Shipboard auditory sensor

Abstract

A Shipboard Auditory Sensor (SAS) for detection and classification of acoustic signaling at sea is capable of detecting whistles blasts from other vessels in accordance with Rules 34 and 35 of COLREGS to support autonomous operations in a maritime environment.

Description

SUMMARY OF THE EMBODIMENTS

In a first exemplary embodiment, a shipboard auditory sensor system for processing audio signals from one or more surface maritime vessels in a vicinity of the ship to support autonomous navigation of the ship includes: an auditory sensor assembly located topside on the ship such that the auditory sensor assembly has a clear line of sight to surface maritime vessels on any bearing, the auditory sensor assembly including: multiple microphone assemblies; a power filter; and a data acquisition board, wherein the auditory sensor assembly receives audio signals from one or more surface maritime vessels in a vicinity of the ship, the received audio signals being in a first auditory range specified by one or more regulations and being indicative of a status of the one or more surface maritime vessels, further wherein the auditory sensor assembly formats the audio signals into audio data packets to support autonomous navigation of the ship.

In a second exemplary embodiment, a shipboard auditory sensor system for processing audio signals from one or more surface maritime vessels in a vicinity of the ship to support autonomous navigation of the ship includes: an auditory sensor assembly including a microphone sensor array for sensing audio signals from one or more surface maritime vessels in a vicinity of the ship, the received audio signals being in one of a first specified auditory range and being indicative of a status of the one or more surface maritime vessels, wherein the auditory sensor assembly formats the audio signals into audio data packets to support autonomous navigation of the ship; and a processing server on the ship for receiving the audio data packets from the auditory sensor assembly, the processing server being programmed to run the received audio data packets through multiple algorithms to support autonomous navigation of the ship.

BRIEF DESCRIPTION OF THE FIGURES

The following figures illustrates various features of the present embodiments and are intended to be considered with the textual detailed description provided herein.

FIG. 1 provides an autonomy system context diagram for an Anti-Submarine Warfare (ASW) Continuous Trail Unmanned Vessels (ACTUV) incorporating inputs from a SAS in accordance with embodiments described herein;

FIG. 2 provides a schematic of a SAS system in accordance with embodiments described herein;

FIGS. 3a-3c provide various views of an exemplary SAS in accordance with embodiments described herein;

FIGS. 4a-4c provide detailed illustrations of an exemplary individual microphone assembly of a SAS in accordance with embodiments described herein;

FIGS. 5a-5c provide top, side and bottom illustrations of an exemplary microphone of the microphone assembly of FIGS. 4a-4c;

FIG. 6 illustrates an exemplary preamplifier circuit configuration within a pre-amplifier 50 of the microphone assembly of FIGS. 4a-4c;

FIG. 7 illustrates an exemplary configuration of board with channel modules within a SAS hardware assembly in accordance with embodiments described herein;

FIG. 8 illustrates an exemplary configuration of the circuitry forming the individual channel modules within a SAS hardware assembly in accordance with embodiments described herein;

FIG. 9 highlights the modular design of the SAS system, illustrating separation of acoustic sensing hardware and SAS processing software allowing the processing hardware to be selected and swapped in as needed in accordance with embodiments described herein; and

FIG. 10 provides an exemplary SAS hardware assembly placement scenario wherein there is a clear line-of-sight to potential surface vessels on any bearing in accordance with embodiments described herein.

DETAILED DESCRIPTION

The SAS embodiments described herein are used in a larger system for supporting autonomous maritime operations such as that depicted schematically in FIG. 1. Related features are also described in commonly owned U.S. patent application Ser. No. 14/968,161 entitled System and Method for Fusion of Sensor Data to Support Autonomous Maritime Vessels.

