Patent Description:
In confined areas, such as in a school or a private or public building, detecting and locating the source of gunshots is a complicated problem. A gunshot typically generates several sounds including the gunshot itself, the bullet's bow shockwave, noise from bullet impacts and noise of reflected gunshot sounds. In addition, numerous noises are generated in buildings that may be mistakenly identified as gunshots.

The broad concept of detecting gunshots utilizing acoustics is known. More specifically, it is known to provide a gunshot detection system including an array of acoustic sensors positioned in a pattern which enables signals from the sensors to be employed to not only detect the firing of a gunshot but to also locate the origin of the shot. One main requirement of such a system is the need to accurately distinguish between the sound produced from a gunshot and a host of other ambient sounds. In at least one known arrangement, a microphone is used to detect each sound, which is then amplified, converted to an electrical signal and then the electrical signal is compared with a threshold value above which a gunshot sound is expected to exceed.

An example of a gunshot detection system is described in <CIT>.

Recently, gunshot detection systems with improved accuracy, dependability, and effectiveness have been described. One such system is described in International Publication Number <CIT> and entitled "System and Method for Acoustically Identifying Gunshots Fired Indoors. " This system provides for low false alarms or false positives and high detection rates by employing two microelectromechanical microphones (MEMs) having different sensitivity levels. Acoustic signals from a first microphone with lower sensitivity (for example, making the anomaly detection microphone essentially deaf to routine sounds) are first analyzed for a peak amplitude level large enough to be a potential gunshot. Then acoustic signals from a second microphone having a higher sensitivity are then analyzed further to confirm that the sound was a gunshot.

Gunshot detection methods have also been proposed that can count the number of gunshots fired, particularly from an automatic or fast acting weapon. One such method is described in International Publication Number <CIT> and entitled "Method for Acoustically Counting Gunshots Fired Indoors. " In this method, an acoustic signature of captured noise is analyzed to accurately count how many shots are fired. The method can be employed to identify that the gun is an automatic or rapid fire weapon, which information can be provided to emergency personnel.

Additionally, gunshot detection system that can accurately determine where sensed events are located have been proposed. One such system is described in International Publication Number <CIT> and entitled "System and Method for Identifying and Locating Sensed Events. " Here, a sensor network is employed to detect an event in the form of an audible signal. The event is time stamped and sent to a controller, which evaluates the event as either unique or a multiple detection using the sensor's time of alarm to determine which sensor activated first and to suppress subsequent alarms for the same event. This process is known as de-confliction.

At the same time, many premises with gunshot detection systems are also equipped with one or more building management systems such as access control systems, building automation systems, and/or fire alarm systems. In general, these building management systems are installed within a premises such as commercial, residential, or governmental buildings. Examples of these buildings include offices, hospitals, warehouses, public infrastructure buildings including subways and bus terminals, multi-unit dwellings, schools or universities, shopping malls, government offices, and casinos.

In general, building management systems include one or more control panels or controllers connected to and controlling distributed devices, which perform the building management functions of the building management system. The controllers and distributed devices communicate via wired and/or wireless networks supporting digital and/or analog communication between the devices.

Access control systems typically include control panels such as system controllers and door controllers, and distributed devices, including door position sensors, access control readers, and actuators like electric door locks, to list a few examples. The access control readers are often installed at access points of the buildings to control access to restricted areas, such as buildings or areas of the buildings. Examples of access points include front and interior doors of a building, elevators, hallways connecting two areas of a building, escalators leading to restricted areas of the building and/or turnstiles. The access control readers read the information of keycards and/or transmitted from mobile computing devices and then the access control systems determine if the individuals are authorized to access the restricted areas. If the individuals are authorized to enter the restricted areas, then the access control readers allow access to the restricted areas by unlocking locked doors or turnstiles, signaling that doors should be unlocked, and/or activating elevators. Alarms can be generated upon unauthorized entry.

