Furuno GP-3500F - Manual (Page 230)

12. MAINTENANCE & TROUBLESHOOTING
12-12
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.