Mobile Phone GPS Tracking Introduction

A couple of worthwhile technical features and functions relevant to GPS cell tracking to think about include: Tracking Application “Persistence”. The tracking software on a handset typically must be enabled by the user. Depending on the device, the application may persist – remaining enabled when the phone is turned on after having been turned off. This feature can be especially handy if cell tracking is important and you do not want to instruct the person using the phone to turn tracking on and off. Another thing relevant to Tracking Application “Persistence” and cell phone GPS location is the possibility of battery drain. It is important to be able to remotely adjust how often of taking GPS position. Choosing real-time or periodic sampling affects both the accuracy of finding position along with how long the battery will last. One typical way of minimizing battery and data use is Passive Tracking. Some handset GPS tracking devices will store location data internally so that it can be downloaded later. Also

known as “data logging,” it can maintain location information even when the device has traveled outside the wireless network. Passive tracking is not a universal feature built-in to standard smartphone, but the most up-to-date mobile phones tend to include Passive tracking features.

A lot of the discussion dealing with cell tracking, cell phone GPS and cell phone tracking 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 is composed of twenty-four to thirty-two satellites that orbit the earth at a height of about 12,000 miles. These satellites are also known as as the GPS Constellation, and they make an orbit once every 12 hours. They are not geostationary, but rather move 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 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 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 force of gravity and centrifugal forces are offset and are in equilibrium. This is the best location to place 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 travel at about 7,000 mph to maintain 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 includes 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 to specification and the information they send to earth is accurate.

The GPS User Segment includes 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 programs that make them function.

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 can be caused when the GPS mobile phone has been turned off for days or weeks, or has been moved a far 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 satellite signals and find initial position faster.

Another way of determining mobile phone position is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation employs signal analysis data to compute the time it takes signals traveling from the cell phone to at least 3 cell towers to calculate position.

With Mobile Location Services (MLS), the GSM cellular network provider uses triangulation algorithms to calculate the location of the smartphone, its accuracy is proven to be much worse than that of GPS. MLS is also affected by the same issues as GPS in the sense of the interference affecting signal strength and the density of GSM towers to help in the triangulation effort. In rural areas location accuracy may be off as much as a mile.

Mobile Phone GPS Tracking Introduction