Different Approaches to Being a Mobile Phone GPS Tracker Raise the Question: Do you really know where they are?
Mobile communications means more than just placing a phone call while moving. The most up-to-date cell phones include GPS position features to track phone location. These features, and others such as text messaging, internet access and the ability to use other software make cell 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 cell phone tracking 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 formulating mobile phone location. GPS Global Positioning System-Satellites, Triangulation, and CellID. All these technologies transform smartphones 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 applications installed on the mobile phone in conjunction with GPS hardware. Triangulation and CellID are Network Based as they use the equipment and information from the cellular provider. Hybrid systems combine methods to make best use of available data and to make location cell phone tracking faster.
GPS on cell phones is what people commonly think of when looking at tracking mobile phones. GPS (Global Positioning System) using satellites is the most well known and more accurate way of tracking. However GPS needs satellites to be in direct line of site of the mobile phone.
Sometimes heavy cloud cover and dense trees impedes with signals.
If the phone is in a building, for example your house, restaurant. Some smartphones will keep the last known GPS location, others might not.
Another issue with cell phone GPS location 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 finding location as well as how long the battery will last.
GPS receivers, whether in a handset, or a dedicated GPS tracking device, determine 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 condition and rough orbits of all GPS satellites (the almanac). GPS receivers often take longer to become ready to use after it’s turned on because it must acquire some basic information in addition to capturing GPS satellite signals. This slow start is sometimes caused when the GPS smartphone 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 position more quickly.
GPS Hot Start is when the GPS enabled device keeps its last calculated position, the satellites that were in range at the time, the almanac data in memory, and attempts to find 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 generally in the same location as when the GPS was last turned off.
GPS Warm Start is when the GPS enabled device recalls its last calculated position, and almanac used, but not which satellites were in view. It performs a reset and tries to find 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 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 information, and attempts to locate satellites and achieve a GPS lock. This takes longer than other methods because there is no known reference information. The GPS enabled cell phone receiver has to try 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 cell phones connected to the cell network. In the United States Sprint, Nextel, Verizon Wireless, and Alltel all use AGPS. This is a method of using 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 mobile phones (and other connected devices) in two ways:
The first method is by helping to obtain a more rapid “time to first fix” (TTFF). Assisted GPS acquires and archivesinformation about satellite positionusing the cellular network so the coordinates information doesn’t require to be downloaded from the the satellite.
The second way is by helping position mobile phones when GPS signals are weak or impeded. As mentioned before 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 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 good substitute to GPS mobile phone tracking. The location of the cell phone can be calculated by the cell network cell id, that identifies the cell tower the phone is connected to. By knowing the position of this tower, then you can know approximately where the cell phone is. However, a tower can cover a huge area, from a few hundred meters, in high density areas, to several miles in lower density areas. This is why location CellID precision is less than than GPS accuracy. Nevertheless tracking using CellID still presents a very viable substitute.
Another way of formulating 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, cell phone companies must be able to provide authorities with mobile 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 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 techniques to calculate the position of the handset, its accuracy is proven to be much worse than that of GPS. MLS is also impacted 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 cell phone settings. Having real time tracking on demand, or preferring to minimize battery use and data transmission should be a minimum requirement. Typically 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 fundamental difference between smartphone GPS Tracking and Navigation. GPS cell tracking is normally related to someone maintaining records of either real-time or historical mobile phone location, while Navigation deals with the mobile phone user figuring out how to get from point A to point B.
A really great software package that includes remote control of cell phone 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 .
Visit this link for more information regarding the latest software for
Mobile GPS .
Tags: cell phone tracking, employee monitoring, GPS tracker, mobile GPS, parental control