| Answer: |
A GPS receiver must track 4 satellites to calculate its position and determine the exact time. The receiver position must be known in order to compute the distance of each satellite from the own location and thus be able to account for the transmission delay of the radio signal. Once the receiver position has been determined and is left unchanged, only a single satellite must be tracked to keep the accurate time. Meinberg GPS receivers are mainly used as reference time sources which are installed in a fixed location, so normally the position changes only if the device has been installed at a new location. This is why 6 channels are more than sufficient for reliable operation.
GPS receivers with 12 channels have been mainly designed for navigation in moving vehicles where more channels have advantages if the vehicle is moving around e.g. between buildings and trees. |
