S-GPS

{{Short description|System to allow GPS and CDMA reception simultaneously}}

Simultaneous GPS (S-GPS) is a method to allow a GPS reception and CDMA communications to operate simultaneously in a mobile phone.

Ordinarily, cellular geolocation and a built-in GPS receiver 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 radio receiver.

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.{{cite book|last1=Milette|first1=Greg|last2=Stroud|first2=Adam|title=Professional Android Sensor Programming|publisher=John Wiley & Sons|isbn=9781118240458|page=6|url=https://books.google.com/books?id=dZjo-254FucC&dq=%22simultaneous+GPS%22&pg=PA5|language=en|date=2012-05-18}} 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.{{cite book |last1=Xu |first1=Y. |last2=Wang |first2=K. |last3=Pals |first3=T. |last4=Hadjichristos |first4=A. |last5=Sahota |first5=K. |last6=Persico |first6=C. |title=2007 IEEE Custom Integrated Circuits Conference |chapter=A Low-IF CMOS Simultaneous GPS Receiver Integrated in a Multimode Transceiver |date=1 September 2007 |pages=107–110 |doi=10.1109/CICC.2007.4405692 |isbn=978-1-4244-0786-6 |s2cid=16237573 }} The commercial availability of S-GPS chipsets from manufacturers such as Qualcomm, has led to adoption of the method in newer handsets.{{cite web |url=http://www2.electronicproducts.com/Improving_S-GPS_sensitivity-article-farr_avago_jun2008-html.aspx |title=Improving S-GPS sensitivity |publisher=Avago Technologies |url-status=dead|archiveurl=https://web.archive.org/web/20120722093231/http://www2.electronicproducts.com/Improving_S_GPS_sensitivity-article-farr_avago_jun2008-html.aspx |archivedate=2012-07-22 }}