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Time to first fix (TTFF) is a measure of the time required for a GPS navigation device to acquire satellite signals and navigation data, and calculate a position solution (called a fix). An animation depicting the orbits of GPS satellites in medium Earth orbit
The time needed to acquire the ephemeris is becoming a significant element of the delay to first position fix, because as the receiver hardware becomes more capable, the time to lock onto the satellite signals shrinks; however, the ephemeris data requires 18 to 36 seconds before it is received, due to the low data transmission rate.
An indoor location tracking map on a mobile phone. An indoor positioning system (IPS) is a network of devices used to locate people or objects where GPS and other satellite technologies lack precision or fail entirely, such as inside multistory buildings, airports, alleys, parking garages, and underground locations. [1]
An indoor location tracking map on a mobile phone. Mobile phone tracking is a process for identifying the location of a mobile phone, whether stationary or moving. . Localization may be affected by a number of technologies, such as the multilateration of radio signals between (several) cell towers of the network and the phone or by simply
The U.S. Department of Defense is required by law to "maintain a Standard Positioning Service (as defined in the federal radio navigation plan and the standard positioning service signal specification) that will be available on a continuous, worldwide basis" and "develop measures to prevent hostile use of GPS and its augmentations without ...
Satellite navigation solution for the receiver's position (geopositioning) involves an algorithm.In essence, a GNSS receiver measures the transmitting time of GNSS signals emitted from four or more GNSS satellites (giving the pseudorange) and these measurements are used to obtain its position (i.e., spatial coordinates) and reception time.
Many mobile phones combine A-GPS and other location services, including Wi-Fi positioning system and cell-site multilateration and sometimes a hybrid positioning system. [ 4 ] High-Sensitivity GPS is an allied technology that addresses some of these issues in a way that does not require additional infrastructure.
Second, historical location can frequently be discerned from service provider records. Thirdly, other devices such as Wi-Fi hotspots or IMSI catchers can be used to track nearby mobile devices in real time. Finally, hybrid positioning systems combine different methods in an attempt to overcome each individual method's shortcomings. [6]