Cell Phone User's Guide

109
Making an Emergency Call
• Between tall buildings or under dense
tree-cover
• Near a powerful radio or television tower
• When your GPS antenna is covered (for
example, by your hand or other object) or
facing the ground
• In temperature extremes outside the
operating limits of your phone
Walking or driving very slowly may also
substantially reduce GPS performance.
Even where location information can be
calculated in such situations, it may take much
longer to do so, and your location estimate may
not be as accurate. Therefore, in any 911 call,
always report the location to the emergency
response center if you can and if you cannot,
remain on your phone for as long as the
emergency response center instructs you.
Even where adequate signals from multiple
satellites are available, your GPS feature will
only provide an approximate location, often
within 150 feet (45 meters) but sometimes
much further from your actual location. Advice
on how to improve GPS performance is
provided in “Enhancing GPS Performance” on
page 111.
While the GPS feature of your phone can be a
valuable navigational aid, it does not replace the
need for careful navigating and good judgment.
Never rely solely on one device for navigation.
Remember that the accuracy of the location
information and the time needed to obtain it will
vary depending on circumstances, particularly the
ability to receive signals from adequate numbers of
satellites.
On emergency calls, your phone uses assistance
information from the phone network to improve the
speed and accuracy of your phone’s location
calculation: if such assistance information
becomes unavailable, it may reduce the speed and
accuracy of the location calculation.
The satellites used by the GPS feature of your
phone are controlled by the U.S. government and
are subject to changes implemented in accordance
with the Department of Defense GPS user policy
and the Federal Radionavigation Plan. These
changes may affect the performance of the GPS
feature of your phone.
Making an Emergency Call
Dial 911 to be connected to an emergency
response center. If you are on an active call, you
must end it before calling 911.