Building automation systems will typically include one or more building automation control panels and distributed devices that control and monitor the physical plant aspects of a building and aspects of business-specific electrical, computer, and mechanical systems. The physical plant typically includes heating, ventilation, and air conditioning (HVAC) systems, elevators/escalators, lighting and power systems, refrigeration and coolant systems, and air and/or water purification systems, in examples. HVAC systems typically include air handlers and systems of ducts and vents for circulating air throughout the building. Business-specific systems include computer systems, manufacturing systems that include various types of computer-aided machinery and test equipment, and inventory control and tracking systems, in examples.

Fire alarm systems typically include fire control panels that function as system controllers. Fire detection/initiation devices and alarm notification devices are then installed, distributed throughout the buildings and connected to the panels. Some examples of fire detection/initiation devices include smoke detectors, carbon monoxide detectors, flame detectors, temperature sensors, and/or pull stations (also known as manual call points). Some examples of fire notification devices include speakers, horns, bells, chimes, light emitting diode (LED) reader boards, and/or flashing lights (e.g., strobes).

The fire detection devices monitor the buildings for indicators of fire. Upon detection of an indicator of fire such as smoke or heat or flames, the distributed device is activated and a signal is sent from the activated distributed device to the fire control panel. The fire control panel then initiates an alarm condition by activating audio and visible alarms of the fire notification devices of the fire alarm system, which are also distributed around the building. Additionally, the fire control panel will also send an alarm signal to a monitoring station, which will notify the local fire department or fire brigade.

It would be beneficial to enhance the capabilities of gunshot detection systems by providing integration between the gunshot detection systems and building management systems, which might be installed in the same building as the gunshot detection systems. For example, distributed devices of building management systems (e.g. light fixtures, sprinkler heads, smoke detectors, thermostats, exit signs) are already positioned throughout these buildings, many with familiar and/or inconspicuous housings mounted to walls or ceilings of the buildings according to their functionality. Incorporation of gunshot sensor units of the gunshot detection system into these distributed building management devices allows the gunshot sensor units to be concealed while also allowing them to take advantage of existing building management infrastructure, among other benefits.

According to embodiments not falling under the scope of the claims, gunshot sensor units can share a common housing with the distributed building management devices, attach to the devices via attachment mechanisms, or even be incorporated into hybrid devices that include gunshot sensors and building management elements for performing building management functions. In one embodiment not falling under the scope of the claims, the gunshot sensor units could even use the shape of a common housing, of any part of the distributed building management device, to create a specifically shaped parabolic microphone allowing more efficient and directional detection of shot sounds.

In general, according to one aspect, the invention features a system for detecting gunshots as set out in claim <NUM>.

The one or more microphones might also be used by the gunshot sensor units to generate audio data depicting the acoustic anomalies in addition to simply detecting the anomalies.

In general, according to another aspect, the invention features a method for detecting gunshots as set out in claim <NUM>.

The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention as defined by the appended claims.

<FIG> is a schematic diagram of an exemplary gunshot detection system <NUM>.

In general, the gunshot detection system <NUM> monitors, detects and reports the occurrence of gunshots or other emergencies within one or more premises <NUM> such as buildings (e.g. offices, hospitals, warehouses, retail establishments, shopping malls, schools, multi-unit dwellings, government buildings). The premises <NUM> also includes one or more building management systems, which control and monitor various equipment and conditions throughout the premises <NUM> and can include building automation systems, fire alarm systems, and/or access control systems, among other examples.

In the illustrated example, the premises <NUM> is a simplified floor example of a building with three areas <NUM> (e.g. rooms, hallways, lobbies, stairways), a lecture hall <NUM>-<NUM>, classroom A <NUM>-<NUM>, and classroom B <NUM>-<NUM>.

