To prove distance accuracy without a Base Station, a test can be carried out with a vehicle driving in a straight line past two light barriers separated by 50 m, The logged VBO file (or live data in VBOX Tools) can be reviewed to prove the measurement accuracy.
In the image below, there are two light barriers on the road side accurately measured to a 50 m separation. With the VBOX and optical sensor fitted to the car, the car will then drive past the first light barrier around 5kph, then increase in speed. When the car gets close to the second light barrier the vehicle will slow down to pass the light barrier and then come to a complete stop.
Using VBOX Tools, you can load the logged VBO file into the software, then either use the measure tool between the two trigger points (light barriers) in the graph display window, or, setup report generator to tell you the distance between the two trigger points. If done correctly, the distance results should match perfectly. Further tests can be done with the light barriers set greater distances apart if required.
Note: Please use a laser measurement system to ensure the distance between the two light barriers is accurate. Long tape measures can tend to stretch and flex which does not make them suitable for verification tests.
For example, two fifty meter tape measures at our head office differed in length by two centimeters! This is why we would recommend using a Bosch laser which is accurate to a few mm (over these type of distances).