Cell Phone GPS Tracking Intro

GPS on cell phones is what consumers usually think about when reviewing tracking cell phones. GPS (Global Positioning System) utilizing satellites is the most recognized and more accurate way of tracking. However, GPS must have satellites to be in direct line of site of the cell phone. It doesn’t work particularly well indoors or in dense metropolitan areas. In the event that the handset is in a structure, for instance your house, restaurant, or often if driving the signals may not reach the smartphone. Sometimes thick cloud cover and heavy trees impedes with reception. Some mobile phones can hold on to the last identified GPS location, others may not.

Much of the discussion dealing with cell tracking, mobile GPS and cell phone tracker 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 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 is comprised of 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 are orbiting twice a day. They are not geostationary, 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 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 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 canceled and are in equilibrium. This is the ideal 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 travel at about 7,000 mph to sustain position. This is just about the same speed as GPS satellites, but since they satellites are 10,000 miles further away they don?t move relative to the earth.

The GPS Control Segment is comprised 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 make sure the satellites are working correctly and the data they beam down 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 work.

GPS receivers often take a long time to become ready to use after it’s turned on because it must acquire some basic information in addition to finding GPS satellite signals. This delay is sometimes caused if the GPS cell phone has been turned off for days or weeks, or has been moved a far 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 capture signals and calculate initial location more quickly.

Another method of formulating handset position is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation employs signal analysis data to compute the time it takes signals traveling from your telephone to no less than three cell towers to judge location.

With Mobile Location Services (MLS), the GSM cellular network provider uses triangulation algorithms to estimate the position of the handset, its accuracy is proven to be less than than that of GPS. MLS is also impacted by factors similar to GPS in the sense of the interference affecting signal strength and the density of GSM towers to assist in the triangulation calculation. In rural areas position accuracy may be off as much as a mile.

Cell Phone GPS Tracking Intro