120 Section 2F. Tools

provided in “Enhancing GPS Performance” on
page 122.
While the GPS feature of your phone can be a valuable
navigational aid, it does not replace the nee d 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 and press N to be connected to an
emergency response center. If you are on an active
call, you must end it before calling 911.
When you make an emergency 911 call, the GPS
feature of your phone begins to seek information to
calculate your approximate location. It will take the GPS
feature of your phone some time to determine your
approximate location. Even where your phone has
good access to sufficient GPS satellite signals and
network assist data, it may take 30 seconds or more to
determine the approximate location. This time will
increase where there is reduced access to satellite
signals. When your approximate location is
determined, it is made available to the appropriate
emergency response center.
In some cases, your local 911 emergency response
center may not be equipped to receive GPS location
information. For this reason, and because the GPS
location informat ion reported is only app roximate or
may not be available in your location (see
“IMPORTANT: Things to Keep in Mind” on page 119),
always report your location to the 911 operator you