Dual frequency ultrasonic locationing system
AssigneeSymbol Technologies, Inc.
InventorsRussell E. Calvarese, Richard J. Lavery
Life of this patent
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Abstract
A dual frequency ultrasonic locationing system includes an emitter operable to emit two different ultrasonic frequencies simultaneously in one ultrasonic burst. A receiver with at least two microphones is operable to receive the ultrasonic burst. A correlator is operable to correlate the signals obtained from each microphone to derive a time difference of arrival of the ultrasonic burst at each microphone. The time difference of arrival of the ultrasonic signal from the emitter impinging on each microphone of the receiver is utilized to determine a location of the emitter.
Claims7
A dual frequency ultrasonic locationing system, comprising:
- at least one emitter operable to emit two different ultrasonic frequencies simultaneously in one ultrasonic burst;
- a receiver with at least two microphones operable to receive the ultrasonic burst;
- and a correlator operable to correlate the signals obtained from each microphone to derive a time difference of arrival of the ultrasonic burst between each microphone, wherein the time difference of arrival of the ultrasonic burst from the emitter impinging on each microphone is utilized with a multilateration locationing technique to determine a location of the emitter;
- and wherein the receiver includes a low pass filter that passes a difference frequency of a multiplied combination of the two different ultrasonic frequency components from each microphone to the correlator.
A dual frequency ultrasonic locationing system, comprising:
- at least one emitter operable to emit two different ultrasonic frequencies simultaneously in one ultrasonic burst;
- a receiver with at least two microphones operable to receive the ultrasonic burst;
- and a correlator operable to correlate the signals obtained from each microphone to derive a time difference of arrival of the ultrasonic burst between each microphone, wherein the time difference of arrival of the ultrasonic burst from the emitter impinging on each microphone is utilized with a multilateration locationing technique to determine a location of the emitter;
- and wherein the receiver includes two band pass filters for each microphone, a first band pass filter passing a first frequency component from the ultrasonic burst and a second band pass filter passing a second frequency component from the ultrasonic burst different from the first frequency component.
A dual frequency ultrasonic locationing system, comprising:
- at least one emitter operable to emit two different ultrasonic frequencies simultaneously in one ultrasonic burst;
- a receiver with at least two microphones operable to receive the ultrasonic burst;
- and a correlator operable to correlate the signals obtained from each microphone to derive a time difference of arrival of the ultrasonic burst between each microphone, wherein the time difference of arrival of the ultrasonic burst from the emitter impinging on each microphone is utilized with a multilateration locationing technique to determine a location of the emitter;
- and wherein the microphones are incorporated in a singular housing and are configured in an array having a maximum dimension of not more than twelve inches.
A dual frequency ultrasonic locationing system, comprising:
- at least one emitter operable to emit two different ultrasonic frequencies simultaneously in one ultrasonic burst;
- a receiver with at least two microphones operable to receive the ultrasonic burst;
- and a correlator operable to correlate the signals obtained from each microphone to derive a time difference of arrival of the ultrasonic burst between each microphone, wherein the time difference of arrival of the ultrasonic burst from the emitter impinging on each microphone is utilized with a multilateration locationing technique to determine a location of the emitter;
- and wherein the receiver can test for a correct time difference of arrival calculation, wherein a qualifying test for a correct TDOA calculation is:
- Δφmic1(t) =Δφmic2(t+TTD0A), where Δφmic1(t) is the difference in phase between fl and f2 at any time t on one microphone and ΔφTmic2(t+TTDOA) is in phase between fl and f2 at time t+TTDOA, where TTDOA is the determined time difference of arrival calculation between the pulses from each microphone.
Dependencies are inferred from the claim text.