Joho the Blog
An Entry from the Archives

The phone will regularly to get a GPS fix location when it is on. It is difficult to a get a fix indoors, so the phone will keep track of the last good location fix.

If you call 911, the phone will attach the last good location fix to the call just as it does with Caller ID info. I'm guessing there's a way to ping the phone for location if desired.

Shortly in the future the telcos will want the phone to consistently announce your location so they can direct localized ads to you. e.g., You drive into the mall parking lot, and your phone pops up with a 10% coupon from Macy's if you shop there in the next hour.

If you are worried about being tracked, the GPS is not the thing 'they' can do it with. In areas with several cell towers, 'they' can triangulate on the radio in your cell phone accurately. As long as 3 cell towers can see you. In most big cities, this is the case.

As McNealy says, your privacy is already gone.

Cell towers, not satellites, so no "GPS" here, but lat-long info like GPS.

I am glad I get to read blogs like this...some of us are too dumb to even ask the "dumb" questions.

My guess for the general lack of knowledge is because the idea would seem of greater harm than good to the average citizen (especially when coupled with the Patriot act and its wonderful extensions)...

So, am I right to conclude that:

1. Location-aware cellphones will NOT be transmitting their location unless you make a 911 call

2. The carriers could figure out where you are if they wanted to but are not routinely recording that info

???

Thanks for the help!

Can't say for certain how or if it works but..... If you recall president Bush snuck off to Iraq to have Thanksgiving with the troops. Along with him on the journey were several media reporters and supporting personel. As the stories I read go all personel were instructed to remove the batteries fron cell phones, pagers and related devices as GPS data could be collected otherwise.

May be more than just 911 calls.

With the Bush-> Baghdad trip, I think the removal of batteries from the cell phones was to guarantee the secrecy of the mission, so absolutely no one would have a heads up, not even a "Hey, honey, guess where I'm secretly sneaking to with the PotUS?" which could then be intercepted with a listening device and the security compromised. Also, if there was GPS data broadcasted from a US phone over seas, it would probably not be received by a non-native network, and if it was, how would they know who owned it, and who that person was with?

I don't know the specifics beyond the background on tech that makes it work, but my understanding is that triangulation is possible with any cell phone already, I believe that's how they judge "hand-offs" when you move from one "cell" to another as you move, and also, I imagine thats how phone calls find you on the network. Whether or not they have a human interface in place to read that info, and then place it over a map is another question. Another option would be to mix tracking of a phone with a GPS: it could simply announce its last position along with it's presence as it pings it's nearest cell tower.

I am no expert on the subject, but there are apparently several technologies that can be used to meet the e911 requirements. Some of them are called "Assited GPS", as the handset only has a partial GPS receiver, and is assisted by GPS receiver in the Cell Towers and a server that calculates the position:

See: http://www.cs.huji.ac.il/~postPC/docs/Geolocation_assistedGPS.pdf

Actually, if a cell phone is on, it constantly keeps in touch with the network. The network "knows" where you are. That's the only way it knows which tower to transmit an inbound call too. Making a call is irrelevant. if the phone is powered on, the "network has a sense of location".

There have already been trials of location specific push of advertising (Chicago, 2 years ago) based on this info.

There's a decent high-level view at http://www.skyaid.org/LifeWatch/E911_June2001.htm

Most of the carriers selecting the network scenario favor a combination of time difference of arrival (TDOA), which calculates a phone's position based on the speed the signal reaches multiple nearby antennas, and angle of arrival (AOA). With AOA, cellular towers identify the direction from which a signal is coming and then plot the direction of the incoming call based on a reading from two towers.

Then there's a hybrid system known as enhanced observed time difference (EOTD). The major supplier of EOTD technology, which only works with GSM terminals, is U.K.-based Cambridge Positioning Systems. CPS's Cursor software doesn't require any hardware modification to the handset, provided that there's sufficient free RAM. Some low-level reprogramming in the DSP is necessary, however, as well as some additional software in the microprocessor. This "off-the-shelf" solution is available from CPS on a licensed royalty basis. The portion of Cursor that runs on the handset microprocessor is optimized for ARM, reducing power consumption as well as the overall system cost for OEMs.

Dated, but still reasonably accurate.

