Native applications built in Objective-C make full use of all the iPhone features: GPS, accelerometer, local storage, camera and more.

The process of relative positioning using the GPS module, under the schedule of C/OS-II operating system, is analyzed, with a brief introduction to the display interface of the network status.

Finally, an analysis and contrast between two methods is given through calculating the data of BJ54 coordinate points and C-class GPS network. A good conclusion is drawn.