The paper contains things about sensor networks, error, ruler distance measurement, the distance measurement, and sensors. There are lots of information like distance measurement, sensor, errors, measurements, and distance measurements are explained inside the paper.
In the paper we can find info around measurement errors, range, the ultrasonic signals, receiver, and ultrasonic signals. These are some excerpt from the paper:
12 Distance measurement distribution TABLE II Distance measurement comparison in an indoor ﬂoor environment distance measurement approach mobileassisted total number of measurements the number of incorrect measurements percentage of incorrect measurements 486 129 26.54% virtual ruler with one time measurement 658 146 22.19% virtual ruler with frequency analysis virtual ruler with threshold strategy 658 100 15.2% 201 2 1% TABLE III Distance measurement comparison in an area with randomly distributed obstructions distance measurement approach mobileassisted total number of measurements the number of incorrect measurements percentage of incorrect measurements 579 159 27.46% virtual ruler with one time measurement 740 166 22.43% Gaussian distributed random error to distance measurement.
Giving more content, this paper contains more such as frequency analysis, accuracy, measurement, and distance.