Patent Description:
There exist several situations in which a worker must enter a confined space in order to perform some work. One example of such a work situation is in the aircraft industry, where workers must climb inside the fuel tanks located in the wings of an aircraft in order to clean and seal the inside of the fuel tanks before they are filled with fuel. Generally, the solvents which are used in cleaning these fuel tanks give off fumes which are toxic in varying degrees.

Access by manufacturing or maintenance personnel to confined spaces - and in particular hazardous confined spaces - is often accompanied by particularly exacting safety precautions. Some solutions utilize a trained attendant to maintain communication with a worker in a confined space. These solutions require that an extra person be placed on the job and often result in a sharp increase in costs and inefficient use of personnel. Other solutions utilize electronic communications equipment to monitor a worker's status in a confined space. Many of these other solutions, however, place responsibility on the worker to operate the equipment when entering or exiting the confined space.

Therefore it would be desirable to have a system and method that takes into account at least some of the issues discussed above, as well as other possible issues.

Document <CIT>, in accordance with its abstract, discloses techniques of range free proximity determination. A mobile device can determine an entry into or exit from a proximity fence upon determining that the mobile device is sufficiently close to a signal source. The proximity fence can be a virtual fence defined by the signal source and associated with a service. The mobile device can detect signals from multiple signal sources. The mobile device can determine that, among the signal sources, one or more signal sources are located closest to the mobile device based on a ranking of the signal sources using signal strength. The mobile device can determine a probability indicating a confident level of the ranking. The mobile device can determine that the mobile device entered or exited a proximity fence associated with a highest ranked signal source satisfying a confidence threshold.

The present disclosure describes a system for tracking entry to and exit from a confined space having the features disclosed at claim <NUM>. The dependent claims outline advantageous forms of embodiment of the system. Furthermore, the present disclosure describes a method of tracking entry to and exit from a confined space including the steps described at claim <NUM>. Dependent claims <NUM>-<NUM> outline advantageous ways of carrying out the method.

The present disclosure is directed to monitoring access to a confined space using measures of received signal strength or quality to and from a mobile device to monitor entry to and exit from the confined space. Some example implementations capture and analyze radio performance to and from a mobile device while the mobile device is outside a confined space, and as the mobile device enters the confined space. This radio performance may be captured and analyzed for as long as the mobile device remains in the confined space, and as the mobile device exits the confined space area.

Example implementations recognize that received signal strength to and from a mobile device may be highly attenuated, and quality degraded, as the mobile device enters a confined space. In the case of confined spaces within an aircraft, the amount of attenuation and quality degradation may vary by location within the aircraft, and the locations from which radio signals are transmitted to the mobile device, and to which radio signals are transmitted from the mobile device, in relation to the confined space. Radio signal performance data variances greater than threshold amounts as experienced in past evaluations may be used to determine that the mobile device and worker carrying the mobile device has entered or exited a confined space.

These and other features, aspects, and advantages of the present disclosure will be apparent from a reading of the following detailed description together with the accompanying figures, which are briefly described below.

Having thus described example implementations of the disclosure in general terms, reference will now be made to the accompanying figures, which are not necessarily drawn to scale, and wherein:.

Example implementations of the present disclosure relate generally to monitoring access to a confined space and, in particular, to monitoring entry to and exit from a confined space using measures of received signal strength or quality to and from a mobile device. As described herein, a "confined space" is any space within a structure (e.g., aircraft or aircraft part) that is large enough and so configured so that a human worker can bodily enter and perform work, has limited or restricted means of entry or exit, and is not designed for continuous human occupancy. A hazardous confined space is a confined space that contains or has potential to contain a hazardous atmosphere, has an internal shape that could cause entrapment or asphyxiation, or that contains any other recognized safety or health hazard. Examples of suitable confined spaces within an aircraft or aircraft part include fuel tanks in the wing or tail section. These confined spaces are locations on an aircraft that are not designed for occupancy but that are accessible for aircraft assembly, inspection, maintenance or other purposes. It should be understood, however, that example implementations are equally applicable to any of a number of different confined spaces in any of a number of different structures.

<FIG>, <FIG> and <FIG> illustrate a system <NUM> for tracking entry to and exit from a confined space <NUM>, according to the present disclosure. The system includes one or more of each of a number of different components including, as shown, a portable radio beacon <NUM>, a mobile device <NUM> and a base station <NUM>. The portable radio beacon is generally a hardware transmitter configured to broadcast or otherwise transmit its identifier - referred to as a portable radio beacon identifier. The mobile device is generally a computing device small enough to be carried by or fixed to a worker. Examples of suitable mobile devices include portable computers (e.g., laptop computer, tablet computer), mobile phones (e.g., cell phone, smartphone), wearable computers (e.g., smartwatch), and the like. The base station is generally a transceiver connecting devices to one another and/or to a wider area.

According to the present disclosure, the portable radio beacon <NUM> is placed proximate to but outside the confined space <NUM>, and configured to transmit a first radio signal <NUM> with its portable radio beacon identifier that is associated with the confined space. The mobile device <NUM> is configured to receive the first radio signal, measure a first real-time value of a first measure of received signal strength or quality from the portable radio beacon, and transmit a second radio signal <NUM> with the portable radio beacon identifier and the first real-time value. Examples of a suitable first measure of received signal strength or quality includes one or more of received signal strength indicator (RSSI), bit error rate (BER) or signal-to-noise ratio (SNR).

