GPS on cell phones is what people typically think about any time reviewing tracking mobile phones. GPS (Global Positioning System) using satellites is the most well known and more accurate means of tracking. Yet, GPS demands satellites to be in direct line of site from the cell phone. It doesn’t work as well indoors or in dense metropolitan areas. If the cellphone is in a building, for example your house, restaurant, or often riding in a car the signals might not reach the mobile phone. From time to time dense cloud cover and thick foliage impedes with signals. Some mobile phones can hold on to the last identified GPS location, others may not.
Much of the discussion surrounding cell 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 is an acronym 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 are orbiting 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 backup 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 have a lifetime of about 10 years until all their fuel is exhausted.
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 offset and are in equilibrium. This is the best location to position 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 move at about 7,000 mph to keep position. This is approximately the same speed as GPS satellites, but since geo-synchronous satellites are 10,000 miles further away they don?t move relative to the earth.
The GPS Control Segment consists 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 data they send to earth is accurate.
The GPS User Segment incorporates 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 compute location by precisely timing the signals sent by GPS satellites. This information 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).
When satellite signals are not readily available, or accuracy and precision is less important than battery life, utilizing Cell-ID is a viable alternative to GPS smartphone location. The location of the mobile phone can be calculated by the cell network cell id, that recognizes the cell tower the phone is using. By having the position of this tower, then you can know approximately the location where the smartphone will be. However, a tower can cover a massive area, from a couple of hundred meters, in higher populationdensity areas, to several kilometers in lower density areas. This is why location CellID accuracy is less than than GPS accuracy. Even so monitoring from CellID still presents a truly useful alternative.
Mobile Phone GPS Tracking Tutorial
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