Cell Phone GPS Tracking Intro

GPS on cell phones is what consumers commonly think of when considering locating mobile phones. GPS (Global Positioning System) utilizing satellites is the most well known and more precise way of tracking. But, GPS needs satellites to be in direct line of site of the handset. It doesn’t work as well indoors or in dense cities. In the event that the cellphone is inside a structure, for example your house, mall, or often sitting in an automobile the signals may not reach the cell phone. Sometimes heavy cloud cover and dense foliage interferes with reception. Some mobile phones can retain the last identified GPS position, others might not.

A lot of the discussion surrounding cell tracking, cell phone GPS and mobile phone track software could be helped by a GPS Satellite primer.

GPS satellites broadcast signals from space that GPS receivers use to determine three-dimensional location (latitude, longitude, and altitude) plus precise time. GPS stands for Global Positioning System and is a network that is composed of 3 primary segments: Space Segment, Control Segment and User Segment.

The GPS Space Segment incorporates twenty-four to thirty-two satellites that orbit the earth at a height of about 12,000 miles. These satellites are also known as as the GPS Constellation, and they are orbiting once every 12 hours. They are not parked over one spot, they travel at over 7,000 mph. GPS satellites are solar powered but have battery backup for when they are in the earth?s shadow. They are placed so that there are at least 4 satellites ?visible? from any point on earth. Small rocket boosters on each satellite keep them properly positioned. The satellites last about ten years until all their fuel runs out.

GPS Satellites are not communications satellites. Geostationary or communications satellites are at a much higher orbit of about 22,300 miles above the equator. These satellites are used for weather forecasting, satellite TV, satellite radio and most other types of global communications. At exactly 22,000 miles above the equator, the earth’s gravitational force and centrifugal forces are offset and are in balance. This is the ideal location to position a stationary satellite. The earth rotates at about 1,000 miles an hour, and because of their high earth orbit the geostationary satellites need to travel at about 7,000 mph to keep position. This is approximately the same speed as GPS satellites, but since geostationary satellites are 10,000 miles further away they stay in place relative to the earth.

The GPS Control Segment is comprised of Master Control Station, an Alternate Master Control Station, and a host of dedicated and shared Ground Antennas and Monitor Stations that work together to ensure the satellites are functioning to specification and the data they send to earth is accurate.

The GPS User Segment incorporates of GPS receivers taking the shape of handsets and , laptops, in-car navigation devices and hand-held tracking units along with the people that use them, and the software programs that make them function.

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 capturing GPS satellite signals. This delay is sometimes caused if the GPS mobile 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 capture satellite signals and calculate initial location faster.

Another way of determining handset position is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation employs signal analysis data to determine the time it takes signals traveling from the phone to a minimum of three cell towers to estimate location.

With Mobile Location Services (MLS), the GSM cellular network provider uses triangulation techniques to compute the location of the device, 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 barriers impeding signal strength and the density of GSM towers to help in the triangulation calculation. In remote areas location accuracy may be off as much as a mile.

Cell Phone GPS Tracking Intro