In the embodiments described herein, the SAS is designed to continuously monitor the acoustic environment in the vicinity of the autonomous vessel upon which it is deployed and to discriminate from that acoustic environment sounds which might be considered as signaling protocols for other vessels in the vicinity. All ships at sea are required to carry acoustic signaling devices to be used when coordinating their movement and that of another vessel on a collision course. The Captains and Masters of all ships are required to know and implement the signaling protocols using these devices. In today's world most ships carry radar and radio sets and they use these to great advantage in coordinating their course changes around other vessels, however they are still required to use and respond to the acoustic signaling protocols' when necessary. These acoustic signaling protocols are defined in the International Regulation for Preventing Collisions at Sea 1972 (COLREGS) Annex III which is incorporated herein by reference in its entirety. The SAS hardware and software system described and illustrated herein, detects COLREGS horn or bell events and then generates COLREGS Rule 34 (Maneuvering and warning) or COLREGS Rule 35 (signals in restricted visibility) messages using an output Ethernet interface.

Referring to FIG. 2 a high level operational schematic of the SAS system 1 of the present embodiments is shown. An exemplary SAS system 1 includes: the SAS topside hardware assembly 5, including the auditory sensor components (see FIGS. 3 through 8 and accompanying descriptions below), data processing hardware/software (analog-to-digital signal converter (ADC), digital signal processor (DSP) for filtering, processing and formatting received data signals with random access memory (RAM)) and interfaces (e.g., Ethernet interface) to one or more below deck SAS servers 10 running processing software which includes sound detection algorithm programming, COLREGS classification algorithm programming, and specified operating environment for the SAS. As discussed further herein, each SAS hardware assembly includes at least microphones, preamplifiers, analog to digital conversion boards and Ethernet connections. The SAS system further includes software interfaces for control and messaging. FIG. 2 also illustrates a contemplated additional dedicated gunshot auditory component 7 for detection of gunshots in the vicinity of the autonomous vessel. An exemplary component for such gunshot and other battlefield signatures and acoustic blasts/bursts could be the B-AMMS boat mounted sensor provided by Microflown Maritime which may be housed with the auditory sensor components topside as shown in FIG. 2.

While the SAS system 1 of FIG. 2 is described above as being an Ethernet based network, wherein the data flow is wired, alternative embodiments contemplate wireless communications of the SAS data in accordance with various wireless protocols and technologies known to those skilled in the art.

Referring to FIGS. 3a-3c, an exemplary SAS hardware assembly 5 includes: microphone array housing 15 having top surface 15a and bottom surface 15b; spacers 20, bottom plate 25 and first end individual microphone assemblies 30. FIG. 3c illustrates the non-exposed face of bottom surface 15b showing a second end of microphone assemblies 30, power filter 35 and SAS data acquisition (DAQ) Circuit Card Assembly (CCA) (hereafter “Board”) 40. Exemplary, non-limiting SAS hardware assembly 10 dimension is 24 inches diameter, 10 inches in height.

FIGS. 4a-4c are detailed illustrations of an exemplary individual microphone assembly 30 which includes pre-amplifier 50 and waterproof microphones 55 held in microphone assembly housing 65 by epoxy 60.

FIGS. 5a-5c provide top, side and bottom illustrations of an exemplary microphone 55 configuration, including exemplary dimensions in both millimeters and inches and hole pattern configuration 70 (FIG. 5c).

FIG. 6 illustrates an exemplary preamplifier circuit configuration within pre-amplifier 50 of microphone assembly 30. One skilled in the art appreciates that the components of the exemplary circuit though illustrated with particular specifications and tolerances, may be substituted with varying components or combinations of components to achieve the preamplification necessary for optimization of the signal processing. Such variations are within the scope of the invention.

FIG. 7 illustrates an exemplary configuration of the Board 40 including channel modules 90 within SAS hardware assembly 5. As illustrated, Channel Modules 01 through 08 are dedicated to 70-700 Hz bandwidth COLREGS sound source microphones 55; Channel Module 09 is dedicated to 0-9 KHz gunshot detection microphone and Channel Modules 10-16 are uninstalled spare channel modules. This Board digitizes data and sends out Ethernet packets with engineering data and timing data embedded. FIG. 7 shows both a COLREGS and gunshot detection channel; the only difference is that the gunshot channel operates at a higher sample rate in order to detect the supersonic shot wave generated by the bullet. The 70-700 Hz bandwidth range for the sound source microphones 55 is selected in accordance with the ranges set out in the COLREGS Annex III Technical Details of Sound Signal Appliances.

