Globalstar Satellite Phones

Several Emergency Preparedness programs in Arizona purchased Globalstar satellite phones a couple of years ago to aid in communications coverage. This was especially critical for remote areas where cell phone coverage was minimal or non-existant.

Globalstar decided to improve coverage by launching additional satellites, however doing so would reduce signal strength making sat phones inoperable at times. At this time, they are experiencing difficulty and hope to become fully operational by late 2009. According to the constellation update, theTwo-Way Voice and Duplex Data Services have been affected.

Globalstar has offered discounts on service to agencies who have made formal requests. In addition, Globalstar is offering a tool located on its website to show when satellites will be overhead for a specific geographic location to have phone coverage. The tool is called the Optimum Satellite Availability T-tool (OSAT).

Please visit Globalstar at http://www.globalstarusa.com/en/index.php and click on Optimum Satellite Availibility Tool or inquire with Globalstar customer service for more information on discounts.

Global Positioning Systems

Global Positioning Systems (GPS)

GPS was developed by the Department of Defense and its specific use was originally intended for the military but during the 1980's it became available to the public. GPS has several key applications: navigation, tracking, mapping and timing.

GPS is a system involving a geospatial reference point located on Earth and approximately 24 satellites orbiting Earth two times a day, which continuously transmit satellite position in space and accurate time 24 hours a day.

GPS provides a signal that is processed in a GPS receiver, reading time, position and velocity. Location of the receiver is determined when at least four GPS satellite signals locked on receiver. It is then able to compute positions in three dimension.

GPS signal strength will determine the accuracy of the receiver. The greater the signal strength and number of signals received from the satellite, the more accurate the reading is, and vice versa.

For more information, please visit:
http://www.colorado.edu/geography/gcraft/notes/gps/gps_f.html