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

Posted: May 6th, 2010 | Author: Research-Team | Filed under: Online Fun | Tags: cell phone tracking, employee monitoring, GPS tracker, mobile GPS, parental control | 1 Comment »

Different Approaches to Being a Cell Phone Tracker Raise the Question:  Do you really know where they are?

Mobile communications means more than just making a phone call while moving.    The most recent cell phones include GPS locator features to track phone location.   These features, along with others such as text messaging, internet access and the capability to utilize other applications make mobiles great gadgets.  However GPS satellites aren’t always available, for example when the handset is in a structure such as an office, shopping center, or even in a car.  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 calculating  smartphone position.  GPS Global Positioning System-Satellites, Triangulation, and CellID.   All these technologies transform mobile phones into mobile tracking devices.   These systems can be viewed as Network Based, Handset Based or a Hybrid approach.  GPS location is Handset based as it requires software programs installed on the cell phone  along with GPS hardware.  Triangulation and CellID are Network Based as they use the equipment and data from the wireless provider.  Hybrid systems combine techniques to make best use of available information and to make location phone tracking faster.  

Mobile phone GPS is what people usually think of when looking at tracking cell phones.   GPS (Global Positioning System) using satellites is the most common and more accurate means of tracking.   But GPS needs satellites to be in direct line of site of the handset. 

Sometimes thick cloud cover and dense foliage impedes with reception. 

If the phone is in a structure, for example your school, shopping center.  Some cell phones will store the last known GPS location, others might not.  

Another issue with handset GPS location is the possibility of battery drain.  It is important to be able to remotely adjust how often 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 mobile phone, or a dedicated GPS tracking device, compute position 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 condition and rough orbits of all GPS satellites (the almanac).  GPS receivers sometimes take a long time to become ready to navigate after being turned on because it must acquire some basic information in addition to finding GPS satellite signals. This delay is sometimes caused when the GPS cell phone  has been unused for days or weeks, or has been transported a far 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 signals and determine initial position more quickly. 

GPS Hot Start is when the GPS enabled device  remembers its last known position, the satellites that were in range before, the almanac information in memory, and attempts to connect to the same satellites and determine a new position based upon the previous information. This is generally 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 mobile phone  remembers its last known position, and almanac used, but not which satellites were in range. It performs a reset and tries  to find satellite signals and calculates 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 dumps all the previous data, 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 attempt to lock onto a satellite signal from any available satellites. 

Assisted GPS, also known as A-GPS or AGPS, enhances the performance of standard GPS in mobile phones connected to the cellular network.   In the US  Sprint, Nextel, Verizon Wireless, and Alltel all use Assisted GPS. Which is a method of utilizing the cellular network to accelerate acquisition of GPS satellites.  GPS Receivers can get a faster lock in exchange for a few kilobytes of data transmission.

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

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

Another way is by helping position  devices 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 utilizes 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 alternative to GPS cell phone location.  The position of the device can be estimated by the cellular network cell id, that 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.  But, a tower can cover a huge area, from a few hundred meters, in high density areas, to several kilometers in lower density areas. This is why location CellID accuracy is lower than GPS accuracy. Nevertheless tracking via CellID still provides a very viable substitute.    

Another way of formulating  mobile phone position 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.  For comparison commercially available GPS systems can achieve accuracy down to less than 10 meters.  This depends upon many factors, as GPS signals are often very weak and are affected  by many variables.   With Mobile Location Services (MLS), the GSM cellular network provider utilizes triangulation techniques to determine the position of the mobile phone, its accuracy is proven to be much worse than that of GPS.  MLS is further affected by factors similar to  GPS in the sense of the interference affecting signal strength and the density of GSM towers to assist in the triangulation effort.   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 handset 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 over 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. 

Consider that there is a basic difference between handset GPS Tracking and Navigation.  GPS cell tracking is normally related to a third-party keeping records of either real-time or historical smartphone  position, while Navigation deals with the smartphone  user figuring out how to get from point A to point B.

A really great software package that includes remote control of smartphone 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    Mobile Monitoring Software  compatible with BlackBerry  and  Android  Smartphones, used or Parental Monitoring and Small Business Employee Monitoring .  

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