The Quilts Zone Blog

Across the country and around the world, Cell tracking, mobile GPS and cell phone track software are attracting attention from consumers, mobile phone companies and application developers.   The latest mobile phones have GPS locator features to track phone location.   These features, and others such as text messaging, internet access and the ability to use other applications make cell phones great gadgets.  But GPS satellites aren’t always available, such as when the phone is in a structure such as an house, shopping center, or even in an automobile.  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 main methods of calculating  smartphone position.  GPS Global Positioning System-Satellites, Triangulation, and CellID.   All these technologies transform smartphones 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 needs software applications installed on the mobile phone  along with GPS hardware.  Triangulation and CellID are Network Based as they use the equipment and information from the wireless provider.  Hybrid systems combine methods to make best use of available data and to make position phone tracking faster.  

GPS on cell phones is what people commonly think of when considering locating smartphones.   GPS (Global Positioning System) using satellites is the most common and more accurate means of tracking.   But GPS requires satellites to be in direct line of site of the cell phone. 

Sometimes thick cloud cover and thick trees impedes with signals. 

If the phone is in a building, for example your office, mall.  Some cell phones will keep the last known GPS location, others might not.  

Another issue with smartphone GPS tracking is the possibility of battery drain.  It is important to be able to remotely adjust the frequency of taking GPS position.  Choosing real-time or periodic sampling affects both the accuracy of determining location as well as battery life.  

GPS receivers, whether in a handset, or a dedicated GPS tracking device, compute position by precisely timing the signals transmitted by GPS satellites.  This data includes the time the message was transmitted, precise orbital information (the ephemeris), and the general system health and rough orbits of all GPS satellites (the almanac).  GPS receivers sometimes take a long time to become ready to navigate after it’s turned on because it must acquire some basic information in addition to finding GPS satellite signals. This delay is sometimes caused when the GPS device  has been turned off for days or weeks, or has been moved a significant distance while turned off 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 acquire satellite signals and find initial position faster. 

GPS Hot Start is when the GPS enabled handset  remembers its last known location, the satellites that were in range before, the almanac information in memory, and tries to find the same satellites and compute a new position based upon the previous data. This is usually the quickest GPS lock but Hot Start only works if the phone is generally in the same location as when the GPS was last turned off. 

GPS Warm Start is when the GPS enabled cell phone  remembers its last calculated location, and almanac used, but not which satellites were in view. It performs a reset and makes an attempt  to find satellite signals and computes a new position. 

The GPS receiver has a general idea of which satellites tolook for because it kept its last known position and the almanac data helps identify which satellites are in range. The Warm Start will take longer than the Hot Start but not as long as a Cold Start. 

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

In order to have better GPS lock times cellular manufacturers and telco operators developed Assisted GPS technology.   In the US  Sprint, Nextel, Verizon Wireless, and Alltel all use AGPS. This is a means of using the cell network to accelerate acquisition of GPS satellites.  GPS Receivers can get a faster lock at the expense of a few kilobytes of data transmission.

A-GPS assists location tracking functions of smartphones (and other connected devices) in two ways:

One way is by assisting to obtain a faster “time to first fix” (TTFF). AGPS acquires and storesinformation about satellite locationusing the cellular network so the coordinates information doesn’t require to be downloaded from the the satellite. 

Another way is by assisting position  smartphones when GPS signals are weak or blocked.  As discussed above GPS satellite signals may be impeded by tall buildings, and do not penetrate building interiors well. Assisted GPS utilizes proximity to cellular towers to calculate 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 alternative to GPS mobile phone tracking.  The location of the device can be computed by the cell 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 smartphone  is.  However, 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 accuracy is less than than GPS accuracy. Nevertheless tracking via CellID still provides a very useful substitute.    

Another way of determining  device 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 device 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 modules can 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 cellular network provider uses triangulation algorithms to try to pinpoint the position of the cell phone, its accuracy is proven to be less than than that of GPS.  MLS is further impacted by factors similar to  GPS in the sense of the interference impeding signal quality and the density of GSM towers to assist in the triangulation calculation.   In remote areas location accuracy may be off as much as a mile. 

Generally speaking it comes down to what location tracking system is available, and the requirements 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. 

Consider that there is a basic difference between mobile phone GPS Tracking and Navigation.  GPS cell tracking is usually related to someone keeping records of either real-time or historical cell phone  position, while Navigation deals with the handset  user figuring out 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    Mobile 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 .