2
detection performance of CXS designed for surface min-
ing haul trucks. Note that we did not evaluate any CXS
in this experiment. We collected measurements while the
GNSS was not in motion—static, and then dynamic while
the GNSS was in motion. Under static conditions, these
measurements included positional data such as latitude,
longitude, and elevation. Under dynamic conditions, these
measurements included latitude, longitude, elevation,
speed, and timestamp. For both conditions, a combination
of sensors is used to validate the measurements. The follow-
ing section describes the test method.
TEST METHOD
Test Course Setup
NIOSH researchers conducted static and dynamic tests to
evaluate the positional accuracies of GNSS receivers in a
parking lot area at the NIOSH campus in Bruceton, PA.
This area has a relatively flat surface area about 80-m (260-
ft) long and 15-m (49-ft) wide. To set up for the tests, we
used surveying equipment to establish known ground truth
or “benchmark” points to compare with measurements of
the GNSS receivers. We used two geodetic points on the
NIOSH campus to localize two types of surveying equip-
ment. One item of our surveying equipment was GNSS
based and the other was a robotic total station (RTS) that
used an optical laser and a prism to collect positional data.
Using the RTS, we surveyed a point for the base station.
During the test, we positioned the base station on that point
to transmit real-time kinematics (RTK) corrections to the
to the receiver or GTI Away from the base station point, we
also surveyed two 64-m (210-ft) parallel lines spaced about
0.61 m (24 inches) apart. Along the lines, we surveyed and
marked 10 points on each line from one end to the next
using nails and marking paint. We placed 10 metal strips
covered with reflective tape (reflectors) perpendicular to the
two lines (as shown in Figure 1). We designated the most
westbound reflector as reflector #1. Reflectors #2 through
#10 were placed with respect to reflector #1 about 9.14 m
(30 ft), 15.24 m (50 ft), 21.34 m (70 ft), 27.43 m (90 ft),
39.62 m (130 ft), 47.72 m (150 ft), 51.82 m (170 ft),
60.96 m (200 ft), and 64.00 m (210 ft) away from point
1—respectively. These 10 reflectors and 21 points consti-
tuted the ground setup for our static and dynamic tests
described in the following paragraphs.
Static Test Setup, Data Acquisition, Instrumentation,
and Test Procedures
NIOSH researchers collected static measurements to evalu-
ate the positional accuracy of the GNSS receivers. We used
commercially available GNSS receivers. These receivers
have RTK using a base station and satellite-based augmen-
tation system (SBAS) capabilities when the base station
is not in use. Using these receivers, we recorded real-time
positional measurements such as longitude, latitude, and
altitude. For the static tests, we recorded measurements
from 20 physical points to compare them to the ground
truth points collected using the robotic total station. These
points were recorded at the two longitudinal ends of the 10
reflectors.
To collect ground truth test points for the static tests,
we used two items of surveying equipment: 1) An RTS with
a 2.4 GHz RC-4 radio mounted on top of one prism and a
field controller to log and store data. At this mode, the RTS
had range of 3,000 m (9840 ft) with a coarse accuracy of ±
(10 mm +2 ppmxD) mean square error. 2) A GNSS-based
surveying system which was comprised of two receivers to
collect data with a data collector to store the collected data.
We used one receiver as a base station to provide RTK cor-
rection and the other as a rover to collect data. This equip-
ment had a 25-cm baseline precision of a differential code
solution for static and kinematic surveys.
During the static test, we placed the GNSS receiver
on the desired location and collected data for about 60
seconds and recorded the average latitude, longitude, and
altitude for 20 points from 10 reflectors. The points were
in the middle center edges of each reflector as illustrated
in Figure 2. Because we already surveyed the ground truth
points using the RTS during the general set-up, we retained
these points as ground truth data for a total of 20 points,
knowing that the locations surveyed were offset about
25.4 mm (1 inch) from the center edges of the reflectors.
We then used the GNSS-based surveying equipment and
our GNSS receiver to collect measurements from the same
20 points. In addition, we surveyed 10 points in the middle
center of each reflector. However, we only used the center
points as ground truth for the dynamic tests.
