Communication Devices in The 21st Century

Methods for Phone GPS Tracking and Cell Phone Location raise the question: Do you really know where they are?

Mobile communications means more than just making a phone call while on the move.    The hottest mobiles include GPS locator features to track phone location.   These features, and others such as SMS message, internet access and the ability to utilize other software make mobiles great gadgets.  However GPS satellites aren’t always available, such as when the phone is in a structure such as an office, shopping center, or even in a car.  That doesn’t mean smartphone locating isn’t possible, but it does mean there are other ways of being a locator.

To track a cell phone involves several primary methods of formulating  cell phone location.  GPS Global Positioning System-Satellites, Triangulation, and CellID.   All these technologies transform cell phones into mobile tracking systems.   These systems can be viewed as Network Based, Handset Based or a Hybrid approach.  GPS location is Handset based as it requires software applications installed on the smartphone  along with GPS hardware.  Triangulation and CellID are Network Based as they use the equipment and information from the wireless provider.  Hybrid systems combine techniques to make best use of available data and to make location cell phone tracking faster.  

Mobile phone GPS is what people usually think of when looking at locating smartphones.   GPS (Global Positioning System) using satellites is the most common and more accurate method of tracking.   However GPS requires satellites to be in direct line of site of the handset. 

It doesn’t work particularly well indoors or in dense cities. 

If driving the signals might not reach the cell phone.  Some smartphones will retain the last known GPS location, others might not.  

Another issue with handset GPS tracking is the potential of draining the battery.  It is important to be able to remotely adjust the frequency of taking GPS position.  Selecting real-time or periodic sampling affects both the resolution of finding location as well as battery life.  

GPS receivers, whether in a cell phone, or a dedicated GPS tracking device, calculate location by precisely timing the signals transmitted by GPS satellites.  This information includes the time the message was transmitted, precise orbital information (the ephemeris), and the general system health and estimated orbits of all GPS satellites (the almanac).  GPS receivers often take longer to become ready to use after being turned on because it must acquire some basic information in addition to capturing GPS satellite signals. This delay is sometimes caused if the GPS mobile phone  has been unused for days or weeks, or has been moved a significant distance while unused for.  The GPS must update its almanac and ephemeris data and store it in memory.  The GPS almanac is a set of data that every GPS satellite transmits. When a GPS receiver has current almanac data in memory, it can capture satellite signals and find initial location faster. 

GPS Hot Start is when the GPS enabled cell phone  keeps its last calculated location, the satellites that were in range at the time, the almanac information in memory, and attempts to obtain the same satellites and compute a new position based upon the previous information. This is usually the quickest GPS lock but Hot Start only works if the phone is in the same general area as when the GPS was last turned off. 

GPS Warm Start is when the GPS enabled cell phone  remembers its last known location, and almanac used, but not which satellites were in view. It performs a reset and attempts  to lock onto satellite signals and computes a new position. 

The GPS receiver narrows the choice of which satellites tolook for because it kept its last known position and the almanac data helps identify which satellites are within view. The Warm Start will take more time than the Hot Start but not as long as a Cold Start. 

With GPS Cold Start, the device dumps all the previous information, and attempts to locate satellites and accomplish a GPS lock. This takes the longest because there is no known reference information.  The GPS enabled smartphone   receiver has to try to lock onto a satellite signal from any available satellites. 

In order to have better GPS lock times mobile phone manufacturers and telco operators introduced Assisted GPS technology.   It downloads the ephemeris and helps triangulate the cell phone   general position.  GPS Receivers can get a faster lock at the expense of a few kilobytes of data transmission.

A-GPS assists location tracking functions of mobile phones (and other connected devices) in a couple of ways:

The first method is by helping to obtain a more rapid “time to first fix” (TTFF). A-GPS acquires and archivesinformation about satellite positionvia the cell network so the position information doesn’t require to be downloaded via the satellite. 

Another way is by helping position  mobile phones when GPS signals are weak or not available.  As discussed above GPS satellite signals may be interfered with by tall buildings, and do not penetrate building interiors well. Assisted GPS uses proximity to cellular towers to estimate position when GPS signals are not available. 

If satellite signals are not available, or accuracy is less important than battery life, using Cell-ID is a viable substitute to GPS cell phone tracking.  The location of the handset can be computed by the cellular network cell id, which identifies the cell tower the phone is using.   By knowing the position of this tower, then you can know approximately where the handset  is.  But, a tower can cover a huge area, from a few hundred meters, in high population areas, to several kilometers in lower density areas. This is why location CellID precision is lower than GPS accuracy. Nonetheless tracking using CellID still presents a very useful alternative.    

Another method of formulating  handset location is Triangulation or Mobile Location Services (MLS).  Cell Tower Triangulation uses signal analysis data to calculate the time it takes signals to travel from your phone to at least three cell towers to estimate position.   

To comply with Federal Communications Commission guidelines, cellular phone companies must be able to provide authorities with cell phone latitude and longitude to an accuracy of 50 to 300 meters.   Cell Tower Triangulation doesn’t always meet this requirement.  By way of comparison commercially available GPS systems are able to achieve accuracy down to 3-10m.  This depends upon many factors, as GPS signals are often very weak and are impacted  by many variables.   With Mobile Location Services (MLS), the GSM cell network provider utilizes triangulation techniques to try to pinpoint the location of the handset, its accuracy is proven to be less than than that of GPS.  MLS is further impacted by the same issues as  GPS in the sense of the interference affecting signal quality and the density of GSM towers to help in the triangulation effort.   In rural areas location accuracy may be off as much as a mile. 

Generally speaking it is a matter of what location tracking system is available, and the need for accuracy.  Hybrid methods are emerging that use various techniques in tandem to provide best available location given available resources.   Generally the application determines the location with a GPS receiver and transmits the tracking data to a server through a data connection. The data connection to the server is usually made using the Internet.  How often GPS samples are taken and how often and by what method the data is sent to the server impact usefulness and costs. 

Keep in mind that there is a basic difference between handset GPS Tracking and Navigation.  GPS mobile phone tracking is normally associated with someone keeping records of either real-time or historical cell phone  position, while Navigation deals with the handset  user determining how to get from point A to point B.

A really great software package that includes remote control of handset settings, and combines Phone GPS Tracking  with SMS text message, Call Log,  MMS multi-media message monitoring, and a web account for storage and review is PhoneBeagle.  

Follow this link if you are interested in    Cell Phone Monitoring Software  compatible with BlackBerry  and  Android  Smartphones, used or Parental Monitoring and Small Business Employee Monitoring .  

Visit this link for more information regarding the latest software for
Cell Phone Tracking .

 

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