I've had similar questions. Here's two links:

• Geo Referenceable Cell Phones: turn the cell phone into a referencing tool
  

As others have said, moost cell phone operators will be using Cell ID (the details of which transmitter you are using). Trouble is, this will mostly not be within 150m accuracy, so other network tricks, such as triangulation, and signal strength, can be used. I don't think many operators use these yet (in Europe anyway).

Adding hardware to the phone is the other option - either a full blown GPS (with associated signal, time and power problems), or assisted GPS, which is cheaper to implement, provides quicker fixes, but requires the base stations to have either a hardware or software upgrade. Either which way, few Western handsets have this additional hardware built in.

So, it's all doable now, but accuracy will remain the problem.

Carriers in Europe use location information in wap and similar services, and now, with permission, third party services have (expensive) API hooks to get this info.

This topic is the basis of what I'm talking about at Emerging Technology - 35 ways to find your location - also looking at other ways than network info to find yourself.

In the UK, at least, the network providers already track and record at least a minimal level of location data (e.g. the cell site handling the call.) I would be very surprised if the US providers didn't also store whatever they could. To be honest, I'm somewhat surprised that they don't seem to routinely calculate position more exactly. On the other hand I would not be surprised if they are fudging it by storing the signal strength and timing data from which you can derive location, but not actually doing the calculations.

Thanks to the recently passed "snooper's charter" bill in the UK, this information will have to be stored for long periods of time, and made available to a wide and interesting variety of minor officials from local and national government. On the plus side, under the data protection act, if you ask for it they must give it to you too.

For more information see this story:

This may affect Orange, which currently retains location data for six months. Vodafone already keeps it for a year, BT Cellnet for "at least a year", and Virgin Mobile has retained it since its foundation in November 1999. It plans to hold such data for six years, citing financial regulations. One2One refused to disclose its retention period. Other than this information, none of the networks would discuss location data further than to say they complied with the law.

Chris: sounds like a very interesting topic, I wish I could make it to Emerging Tech! Will you be posting the talk online anywhere?

Wow, y'all are amazing. Thank you!

(Coder, I'm not giving a talk on this at Emerging Tech. This is for a brief radio piece I'm doing for "Here and Now.")

VirginMobile already offers e911 service, and my Audiovox 8500 phone has a "Location" setting which swtiches how the phone's location is "available on the network". The setting switches between the location being always available and it being available only during 911 calls.

I am pretty sure that the 8500 uses assited GPS for positioning accuracy beyond the tracking by cellphone towers.

I Purchased a Virgin Mobile Phone knowing it had GPS, for my Daughter. As I feared it was stolen. I had it set to always transmit the Location. A lot of good it did. The Sprint People would not give me the Data. (Sprint sells time to Virgin) Why have it if they won't let you use it? I guess maybe in the future they may.

I have a LG VX 4400 phone with GPS, it has the option to turn on E911 only or have it set to location 911. I am confused which to use. Also, does it use more of my battery to keep sending my location when I have location on. So if with the E911 they are tracking my position why would I need Location 911. I think that is the only way to track where I have been and the e911 is only tracked when you call. Any ideas how i should set the phone - to location or e911 only? I was thinking when I am traveling and may need the 911 feature to have it set on location. It is not easy to turn location on and off.

Deb, excellent questions to which I have no answers. Sorry!

I am working on a slightly different issue: I am wondering if the cellphone maintains a record of which antenna (CELL tower) it can connect to. I know my phone in Australia displays the cell info(as a street/suburb name). But in the US do phones have a way of knowing this information and further more can this data be programatically queried by applications running on the phone's Operating system?

Im very happy BENEFON ESC NT GSM/GPS phone owner.

heres some info about Benefon gps phones..

www.benefon.com

www.accutracking.com has a free Java application tracking Nextel phones.

I have an LG VX4400 also. David, you want to set it to "E911 Only"(only gives the info when you dial 911). Location broadcasts all the time.

David Weinberger: AFAIK, U.S. phones do not do this the same. If you can get the info from the phone, it would be an assigned letter and/or number ID for the tower. Unless you know which is which, it doesn't help much. :( Someone please tell me if I am wrong here...

Jay Fienberg: I fell your pain. I am looking for a way to do this. About a month ago my wife's car broke down. She had trouble telling me exactly where she was (don't ask...I finally found her). It would have been nice if I could have fired up my web browser and looked at the location on a map. (or God forbid I ever got lost LOL)

Edit: Please forgive me, looked at the layout wrong! LOL I do believe I have the proper names now... My apologies!

