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Accuracy |
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Under open sky conditions, the VBOX can provide one of
the most accurate ways of measuring Velocity and Distance travelled. The first
VBOX was shipped in 2001, and since then the majority of vehicle manufacturers
and tyre companies have tested the VBOX back to back with their existing
equipment, and gone on to purchase VBOX for their own testing. Have a look at
our
customer list to see just
how many people now use the VBOX for brake, acceleration and chassis
development.
The best way to see if the VBOX is accurate enough for
your tests is to try one out. We offer a full money back guarantee if you are
not satisfied and wish to return your VBOX within 30 days of purchase.
Example of Brake Stop accuracy
The following is a video of a test we carried out to
check the Accuracy of the Braking distance of the VBOXIII
Brake Test Video
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Calibration
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We provide fully traceable calibration
certificates for each VBOX, by using a sophisticated GPS Doppler shift
simulator from Spirent Communications. This unit allows us to test the
VBOX under a number of different conditions, and provide a calibration
certificate for all of the outputs from the VBOX. This is regarded as
the definitive method of checking calibration on GPS devices, and we are
the only company involved in vehicle test equipment who have invested in
this equipment. Other companies who use this level of equipment include
the National Physics Laboratory, NASA, The European Space Agency, and
the US Military.
We have also done back to back testing with optical
sensors (see
Comparison of non contact speed sensors.pdf).
(comp-graph.gif)
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Units |
Resolution |
Accuracy |
Accuracy with DGPS |
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Velocity |
0.01 kmh |
0.1 kmh full scale |
0.1 kmh full scale |
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Distance |
1 cm |
0.05% |
0.05% |
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Absolute position |
1 cm |
3 m 95% CEP** |
1.8m 95% CEP* |
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Height |
1 cm |
6 m 95% CEP** |
3m 95% CEP* |
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Lateral accel |
0.01 g |
0.5% |
0.5% |
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Longitudinal accel |
0.01 g |
0.5% |
0.5% |
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Heading |
0.01 ° |
0.1 ° |
0.1 ° |
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Time |
0.01 s |
0.001 s |
0.001 s |
| *95% CEP (Circle Error Probable) means 95% of the time
the position readings will fall within a circle of the stated radius. Note: to obtain these accuracies, good
visibility to the sky must be maintained. If you test close to trees, bridges or
tall buildings, then these accuracies will be degraded.
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| On request from customers, we have carried out detailed
checks on the distance calculations using a survey grade GPS RTK system. See
Brake Distance Evaluation.pdf
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