Furuno GP-3500 - Manual (Page 180)

11. MAINTENANCE & TROUBLESHOOTING
11-10
11.8 Cold Start
Cold start is automatically executed at initial power application or when the GPS
memory is cleared. This is done to acquire the Almanac to receive a GPS
satellite. You can also do the cold start manually when the Almanac is too old to
acquire a satellite; for example, when the equipment has not been used for one
year or more. Manually cold starting the receiver erases the existing Almanac to
receive the current one.
1. Press the [MENU] key to show the main menu.
2. Press the [0] key to show the SYSTEM SETUP menu.
3. Press the [6] key to show the TEST & MEMORY CLEAR menu.
4. Press the [5] key to show the following window.
BEGIN COLD START
TO CLEAR GPS MEMORY.
ARE YOU SURE?
YES ... PRESS KNOB
NO ... PRESS CLEAR KEY
5. Press the [ENTER] knob to begin the cold start. Cold start takes about 90
seconds to complete.
Note:
To cancel, press the [CLEAR] key.
6. Press the [MENU] key for several times to close the menu.
The Almanac description is shown below.
Almanac
Every GPS satellite is broadcasting general orbital data (called Almanac) about
all other satellites. The GPS receiver decodes the Almanac to calculate when
and at what angle the GPS satellite is to appear. If there is no Almanac in the
receiver the estimated arrival time of the GPS satellite cannot be found and thus
GPS position fix cannot be calculated. The GPS receiver is shipped with no
Almanac in its memory. When the power is first turned on after installation the
receiver starts receiving the Almanac. This is called “cold start.” Each time the
GPS receiver receives orbital data the Almanac is replaced with the latest one.