I have an LG VX4400 also. Deb, you want to set it to "E911 Only"(only gives the info when you dial 911). Location broadcasts all the time.

Prashanth: AFAIK, U.S. phones do not do this the same. If you can get the info from the phone, it would be an assigned letter and/or number ID for the tower. Unless you know which is which, it doesn't help much. :( Someone please tell me if I am wrong here...

David: I fell your pain. I am looking for a way to do this. About a month ago my wife's car broke down. She had trouble telling me exactly where she was (don't ask...I finally found her). It would have been nice if I could have fired up my web browser and looked at the location on a map. (or God forbid I ever got lost LOL)

i would like to now can we track it or not so i can see were my kids are or about

This feature was very usefuk when i lost my phone in California

hey ppl i waws jus kidding lol

Sorry for the late post, but I came across this topic and thought that I had something interesting to add. My company maintains a database of towers and consults on cell tower leases. (see Steel in the Air) One of my more common inquiries lately is from companies that want to provide location based services (LBS)like those mentioned earlier in the post. Some of these companies have even contacted me.

There are two manners of providing LBS- having GPS in the phone directly and the triangulation talked about previously. GPS requires line of site to satellites and currently most of the providers don't use GPS in phone to meet their E-911 obligations. The majority are looking at triangulation.

Triangulation by the carriers is relatively easy- each cell site is given a unique cell ID which is attached in a database to a latitude and longitude coordinate. From there it is easy to find out where the phone is by talking to many towers simultaneously and triangulating the location.

While the carriers have this data and can use it easily- the external vendors who are trying to provide LBS are looking for a source of the cell IDs. Unfortunately, this information is not publically available except through one or two data aggregators who maintain this data for the carriers.

So these LBS companies are out of luck unless they deal directly with the carriers.

Although it is very likely that government agencies have the technology to track us through our cell phones, they must have a court order that states that they can legally do so. To answer the question about the ability to track a cell phone; this seems to be the most likely answer. To the best of my knowledge, cell towers send out a singnal to any phone within range. The phone then responds with it's own signal which tells the cell phone network that it's within range of that certain tower and that it will be using that certain tower for its uses while it is within range. All that the tower can tell is that the cell phone is within a certain distance from the tower's location. If somebody we to try to pinpoint your location they would need at least three cell towers from the the same cell company within range of the said cell phone. With those three cell towers, they can locate your position to within, oh, say twenty feet using triangulation.

great comments - just got a new cell phone with the location vs e911 location choices and I didn't know which to select and the docs as always provided no information. so I googled "cell phones location feature e911" and found this site.

so now I know! E911 only.

Thanks folks.

Hello,
I own a Virgin Mobile 8500 cell phone. Does anyone know about any info available on the net about that phone's API? Say, for example, you connect the phone via USB to your Linux PC, and then what to send to the phone to get data from it?
Thanks,

Mark

I was just wondering if there is ANY way of tracking a lost cell phone. It is a Motorola V220 . It just goes straight to voicemail and I am so stressed out. I just got it too! Please help!!!

Sure you can if you have the right tools
GPS Cell Phone Tracking
AccuTracking software turns your Motorola iDEN i58sr, i88s, i325, i355, i265, i285, i605, i710, i730, i830, i850 or i860 cell phone carried by Nextel, SouthernLINC (US) or Telus (Canada) into a GPS tracking device. The free online GPS cell phone tracking service provided by AccuTracking.com lets you see locations, speed, and headings of your mobile clients, family members or valuable assets.

My cell phone asks me if I want my location to be broadcast continuously or not. If not, it says 911 will still know my location.

My cell phone asks me if I want my location to be broadcast continuously or not. If not, it says 911 will still know my location.

HOW CAN I FIND OUT WHERE A CELL PHONE WAS LAST USED, AT A REALSOABLE FEE ? PLEASE HELP ME FIND MY GRAND-DAUGHTER.

