Cell Phone GPS Tracking Basics

Much of the discussion surrounding cell tracking, mobile 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 determine three-dimensional location (latitude, longitude, and altitude) plus precise time. GPS is an acronym 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 incorporates twenty-four to thirty-two satellites that orbit the earth in medium earth orbit MEO. These satellites are referred to as the GPS Constellation, and they make an orbit once every 12 hours. They are not geostationary, 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 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 have a lifetime of about 10 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 equilibrium. This is the ideal location to position 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 maintain position. This is just about the same speed as GPS satellites, but since stationary satellites are 10,000 miles further away they don?t move relative to the earth.

The GPS Control Segment made up of Master Control Station, an Alternate Master Control Station, and numerous dedicated and shared Ground Antennas and Monitor Stations that work together to make sure the satellites are functioning to specification and the information they send to earth is accurate.

The GPS User Segment consists 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 applications that make them function.

GPS receivers, whether or not inside of a handset, or simply a spucific Portable gps tracking system, compute specific location by precisely timing the signals transferred by GPS satellites. This information contains the time the message was transmitted, precise orbital details (technically referenced as the ephemeris), plus the general system condition and calculated orbits of all GPS satellites (formally called the almanac).

When satellite signals are not available, or accuracy and precision is less important than life of the battery, applying Cell-ID is a useful substitute to GPS cell phone location. The location of the mobile phone may be estimated by the cell network cell id, that recognizes the cell tower the cell phone is using. By having the position of this tower, you’ll be able to know approximately the spot where the mobile phone might be. Nonetheless, a tower can cover a huge area, from a couple of hundred meters, in high populationdensity regions, to several miles in lower density zones. For this reason location CellID accuracy is less than than GPS accuracy. Nonetheless tracking using CellID still presents a truly useful alternative.

Cell Phone GPS Tracking Basics