I am currently analysing the accuracy of an ultrasonic distance sensor: HY-SRF05
Using this sensor, I have measured the distance towards an obstacle at
, where the reference distance has been measured with measurement tape.
I was expecting the measurement errors to be Gaussian distributed with zero mean. However, I have encountered some issues in verifying this assumption:
1) I assumed the distance sensor returns the distance from the circuit board towards the obstacle. In most measurements, however, it seems the sensor returns the distance from the end of the transmitter (which is mounted on the circuit board) to the obstacle.
2) The transmitter has a length of 1.1mm. Assuming now that the sensor returns the distance from the end of the transmitter to the obstacle, the errors still do not have a mean of 0.
3) Strangely, at 10cm distance, it seems the sensor returns the distance from the circuit board to the obstacle. I have double checked that I did not measure the distance wrong with the measurement tape.
So, my question to you is: Does anyone know from where the HY-SRF05 starts its measurements? If so, what would you suggest me to do, in order to determine the accuracy of this sensor, or the probability distribution of its errors ?
I kind of need the errors to be Gaussian distributed with zero mean, in order to justify why a Kalman Filter could be used to smooth these measurements.