A Look At Smartphone GPS Tracking

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

GPS satellites broadcast signals from space that GPS receivers utilize to provide three-dimensional location (latitude, longitude, and altitude) plus precise time. GPS stands for Global Positioning System and is a network that is made up of 3 main 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 referred to as the GPS Constellation, and they make an orbit once every 12 hours. They are not geosynchronous, but rather move at over 7,000 mph. They are solar powered but have battery reserve for when they are in the earth?s shadow. They are positioned 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 parked in space 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 canceled and are in balance. This is the ideal location to park a stationary satellite. The earth rotates at about 1,000 miles an hour, and because of their high earth orbit the earth-synchronous satellites need to move at about 7,000 mph to sustain position. This is just about the same speed as GPS satellites, but since they satellites are 10,000 miles further away they stay in place relative to the earth.

The GPS Control Segment consists 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 information they send to earth is accurate.

The GPS User Segment made up of of GPS receivers taking the shape of mobile phones 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, irrespective of whether inside of a cell phone, or a spucific Portable gps tracking device, calculate location by accurately timing the signals sent by GPS satellites. This critical information incorporates the time the message was transmitted, specific orbital information (technically referenced as the ephemeris), and also the basic system condition and believed orbits of all GPS satellites (formally referenced as the almanac).

Another way of calculating mobile phone position is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation utilizes signal analysis data to compute the time it takes signals to travel from your mobile phone to no less than 3 cell towers to determine location.

With Mobile Location Services (MLS), the GSM cell network provider utilizes triangulation techniques to estimate the position of the handset, its accuracy is proven to be much worse than that of GPS. MLS is further impacted 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 location accuracy may be off as much as a mile.

A Look At Smartphone GPS Tracking