Differential Mode Selection - ashtech ZY-12 Information Supplement

Table 3.8. Position Fix Parameters (continued)
Parameter
HDOP MASK
VDOP MASK
FIX ZONE
UNHEALTHY
ION/TROP
POS COMP
UTM COORD
POINT POS

Differential Mode Selection

The differential mode subscreen allows you to set up the receiver as an RTCM
differential base or rover (Figure 3.8). This screen also gives access to lower-level
screens where you specify parameters such as RTCM format parameters. This is
accessed by selecting DIFFERNTL on Screen 4 and pressing the [e] key. If you
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Lets you define horizontal dilution-of-precision. Effective only when
POSITION MODE is set to 3. The default is 4.
Lets you define the vertical dilution-of-precision parameter. Effective only
when ALT MODE is 0. Default is 4.
Lets you set the UTM zone to be held fixed as described above for FIX
UTM. Must be used in conjunction with FIX UTM.
Lets you specify whether or not to include unhealthy satellites in the
position computation. If Y is specified, a satellite broadcasting an
unhealthy message is used to compute a navigation position. Please
note that this parameter does not affect data collection for an unhealthy
satellite.
Allows you to enable or disable the ionospheric and tropospheric models
to be used in position computation.
• M = mathematical ionosphere and mathematical tropospheric models
• R = real dual-frequency ionospheric model used, together with the
mathematical tropospheric model
• N = no model used (default)
Lets you enable or disable the computation of position. USE WITH
CAUTION.
Lets you specify whether to display the compound position in Screen 2
using geodetic coordinates (latitude, longitude) or UTM (east, north)
coordinates. If set to Y, UTM coordinates are computed and displayed
using the current grid zone.
POINT POS improves the accuracy of a stand-alone absolute position of
a stationary receiver from about 50 meters to less than five meters over a
period of four hours. Point positioning uses an averaging technique to
reduce the effects of SA and other fluctuating errors. Point positioning is
standard with the software (no option required).
Description
ZY-12 GPS Receiver