SUUNTO X10 - Manual (Page 68)

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If possible, stay clear from people, trees or other dense vegetation when activating
the GPS. They can cause problems to the signal reception. If you are in a forest, try
to find an open or scarcely wooded area before activating the GPS.
• Rocks, buildings or any metallic materials
The GPS signals will not penetrate any solid constructions. Therefore do not try to
activate the GPS inside caves, buildings or any other equivalent constructions.
ACTIVATE THE GPS AT LEAST ONCE BEFORE LEAVING FOR AN EXTENDED
OUTDOOR ACTIVITY
When you activate the GPS for the first time, it will take longer than usual since the
GPS has no reference to its current location. This may also happen if the GPS has not
been used for a long time. Subsequent GPS starts will take less time. The reason for
the slow initial fix is that the antenna is optimized for a wrist unit use. Hand-held GPS
receivers typically have a patch antenna with highly directional radiation pattern. This
gives good sensitivity and uninterrupted data flow when the unit is facing up.
Suunto X10 has a loop antenna that has a wide radiation pattern. It receives data from
a very wide angle. There is a clear functional reason for this: Wide reception angle is
necessary for the Suunto X10 to ensure fluent operation in all positions when the unit
is worn around the wrist. However, due to the wide angle, the sensitivity of reception is
not as good as in hand-held GPSs with a narrow radiation pattern.
To minimize the GPS initiation time, hold the unit steady in one position with the
display facing up and make sure you are located in an open area so that the unit has a
clear view to the sky.
RESERVE ENOUGH TIME FOR THE MEASUREMENT
When the GPS is activated, the receiver starts searching for radio signals from the
satellites and as soon as one is found, data starts flowing from the satellite to the
receiver. The data flows quite slowly and usually a little less than a minute is needed
for the first position estimate. The data includes a list of the satellite positions and the
GPS time. You need these before you can perform the actual position calculation and
before the GPS becomes functional. The GPS time is highly accurate because each
satellite has an atomic clock on board.
After the first position fix has been established, it still takes additional 12 minutes
before the GPS has received all optional data from the satellites. After it has a fix, you
can move the unit more freely without losing the connection to the satellites.
The downloaded data is valid roughly for the next four hours during which you can