WO1996034298A1 - A method for the automatic calibration of an operational passive acoustic listening system - Google Patents

A method for the automatic calibration of an operational passive acoustic listening system Download PDF

Info

Publication number
WO1996034298A1
WO1996034298A1 PCT/NO1996/000096 NO9600096W WO9634298A1 WO 1996034298 A1 WO1996034298 A1 WO 1996034298A1 NO 9600096 W NO9600096 W NO 9600096W WO 9634298 A1 WO9634298 A1 WO 9634298A1
Authority
WO
WIPO (PCT)
Prior art keywords
listening
microphones
sound
calibration
listening system
Prior art date
Application number
PCT/NO1996/000096
Other languages
French (fr)
Inventor
Arve Gustavsen
Ragnvald Otterlei
Tore Endresen
Original Assignee
Arve Gustavsen
Ragnvald Otterlei
Tore Endresen
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Arve Gustavsen, Ragnvald Otterlei, Tore Endresen filed Critical Arve Gustavsen
Priority to AU57051/96A priority Critical patent/AU5705196A/en
Priority to EP96915230A priority patent/EP0827592A1/en
Publication of WO1996034298A1 publication Critical patent/WO1996034298A1/en

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V13/00—Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
    • G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
    • G01S3/023—Monitoring or calibrating
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/001—Acoustic presence detection

Definitions

  • the present invention relates to systems installed for listening purpose, consisting of listening stations with microphones, capable of detecting sound in general or together with a feature for the detection of correct direction to and/or the position of any distinct sound received from a 2 or 3 dimensional geographical field of vision.
  • the present invention is an automatic method to maintain the synchronising of the clocks in each individual station and the correction of the receiver characteristics of the microphones.
  • the synchronising of die clocks for the listening stations is important and necessary for the accuracy of the measurements of the listening system.
  • the quality of the relative time measurement between the individual listening stations are important for the quality in the direction- and position-finding of distinct sound originated within any area of interest.
  • the capabilities of correcting the receiver characteristics of a microphone compensates for the ageing of a microphone, thereby improving the long term quality in identifying signals with the same intensity.
  • the present method enables calibration during normal operation for a listening system, utilising one or more sound generators located in known positions within hearing distance and line of sight from one or more microphones, included in the said listening system.
  • the method is of a general nature. It requires knowledge about the relative position of the sound generators. To enable microphone calibration, the said listening system must be designed for the active use of the calibration signals received from the sound generators.
  • a listening system prepared for automatic operational calibration, may in its simplest form just detect any environmental sound, while the more sophisticated solutions are used for the direction and/ or position determination of the origin of sound.
  • a specific application determines the minimum amount of listening stations and microphones. For sound detection only, one listening station with one microphone is sufficient. In such a minimum configuration, only calibration of microphone characteristics is required.
  • a listening system, for determination of the direction to the origin of sound, the minimum equipment solution is one listening station with 2 microphones, also requiring only calibration of microphone characteristics.
  • the microphones in the listening system shall be capable of relaying signals, relevant for all available acoustics within the frequency range of the microphones for a further calculation in the listening system.
  • One or more sound generator may at any time be installed in defined positions provided that the listening stations have been installed and initially calibrated, the relative position and the directions between the listening stations have been defined, and that the internal clocks of the listening stations have been synchronised.
  • calibration during operation is made by installing one or more sound generators at known positions within hearing distance and line of sight from one or more microphones mounted at the listening stations.
  • the calibration starts when the sound generators are producing calibration signals.
  • These calibration signals' series are adapted to the features in the listening system. It is a precondition that the listening system is utilising signal intensity, time measurements, phase measurements or combinations thereof for the detection of sound alone or together with features to find the position of and the direction to the origin of the sound.
  • each of the sound generators may transmit periodic measuring series, or such measuring series may be transmitted when required.
  • Another feature of the present invention is that the calibration can be made without interrupting normal operation, enabling the results of the calibration directly to be used.
  • a final feature of the invention is that a listening station can have producer corrections to the calibration of the microphone characteristics, and that these characteristics can be adjusted and automatically updated during operation.

