Mobile phone GPS is what people generally think about when looking at locating cell phones. GPS (Global Positioning System) using satellites is the most common and more accurate technology of tracking. But, GPS requires satellites to be in direct line of site of the handset. It doesn’t work particularly well indoors or in dense metropolitan areas. If the phone is in a structure, for instance your school, mall, or often riding in a car the signals might not get to the smart phone. Often heavy cloud cover and dense trees interferes with reception. Some mobile phones may store the last identified GPS position, others may not.
A few worthwhile technical features and functions relevant to GPS cell tracking to think about include: Tracking Application “Persistence”. The tracking application on a cell phone usually must be enabled by the user. Depending on the handset, the application may persist – remaining enabled when the phone is turned on after having been turned off. This feature can be particularly important if mobile phone tracking is important and you do not want to require the person using the phone to turn tracking on and off. Another issue related to Tracking Application “Persistence” and mobile phone GPS tracking is the possibility of over using the battery. It is important to be able to remotely adjust the frequency of taking GPS position. Choosing real-time or periodic sampling affects both the resolution of determining position as well as how long the battery will last. One typical means 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 when preferred. Also known as “data logging,” it can keep location data even when the device has traveled outside the wireless network. Passive tracking is not a universal feature built-in to standard cell phone, but the newest mobiles tend to have Passive tracking ability.
Much of the discussion surrounding GPS 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 use to provide three-dimensional location (latitude, longitude, and altitude) plus precise time. GPS stands for Global Positioning System and is a system that is composed 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 in medium earth orbit MEO. These satellites are also known as as the GPS Constellation, and they are orbiting once every 12 hours. They are not geosynchronous, they travel at over 7,000 mph. They are solar powered but have battery reserve for when they are in the earth?s shadow. 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 last about ten years until all their fuel runs out.
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 gravitational force and centrifugal forces are offset and are in balance. This is the best location to park 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 they satellites are 10,000 miles further away they stay in place 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 information they send 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 sometimes 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 slow start can be caused when the GPS device 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 acquire satellite signals and calculate initial position more quickly.
Another way of determining cell phone location is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation utilizes signal analysis data to compute the time it takes signals traveling from the cellular phone to no less than 3 cell towers to estimate location.
With Mobile Location Services (MLS), the GSM cell network provider utilizes triangulation techniques to compute the position of the mobile phone, its accuracy is proven to be much worse than that of GPS. MLS is also impacted by factors similar to GPS in the sense of the barriers impeding 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.
A Summary Of Smartphone GPS Tracking
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