eTrex Screen GPS Made Easy
  Page number: Topic		 GPS Made Easy synopsis
scr01.jpg (11121 bytes) Page 29-34: Accuracy The satellite page displays the accuracy of the receiver's GPS position. The accuracy on this screen is shown as 34 ft.

GPS Made Easy explains accuracy and how it is affected by ionosphere interference, satellite geometry and multipath signals. Selective Availability is also explained and why it is so nice to not have it any more.
Page 11: Why four satellites
Page 34: 2D vs. 3D		 The satellite page also displays the number of satellites required for a position lock.

GPS Made Easy explains why four satellites are required for a 3D position lock. It also explains how accuracy is affected if only three satellites are visible and a 2D position lock is achieved.
Skyview
Satellite Page		 Page 26-28: Signal strength and the importance of a good antenna.

Page 31-32: Low signal strength and outages.

 The satellite page shows a signal strength bar that indicates how good a signal the receiver is picking up from the satellites.

GPS Made Easy explains the importance of strong satellite signals and its relationship to the receiver's antenna and external antennas. It also explains what an outage is and how weak signal strengths can cause an outage.


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