FIG. 8 illustrates an exemplary configuration of the circuitry forming the individual channel modules 90 which perform the initial signal processing on the audio signals received from the sound source microphones 55. The circuitry includes an input power regulation and monitoring path having the following exemplary components: current limiter 92, linear voltage regulator 94 as well as a differential amplifier 96 for monitoring current. And the circuitry further includes a signal output path for filtering and processing the audio signals having the following exemplary components: input buffer 98, gain stage amplifier 100, low pass filter 102, programmable-gain amplifier (PGA) 104 and a successive-approximation-register (SAR) analog-to-digital (ADC) converter/finite impulse response (FIR) filter 106. The cut-off frequency for the low pass filter 102 is different for the channel module receiving COLREG microphone audio signals (1.25 kHz) and the channel module receiving gun shot microphone audio (10 kHz).

An exemplary SAS system 1 in accordance with the present embodiments is designed to conform to the COLREGS specification classifying ship whistles using rules 34 and 35. For example, the SAS system 1 described and illustrated herein is able to classify acoustic maneuvering signals identified in COLREGS Rule 34 (maneuvering & warning) and COLREGS Rule 35 (signals in restricted visibility) for both international waters and Inland waters. COLREGS Rule 34 (auditory only; visual omitted) is set forth in the text and Tables 1 and 2 below and COLREGS Rule 35 (auditory only) is set forth in text and Tables 3 and 4 as copied from the U.S. Coast Guard Navigation Center website updated as of Dec. 29, 2015.

Rule 34:

TABLE 1
International                  Inland
(a) When vessels are in sight  (a) When power-driven vessels
of one another, a power-       are in sight of one another
driven vessel underway, when   and meeting or crossing at a
maneuvering as authorized or   distance within half a mile of
required by these Rules, shall each other, each vessel
indicate that maneuver by the  underway, when maneuvering as
following signals on her       authorized or required by
whistle:                       these Rules:
(i) one short blast to mean                            (i) shall indicate that
“I am altering my course to                            maneuver by the following
starboard”;                                            signals on her whistle:
(ii) two short blasts to mean                          one short blast to
“I am altering my course to                            mean “I intend to
port”;                                                 leave you on my
(iii) three short blasts to                            port side”;
mean “I am operating astern                            two short blasts to
propulsion                                             mean “I intend to
                                                       leave you on my
                                                       starboard side”;
                                                       three short blasts to
                                                       mean “I am
                                                       operating astern
                                                       propulsion”.
                               (ii) upon hearing the one
                               or two blast signal of
                               the other shall, if in
                               agreement, sound the
                               same whistle signal and
                               take the steps necessary
                               to effect a safe passing.
                               If, however, from any
                               cause, the vessel doubts
                               the safety of the
                               proposed maneuver, she
                               shall sound the danger
                               signal specified in Rule
                               34(d) and each vessel
                               shall take appropriate
                               precautionary action
                               until a safe passing
                               agreement is made.
(b) (Omitted, light signals)   (b) (Omitted, light signals)
(c) When in sight of one       (c) When in sight of one another:
another in a narrow channel                            (i) a power-driven vessel
or fairway:                                            intending to overtake
                               (i) a vessel intending  another power-driven
                               to overtake another     vessel shall indicate
                               shall in compliance     her intention by the
                               with Rule 9 (e)(i)      following signals on her
                               indicate her intention  whistle:
                               by the following        one short blast to
                               signals on her whistle: mean “I intend to
                               two prolonged           overtake you on your
                               blasts followed by      starboard side”
                               one short blast to      two short blasts to
                               mean “I intend to       mean “I intend to
                               overtake you on         overtake you on your
                               your starboard          port side”.
                               side”                   (ii) the power-driven
                               two prolonged           vessel about to be
                               blasts followed by      overtaken shall, if in
                               two short               agreement, sound a similar
                               blasts to mean “I       signal. If in doubt she
                               intend to overtake      shall sound the danger
                               you on your port        signal prescribed in
                               side”                   Rule 34(d).
                               (ii) the vessel about
                               to be overtaken when
                               acting in accordance
                               with 9(e)(i) shall
                               indicate her agreement
                               by the following
                               signal on her whistle:
                               one prolonged, one
                               short, one
                               prolonged and one
                               short blast, in
                               that order.

