How do GPS devices determine your position?

[doc.madani]

Hello i need help regarding GPS devices and the physics that goes into them.
This may include, how the signal travels from source to GPS. Refractional waves and atmosphere interference.

The process that goes into GPS devices in finding ur position. (Physics Based)

thank you =]

 

[tiny-tim]

Hi doc.madani !

See wikipedia, particularly http://en.wikipedia.org/wiki/Global_Positioning_System#Atmospheric_effects and http://en.wikipedia.org/wiki/Global_Positioning_System#Possible_Sources_of_Interference

 

[mplayer]

Geosynchronous orbit
Triangulation

Finding Position:
time transfer - to correct for relativistic effects
Geometric trilateration

Here's a short video on geometric trilateration:
https://www.youtube.com/watch?v=http://www.youtube.com/watch?v=3zRlbboMvb0
Here's a short video on relativistic time dilation and implications for GPS:
https://www.youtube.com/watch?v=http://www.youtube.com/watch?v=EOwMkFsJXRI&feature=related
http://www.youtube.com/watch?v=EOwMkFsJXRI&feature=related

* L1 (1575.42 MHz): Mix of Navigation Message, coarse-acquisition (C/A) code and encrypted precision P(Y) code, plus the new L1C on future Block III satellites.
* L2 (1227.60 MHz): P(Y) code, plus the new L2C code on the Block IIR-M and newer satellites.
* L3 (1381.05 MHz): Used by the Nuclear Detonation (NUDET) Detection System Payload (NDS) to signal detection of nuclear detonations and other high-energy infrared events. Used to enforce nuclear test ban treaties.
* L4 (1379.913 MHz): Being studied for additional ionospheric correction.
* L5 (1176.45 MHz): Proposed for use as a civilian safety-of-life (SoL) signal (see GPS modernization). This frequency falls into an internationally protected range for aeronautical navigation, promising little or no interference under all circumstances. The first Block IIF satellite that would provide this signal is set to be launched in 2009.