S-GPS

Simultaneous GPS or S-GPS is a method to enhance a mobile phone's satellite-based position reporting ability to a mobile network operator.

Ordinarily, a built-in, multi- dimensional GPS device is used to determine the location of an E911 call made from CDMA phones. By using a time-multiplexed scheme called TM-GPS, the reception of the telephone call and the GPS signal are alternated one after the other, requiring only one RF radio.

As the name implies, Simultaneous GPS allows a cellphone to receive both GPS and voice data at the same time, which improves sensitivity and allows service providers to offer location-based services. The use of two radios with a single antenna imparts new design challenges, such as leakage of the voice transmitter signal into the GPS receiver circuitry. The commercial availability of S-GPS chipsets, however, from manufacturers such as Qualcomm, has led to adoption of the method in newer handsets and Samsung's latest processors (as the ones used in Galaxy S III, Note 10.1, Note 2).

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