Mobile Phone GPS Tracking Help

GPS on cell phones is what people commonly think about whenever investigating locating cell phones. GPS (Global Positioning System) using satellites is the most common and more accurate means of tracking. Still, GPS must have satellites to be in direct line of site of the cell phone. It doesn’t work very well indoors or in dense cities. In the event that the device is inside a structure, for instance your office, shopping center, or often if driving the signals may well not get to the cell phone. Sometimes dense cloud cover and heavy foliage impedes with reception. Some cell phones will retain the last identified GPS position, others may not.

Much of the discussion surrounding GPS 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 utilize to provide three-dimensional location (latitude, longitude, and altitude) plus precise time. GPS stands for Global Positioning System and is a system that is made up of 3 primary segments: Space Segment, Control Segment and User Segment.

The GPS Space Segment includes 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, but rather move 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 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 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 offset and are in balance. 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 geostationary satellites need to travel at about 7,000 mph to sustain position. This is approximately 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 is composed 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 working correctly and the information they send to earth is accurate.

The GPS User Segment is comprised of of GPS receivers taking the shape of cell 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 work.

GPS receivers sometimes take longer 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 slow start can be caused if the GPS cell phone has been turned off for days or weeks, or has been transported a significant distance while turned off 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 acquire signals and calculate initial location more quickly.

Another method of calculating handset location is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation uses signal analysis data to determine the time it takes signals to travel from the cell phone to a minimum of three cell towers to judge location.

With Mobile Location Services (MLS), the GSM cellular network provider utilizes triangulation techniques to estimate the location of the device, its accuracy is proven to be much worse than that of GPS. MLS is also impacted by the same issues as GPS in the sense of the barriers affecting signal quality and the density of GSM towers to assist in the triangulation calculation. In remote areas position accuracy may be off as much as a mile.

Mobile Phone GPS Tracking Help