(d) When vessels in sight of one another are approaching each other and from any cause either vessel fails to understand the intentions or actions of the other, or is in doubt whether sufficient action is being taken by the other to avoid collision, the vessel in doubt shall immediately indicate such doubt by giving at least five short and rapid blasts on the whistle. Such signal may be supplemented by at least five short and rapid flashes.

(e) A vessel nearing a bend or an area of a channel or fairway where other vessels may be obscured by an intervening obstruction shall sound one prolonged blast. Such signal shall be answered with a prolonged blast by any approaching vessel that may be within hearing around the bend or behind the intervening obstruction.

(f) If whistles are fitted on a vessel at a distance apart of more than 100 meters, one whistle only shall be used for giving maneuvering and warning signals.

TABLE 2
International Inland
(g) When a power-driven vessel is leaving
a dock or berth, she shall sound
one prolonged blast.
(h) A vessel that reaches agreement with
another vessel in a head-on, crossing, or
overtaking situation, as for example, by
using the radiotelephone as prescribed by
the Vessel Bridge-to-Bridge
Radiotelephone Act (85 Stat. 164; 33
U.S.C. 1201 et seq.), is not obliged to
sound the whistle signals prescribed by
this Rule, but may do so. If agreement is
not reached, then whistle signals shall be
exchanged in a timely manner and shall
prevail.

RULE 35: In or near an area of restricted visibility, whether by day or night the signals prescribed in this Rule shall be used as follows:

(a) A power-driven vessel making way through the water shall sound at intervals of not more than 2 minutes one prolonged blast.

(b) A power-driven vessel underway but stopped and making no way through the water shall sound at intervals of no more than 2 minutes two prolonged blasts in succession with an interval of about 2 seconds between them.

TABLE 3
International                  Inland
(c) A vessel not under         (c) A vessel not under command,
command, a vessel restricted   a vessel restricted in her
in her ability to maneuver, a  ability to maneuver whether
vessel constrained by her      underway or at anchor, a sailing
draft, a sailing vessel, a     vessel, a vessel engaged in
vessel engaged in fishing and  fishing whether underway or at
a vessel engaged in towing or  anchor and a vessel engaged in
pushing another vessel shall,  towing or pushing another vessel
instead of the signals         shall, instead of the signals
prescribed in Rule 35(a) or    prescribed in Rule 35(a) or (b),
(b), sound at intervals of not sound at intervals of not more
more than 2 minutes three      than 2 minutes three blasts in
blasts in succession, namely   succession, namely one prolonged
one prolonged followed by two  followed by two short blasts.
short blasts.
(d) A vessel engaged in
fishing, when at anchor, and a
vessel restricted in her
ability to maneuver when
carrying out her work at
anchor, shall instead of the
signals prescribed in Rule
35(g) sound the signal
prescribed in Rule 35(c).

(e) A vessel towed or if more than one vessel is towed the last vessel of the tow, if manned, shall at intervals of not more than 2 minutes sound four blasts in succession, namely one prolonged followed by three short blasts. When practicable, this signal shall be made immediately after the signal made by the towing vessel.

(f) When a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit they shall be regarded as a power-driven vessel and shall give the signals prescribed in Rule 35(a) or (b).

