ? Your question presumes... 1. the phone is still turned on 2. the battery hasn't gone dead yet 3. the 'finder' system is always completely functional 4. the phone is actually in a trackable location 5. the phone was ever trackable in the first place 6. anybody cares about finding it in the second place Signaturejer email reply - I am not a 'ten' >>Big Brother is watching you >> [quoted text clipped - 14 lines] > All new handsets must have GPS fitted ? > That was one consideration in the early stages of planning. But handsets often disappear into an overhead areas where GPS won't work. However, here's the skinny for some U.S. wireless carriers... http://www.trueposition.com Signaturejer email reply - I am not a 'ten' "All that we do is touched with ocean, yet we remain on the shore of what we know." -- Richard Wilbur Wondering how they can find you ?! Well using the time advance method is not accurate due to reflections. It is not the first time that I am just under the base station and I have 20 time advances marked. What is really done is to feed several time advance readings from several base stations to a neural network. The neural network acts as a sort of a filter to those readings. Training the neural network however requires some time since training involves "you" going around with a mobile and a GPS gathering readings. Sounds simple and infact it is. David Joseph Bonnici > Wondering how they can find you ?! > [quoted text clipped - 11 lines] > > David Joseph Bonnici As I understand it, this is how the True Position system works. Signaturejer email reply - I am not a 'ten' This is however still experimental. The same system is also used for credit cards. Lets say that for example you use your credit card two times a week and you never spend over 50 Dollars each time. A neural network is trained with this data:- i.e. amount of money spent, what it is purchased if possible, where it is purchase and the time of purchase. Lets say, they have pickpocketed you and you did not notice it. Lets assume also that they use your credit card to pay porn sites. The neural network will notice that this does not form part of the normal chaos and so will issue a warning at the bank that something smelly is happening. Then bank officers will call you on the mobile upoun the report generated. Interesting no. This is also a form of big brother. David Joseph Bonnici > This is however still experimental. > [quoted text clipped - 17 lines] > > David Joseph Bonnici Well, it's like I said, this sounds exactly like how the True Position system works. I do know that when a TP system is installed, calibrating the network is key to it's function. Each and every street all across the coverage territory is drive tested w/GPS, so that the RF characteristics of a radio transmitter are known (and therefore predictable) from any particular location. A drive tester I met was equipped with a roof-mounted Trimble GPS and a call simulator all tied into a laptop with a full-time active wireless network connection. Presumably the simulated calls were constantly being analysed by the BTS, and the GPS coordinates were being recorded into a database where an overlay to a street map was created. Personally, I found the whole deal quite interesting and seems to offer plausiblility to the idea of it actually working as intended. Signaturejer email reply - I am not a 'ten' |
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