The Global Positioning System (GPS) was first created and utilized by U.S. Department of Defense and consisted of 24 geosynchronous satellites. This, coupled with a GPS enabled device, allowed an individual or weapon system to receive a value that would fix its location. These values were broken into latitudinal and longitudinal numbers and further delineated into degrees, minutes, and seconds. As we discussed in Chapter 1, the iPhone 3G brought GPS to the iPhone. GPS on the iPhone 3G, was really Assisted GPS, meaning that radio tower triangulation was first utilized to ascertain the location of the device, and then the GPS receiver would then more accurately point to where the device was located. Therefore, with the iPhone 3G, the accuracy of this device was not very good. With firmware updates, though, the accuracy improved. The iPhone 3GS was a marked improvement in the accuracy of the device. In this chapter, we will discuss the artifacts located on an iDevice in reference to GPS.
KeywordsAzimuth DGPS NMEA
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