(g) A vessel at anchor shall at intervals of not more than 1 minute ring the bell rapidly for about 5 seconds. In a vessel 100 meters or more in length the bell shall be sounded in the forepart of the vessel and immediately after the ringing of the bell the gong shall be sounded rapidly for about 5 seconds in the after part of the vessel. A vessel at anchor may in addition sound three blasts in succession, namely one short, one long and one short blast, to give warning of her position and of the possibility of collision to an approaching vessel.

(h) A vessel aground shall give the bell signal and if required the gong signal prescribed in Rule 35(g) and shall, in addition, give three separate and distinct strokes on the bell immediately before and after the rapid ringing of the bell. A vessel aground may in addition sound an appropriate whistle signal.

(i) A vessel of 12 meters or more but less than 20 meters in length shall not be obliged to give the bell signals prescribed in Rule 35(g) and (h). However, if she does not, she shall make some other efficient sound signal at intervals of not more than 2 minutes.

(j) A vessel of less than 12 meters in length shall not be obliged to give the above mentioned signals but, if she does not, shall make some other efficient sound signal at intervals of not more than 2 minutes.

(k) A pilot vessel when engaged on pilotage duty may, in addition to the signals prescribed in Rule 35(a), (b) or (g), sound an identity signal consisting of four short blasts.

TABLE 4
International Inland
(1) The following vessels shall not be
required to sound signals as prescribed in
Rule 35(g) when anchored in a special
anchorage area designated by the Coast
Guard:
(i) a vessel of less than 20 meters in
length; and
(ii) a barge canal boat, scow, or other
nondescript craft.

SAS localizes the whistles to within approximately +/−22.5 degrees bearing accuracy and detects COLREGS compliant whistles from vessels at frequency and audibility ranges specified in COLREGS Annex III which includes the Technical Details of Sound Signal Appliances, the substance of which is incorporated herein by reference in its entirety. The design utilizes custom acoustic sensing hardware in combination with commercial off-the-shelf (COTS) hardware to capture and process COLREGS events and, if desired, gun shots. The separation of acoustic sensing hardware 5 and SAS processing software/hardware 10 ensures a modular design that allows the processing software/hardware to be selected and swapped in/out at any time, see FIG. 9. As shown in FIG. 9, microphones M1-M9 are arranged as shown. The exemplary SAS system hardware uses well-established open system interface standards. And the exemplary SAS software is written to work on Linux without any particular hardware dependency. One skilled in the art recognizes that proprietary interfaces and software may be used. Additionally, one skilled in the art appreciates that other audio signals provided for in the COLREGS, i.e., horns, bells and other relevant audio sources may also be detected and processed by independent modules of the SAS.

The SAS acoustic sensing hardware enclosure is designed for rugged at sea use and to withstand an electromagnetic interference (EMI) environment. SAS is required to operate near RADAR and other high energy EMI sensors. The SAS sensor rejects EMI while simultaneously capturing acoustic energy for processing. The acoustic sensing hardware is designed to be salt water resistant. The SAS processing software is designed to reject constant tones and off axis interface noise generated by other ships systems. The processing also rejects repetitive mechanical ship noise such as wave slap and wind noise.

Input and output interfaces are selected based on an analysis of requirements for shipboard installation, human inspection, diagnosis, control, and supervision of the SAS platforms. To facilitate diagnostics, the SAS system reports sensor utility and state of health information.

FIG. 10 provides an exemplary SAS hardware assembly 5 placement scenario wherein there is a clear line-of-sight to potential surface vessels on any bearing. This allows for localization in bearing of COLREGS signals.

One skilled in the art recognizes the variations to the embodiments and features described herein. By way of example, the number of microphones may vary as well as the individual microphone configurations. Circuitry and hardware substitutes are contemplated in order to perform the functions described herein. Such variations are considered to be within the scope of this description.

