Ultrasonic locationing system using a dual phase pulse

Patent metadata

Field	Value
Publication number	US-9791546-B2
Application number	US-201414448161-A
Country	US
Kind code	B2
Filing date	Jul 31, 2014
Priority date	Jul 31, 2014
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

An ultrasonic locationing system using a dual phase pulse includes an emitter emitting two consecutive frequency bursts, each having a different phase, within one ultrasonic pulse. A receiver microphone receives the ultrasonic pulse, and a processor runs an amplitude-based detection algorithm on the pulse for a band of frequencies of interest and detects a first burst of the pulse within the proper frequency band and having an amplitude exceeding a threshold. Whereupon, the processor determines a relative phase difference between the first burst and a second burst of the pulse and determines whether the relative phase difference is within a predetermined acceptance window, indicating that the pulse is valid for use in locationing the emitter and associated mobile device.

First claim

What is claimed is:

1. An ultrasonic locationing system using a dual phase pulse, comprising:
an emitter operable to emit two consecutive frequency bursts, each having a different phase, within one ultrasonic pulse;
a receiver with at least one microphone operable to receive the ultrasonic pulse;
a processor operable to run an amplitude-based detection algorithm on the pulse for a band of frequencies of interest, and detect a first burst of the pulse within the proper frequency band and having an amplitude exceeding a threshold, whereupon the processor is further operable to determine a relative phase difference between the first burst and a second burst of the pulse, wherein a relative phase difference within a predetermined acceptance window indicates that the pulse is valid for use in locationing the receiver; and
a position history where previously stored receiver locations are stored by the processor,
wherein the processor is further operable to calculate a motion vector of the receiver from the position history, calculate a Doppler frequency and in turn the expected phase shift due to the motion vector, given the frequency of the frequency burst, and adjust the acceptance window by the expected phase shift, Z.

2. The system of claim 1 , wherein the two different phases are approximately 180 degrees apart.

3. The system of claim 1 , wherein the band of frequencies of interest is ultrasonic frequencies in the range of 19-22 kHz.

4. The system of claim 1 , wherein the two different phases emitted in the pulse are chosen to be X degrees apart, and wherein the acceptance window is X+Z±Y, where Y is a predetermined tolerance for phase measurements.

5. A method of ultrasonic locationing using a dual phase pulse, comprising:
emitting two consecutive frequency bursts each having a different phase within one ultrasonic pulse;
running an amplitude-based detection algorithm on the received pulse for a band of frequencies of interest;
detecting a first burst of the pulse within the proper frequency band and having an amplitude exceeding a threshold; whereupon
detecting a relative phase difference between the first burst and a second burst of the pulse;
determining whether the relative phase difference is within a predetermined acceptance window, indicating that the pulse is valid for use in locationing; and
locationing of a mobile device using the valid pulse

establishing a position history of the mobile device using previously stored device locations;
calculating a motion vector of the mobile device from the position history;
calculating a Doppler frequency and in turn the expected phase shift due to the motion vector, given the frequency of the frequency burst; and
adjusting the acceptance window by the expected phase shift, Z.

6. The method of claim 5 , wherein the two different phases emitted in the pulse are chosen to be X degrees apart, and wherein the acceptance window is X+Z±Y, where Y is a predetermined tolerance for phase measurements.

7. The method of claim 6 , wherein X is approximately 180 degrees.

Assignees

• Symbol Technologies Inc
• Symbol Technologies Llc

Inventors

• Calvarese Russell E
• Lavery Richard J

Classifications

• G01S11/16

  using difference in transit time between electrical and acoustic signals · CPC title

• G01S1/805

  the synchronised signals being pulses or equivalent modulations on carrier waves and the transit times being compared by measuring the difference in arrival time of a significant part of the modulations · CPC title

• G01S1/753 Primary

  Signal details · CPC title

• G01S5/26 Primary

  Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/28 takes precedence) · CPC title

• G01S1/74

  Details · CPC title