Ok to clear things up:
A TDOA antenna used with an AOA array, you need only one recieve site. as long as the antennas are more than one wavelength apart. (do a google search for "fox hunting" or "hidden transmitter hunting") Then wave length of a 1800 MHZ signal is about 16cm, and at 800Mhz 37.5cm (base on the 300/f f=Frequency in MHZ). Signal strength is no longer a factor. So most to all NEW cell sites can pin point your phone withing a few hundred meters. BUT what makes cells phone so successful, in this respect is also their downfall, it that the higher the frequency the more the radio waves bounce off of nearby object (in reference to the transmitter). Which can be antenuated at the receive site and almost completely defeated with CDMA.

So now we are withing a few hundred meters of the phone, which can be further reduced by kind of a PRMLP (partical read most likly propibiltiy), so shave off 25% of the places it CAN NOT BE. give or take 175 meters.

In 1999 Motorola developed GPS single chip. about the size of a dime and even smaller today. But the chip does not do the plotting calculations, that is up to the phone's processor. being the limitations of the accuacy of the clock in your phone the most accurate your phone can plot its position is about 100 meters. (look at the parts/price list of a gps, the most expencive part is the internal referance clock) so now based off of statistics, we can get the phones location within 75 meters on 4 plots. where the circles cross, start looking there.

The problem is, the amount of data the cell carriers are currently trying to pass to make a buck. Internet, text messages, etc, etc... The most accuratet report I have ever been able to pull was from Sprint, they could tell me what tower, and direction, but that was it. Unless I asked them to track my POS, then they could tell me within about 50~100Meters of my POS.

Nextel, now part of sprint, could tell me the tower. Verison, could narrow it down to 3 towers, US CELL, could tell me the trunk it came in on. (over 50 sites) and the list goes on.

So if you think about it, unless they have a reason to track you, they are not going to waste their time.

I am so glad to find this website. It seams though, that no one really knows how this works or who has access to it. The person with the coment about a court order is obviouly wrong, atleast while Emperor Duba is in charge.

So the questions still remain:
How does this work?
Who has access to it? (Under what conditions?)
What is done with this information?
How can I turn it off or disable it or filter out this 'shadow' location signal? (Besides just turning off the phone?)
And why the hell aren't the telecom companies doing something to educate people about this? We are paying for their service, we should be able to know how it works. Personally I have demanded this information but none seem willing to comply with my request. Since when did doing business with ANY company become my privledge?

Thank you Cingular, Nextell/Sprint, Verizon and T-Mobile I feel so belssed that you take my money every month for crapy second rate service that I cannot even get a fair description of. Just tell me when you want to come over and I will open a vein and hemorage for you too.

Is there a way to track someone else's cell phone signal, for instance: one of my family member's cell phone? I'd like to know if there is a way to do this just in case an emergency was to occur like a car wreck, etc.

Great info!!

I have a much simpler need about cell phone.

All I need to know is cell phone 'status'. I just want to know if the cell phone is ON the network or not and I dont care where the phone is located as long as it is ON somewhere in the networks (Verizon, Cingular, Nextel,...) The target phone could be in any providers' networks (GSM, CDMA,...,etc), though. But, which network it is on is not interested to me either.

Is this "cell phone ping" feasible without dealing with cellular network providers? Or, it requires the network provider to release certain information .

Thanks. Great discussion and certainly help me to better understanding how the mobile networks work.

Ted

I phoned the cell company, who put me through to the manufacturer, who said “the E911 only allows the emergency services to find out where you are, as your location is broadcast to them during the (emergency) phone call. The ‘Location On’ allows the service provider, or Phone Company, or Verizon in my case, to locate you at any time.” They then stressed that this information would not be used lightly, but giving no real indication of when, or why such a feature may be utilized. They said that I (as Joe Citizen) would NOT be able to use it to locate anyone.

Does anyone know of a complete list of cell phones that do not have e911 or allow you to turn it off?
Please let me know. Email: william_sterner@mymacmail.com

can you tell me if you can track a cell phone to the last place it was used. if a cell phone is off then i know it cant be tracked but if it was on and used for text messaging does the info get stored of where the last texts were sent from and who has acces to that information. is it difficult to get the information ?

I also would like info on phones that do not have e911 or allow you to turn it off entirely, not just partially.

I am looking to buy a new phone but am concerned that just about anyone can track my daily activities without my knowing it

Thank you

Jim97205@hotmail.com

is it possible to remove a gps chip from a cell phone ?

