This video shows the performance of an ultrasonic LPS system composed of five beacons on the ceiling that emit synchronoulsy. Each one of the beacons has assigned a 1023-Kasami code that modulates a carrier signal of about 40kHz. The receiver, on the mobile, performs a discriminatation of the signals coming from the different beacons by correlation, calculates the Time Difference of Arrivals and performs the positioning using trilateration. In the video:
- The mobile follows a constrained circular trajectory, as ground truth.
- Different reflectors provoke multipaht (the worst situation for a US-LPS system).
- In the last part of the video a drill machine is turned on introducing a big amount of acoustic noise.
- To see:
* Top left: real movement, on the screen of the computer the actual signal captured by the receiver.
* Top center: calculated positions, in black using standard cross-correlation (CC) and in red using GCC.
* Top right: A zoom of the top-center image.
* The bottom part of the video is composed of ten figures: the upper part of them correspond to the CC for each one of the beacons and the lower part correspond to the GCC.
