Throughout this discussion keep in mind that there is a basic difference between smartphone GPS Tracking and Navigation. GPS cell phone tracking is typically related to a third-party keeping records of either real-time or historical smartphone location, while Navigation deals with the mobile phone user determining how to get from point A to point B. Just because a cell phone has GPS doesn?t mean that it can necessarily be used as a navigation device. Just like cell phone tracking, navigation requires third-party software.
Much of the discussion surrounding GPS tracking, mobile 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 is an acronym for Global Positioning System and is a system that is made up of 3 main segments: Space Segment, Control Segment and User Segment.
The GPS Space Segment includes 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 twice a day. 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 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 last about ten years until all their fuel is exhausted.
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 equilibrium. This is the ideal location to place a stationary 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 geostationary satellites are 10,000 miles further away they stay in place relative to the earth.
The GPS Control Segment incorporates Master Control Station, an Alternate Master Control Station, and numerous dedicated and shared Ground Antennas and Monitor Stations that work together to ensure the satellites are functioning to specification and the information they beam down to earth is accurate.
The GPS User Segment made up of of GPS receivers taking the shape of mobiles 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 sometimes take a long time to become ready to navigate after it’s turned on because it must acquire some basic information in addition to capturing GPS satellite signals. This delay is sometimes caused when the GPS smartphone has been unused for days or weeks, or has been transported a significant distance while unused 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 signals and determine initial position more quickly.
When satellite signals are not available, or accuracy and precision is less important than life of the battery, using Cell-ID is a good substitute to GPS smartphone location. The location of the device can be computed by the cellular network cell id, which determines the cell tower the cellphone is using. By understanding the position of the tower, you may know approximately where the device will be. Still, a tower can cover a large area, from a couple of hundred meters, in high populationdensity zones, to several kilometers in lower density regions. This is why location CellID precision is lower than GPS accuracy. Having said that monitoring using CellID still offers quite a handy alternative.
Smartphone GPS Tracking Guide
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