User guide

Configuring Dart RTLS
D2119 Dart RTLS User Guide 40
data output.
Example 3—Groups having a mixture of equal and unique priorities. For example, there
could be four Virtual Groups with the following results from a given tag transmission:
Virtual Group 1 with priority 1 does not compute data successfully.
Virtual Group 2 with priority 2 does compute data successfully.
Virtual Group 3 with priority 2 does compute data successfully.
Virtual Group 4 with priority 3 does compute data successfully.
In this case, Virtual Groups 2 and 3 have equal priority and have higher priority than
other groups with successful computations. Therefore, the computation result from both
group 2 and group 3 are evaluated by the hub to determine which VG output had the
earliest transmission time. The VG with the earliest transmission time is sent as output
from the hub. Filtering output-based virtual group priorities is considered an advanced
feature requiring experimentation.
Note : In FW version 5.0.0 and up, to optimize calculation time, the lower priority VGs
are calculated only if high priority VG do not yield locates. In Example 3, if VG 2 and 3
computes data successfully, data from VG 4 is not computed.
 DQI Filter: Double-click this field to turn on or off the suppression of tag location data
with quality indicators (DQI) greater than the value specified in the DQI Threshold
field.
 DQI Threshold: Specify the value beyond which tag location data will be suppressed.
Larger DQI values generally indicate a larger data error, or poorer accuracy in the
position measurement. In an ideal world without measurement errors, the DQI value
would be zero.
 GDOP Filter: Geometric Dilution of Precision (GDOP) is used to quantify the location
accuracy of each tag blink based on the geometry of the receivers detecting the tag blink
and the calculated tag location. Double-click this field to turn on or off the suppression of
tag location data with Geometric Dilution of Precision (GDOP) greater than the value
specified in the GDOP Threshold field.
 GDOP Threshold: Specify the value beyond which tag location data will be suppressed.
Larger GDOP value generally indicates lower reliability on the position measurement
(indicates poor geometry). Normally, a location calculated with GDOP value above 2.0 is
not that trustable. GDOP filter is a site specific setting. In theory, GDOP threshold in the
range of 1.0 to 1.4 is a good setting for a well-designed deployment.
Filtering output based on DQI or GDOP values is considered an advanced feature requiring
experimentation; initial and possibly most installations should avoid using this feature.
The DQI Filter, DQI Threshold, GDOP filter and GDOP threshold options only apply to successful data
computations. Data computation is successful when a computed position that is based on a tag event
satisfies the group boundary constraints and computation options described above.