Abstract

The calibration of a listening system during operation is achieved with regard to a clock synchronising of the listening stations included in the listening system, and the receiver characteristics of the microphones located in each listening station. These parameters are automatically adjusted by utilising a method for automatic calibration, using one or more sound generators to transmit special correction signals. The geographic position of each sound generator included in the calibration must be known to the listening system, and be within hearing distance and line of sight of the microphones in the listening system. The invention is a method for the correct calibration of a passive acoustic listening system while such a listening system is used for the determination of the direction to, or the position of the origin of sound signals. The automatic clock synchronising of listening stations is important for accurate determination of the direction to and/or the position of the origin of distinct sound. Long term stability and the accuracy of the listening system is secured by the clock calibration and the adjustment of the microphone characteristics. Microphone characteristics from the microphone producers can support the corrections. The calibration can be utilised for listening systems working in 2 or 3 geographical dimensions, and can be performed either continuous or periodic.

Description

A method for the automatic calibration of an operational passive acoustic listening system.
The present invention relates to systems installed for listening purpose, consisting of listening stations with microphones, capable of detecting sound in general or together with a feature for the detection of correct direction to and/or the position of any distinct sound received from a 2 or 3 dimensional geographical field of vision.
The present invention is an automatic method to maintain the synchronising of the clocks in each individual station and the correction of the receiver characteristics of the microphones.
The synchronising of die clocks for the listening stations is important and necessary for the accuracy of the measurements of the listening system.
The quality of the relative time measurement between the individual listening stations are important for the quality in the direction- and position-finding of distinct sound originated within any area of interest.
The capabilities of correcting the receiver characteristics of a microphone compensates for the ageing of a microphone, thereby improving the long term quality in identifying signals with the same intensity.
No methods have been found, describing the present invention.
The present method, described in the following, enables calibration during normal operation for a listening system, utilising one or more sound generators located in known positions within hearing distance and line of sight from one or more microphones, included in the said listening system.
The method is of a general nature. It requires knowledge about the relative position of the sound generators. To enable microphone calibration, the said listening system must be designed for the active use of the calibration signals received from the sound generators.
This is achieved by methods as described in the following claims.
A listening system, prepared for automatic operational calibration, may in its simplest form just detect any environmental sound, while the more sophisticated solutions are used for the direction and/ or position determination of the origin of sound.
A specific application determines the minimum amount of listening stations and microphones. For sound detection only, one listening station with one microphone is sufficient. In such a minimum configuration, only calibration of microphone characteristics is required. A listening system, for determination of the direction to the origin of sound, the minimum equipment solution is one listening station with 2 microphones, also requiring only calibration of microphone characteristics.
When there are two or more listening stations in the listening system, clock synchronising is necessary due to the long term drift of in internal clocks of the listening stations. Such drift in internal clocks increases the inaccuracy in the determination of the direction- and/or position measurements of the origin of sound.
The microphones in the listening system shall be capable of relaying signals, relevant for all available acoustics within the frequency range of the microphones for a further calculation in the listening system.
One or more sound generator may at any time be installed in defined positions provided that the listening stations have been installed and initially calibrated, the relative position and the directions between the listening stations have been defined, and that the internal clocks of the listening stations have been synchronised.
According to the invention, calibration during operation is made by installing one or more sound generators at known positions within hearing distance and line of sight from one or more microphones mounted at the listening stations.
The calibration starts when the sound generators are producing calibration signals.
These calibration signals' series are adapted to the features in the listening system. It is a precondition that the listening system is utilising signal intensity, time measurements, phase measurements or combinations thereof for the detection of sound alone or together with features to find the position of and the direction to the origin of the sound.
According to the present invention, each of the sound generators may transmit periodic measuring series, or such measuring series may be transmitted when required.
Another feature of the present invention is that the calibration can be made without interrupting normal operation, enabling the results of the calibration directly to be used.
A final feature of the invention is that a listening station can have producer corrections to the calibration of the microphone characteristics, and that these characteristics can be adjusted and automatically updated during operation.

