Methods for Mobile Phone 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 moving.    The newest mobile phones have GPS position functionality to track phone location.   These features, along with others such as text messaging, web access and the capability to utilize other software make mobile phones great gadgets.  However GPS satellites aren’t always available, such as when the phone is in a building such as an office, mall, or even when driving.  That doesn’t mean smartphone tracking isn’t possible, but it does mean there are other methods of being a locator.

To track a cell phone involves several primary ways of determining  mobile phone position.  GPS Global Positioning System-Satellites, Triangulation, and CellID.   All these technologies convert 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 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 phone tracking faster.  

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

Sometimes heavy cloud cover and dense foliage interferes with reception. 

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

Another thing with handset GPS tracking is the possibility of wasting the battery.  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 finding position as well as battery life.  

GPS receivers, whether in a handset, or a dedicated GPS tracking device, compute 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 sometimes take a long time to become ready to use after being turned on because it must acquire some basic information in addition to finding GPS satellite signals. This delay is sometimes caused if the GPS cell phone  has been turned off for days or weeks, or has been transported a far 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 device  recalls its last known location, the satellites that were in view before, the almanac information in memory, and tries to lock onto the same satellites and calculate 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 calculated position, and almanac used, but not which satellites were in view. It performs a reset and attempts  to connect to satellite signals and calculates a new position. 

The GPS receiver narrows the choice of which satellites tolook for because it stored its last known position and the almanac data helps identify which satellites are visible in the sky. The Warm Start will take longer 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 achieve a GPS lock. This takes the longest because there is no known reference information.  The GPS enabled device   receiver has to attempt to lock onto a satellite signal from any available satellites. 

Assisted GPS, also known as A-GPS or AGPS, improves the performance of standard GPS in devices connected to the cell network.   It downloads the ephemeris and helps triangulate the cell phone   general position.  GPS Receivers can get a faster lock in exchange for a few kilobytes of data transmission.

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

The first method is by assisting to obtain a faster “time to first fix” (TTFF). Assisted GPS acquires and archivesinformation about satellite locationvia the cellular network so the position information does need to be downloaded via the satellite. 

Another way is by assisting locate  devices when GPS signals are weak or blocked.  As discussed above GPS satellite signals may be interfered with by tall buildings, and do not penetrate building interiors well. AGPS uses proximity to cellular towers to calculate location 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 good alternative to GPS cell phone tracking.  The position of the cell phone can be calculated by the cellular network cell id, which identifies the cell tower the phone is connected to.   By knowing the location of this tower, then you can know approximately where the device  is.  However, a tower can cover a huge area, from a few hundred meters, in high population areas, to several miles in lower density areas. This is why location CellID precision is lower than GPS accuracy. Nonetheless location via CellID still provides a very useful alternative.    

Another way of determining  mobile phone 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 handset latitude and longitude to an accuracy of 50 to 300 meters.   Cell Tower Triangulation doesn’t always meet this requirement.  For comparison commercially available GPS modules can obtain accuracy down to less than 10 meters.  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 utilizes triangulation techniques to estimate 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 barriers affecting signal strength 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. 

It may be critical to consider how GPS location software programs handle the data and controls mobile phone settings.   Having real time tracking on demand, or preferring to minimize battery use and data transmission should be offered.   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 via the Internet.  How often GPS samples are taken and how often and by what method the information is sent to the server affect effectiveness and costs. 

Keep in mind that there is a basic difference between mobile phone GPS Tracking and Navigation.  GPS cell phone tracking is typically associated with a third-party maintaining records of either real-time or historical mobile phone  location, while Navigation deals with the cell phone  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 Cell Phone 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
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Tags: cell phone tracking, employee monitoring, GPS tracker, mobile GPS, parental control

This entry was posted on Wednesday, May 12th, 2010 at 6:17 am and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. Responses are currently closed, but you can trackback from your own site.