Regarding Barry's post about the government needing a warrant to track you, access your personal information, use a wiretap, etc. That is absolutely no true any more. The government can do what they want, when they want, with whatever information they want. This goes against many court ruleings, implied law from the constitution and declaration of independance, and many many other things, but all for naught when the USA Patriot Act was put into commission. All checks and balances are out the window. Do a search for privacy rights, civil rights, or any case the ACLU has taken on in the past couple years, and you'll be amazed at what you find.

You don't need to post this comment, but I applaud you at doing things, such as your approval method before allowing posts, to thwart spammers. Thankyou.

Regarding Eric's post about the government being able to do what they want when they want is not true. Seeing that I work for the government (not military) we have to jump thru so many flaming hoops to get information you would not believe. I'm glad its that way. If it were as you believe it is more predators could be captured however more innocent people could be accused and convicted. With that being said...good day to you!

whats the name of the number of each phone how do i know what my number is?

So is there a way to track someone using the GPS on their cell phone? Or can this tracking only be done when someone calls 911 from their cell phone?

We offer a GPS "ping" location of any cell phone. We can give you the GPS location of the last use of any target cell phone. It will be accurate to within 100 yds. This will enable you to know the location of the last time the target cell phone was used. Or if you know an exact time that a call was made using the Target Cell phone, we can locate the GPS of that exact phone call. Price is $300 per location. www.bountyhunt.com billy20772@Gmail.com, 1-877-524-0157

I would like to tell you how it is for real. I didn`t red all coments but i know one thing that your mobile phone can be tracked eaven when it`s turned off. It can`t be tracked only if your phone baterry is taken out of the phone. thats because your phone is connecting to the mobile towers (or something, i don`t know how it is in english)but not 1 tower but about 10 or maby 20 (ofcourse on your screen it`s showing only one) so these towers are working like satelites only on the ground and your phone can be tracked within a radius of 10 meters. trust me i know. in our country police chases mobile phone thewes that way u can not escape the police if u stole a telephone and eaven u insered another sim and your telephone is turned off. because sim card is allways sending signal to the towers and it`s not neceseraly to be turned on

I am interested to know if I can track a phone for a family member who might be stuck on the side of the road. I would be interested in being able to get their longitude and latitude so I can pin point where they are. This is only for emergency use, so I do not want to pay a monthly fee or need them to download any software. Are there any companies that do this type of thing?

I'm very new to this information. I came upon your site when I Googled "cell triangulation." I need know how precisely a cell phone's location can be determined; both for incoming and outtgoing calls. I am a prosecutor preparing for a Northern California murder trial, a key issue is placing the defendant and his phone near the victim at the time of the killing. His service provider claims that for several calls logged on his phone bill no cell site info is available. Any suggestions?

I have a couple quick comments. I used to work for one of the main wireless carriers. We were told that the government can track your cell phone GPS as long as it has a battery attached to it. Whether the battery is charged, dead, phone on or off, they can track it. The towers are NOT used for GPS. End of story. The url listed is for populard mechanics that shows a couple of web sites to track cell phone using GPS. For Burke, the wireless carriers definitely keep track of what tower the call was made on. That's how they know how to bill you. On calling plans with roaming, how else would they know if you were roaming? Don't deal with a store or regular cstmr srvc reps. Call and ask for a manager or the legal department. Usually you need a subpena (sorry about spelling), but that is DEFINITELY recorded info.

Does anybody know if there is a program extant whereby intelligence or police agencies can call your phone, let it ring once, then track your location? This is not fantasy. Legitimate comments only, please?

I would like to know exactly how to track a persons cell phone myself... I have heard that google earth pro may be able to do this. but it's very inportant to the bailbond business.. and most sights that offer gps locations for cell phones are rip off's or they charge way too much. for example they will charge 300 dollars then goto icu and pay 200 for the information. but i still feel both those prices are way too much there has to be away to aquire the software or equipment to do it our self. Please help we are in need of this badly

scary.

http://www.legalaffairs.org/issues/July-August-2003/feature_koerner_julaug03.msp

FWIW.
There is a retail cell phone tracking device available. I have no financial interest in it or the corporation which markets it.

It is a GPS enabled cell phone. It costs $99.95 on Amazon. The monthly service starts at $19.95.

The phone works like a normal phone (without a dial pad). In addition the location of the phone can be tracked by you from any internet connected computer.

