Showing posts with label broadcast signals. Show all posts
Showing posts with label broadcast signals. Show all posts

Saturday, October 26, 2013

A Short Intro To Mobile Phone GPS Tracking

Throughout this discussion consider that there is a fundamental difference between cell phone GPS Tracking and Navigation. GPS phone tracking is usually associated with someone keeping records of either real-time or historical smartphone location, while Navigation deals with the handset user figuring out how to get from point A to point B. Just because a cell phone has GPS doesn?t mean that it can easily be used as a navigation device. Just like cell tracking , navigation requires third-party software.



 Locate Cell Phone


Much of the discussion dealing with cell 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 use to determine 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 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 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 gravitational force and centrifugal forces are offset and are in equilibrium. This is the ideal 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 travel at about 7,000 mph to keep position. This is approximately the same speed as GPS satellites, but since stationary satellites are 10,000 miles further away they don?t move relative to the earth.


The GPS Control Segment is composed 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 working to specification and the information they beam down to earth is accurate.


The GPS User Segment is composed of of GPS receivers taking the shape of devices 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 longer to become ready to use after it’s turned on because it must acquire some basic information in addition to capturing GPS satellite signals. This delay is sometimes caused when the GPS cell phone has been turned off for days or weeks, or has been transported a significant 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 signals and find initial position more quickly.


If satellite signals are not obtainable, or accuracy is less important than battery life, making use of Cell-ID is a good alternative to GPS mobile phone tracking. The position of the handset may be computed by the cell network cell id, that determines the cell tower the cellphone is connected to. By having the position of this tower, then you can know roughly the place that the handset might be. Still, a tower can cover an enormous area, from a couple of hundred meters, in higher populationdensity zones, to a few kilometers in lower density areas. For this reason location CellID precision is less than than GPS accuracy. Even so location from CellID still supplies a very useful substitute.



A Short Intro To Mobile Phone GPS Tracking

Tuesday, October 8, 2013

A Quick Introduction To Cell Phone GPS Tracking

GPS on cell phones is what people usually think about whenever reviewing tracking smartphones. GPS (Global Positioning System) using satellites is the most common and more accurate method of tracking. Yet, GPS must have satellites to be in direct line of site from the cell phone. It doesn’t work really well indoors or in dense urban centers. If the cellular phone is inside a structure, for instance your office, shopping center, or often riding in a car the signals might not get to the smart phone. Sometimes dense cloud cover and heavy trees impedes with signals. Some cell phones may hold on to the last identified GPS position, others might not.



 Mobile Tracker


Much of the discussion surrounding GPS tracking, mobile GPS and mobile phone tracking software could be helped by a GPS Satellite primer.


GPS satellites broadcast signals from space that GPS receivers utilize to determine 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 made up of twenty-four to thirty-two satellites that orbit the earth in medium earth orbit MEO. These satellites are referred to as the GPS Constellation, and they are orbiting twice a day. They are not geosynchronous, but rather move at over 7,000 mph. They are solar powered but have battery backup 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 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 park 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 keep position. This is just about the same speed as GPS satellites, but since earth-synchronous satellites are 10,000 miles further away they stay in place relative to the earth.


The GPS Control Segment includes 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 correctly and the data they send to earth is accurate.


The GPS User Segment made up of of GPS receivers taking the shape of devices 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 compute position by precisely timing the signals sent by GPS satellites. This data 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).


Another way of calculating cell phone location is Triangulation or Mobile Location Services (MLS). Cell Tower Triangulation makes use of signal analysis data to compute the time it takes signals to travel from the cellphone to a minimum of three cell towers to calculate position.


With Mobile Location Services (MLS), the GSM cell network provider utilizes triangulation algorithms to try to pinpoint the location of the mobile phone, its accuracy is proven to be much worse than that of GPS. MLS is further impacted by factors similar to GPS in the sense of the barriers affecting signal strength and the density of GSM towers to assist in the triangulation calculation. In rural areas location accuracy may be off as much as a mile.



A Quick Introduction To Cell Phone GPS Tracking

Sunday, September 29, 2013

Cell Phone GPS Tracking Tutorial

A couple of worthwhile technical capabilities related to GPS cell tracking to consider include: Tracking Application “Persistence”. The tracking application on a cell phone 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 particularly usefull if 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 location is the potential of wasting the battery. 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 location as well as how long the battery will last. One typical method of minimizing battery and data use is Passive Tracking. Some cell phone GPS tracking devices will record location data internally so that it can be downloaded late


r. Also known as “data logging,” which can keep position information 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 most up-to-date mobile phones tend to include Passive tracking features.


 Cell Phone Tracking


Much of the discussion surrounding 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 determine three-dimensional location (latitude, longitude, and altitude) plus precise time. GPS is an acronym 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 referred to as the GPS Constellation, and they make an orbit twice a day. They are not geostationary, but rather move at over 7,000 mph. They are solar powered but have battery backup for when they are in the earth?s shadow. 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 properly positioned. The satellites last about ten years until all their fuel is exhausted.


GPS Satellites are not communications satellites. Geostationary or communications satellites are at a much higher orbit of about 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 place a communications 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 approximately the same speed as GPS satellites, but since earth-synchronous 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 numerous dedicated and shared Ground Antennas and Monitor Stations that work together to make sure the satellites are working correctly and the data they send to earth is accurate.


The GPS User Segment includes 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 work.


GPS receivers determine position 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 life of the battery, employing Cell-ID is a good substitute to GPS mobile phone tracking. The location of the smartphone might be determined by the cellular network cell id, that pinpoints the cell tower the phone is connected to. By understanding the position of the tower, you may know approximately the spot where the smartphone might be. But, a tower can cover an enormous area, from a couple of hundred meters, in high populationdensity zones, to a few kilometers in lower density zones. For this reason location CellID precision is less than than GPS accuracy. Having said that monitoring from CellID still provides a truly helpful substitute.



Cell Phone GPS Tracking Tutorial