one of my friends is thinking of a startup in which we will use GPS technology . The thing is we are thinking of making a cheap gps receiver indigeneously but i am not able to find good links on the internet regarding the in-depth electronic working of the GPS receiver . I have understood the concept of how gps is used to locate a location .
closed as not a real question by Leon Heller, Phil Frost, placeholder, Nick Alexeev♦, Dave Tweed♦ Jun 10 '13 at 20:43
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You'll never be able to make a GPS cheaper than the IC solutions that are out there without dumping some money into spinning silicon dies.
But in general GPS is a spread spectrum signal at 1.575GHz. You have to receive the signal then use a variety of PRN (pseudorandom) codes to correlate to the spread signal to de-spread it. (Not trivial). Once you've done that you can receive some of the timing information. However all GPS satellites share the same frequency so your receiver has to process multiple PRN codes on the same signal to find more satellites. Once you have at least 4 you can start processing position information. Trilateration is the most common technique. I've written tools to trilaterate in 3d. The solution is about 3 pages of algebra but it is the simplest. More modern receivers use more complex solutions and there are simulation packages for Matlab you can buy. Wikipedia has a good overview.
I think first you should evaluate some of the GPS Modules from U-Blox and other companies to get their clear working idea. There are different GPS modules for different applications like Dead Reckoning GPS, etc. Round the world there are only few countries which have their GPS Satellites in Space like US and Russia, namely GPS and GLONASS. There are some Taiwan companies also making GPS Modules, you can look into their devices and products to get and idea.