In one configuration (illustrated), the gunshot detection system <NUM> includes gunshot sensor units <NUM> and a gunshot detection system control panel <NUM>. The gunshot sensor units <NUM> detect conditions indicative of the gunshots or other emergencies and alert the control panel <NUM>, which takes one or more responsive actions such as alerting building personnel, law enforcement, and/or a monitoring center, or collecting and presenting data pertaining to the detected gunshots to an operator of the gunshot detection system control panel <NUM>. In other configurations, the gunshot sensor units <NUM> could be standalone devices that perform the gunshot detection functions (e.g. generating and sending alerts to users) without communicating with a control panel <NUM>.

Similarly, the building management systems typically include building management system control panels <NUM> and distributed building management system devices <NUM> positioned throughout the premises <NUM>. The control panels <NUM> direct the functionality of the respective building management systems by receiving signals and/or data (for example, from the distributed devices <NUM>), sending instructions, and determining and sending status information or sensor data, among other examples, to be displayed on or utilized by the distributed devices <NUM>.

In both the gunshot detection system <NUM> and in the building management systems, the gunshot sensor units <NUM> and distributed devices <NUM> communicate with their respective control panels <NUM>, <NUM> over wired and/or wireless communication networks <NUM>. In general, these communication networks <NUM> support digital and/or analog communication between the gunshot sensor units <NUM> or distributed devices <NUM> and the respective control panels <NUM>, <NUM>. In some embodiments (not illustrated), the distributed devices <NUM> from multiple different building management systems, and even the gunshot sensor units <NUM> and control panel <NUM> from the gunshot detection system <NUM>, could all be connected to the same communication network <NUM>. However, in the illustrated example, the gunshot sensor units <NUM> communicate with the gunshot detection system control panel <NUM> via the gunshot detection communication network <NUM>-<NUM>, and the building management system distributed devices <NUM> communicate with the building management system control panels <NUM> via a separate building management communication network <NUM>-<NUM>.

The gunshot sensor units <NUM> are distributed throughout the premises <NUM>, for example, in the different areas <NUM> of the premises <NUM>. The gunshot sensor units <NUM> detect acoustic anomalies indicating potential gunshots and generate audio data depicting the acoustic anomalies. The gunshot sensor units <NUM> also generate event data based on and descriptive of the acoustic anomalies and locally store and/or send the event data to the control panel <NUM>.

The event data often includes audio data (e.g. digitized audio clips) depicting the acoustic anomalies, metadata including, for example, time information indicating when the acoustic anomalies started and/or stopped, duration information for the acoustic anomalies and/or the audio data depicting the acoustic anomalies, file information, and identification information for the gunshot sensor unit <NUM>, and sensor data generated by the gunshot sensor unit <NUM>. The event data can be locally stored, collected by the control panel <NUM>, transferred to remote servers, and/or transferred to devices of law enforcement entities for forensic analysis, for example.

On the other hand, the gunshot detection system control panel <NUM> directs the overall functionality of the gunshot detection system <NUM> by sending instructions (e.g. control messages) to be executed by the gunshot sensor units <NUM>, receiving the event data from the gunshot sensor units <NUM> and taking the responsive actions based on the event data. The control panel <NUM> might receive preliminary event data (e.g. metadata indicating time and date information) from multiple gunshot sensor units <NUM> and perform a de-confliction process in order to determine which event data from the different sensor units <NUM> pertains to the same detected acoustic anomaly and which of the gunshot sensor units <NUM> is closest to the source of the acoustic anomaly based on, for example, which of the units first detected the acoustic anomaly. The control panel <NUM> might then send instructions to the gunshot sensor unit <NUM> closest to the source to send full event data (e.g. including a full audio data sample, environmental data, and other sensor data) to the control panel <NUM> for further processing and/or to be presented to the operator. The gunshot detection system control panel <NUM> also presents information to an operator of the control panel <NUM> and receives selections, for example, via a graphical user interface (GUI), the selections indicating various configuration settings and/or actions to be taken by the control panel <NUM> with respect to the gunshot sensor units <NUM>, to list a few examples.

