Calibrating a Hiveboard

Interlocalisation - Calibration

The interlocalisation system is very sensitive to any hardware changes. For this reason, the BeeBoard assembly should be calibrated in order to know exactly the system behavior and to correctly map the different measured parameters and the output angle, this, for one precise assembly.

Objective

As explained in how the angle is calculated, what is called the angle cannot be directly obtained from the values extracted from the DW1000 chips. In fact, there is no one-to-one correspondence as there are many angle possiblities. To allow this correspondence a transformation has to be made on the angle measured from the PDOA values. The transformation is made from the following graph :

These values are obtained from the extractRawData and Parser scripts using the test-bench TurningStation.

Note that the theoretical values should follow the following trends :

As there is a considerable difference between the real and theoretical values, the real data has to be characterized, theoretical values will not give a proper rendition of the reality. This characterization will permit the interlocalisation algortihm to compute actual angles from PDOA values. The theoretical values show a correspondence made of two linear slopes, one falling and one rising which repete themselves at each full turn. The calibration procedure will permit the extraction of these slopes for each antenna pair.

Procedure

The complete procedure on how to perform a calibration and how to validate the results is found here. Follow the flow chart to execute each scripts in the right order.

After the final validation step is successful, the assembly is ready to be mounted on its final destination, and the interlocalisation system should be operationnal.

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