Figure 1. Test setup for static and dynamic tests. Starting
from the top left, the two rows of points represent the
ground truth marked by the RTS and the point on the
bottom is the point surveyed for the base station
detection performance of CXS designed for surface min-
ing haul trucks. Note that we did not evaluate any CXS
in this experiment. We collected measurements while the
GNSS was not in motion—static, and then dynamic while
the GNSS was in motion. Under static conditions, these
measurements included positional data such as latitude,
longitude, and elevation. Under dynamic conditions, these
measurements included latitude, longitude, elevation,
speed, and timestamp. For both conditions, a combination
of sensors is used to validate the measurements. The follow-
ing section describes the test method.
TEST METHOD
Test Course Setup
NIOSH researchers conducted static and dynamic tests to
evaluate the positional accuracies of GNSS receivers in a
parking lot area at the NIOSH campus in Bruceton, PA.
This area has a relatively flat surface area about 80-m (260-
ft) long and 15-m (49-ft) wide. To set up for the tests, we
used surveying equipment to establish known ground truth
or “benchmark” points to compare with measurements of
the GNSS receivers. We used two geodetic points on the
NIOSH campus to localize two types of surveying equip-
ment. One item of our surveying equipment was GNSS
based and the other was a robotic total station (RTS) that
used an optical laser and a prism to collect positional data.
Using the RTS, we surveyed a point for the base station.
During the test, we positioned the base station on that point
to transmit real-time kinematics (RTK) corrections to the
to the receiver or GTI Away from the base station point, we
also surveyed two 64-m (210-ft) parallel lines spaced about
0.61 m (24 inches) apart. Along the lines, we surveyed and
marked 10 points on each line from one end to the next
using nails and marking paint. We placed 10 metal strips
covered with reflective tape (reflectors) perpendicular to the
two lines (as shown in Figure 1). We designated the most
westbound reflector as reflector #1. Reflectors #2 through
#10 were placed with respect to reflector #1 about 9.14 m
(30 ft), 15.24 m (50 ft), 21.34 m (70 ft), 27.43 m (90 ft),
39.62 m (130 ft), 47.72 m (150 ft), 51.82 m (170 ft),
60.96 m (200 ft), and 64.00 m (210 ft) away from point
1—respectively. These 10 reflectors and 21 points consti-
tuted the ground setup for our static and dynamic tests
described in the following paragraphs.
Static Test Setup, Data Acquisition, Instrumentation,
and Test Procedures
NIOSH researchers collected static measurements to evalu-
ate the positional accuracy of the GNSS receivers. We used
commercially available GNSS receivers. These receivers
have RTK using a base station and satellite-based augmen-
tation system (SBAS) capabilities when the base station
is not in use. Using these receivers, we recorded real-time
positional measurements such as longitude, latitude, and
altitude. For the static tests, we recorded measurements
from 20 physical points to compare them to the ground
truth points collected using the robotic total station. These
points were recorded at the two longitudinal ends of the 10
reflectors.
To collect ground truth test points for the static tests,
we used two items of surveying equipment: 1) An RTS with
a 2.4 GHz RC-4 radio mounted on top of one prism and a
field controller to log and store data. At this mode, the RTS
had range of 3,000 m (9840 ft) with a coarse accuracy of ±
(10 mm +2 ppmxD) mean square error. 2) A GNSS-based
surveying system which was comprised of two receivers to
collect data with a data collector to store the collected data.
We used one receiver as a base station to provide RTK cor-
rection and the other as a rover to collect data. This equip-
ment had a 25-cm baseline precision of a differential code
solution for static and kinematic surveys.
During the static test, we placed the GNSS receiver
on the desired location and collected data for about 60
seconds and recorded the average latitude, longitude, and
altitude for 20 points from 10 reflectors. The points were
in the middle center edges of each reflector as illustrated
in Figure 2. Because we already surveyed the ground truth
points using the RTS during the general set-up, we retained
these points as ground truth data for a total of 20 points,
knowing that the locations surveyed were offset about
25.4 mm (1 inch) from the center edges of the reflectors.
We then used the GNSS-based surveying equipment and
our GNSS receiver to collect measurements from the same
20 points. In addition, we surveyed 10 points in the middle
center of each reflector. However, we only used the center
points as ground truth for the dynamic tests.
Figure 1. Test setup for static and dynamic tests. Starting
from the top left, the two rows of points represent the
ground truth marked by the RTS and the point on the
bottom is the point surveyed for the base station