The building management system distributed devices <NUM> are positioned throughout the premises <NUM> and perform the management and/or automation functions of the building management system via building management system elements including controllers or control panels, sensors, user interface elements, and/or actuators, among other examples. Of these, the sensors detect environmental conditions of the premises <NUM> and send sensor data to be used by the controllers. The user interface elements present information to occupants of the premises <NUM> and receive user input (e.g. via touchscreen displays). The actuators effect changes throughout the premises <NUM> in order to, for example, control the environmental conditions or building equipment. The controllers direct the functionality of the respective building management systems by receiving signals and/or sensor data (for example, from other distributed devices <NUM> such as the sensors or user interface elements), and generating and sending status information and/or instructions, among other examples, to other distributed devices <NUM> (for example, to the actuators and/or the user interface elements). Some distributed devices <NUM> (e.g. thermostats of building automation systems) combine functionality of controllers, sensors, user interface elements and actuators in one device.

More specifically, among the building management systems installed at the premises <NUM> might be a building automation system, a fire alarm system, and/or an access control system, among other examples. For the sake of clarity, in the illustration, only one building management system control panel <NUM> and building management communication network <NUM>-<NUM> is represented, with distributed devices <NUM> from different types of systems connected to the same control panel <NUM> via the same network <NUM>-<NUM>. In practice, the premises <NUM> could include more than one building management control panel <NUM> or building management communication network <NUM>-<NUM>, the distributed devices <NUM> could connect to different control panels <NUM> via different networks <NUM>-<NUM>, and/or the distributed devices <NUM> could be standalone devices that perform their building management functions without communicating with a control panel <NUM>.

The building automation system controls and monitors physical plant aspects of the premises <NUM> and aspects of business-specific electrical, computer, and mechanical systems. The building automation system might include a control panel <NUM>, which is connected via the communication network <NUM>-<NUM> to the building automation distributed devices <NUM>, lighting units <NUM>-<NUM>, exit signs <NUM>-<NUM>, air handlers, thermostats, projector units, and blinds units, to list a few examples. The air handler heats, cools and/or circulates air throughout the premises via ducts and vents. The projector unit raises or lowers a projector screen. The blinds units control window coverings such as blinds by, for example, raising, lowering, opening, closing and/or controlling other physical mechanisms for adjusting the amount of light allowed to pass through the window. The lighting units <NUM>-<NUM> provide and control illumination (e.g. of an indoor space), for example, via lighting mechanisms such as light bulbs. The exit signs <NUM>-<NUM> indicate and illuminate access points positioned at or along exit routes leading to an exterior of the building. The thermostat <NUM>-<NUM> generates sensor data indicating climate conditions for particular areas <NUM> of the premises <NUM> (e.g. via temperature, humidity, and/or other sensors), displays or otherwise indicates status information, receives input indicating climate preferences (e.g. via a touchscreen display or other user interface), and controls the climate conditions by sending the sensor data to the building automation control panel <NUM>-<NUM> and/or sending instructions to the air handler based on the sensor data.

The fire alarm system monitors for indications of fire in the premises <NUM> and initiates fire alarms alerting occupants of the premises <NUM>. The fire alarm system includes a control panel <NUM>, which is connected via a communication network <NUM>-<NUM> to the fire alarm distributed devices <NUM>, including alarm initiation devices and fire notification devices. The alarm initiation devices include smoke detectors <NUM>-<NUM> and manually activated devices such as call points and pull stations, carbon monoxide detectors and heat detectors, to list a few examples. The alarm initiation devices monitor the buildings for indicators of fire. Upon detection of indicators of fire, device signals are sent from the alarm initiating devices to the control panel <NUM>. The fire notification devices notify occupants of the premises <NUM> of a potential fire and generally include sounders, which might include speakers, horns, bells, and/or chimes, and flashing lights (e.g., strobes), and light emitting diode (LED) reader boards, to list a few examples. In response to detection of indicators of fire, the control panel <NUM> initiates an alarm state, which activates the fire notification devices. Additionally, fire suppression devices can be activated by the control panel in response to detecting the indicators of fire. For example, fire sprinklers release and direct water over an area of the premises <NUM> to suppress fires in response to instructions from the control panel.