Claims

Claims
1 . A method for the automatic calibration of an operational passive acoustic listening system, for the detection of sound in general or for the direction- and position- finding of the origin of sound that is distinct from the normal environmental sound, with processing means for the co-ordination of the analysis of sound signals received from listening stations in the said listening system, with one or more microphones for each of the said listening stations, for the calibration of one or more microphone receiver characteristics, and clock synchronising in two or more listening stations, and that said synchronising and said correction of microphone characteristics is made together or independently, when each listening station receives special correction signals from one or more sound generators, when each sound generator produces such said signals from known geographical positions within hearing distance and line of sight of the microphones, characterised in that each involved listening station in the acoustic listening system receives the same correction signals from one or more sound generators, that all the sound generators have known positions and are located within hearing distance and line of sight from one or more microphones, that the said microphones and the said listening stations are included in the automatic operational calibration correction, that clock synchronising is performed in two or more listening stations, that the receiver characteristics of the microphones are determined for the said microphones, that the clocks and the receiver characteristics are adjusted together or independently, and that any of these adjustments are made automatically.
2. A method according to claim 1 , characterised in that the correction signals are transmitted continuos or periodic from one or more sound generators.
3. A method according to claim 1 , characterised in that the automatic calibration can be made during normal operation or in a separate calibration mode.
4. A method according to claim 1 , characterised in that the listening system has available references for the receiver characteristics for one or more microphones in the listening system, and that these references are supplied from the producers of the microphones, independent of the installation and the commissioning of the listening system, and that these references are utilised in the correction of the receiver characteristic of the microphones.
PCT/NO1996/000096 1995-04-28 1996-04-25 A method for the automatic calibration of an operational passive acoustic listening system WO1996034298A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU57051/96A AU5705196A (en) 1995-04-28 1996-04-25 A method for the automatic calibration of an operational pas sive acoustic listening system
EP96915230A EP0827592A1 (en) 1995-04-28 1996-04-25 A method for the automatic calibration of an operational passive acoustic listening system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO951668 1995-04-28
NO951668A NO951668L (en) 1995-04-28 1995-04-28 Operating calibration of listening equipment

Publications (1)

Publication Number Publication Date
WO1996034298A1 true WO1996034298A1 (en) 1996-10-31

Family

ID=19898154

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO1996/000096 WO1996034298A1 (en) 1995-04-28 1996-04-25 A method for the automatic calibration of an operational passive acoustic listening system

Country Status (4)

Country Link
EP (1) EP0827592A1 (en)
AU (1) AU5705196A (en)
NO (1) NO951668L (en)
WO (1) WO1996034298A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1085306A2 (en) * 1999-09-16 2001-03-21 L3 Communications Corporation In place calibration of sonar receive array
US20150260861A1 (en) * 2014-03-12 2015-09-17 Sercel Method for controlling quality of operation of a pam system, corresponding computer program product, non-transitory computer-readable carrier medium and quality control device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0585101A2 (en) * 1992-08-28 1994-03-02 Teem Systems, Inc. Object locator system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0585101A2 (en) * 1992-08-28 1994-03-02 Teem Systems, Inc. Object locator system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1085306A2 (en) * 1999-09-16 2001-03-21 L3 Communications Corporation In place calibration of sonar receive array
EP1085306A3 (en) * 1999-09-16 2001-06-20 L3 Communications Corporation In place calibration of sonar receive array
US20150260861A1 (en) * 2014-03-12 2015-09-17 Sercel Method for controlling quality of operation of a pam system, corresponding computer program product, non-transitory computer-readable carrier medium and quality control device
EP2930542A3 (en) * 2014-03-12 2016-02-17 Sercel Method for controlling quality of operation of a PAM system, corresponding computer program product, non-transitory computer-readable carrier medium and quality control device
US9557428B2 (en) 2014-03-12 2017-01-31 Sercel Method for controlling quality of operation of a PAM system, corresponding computer program product, non-transitory computer-readable carrier medium and quality control device

Also Published As

Publication number Publication date
NO951668L (en) 1996-10-29
EP0827592A1 (en) 1998-03-11
AU5705196A (en) 1996-11-18
NO951668D0 (en) 1995-04-28

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