Topcon HiPer II, Operator'S Manual, Page: 51 / 140

Collecting Almanacs and Ephemerides
P/N 7010-0982
2-7
Figure 2-4. Stages for Connecting to the Receiver via Bluetooth
6. To close the connection to the receiver, click
Device Disconnect
:
Collecting Almanacs and
Ephemerides
Each satellite broadcasts a navigation message that includes the
ephemeris parameters of the satellite, the almanac, and various other
information. The ephemeris parameters describe the orbital motion of
the tracked satellite and are used to predict its location/trajectory. The
almanac gives the approximate orbit (course) for the transmitting
satellite as well as all other satellites in the same system.
• GPS and GLONASS satellites broadcast ephemeris data
cyclically, with a period of 30 seconds.
• GPS satellites broadcast almanac data cyclically with a period of
12.5 minutes; GLONASS satellites broadcast almanac data
cyclically with a period of 2.5 minutes.
If the receiver has an almanac, the time needed to search for and lock
onto satellite signals is considerably reduced.
HiPerII_OM.book Page 7 Wednesday, December 15, 2010 9:07 AM