The access control system controls access through access points (e.g. doors, elevators, escalators, turnstiles) to restricted areas of the premises <NUM>. The access control system includes one or more control panels <NUM>, which are connected via the communication network <NUM>-<NUM> to access control distributed devices <NUM>, including, for example, access point controllers with access control readers for receiving input from the occupants of the premises <NUM> seeking access through the access points to the restricted areas. The access point controllers verify the input by, for example, confirming that the occupant who entered the input is authorized to pass through or access the access point based on authorization information, which might include a list of users authorized to enter restricted areas. The access point controllers also control access through the access points (e.g. by unlocking a door via a door strike, activating a door opening and/or movement mechanism on an elevator, unlocking a turnstile). In one example, the access control reader includes a wireless receiver, which receives identification information broadcast or otherwise transmitted by the user devices such as mobile computing devices, identification badges, and/or beacon devices of the occupants, among other examples.

The gunshot detection system <NUM> provides integration between the gunshot sensor units <NUM> and the building management system distributed devices <NUM>. Specifically, gunshot sensor units <NUM> are incorporated into, attached to, and/or combined with the building management distributed devices <NUM>.

In the illustrated example, two gunshot sensor units <NUM>-<NUM>, <NUM>-<NUM>, two lighting units <NUM>-<NUM>-<NUM>, <NUM>-<NUM>-<NUM>, and a smoke detector <NUM>-<NUM> are located in the lecture hall <NUM>-<NUM>, while one gunshot sensor unit <NUM>-<NUM> and one lighting unit <NUM>-<NUM>-<NUM> is located in classroom A <NUM>-<NUM>, and one gunshot sensor unit <NUM>-<NUM> and an exit sign <NUM>-<NUM> is located in classroom B <NUM>-<NUM>. The gunshot sensor unit <NUM>-<NUM> is integrated with (e.g. incorporated into, attached to, combined with) the smoke detector <NUM>-<NUM>, the gunshot sensor unit <NUM>-<NUM> is integrated with the lighting unit <NUM>-<NUM>-<NUM>, the gunshot sensor unit <NUM>-<NUM> is integrated with the lighting unit <NUM>-<NUM>-<NUM>, and the gunshot sensor unit <NUM>-<NUM> is integrated with the exit sign <NUM>-<NUM>.

<FIG> is a block diagram showing an exemplary gunshot sensor unit <NUM>.

The gunshot sensor unit <NUM> is integrated with the building management system distributed device <NUM> via an attachment mechanism <NUM>.

The attachment mechanism <NUM> can take different forms according to different embodiments of the invention. In one example, the attachment mechanism <NUM> simply secures two discrete devices having separate housings and components together (e.g. via screws, adhesive, clamps, ties). In another example, the attachment mechanism <NUM> is a common housing shared by the two devices <NUM>, <NUM> and enclosing at least some of the components of the two devices. In yet another example, gunshot sensor elements of the gunshot sensor units <NUM> and building management elements of the building management devices <NUM> are combined into hybrid devices, the hybrid devices including a common housing <NUM> and a common controller directing both gunshot and building management functionality via the gunshot sensor elements and building management elements.

The gunshot sensor unit <NUM> includes gunshot sensor elements such as a controller <NUM>, local nonvolatile storage <NUM>, a wired and/or wireless network interface <NUM>, an anomaly detection microphone <NUM>, and an audio capture microphone <NUM>.

The controller <NUM> executes firmware/operating system instructions and generally directs the functionality of the gunshot sensor unit <NUM>. In one example, the controller <NUM> is small single-board computer. In other examples, the controller is a microcontroller unit or a system on a chip (SoC), including one or more processor cores along with memory and programmable input/output peripherals such as analog to digital converts and digital to analog converters.

