GEOG 862
GPS and GNSS for Geospatial Professionals

The Space Segment

 detailed, labeled image of GPS Satellite
GPS Satellite
Source: GPS for Land Surveyors

GPS satellites. All GPS satellites have some common characteristics. They weigh about a ton, and with solar panels extended are about 27 feet long. They generate about 700 watts of power. They all have three-dimensional stabilization to ensure that their solar arrays point toward the sun and their 12 helical antennae to the earth. GPS satellites move at a speed of about 8,700 miles per hour. Even so, the satellites must pass through the shadow of the earth from time to time, and onboard batteries provide power. All satellites are equipped with thermostatically controlled heaters and reflective insulation to maintain the optimum temperature for the oscillator’s operation. Prior to launch, GPS satellites are checked out at a facility at Cape Canaveral, FL.

GPS satellites move at a speed of about 8,700 miles per hour, an extraordinary rate. This underlines the importance of the solution of time in the positioning using GPS.