Now, what’s tomorrow’s challenge?
APN-005 Rev 1 November 12, 1997
TECHNICAL BULLETIN
OBTAINING AN ALMANAC FILE FOR THE SOFTSURV PLANNER
The Planner module of SoftSurv requires a binary file called an almanac that describes the orbits
of the GPS satellites. The almanac file is continuously broadcast by the satellites and is recorded
by the GPS receivers and data collectors. The following steps describe the procedure for
downloading an almanac file:
1. Set up a GPS receiver as per the Quick Step Guide in the OutRider/GISMO manual.
2. Let the receiver track satellites for about 15 minutes. This will allow sufficient time to
download the entire almanac file. Note: the almanac is automatically downloaded while
normal GPS operations are carried out.
3. After completing the GPS operations, connect the data collector to a PC for standard
download.
4. Use the UTILITIES module of SoftSurv/GISMO to receive files from the data logger.
5. When selecting the file to transfer from the data collector after the communication settings
have been established, select the TRANSMIT – ALMANAC option.
6. The most recently downloaded almanac file is called almanac.alm. Toggle this file to send.
7. Once the almanac file has been received, it can be renamed as desired, however it is
suggested that the extension, .alm, is retained.
It is recommended that the almanac file be updated every 10 days or so since the true satellite
orbits tend to deviate from the predicted orbits over time. Once the almanac is downloaded to
the PC, it is common to rename the file to reflect the date that the file was collected. For
example, a filename such as ALM0211.ALM can represent an almanac file that was collected on
February 11
th
.
If you require a more in depth information about collecting an almanac, please contact:
NovAtel, Inc.
1120 – 68
th
Avenue N.E.
Calgary, Alberta
Canada, T2E 8S5
Phone: (403) 295-4900 or toll free in Canada and the U.S. only 1-800-NOVATEL
Fax: (403) 295-4901
Email: support@novatel.ca
