Symmetricom ET6000, User Manual

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GENERAL INFORMATION
The number of positions used to calculate the averages is user selectable via the RS-232 I/O
interface. Once the average position has been determined, the unit will switch to the
STATIONARY mode. The AUTO mode provides an averaged solution of the time information
from as many satellites as the receiver is tracking.
In the DYNAMIC mode, the system will select the best available satellites based on PDOP
(Position Dilution Of Precision) and provide a continuous navigational solution in three dimensions
(latitude, longitude, and altitude). The DYNAMIC mode does not automatically switch to the
STATIONARY mode.
1.6.8 ELEVATION MASK ANGLE
This mask is used to specify the elevation angle below which the use of satellites is prohibited.
Signal integrity from satellites very low on the horizon can be degraded. Obstructions will block
the signal. For land-based applications where there are local obstructions (foliage, buildings, etc.)
system performance will be smoother with an elevation mask of fifteen to twenty degrees. For
marine or aircraft applications, it is usually possible to use the satellites very close to the horizon,
although the pitch/roll should be considered. The system default is that set by the user. Refer to
Chapter Four, paragraph titled “ENTER ELEVATION MASK ANGLE” for instruction on selecting
elevation mask.
Symmetricom Inc ET6xxx ExacTime GPS TC & FG (Rev C) 1-17