The wired and/or wireless network interface <NUM> provides connectivity with the gunshot detection system control panel <NUM> and possibly other devices via the gunshot detection communication network <NUM>-<NUM>. In addition, the network also provides power to the devices, in many examples. Direct current (DC) is superimposed upon the data that is transmitted between the devices and other nodes on the network.

The anomaly detection microphone <NUM> detects the acoustic anomalies, while the audio capture microphone <NUM> captures ambient sound and generates the audio data. In one embodiment, both microphones <NUM>, <NUM> are micro electro-mechanical system (MEMS) microphones having different sensitivity levels, and the controller <NUM> is configured to sample the microphones <NUM>, <NUM> such that outputs from the microphones can be continuously analyzed in near real time for an acoustic signature. The anomaly detection microphone <NUM> has the lower sensitivity level and a high clipping level, while the audio capture microphone <NUM> has the higher sensitivity level. The audio capture microphone <NUM> continuously captures ambient sound, which is stored in a <NUM> second (for example) loop in a ring buffer of the controller <NUM>. At the same time, incoming acoustic signals from the anomaly detection microphone <NUM> are continuously analyzed to detect acoustic anomalies, particularly by searching the incoming acoustic signal for a peak amplitude level large enough to be at least preliminarily identified as a gunshot.

Once an indication of a possible gunshot has been triggered utilizing the anomaly detection microphone <NUM>, further processing may be performed by the controller <NUM>. The controller <NUM> analyzes the sound stored in the loop to confirm that the acoustic anomaly is a gunshot. If confirmed as gunshot, the controller stores the captured sound stored in the loop buffer, which would include the acoustic anomaly and the previously captured sound (up to <NUM> seconds, in this example) as audio data <NUM> in the local nonvolatile storage <NUM> associated with different event files <NUM> or instances of event data for different gunshot detection events, along with the metadata <NUM>, which includes the time and/or date information for the events. In embodiments, the local nonvolatile storage <NUM> could be fixed storage such as flash memory, or removable storage such as an SD card, among other examples.

<FIG> is an illustration of an exemplary gunshot sensor unit integrated with a fire sprinkler <NUM>-<NUM> of a fire alarm system. In the illustrated example, which does not fall under the scope of the claims, the gunshot sensor unit <NUM> shares a common housing <NUM> with the fire sprinkler <NUM>-<NUM>, which is mounted to a ceiling <NUM> of an area <NUM> of the premises <NUM>.

The common housing <NUM> fully or partially encloses the gunshot sensor elements such as the controller <NUM>, memory <NUM>, network interface <NUM>, and microphones <NUM>, <NUM> in addition to the building management elements of the fire sprinkler <NUM>-<NUM>. The common housing <NUM> might also include a mount for securing the fire sprinkler <NUM>-<NUM> to the ceiling <NUM> and concealing wiring between the gunshot sensor elements and the gunshot detection communication network <NUM>-<NUM> and/or between the building management elements and the building management communication network <NUM>-<NUM>. The anomaly detection microphone <NUM> and audio capture microphone <NUM> might be positioned with respect to the common housing <NUM> and features of the common housing to allow exposure of the microphones to sound waves in an environment surrounding the fire sprinkler <NUM>-<NUM>. In the illustrated example, the anomaly detection microphone <NUM> is recessed within the common housing <NUM>, while the audio capture microphones <NUM> protrude from a top side of the common housing <NUM> and operate within a space between the housing <NUM> and the ceiling <NUM>. Such a configuration enables full operation of the microphones <NUM>, <NUM> while also concealing the microphones from the view of building occupants. In one embodiment, the fire sprinkler <NUM>-<NUM> might even include a mounting plate surrounding a base of the mount securing the fire sprinkler <NUM>-<NUM> to the ceiling <NUM>. This mounting plate could serve as a reflector for collecting and focusing sound waves onto the microphones <NUM>, <NUM>.