You'll get a street map, or a photograph of the location of the person. You could also track a briefcase, or a car, or a horse (if the phone were in the halter).

There's a lot more info at www.wherify.com

Dave

i can't believe there isn't a service that will tell you where your cell phone is.... this is a million dollar business! if you get the authority to do it correctly- only let people track their own cell phones- people would pay rediculous amounts of money to know where they are! well i'm going to start the business then.

All I want to know is if big brother can determine my location by GPS or otherwise with out me making a call other than E911. I have a Motorola i830. Where I work everyone is in a panic that the boss is going to know exactly where any one of his employees is at any time of the day, even after hours, simply by using some software supplied by nextel to track his workers. Is this possible?

It might be possible only if your phones belong to the company/your boss. If you have a personal phone, then the answer is NO. Only the police can get that info. I do not know your laws, but a provider might have the "tracking" option for his clients. The precision is about 1 meter (depends of the area where U are) and U can be tracked at all times, even if you don't talk to your phone. If you don't want to be tracked, just close your phone.

Yes, it is possible. Every cell phone knows a cell id (the tower that it currently is "paired" with), and the wireless provider also knows at all times (given that your phone is on) where you are. They know with about 100 m precision, plus or minus.

Some phones, including your i830, has a built-in GPS chip. In addition, Nextel uses A-GPS (assisted GPS) technology which works by sending certain info from your phone to their server which performs some calculations and sends back location assistance info. Typically, getting precise location (within few meters) via GPS chip requires some time (from seconds to a couple of minutes), so cell id, etc. are used for instant location (with some loss of precision). That's what most tracking programs use.

Vadim
http://veripath.us
Cell Phone Navigation with Traffic Avoidance

I have a similar location question. Does anyone know if cell phones in the US know what cell tower they are connected to, i.e. so an app. can use this to determin location although coarse? I have seen in Denmark, that the phone displays the tower information, but never in the US.

This is probably a stupid question but cant the police use Edwin Halls cell phone to track where his cell phone communicated with towers on the day the first girl went missing
or would he have had to make a call
i thought your cell phone is constantly communicating-is this insane or no?
god that would be nice in this case

Need Help.

An acquaintance visited our place. When he went out of our home, some important valuables were missing. upon investigation, all the odds point to him. but our problem is, we do not know if all info, like name, residence etc are true because his address is not a valid one. the only thing that is sure is, his mobile phone is still active, and we are able to sent SMS and he answered back. am from the philippines. is it possible to locate him? please advice me on what to do. thanks to all. my email is arnaizs@yahoo.com

Posted news article from http://blog.cleveland.com/pdworld/2007/07/gps_joins_the_police_toolbox.html

