ashtech ZY-12 Information Supplement page 31

Table 3.4. Screen 2 - Page 1 Parameters (continued)
Parameter
SOG SOG (speed over ground) is the receiver's velocity. Can be displayed in
miles per hour (labeled MPH), kilometers per hour (KM/H), or knots (KN).
The units are set on Screen 6, function 8: Unit Selection option.
FOM FOM (figure of merit) indicates the accuracy of the stand-alone position
based upon satellite range residuals and PDOP. 1 is the best. 9 indicates
that a position is not being computed.
PDOP PDOP (position dilution of precision) is a measure of the strength of the
satellite geometry. If the satellites are scattered around the sky, the
certainty of a position is better and PDOP is lower than if they are close
together. A number above 6 indicates a bad PDOP.
HDOP HDOP (horizontal dilution of precision) is the two-dimensional horizontal
component of PDOP.
VDOP VDOP (vertical dilution of precision) is the height component of PDOP.
TDOP TDOP (time dilution of precision) is the time component of PDOP.
SVS The number of satellites currently being used for the position calculation.
AGE Reports how many minutes since the position was computed.
Access page 2 of Screen 2 (Figure 3.4) by pressing the up or down arrows. Table
3.5 describes the page 2 parameters.
Screen Descriptions
Description
Figure 3.4. Screen 2 - Page 2
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