<FIG> is an illustration of an exemplary gunshot sensor unit <NUM> integrated with a fire notification device <NUM>-<NUM> of a fire alarm system. In the illustrated example, which does not fall under the scope of the claims, the gunshot sensor unit <NUM> shares a common housing <NUM> with the fire notification device <NUM>-<NUM>, which is mounted to a wall of an area <NUM> of the premises <NUM>.

As with the previous example, the common housing <NUM> fully or partially encloses the gunshot sensor elements in addition to the building management elements of the fire notification device <NUM>-<NUM> such as a controller, sounders, and/or lights, for example. In the illustrated example, the building management elements of the fire notification device <NUM>-<NUM> include a strobe <NUM> for intermittently emitting light to alert occupants of the premises <NUM>. The integrated gunshot sensor unit <NUM> and/or gunshot sensor elements, indicated with dashed lines, are concealed within the common housing <NUM>. A grill <NUM> is cut or formed at a front face of the common housing <NUM> near the location of the integrated gunshot sensor unit <NUM>. From the viewpoint of a building occupant, the grill <NUM> appears to provide ventilation for the internal components of the strobe device fire notification device <NUM>-<NUM>. Though the grill <NUM> does provides ventilation, its primary is to enable the microphones <NUM>, <NUM> of the included gunshot sensor unit <NUM> to operate while also being hidden from view of occupants.

<FIG> is an illustration of an exemplary gunshot sensor unit <NUM> integrated with a thermostat <NUM>-<NUM> of a building automation system. In the illustrated example, which does not fall under the scope of the claims, the gunshot sensor unit <NUM> shares a common housing <NUM> with the thermostat <NUM>-<NUM>, which is mounted to a wall of an area <NUM> of the premises <NUM>.

As with the previous examples, the common housing <NUM> fully or partially encloses the gunshot sensor elements in addition to the building management elements of the thermostat <NUM>-<NUM> such as a controller, sensors and/or user interface elements, for example. In the illustrated example, the building management elements of the thermostat <NUM>-<NUM> include a control buttons <NUM> which enable occupants to input a set temperature, and a screen <NUM> for displaying information such as the set temperature or current temperature. The integrated gunshot sensor unit <NUM> and/or gunshot sensor elements, indicated with dashed lines, are concealed within the common housing <NUM>, which includes the grill <NUM> cut or formed at a front face of the common housing <NUM> near the location of the integrated gunshot sensor unit <NUM> as in the fire notification device <NUM>-<NUM> example.

<FIG> is an illustration of an exemplary gunshot sensor unit <NUM> integrated with a lighting unit <NUM>-<NUM> of a building automation system. In the illustrated example, which does not fall under the scope of the claims, the gunshot sensor unit <NUM> shares a common housing <NUM> with the lighting unit <NUM>-<NUM>, which is mounted to a ceiling of an area <NUM> of the premises <NUM>, for example.

As before, the gunshot sensor unit <NUM> shares a common housing with the lighting unit <NUM>-<NUM>. Now, however, the common housing includes a hemi-spherically or paraboloidally shaped reflector <NUM>, which is normally used by the lighting units <NUM>-<NUM> to direct light emitted by the lighting units <NUM>-<NUM> into or toward areas <NUM> of the premises <NUM> being illuminated by the lighting units <NUM>-<NUM>. The reflector <NUM> also collects and focuses sound waves onto the microphones <NUM>, <NUM>, which, in the illustrated embodiment, are external to a main housing for the gunshot sensor unit <NUM>, electrically connected to the gunshot sensor unit <NUM> (e.g. via a wire), and secured in a position enabling the reflector <NUM> to collect and focus the sound waves onto the microphones <NUM>, <NUM> (e.g. at a focal point of the reflector <NUM>).

According to the invention, the attachment mechanism <NUM> is not a common housing but, instead, a means for securing the gunshot sensor unit <NUM> to an existing lighting unit <NUM>-<NUM> comprising a reflector <NUM> in a position enabling the reflector <NUM> to collect and focus the sound waves onto the microphones <NUM>, <NUM>.

