Signal chosen because: The complex pattern ensures that the receiver does not accidentally synchronize up to some other signal or so the receiver won’t accidentally pick up another satellite’s signal
the dashed lines show the actual intersection point, and the gray bands indicate the area of uncertainty. the solid lines indicate where the GPS receiver "thinks" the spheres are located. Because of errors in the receiver's internal clock, these spheres do not intersect at one point. The GPS receiver must change the size of the spheres until the intersection point is determined. The relative size of each sphere has already been calculated, so if the size of one sphere is changed, the other spheres must be adjusted by exactly the same amount .
![What is GPS? ,[object Object],[object Object],[object Object],[object Object],[object Object]](https://image.slidesharecdn.com/gpseser-100512190025-phpapp02/85/Gps-eser-1-320.jpg)
![Satellites ,[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)