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Communication and tracking system performance 139

coordinates (TSPs). These values are used in subsequent calculations. Estimates rep-
resent the answer from the model; they are not inputs to the design. If values are unac-
ceptable, areas of the mine must be examined to modify tracking accuracy. This
process is consistent with the current standard practice.

8.3.2 Metric values in example layout
Following are examples of metric calculations to describe the tracking system as
installed. Some metrics are not described because they are not predicted in this analysis.
For instance, latency will not be described. The scenario-based metrics—reliability,
availability, susceptibility, and robustness—are not described. For all of the following
metrics, areas of the mine are modeled. For instance, all of the intersections along the
primary EW are listed out as the GTPs of interest. For each of these GTPs, 250 TSPs are
generated. These TSPs are used in the calculations.
For the static testing area in the test mine, the active TCA is highlighted blue in
Fig. 8.2. The Inferred TCA will sporadically occur in the entries adjacent to the
escapeways as shown in Figs. 8.21–8.23. No escapeway inside the test area will have
a tracking error greater than 2000ft and no strategic area will have a tracking error
greater than 200ft. Therefore, this FMN configuration will mean that the static testing
area in test mine will be included in the compliant TCA. The compliant TCA is the
area inside the TCA where tracking quality guidelines are met.
For the primary EW in the Test Mine, it is expected that the instantaneous accuracy
(IA) of measurements ranges from 1.14 (nearly perfect IA) to 1237ft. For the second-
ary EW, IA is calculated to range from 1.33 to 985ft. The beltline is covered, but in
spite of its much higher attenuation, rendering lower signal strengths, the IA range
from 1.25 to 896ft remains comparable to that of the escapeways.
Based on this estimated installation of Test System equipment, the simulation pre-
dicts the primary EW in Test Mine will have an AA of 267ft and AA will be 334ft in
the secondary EW. The calculated AA in the beltway is 383ft.
The primary EW simulation IAs have an SDA of 248ft and the secondary EW is
comparable with SDA of 217ft. The beltway SDA is 221ft.
Figs. 8.24–8.26 graphically show the average error vector and the average cluster
radius for the three areas of interest in the mine. The primary EW has an ACR of 94ft
with an AEV of {212, 26}. The secondary EW has an ACR of 73ft with an AEV of
{152, 7}. The belt entry has an ACR of 89ft with an AEV of {95, 25}. These
AEVs are consistent with the angle of the mine, meaning the tracking system is cal-
culating the TSPE in the correct entry, but the distance inby is variable. The linearity
of the primary and secondary EWs is therefore expected. The belt entry shows a
greater spread, and this can also be anticipated because the entry does not contain
any transmitter equipment. Therefore, some TSPEs tend to be drawn to the primary
and secondary EWs where the signal is stronger, located in this mine, respectively,
on either side of the belt entry. This is the value of two-dimensional metrics; they
show bias in the system that can be engineered out by changing antenna and node
locations.