Mobile phone GPS is what consumers generally think about when considering locating cell phones. GPS (Global Positioning System) using satellites is the most known and more accurate means of tracking. Yet, GPS requires satellites to be in direct line of site from the smartphone. It doesn’t work very well indoors or in dense cities. If the handset is inside a building, for example your office, restaurant, or often sitting in an automobile the signals may not get to the mobile phone. From time to time heavy cloud cover and dense foliage impedes with reception. Some mobile phones can store the last identified GPS location, others might not.
Much of the discussion surrounding GPS tracking, mobile GPS and mobile phone tracker 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 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 also known as as the GPS Constellation, and they make an orbit 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 reserve for when they are on the dark side of the earth. 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 have a lifetime of about 10 years until all their fuel is exhausted.
GPS Satellites are not communications satellites. Geostationary or communications satellites use a higher altitude 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 best location to park a communications satellite. The earth rotates at about 1,000 miles an hour, and because of their high earth orbit the geostationary satellites need to move at about 7,000 mph to maintain position. This is just about 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 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 beam down to earth is accurate.
The GPS User Segment is comprised of of GPS receivers taking the shape of devices 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 work.
GPS receivers compute position by precisely timing the signals transmitted 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 way of calculating mobile phone location is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation employs signal analysis data to calculate the time it takes signals traveling from the smartphone to a minimum of three cell towers to estimate location.
With Mobile Location Services (MLS), the GSM cellular network provider utilizes triangulation algorithms to determine the position of the mobile phone, its accuracy is proven to be much worse than that of GPS. MLS is also affected by factors similar to GPS in the sense of the interference impeding signal quality and the density of GSM towers to help in the triangulation effort. In remote areas position accuracy may be off as much as a mile.
An Introduction To Cell Phone GPS Tracking
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