Patent ID: 8098544

Claim:
A method for short range alignment using ultrasonic sensing, comprising: shaping an ultrasonic pulse signal on a first device to produce a pulse shaped signal and transmitting the pulse shaped signal from the first device to a second device; receiving the pulse shaped signal and determining an arrival time of the pulse shaped signal received at the second device; identifying a relative phase of the pulse shaped signal with respect to a previously received pulse shaped signal at the second device; identifying a pointing location of a tip of the first device with respect to the second device from the arrival time of the received pulse shaped signal and the relative phase; saving most recent pulse shaped signals to a history; selectively discarding pulse shaped signals less recently saved in the history based on a similarity measure between pulse shaped signals in the history for further resolving the pointing location; determining positional information of the pointing location of the first device at three or more points in three-dimensional space; and reporting the positional information and an alignment of the three or more points, wherein the shaping uses a combination of amplitude modulation, frequency modulation, and phase modulation.