Description: The mode of the GPS receiver defined as follows:
======================================================
Receiver Mode: Survey. 

The receiver is surveying and averaging its position. 
When it has finished surveying, the receiver switches 
to Position Hold mode. Survey mode and Position Hold 
mode are appropriate for static applications, such as a 
typical server room environment. This is the default mode 
when the SyncServer starts.

Receiver Mode: Dynamic. 

The GPS receiver surveys continuously to determine its 
position and doesn't switch to another mode. This mode 
must be initiated by a user, and is appropriate for mobile 
applications such as ships, land vehicles, and aircraft. 
The degree of accuracy this mode offers is fine for NTP 
time over networks, but is less than optimal for the IRIG-B, 
1 PPS, 10 MHz outputs available on some SyncServer models.  

Receiver Mode: Hold. 

The GPS receiver has completed Survey mode and switched to 
this mode, or the user has manually entered a position and 
forced it into this mode. The accuracy and stability of the 
SyncServer's timing outputs are optimal when the receiver 
has its exact position and is in this mode.
======================================================