In another embodiment, which does not fall under the scope of the claims, the gunshot sensor units <NUM> might simply comprise the reflector <NUM> independent of the lighting units <NUM> or other distributed devices <NUM>.

<FIG> is a sequence diagram illustrating operation of the gunshot detection system <NUM> according to the present invention.

First, in step <NUM>, one or more of the gunshot sensor units <NUM> detect gunshots. These gunshot sensor units <NUM> might be integrated with building management distributed devices <NUM>. For example, gunshot sensor unit <NUM>-<NUM> might be integrated with the fire sprinkler <NUM>-<NUM> as described with respect to <FIG>, gunshot sensor unit <NUM>-<NUM> might be integrated with the thermostat <NUM>-<NUM> as described with respect to <FIG>, and gunshot sensor unit <NUM>-<NUM> might be integrated with the lighting unit <NUM>-<NUM> as described with respect to <FIG>. The gunshot sensor units <NUM> detect the gunshots by detecting acoustic anomalies indicative of the gunshot via the anomaly detection microphones <NUM>, for example, generating an acoustic signal based on sound waves and searching the acoustic signal from the anomaly detection microphone <NUM> for a peak amplitude level large enough to be identified as a gunshot. Reflectors <NUM>, either of the distributed devices <NUM>, the gunshot sensor units <NUM>, or hybrid gunshot sensor units, might collect and focus the sound waves onto the anomaly detection microphone <NUM>.

In step <NUM>, the gunshot sensor units <NUM> generate event data including audio data depicting the gunshots. For example, the gunshot sensor units <NUM> might record timestamps for the detected shots and generate the audio data based on the sound waves collected and focused onto the audio capture microphone <NUM>. The gunshot sensor units <NUM> alert the gunshot detection control panel <NUM> that gunshots were detected and send the event data to the control panel <NUM> in step <NUM>.

In step <NUM>, the control panel <NUM> performs a de-confliction process and determines which gunshot sensor unit <NUM> was closest to the source of the acoustic anomaly based on the received event data. This process involves determining which event data received from the gunshot sensor units <NUM> pertain to the same acoustic anomalies and then determining which of the gunshot sensor units <NUM> detected each of the acoustic anomalies first (e.g. based on the metadata indicating the timing information for the gunshots).

In step <NUM>, the control panel <NUM> sends instructions to the gunshot sensor unit <NUM>-<NUM> that was determined to be closest to the gunshots to send its full event data, including a full captured audio data sample depicting the gunshots and any ambient sound before and/or after the gunshots. In response, the gunshot sensor unit <NUM>-<NUM> sends the full event data including the full audio data sample to the control panel <NUM> in step <NUM>.

In step <NUM>, the control panel <NUM> alerts the operator <NUM> of the gunshots and provides audio playback of the audio data depicting the gunshots via the speakers <NUM>. The control panel <NUM> might also take other responsive actions such as storing the event data in a database and/or nonvolatile memory of the control panel <NUM>.

Claim 1:
A system for detecting gunshots, the system comprising:
gunshot sensor units (<NUM>) for detecting gunshots, the gunshot sensor units (<NUM>) comprising one or more microphones (<NUM>, <NUM>) for detecting acoustic anomalies; and
reflectors (<NUM>) for collecting and focusing sound waves onto the one or more microphones (<NUM>, <NUM>), wherein the reflectors (<NUM>) are arranged to direct light emitted by lighting units (<NUM>-<NUM>) for illuminating areas of a premises where the gunshot sensor units (<NUM>) are located,
wherein the gunshot sensor units (<NUM>) further comprise attachment mechanisms (<NUM>) for securing the gunshot sensor units (<NUM>) to the lighting units (<NUM>-<NUM>) in positions enabling the reflectors (<NUM>) to collect and focus the sound waves onto the one or more microphones (<NUM>, <NUM>), wherein the lighting units (<NUM>-<NUM>) comprise the reflectors (<NUM>).