Claims

1. A shipboard auditory sensor system for processing audio signals from one or more surface maritime vessels in a vicinity of the ship to support autonomous navigation of the ship, the shipboard auditory sensor comprising: an auditory sensor assembly located topside on the ship such that the auditory sensor assembly has a clear line of sight to surface maritime vessels on any bearing,the auditory sensor assembly including: multiple microphone assemblies;a power filter; anda data acquisition board,wherein the multiple microphone assemblies receive audio signals from one or more surface maritime vessels in a vicinity of the ship,wherein the received audio signals are filtered and determined by the filter and the data acquisition board as being in a first auditory range specified by one or more regulations and being indicative of a status of the one or more surface maritime vessels, furtherwherein the auditory sensor assembly formats the determined audio signals into audio data packets to support autonomous navigation of the ship.

2. The shipboard auditory sensor system of claim 1, wherein each of the multiple microphone assemblies comprises: a microphone operating within the first specified auditory range and a preamplifier circuit.

3. The shipboard auditory sensor system of claim 1, wherein the data acquisition board comprises: at least one channel module for each of the multiple microphone assemblies, a programmable gate array, an analog-to-digital converter and an Ethernet interface.

4. The shipboard auditory sensor system of claim 1, further comprising: a processing server on the ship for receiving the audio data packets from the auditory sensor assembly, the processing server being programmed to run the received audio data packets through multiple algorithms to support autonomous navigation of the ship.

5. The shipboard auditory sensor system of claim 4, wherein the multiple algorithms include: a sound detection algorithm and a marine vessel status algorithm.

6. The shipboard auditory sensor system of claim 5, wherein the marine vessel status algorithm includes COLREGS audio classifications in accordance with COLREGS rules 34 and 35.

7. The shipboard auditory sensor system of claim 6, wherein the multiple algorithms further include: an operating environment algorithm for determining if the ship is in international waters or inland waters.

8. The shipboard auditory sensor system of claim 1, wherein the first specified audio range is 70 to 700 Hz.

9. The shipboard auditory sensor system of claim 1, wherein the auditory sensor assembly further includes a gunshot detection microphone operating in a second specified auditory range.

10. The shipboard auditory sensor system of claim 9, wherein the data acquisition board further comprises: at least one channel module for each of the multiple microphone assemblies, at least one channel module for the gunshot detection microphone, a programmable gate array, and analog-to-digital converter and an Ethernet interface.

11. The shipboard auditory sensor system of claim 10, wherein the second specific auditory range is greater than 0 and up to 9 KHz.

12. A shipboard auditory sensor system for processing audio signals from one or more surface maritime vessels in a vicinity of the ship to support autonomous navigation of the ship, the shipboard auditory sensor comprising: an auditory sensor assembly including a microphone sensor array for sensing audio signals from one or more surface maritime vessels in a vicinity of the ship,wherein the received audio signals are determined by the auditory sensor as being in one of a first specified auditory range and being indicative of a status of the one or more surface maritime vessels,wherein the auditory sensor assembly formats the determined audio signals into audio data packets to support autonomous navigation of the ship; anda processing server on the ship for receiving the audio data packets from the auditory sensor assembly, the processing server being programmed to run the received audio data packets through multiple algorithms to support autonomous navigation of the ship.

13. The shipboard auditory sensor system of claim 12, wherein the auditory sensor assembly further includes a gunshot audio sensor for detecting gun shots in the vicinity of the ship, the detected gun shots being in a second specific auditory range and the auditory sensor assembly formats the gun shot audio into audio data packets to support autonomous navigation of the ship.

14. The shipboard auditory sensor system of claim 12, wherein the multiple algorithms include: a sound detection algorithm and a marine vessel status algorithm.

15. The shipboard auditory sensor system of claim 14, wherein the marine vessel status algorithm includes COLREGS audio classifications in accordance with COLREGS rules 34 and 35.

16. The shipboard auditory sensor system of claim 15, wherein the multiple algorithms further include: an operating environment algorithm for determining if the ship is in international waters or inland waters.

17. The shipboard auditory sensor system of claim 12, wherein the first specified audio range is 70 to 700 Hz.

18. The shipboard auditory sensor system of claim 13, wherein the second specific auditory range is greater than 0 and up to 9 KHz.