An Overview Of Mobile Phone GPS Tracking

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

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

The GPS Space Segment made up of twenty-four to thirty-two satellites that orbit the earth in medium earth orbit MEO. These satellites are also known as as the GPS Constellation, and they make an orbit once every 12 hours. They are not geosynchronous, they travel at over 7,000 mph. They are solar powered but have battery backup for when they are on the dark side of the earth. They are placed so that at any given time there are at least 4 satellites ?visible? from any point on earth. Small rocket boosters on each satellite keep them flying in the correct path. 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 force of gravity and centrifugal forces are canceled and are in balance. This is the ideal location to place a communications satellite. The earth rotates at about 1,000 miles an hour, and because of their high earth orbit the geo-synchronous satellites need to travel at about 7,000 mph to keep position. This is approximately the same speed as GPS satellites, but since earth-synchronous satellites are 10,000 miles further away they stay in place relative to the earth.

The GPS Control Segment is composed 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 make sure the satellites are functioning correctly and the data they send to earth is accurate.

The GPS User Segment is comprised of of GPS receivers taking the shape of smartphones 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 work.

GPS receivers compute position by precisely timing the signals sent by GPS satellites. This data includes the time the message was transmitted, precise orbital information (the ephemeris), and the general system health and rough orbits of all GPS satellites (the almanac).

Another method of determining smartphone position is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation utilizes signal analysis data to calculate the time it takes signals traveling from your cellular phone to at least 3 cell towers to determine location.

With Mobile Location Services (MLS), the GSM cell network provider uses triangulation algorithms to estimate the location of the device, its accuracy is proven to be much worse than that of GPS. MLS is also affected by the same issues as GPS in the sense of the barriers impeding signal strength and the density of GSM towers to assist in the triangulation calculation. In remote areas position accuracy may be off as much as a mile.

An Overview Of Mobile Phone GPS Tracking