Phone Tracking Concepts

GPS tracking, mobile GPS and mobile phone track programs are undoubtedly attracting particular attention from potential buyers, cellular phone businesses and program developers. The latest smartphones provide GPS location attributes to track smartphone position.

GPS receivers, irrespective of whether inside of a mobile phone, or a dedicated Portable gps tracking device, compute location by way of accurately timing the signals transferred by GPS satellites. This information comes with the time the message was transmitted, precise orbital details (technically referred to as the ephemeris), along with the overall system status and rough orbits of all GPS satellites (technically called the almanac). GPS receivers sometimes take longer to become ready to use after it’s turned on because it must acquire some basic information in addition to finding GPS satellite signals. This slow start is sometimes caused when the GPS device has been unused for days or weeks, or has been transported 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 signals and find initial position faster.

GPS Hot Start is the term for when the GPS enabled cell phone keeps its last identified location, the satellites which were in range before, together with the almanac data in memory, and tries to find the same satellites and determine a new location based upon the previous data. This is generally the quickest GPS lock but Hot Start only works if the phone is in the same general area as when the GPS was last switched off. GPS Warm Start is the term for when the GPS enabled device remembers its last known position, and almanac used, but not which satellites were in view. It resets and makes an attempt to lock onto satellite signals and calculates a new location. The GPS receiver has a general idea 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 more time than the Hot Start although not as much as a Cold Start. With GPS Cold Start, the device deletes all the previous information, and attempts to locate satellites and attain a GPS lock. This normally takes the longest because there is no known reference data. The GPS enabled cell phone receiver must attempt to lock onto a satellite transmission from any accessible satellites.

In order to have improved GPS lock times cellular phone manufacturers and system providers created Assisted GPS technology. This downloads the ephemeris and helps triangulate the mobile phone general position. GPS Receivers can get a quicker lock in exchange for a few kilobytes of data transmission. Assisted GPS, also called A-GPS or AGPS, boosts the performance of standard GPS in handsets connected to the cell network. In the US Sprint, Nextel, Verizon Wireless, and Alltel all use AGPS. Which is a means of using the cell network to speed up acquisition of GPS satellites.

A-GPS improves location tracking functions of cell phones (and other related devices) in two ways:

The first method will be assisting to get a more rapid “time to first fix” (TTFF). AGPS acquires and stores data about satellite location utilizing the cell network so the position information does not need to be downloaded via the satellite.

The second way is by helping position handsets when GPS signals are weak or blocked. Because GPS satellite signals may be impeded by tall buildings, and do not pass through building interiors well AGPS uses proximity to cellular towers to compute location when GPS signals are not obtainable.

When satellite signals are not readily available, or accuracy is less important than battery life, employing Cell-ID is a useful alternative to GPS smartphone location. The position of the mobile phone can be approximated by the cell network cell id, which recognizes the cell tower the smartphone is connected to. By knowing the position of this tower, you’ll be able to know roughly the location where the mobile phone is. But, a tower can cover a huge area, from a couple of hundred meters, in high populationdensity regions, to a few miles in lower density areas. This is why location CellID accuracy is lower than GPS accuracy. Having said that location from CellID still delivers a truly helpful substitute.

Another way of determining cell phone position is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation uses signal analysis data to calculate the time it takes signals traveling from your cellphone to at least 3 cell towers to estimate position.

Phone Tracking Concepts