GPS joins the police toolbox
Posted by Mark Puente July 31, 2007 06:22AM

Previous story: GPS watches over us
Interactive graphic: GPS systems made simpleA small tracking device has become so useful in solving crimes that many local police and prosecutors refuse to talk about it for fear of giving away investigative secrets. But chances are one is attached to your hip or tucked in your bag. Global Positioning System chips -- built into cell phones -- allow authorities to track criminals and people in need of help. Cell phones have become increasingly important in criminal investigations as people rely more on their phones for conducting business, whether legal or illegal. The technology played a key role in the investigation of the slaying of a Pennsylvania doctor on the Ohio Turnpike, and the convictions of his wife and her lover in the killing. All cell phones leave a trail for detectives to follow.
Every time a cell phone is turned on it sends a registration message, including the serial and phone numbers, to the closest cellular tower.
A tower receives signals from cell phones on all sides of it. The tower divides the area around it into three equal sectors. A GPS locator pinpoints the sector where the phone is. More than 195,000 towers dot the landscape of the United States.
And a phone sends updates to towers every few minutes as long as the phone is turned on, said Dave Houglan, an engineering manager at Verizon Wireless in Independence.
That capability helps find people who are lost or missing.
At the end of 2006, more than 233 million people subscribed to cellular service, according to CTIA-The Wireless Association, a trade group for wireless providers. Cell phone users make about 240,000 calls a day to 9-1-1 across the country.
In most areas, a local 9-1-1 center has equipment and database information that displays a cellular caller's phone number and location. Even if callers are unable to say where they are, dispatchers can then deploy searchers to within 100 feet of the location.
If callers use an older phone without a GPS chip, searchers can narrow the caller's location by using three towers to triangulate its last known spot by measuring the time it takes signals to reach the towers.
The technology can also be used to track the movements of crime victims and people suspected in crimes.
Some police and prosecutors say that talking about how they use GPS locators would help criminals get away with more crimes.
U.S. Attorney Greg White declined to discuss it. U.S. Marshal Peter Elliott said fugitive hunters use many tools to nab criminals, but he also declined to talk about it.
Special Agent Scott Wilson, spokesman for the Cleveland FBI, said cell phones are extremely beneficial in solving many cases.
It helps us if someone is in danger and foul play is suspected," he said.
Using cell phones to solve crimes in not a secret.
"People, including criminals, watch forensic dramas on television every night," said Aric Dutelle, a former narcotics detective and now a criminal justice professor at the University of Wisconsin.
Detectives can follow a drug dealer's movements or eavesdrop by having a wireless provider reverse the signal. And some police agencies, Dutelle said, have equipment to track fugitives nearly in real time if officers have access to phone records.
Criminals commonly use prepaid cell phones because they are hard, but not impossible, to trace. Users do not have to show identification or sign a contract to purchase the phones.
Local police and prosecutors have used cell phone technology in court cases for years.
Recently, cell phones helped federal authorities solve the murder of Dr. Gulam Moonda. Donna Moonda will spend the rest of her life in prison for orchestrating her husband's May 2005 murder at the hands of her lover, Damian Bradford.
She called Bradford nearly two dozen times with her cell phone on the day her husband was shot and killed along the Ohio Turnpike.
Investigators tracked the calls and messages through cell phone towers, a state trooper said during the recent trial. They could show that Bradford had trailed the Moonda's car on the turnpike and abruptly turned around after the shooting. Bradford was sentenced to 17½ years in prison after admitting to killing Moonda.
And cell phone data could be the key evidence in the Jessie Davis case, a law enforcement source said. The pregnant mother was killed last month by Canton police officer Bobby Cutts Jr., police said. Authorities discovered her body in a Summit County park a week after she disappeared.
Cell phone records may be used to track Cutts' movements or to determine if he contacted Myisha Ferrell, who is accused of helping him dispose of Davis' body.
But the technology can also be used by defendants in criminal cases to try to establish their whereabouts and prove alibis.
Aside from being used as evidence in cases, Dutelle said the use of cell phone technology will also trigger court cases over individual rights and government snooping.
Consumers can decide if they want to be tracked by their wireless provider.
The GPS can be manually turned on and off. The phone, however, will automatically activate the GPS when a call is placed to 9-1-1.
There are some safeguards against Big Brother watching customers' every move. Most telephone companies will not release any data without a subpoena.
"There is no open access to anybody," said Houglan of Verizon Wireless.
Citizens applaud new technology, Dutelle said, when it's used to locate missing persons, but criminals cry foul when it's used to lock them up.
He added: "If you have nothing to hide, then you have nothing to worry about."

"They can track you!!!"

I talk quite a bit about cell phone towers and signal strength and how to avoid dropped calls on my website. I have yet to be asked about any kind of tracking system from cell phones though and I have to wonder if it's because most people don't even know about it! with all the rapid advancements in technology, I'm suprised most don't even know what RFID tags are! I would think it is common logic that if you can talk on the phone while moving and your call is being handed off from tower to tower that you are being tracked because the cell phone towers have to know where you are to handle your call properly. Your phone is more like a two way radio than a phone and whether your on the phone talking or not it would seem that the cell towers are tracking you anyway. How else would your phone know how many signal bars are available if this is not the case?

Ok I am dieing to find a program that will track any phone using just a phone number. It is all family so I don't care how many safety precautions they take. And money is not an object, but it can be a new phone, and the ones we have don't have GPS in them. It also needs to work in the United States. If anyone knows about this, please post it.

As I said in my website, all phones not having e911 location service will be completely phased out by next year. there are still phones being made which do not have e911 locater software built into them and the phone company that turns service on for it pays a hefty fine. That has been enough to make the phone companies comply whether it's legal or not to have e911 capabilities! I believe that the only phone service where you couldn't be tracked at all was AMPS, which was basically a two way radio with a keypad! http://www.mobile-phone-solutions.com