The portable radio beacon <NUM> is configured to transmit the first radio signal <NUM> according to a first radio access technology, and the mobile device <NUM> is configured to transmit the second radio signal <NUM> according to a second radio access technology that is different from the first radio access technology. In other examples, the portable radio beacon and mobile device are configured to transmit respectively the first radio signal and the second radio signal according to a common radio access technology. Examples of suitable radio access technologies include 3GPP radio access technologies including GSM, UMTS, LTE, <NUM> NR and the like, wireless local area network (WLAN) technologies (e.g., IEEE <NUM>. xx, e.g., <NUM>. 11a, <NUM>. 11b, <NUM>, <NUM>. 11n), IEEE <NUM>, IEEE <NUM>, Bluetooth®, Bluetooth Low Energy (BLE), and the like.

The base station <NUM> is configured to receive the second radio signal <NUM>, and measure a second real-time value of a second measure of received signal strength or quality from the mobile device <NUM>. This second measure of received signal strength or quality is the same as or different from the first measure of received signal strength or quality. In this regard, as before, examples of a suitable second measure includes RSSI, BER or SNR.

Additionally, or alternatively, the base station <NUM> may be configured to transmit a radio signal with a base station identifier. The mobile device <NUM> is configured to receive the radio signal, and measure a real-time value of a measure of received signal strength or quality (e.g., RSSI, BER, SNR) from the base station. The second radio signal <NUM>, then, further includes the base station identifier and the real-time value. This measure of received signal strength or quality, and real-time value, may take the place of the above-described second measure and second real-time value, or may be an additional second measure and second real-time value, as between the mobile device and base station.

The base station <NUM> is configured to transmit data including the portable radio beacon identifier (and possibly the base station identifier), and real-time values including the first real-time value and the second real-time value(s). In this regard, the base station is configured to transmit the data to cause a computer <NUM> in receipt of the data to determine proximity of the mobile device <NUM> to the confined space <NUM> from the portable radio beacon identifier, and determine whether the mobile device is outside or inside the confined space from the real-time values. The system <NUM> further includes the computer configured to determine the proximity of the mobile device to the confined space from the portable radio beacon identifier that is associated with the confined space, and determine whether the mobile device is outside or inside the confined space from the real-time values.

As indicated above, example implementations of the present disclosure recognize that received signal strength to and from a mobile device may be highly attenuated, and quality degraded, as the mobile device enters a confined space. Variances of the real-time values greater than threshold amounts as experienced in past evaluations may be used to determine that the mobile device <NUM> has entered or exited a confined space. In some examples, then, the real-time values are within a first range of corresponding values that indicate the mobile device <NUM> is outside the confined space <NUM>, or a second range of corresponding values less than the first range of corresponding values and that indicate the mobile device is inside the confined space.

The real-time values are described by a real-time value vector. The base station <NUM> is configured to transmit the data to cause the computer <NUM> in receipt of the data to perform a similarity match between the real-time value vector and a database <NUM> of feature vectors that describe corresponding values of the mobile device <NUM> outside and inside the confined space <NUM>. The computer is thereby caused to determine whether the mobile device is outside or inside the confined space from the real-time values. As shown in <FIG>, the database is coupled to the computer. In other examples, as shown in <FIG> and <FIG>, the database is coupled to and accessible from the core network <NUM>. In yet other examples, the database is coupled to and accessible from the external network <NUM>.

In some examples, the mobile device <NUM> has a mobile device identifier that is associated with a worker. In some of these examples, the mobile device is configured to transmit the second radio signal <NUM> further with the mobile device identifier. The base station <NUM>, then, is configured to transmit the data further including the mobile device identifier, causing the computer <NUM> in receipt of the data to further identify the worker from the mobile device identifier.

As shown in <FIG>, the computer <NUM> is coupled to the base station <NUM>, and the base station is configured to transmit the data directly to the computer. In <FIG>, the base station is of a radio access network (RAN) <NUM> coupled to a core network <NUM> to which the computer is coupled. In these examples, the base station is configured to transmit the data addressed to the computer on the core network. In yet other examples, as shown in <FIG>, the core network is coupled to an external network <NUM> to which the computer is coupled. In these examples, the base station is configured to transmit the data addressed to the computer on the external network coupled to the core network.

In some examples, the system <NUM> further includes fixed radio beacons <NUM> at fixed locations in or around an area <NUM> including a structure <NUM> that defines the confined space <NUM>. In some of these examples, the fixed radio beacons are configured to transmit radio signals <NUM> with respective fixed radio beacon identifiers. The mobile device <NUM> is further configured to receive the radio signals, and measure third real-time values of a third measure of received signal strength or quality (e.g., RSSI, BER, SNR) from the fixed radio beacons. Here, the third measure of received signal strength or quality is the same as or different from either or both the first measure of received signal strength or quality, or the second measure of received signal strength or quality.

Also in some of these examples, the mobile device <NUM> is configured to transmit the second radio signal <NUM> further with the respective fixed radio beacon identifiers and the third real-time values. The base station <NUM> is configured to transmit the data further including the respective fixed radio beacon identifiers and the third real-time values, causing the computer <NUM> in receipt of the data to further determine a location of the mobile device in the area <NUM> from the respective fixed radio beacon identifiers and the third values.

The location of the mobile device <NUM> in the area <NUM> may be determined from the respective fixed radio beacon identifiers and the third values in any of a number of different manners. In some examples, the location may be determined using a localization technique based on received signal strength or quality (e.g., RSSI, BER, SNR) that makes use of the radio signals <NUM> to estimate the distances between the fixed radio beacons <NUM> and the mobile device. One example of a suitable technique is described in <NPL>).

In some examples, satellite-based navigation may be used to locate the mobile device <NUM>, which may be particularly useful when the structure <NUM> that defines the confined space <NUM> is outdoors. <FIG> illustrates part of the system <NUM> in some example implementations in which location of the mobile device is determined according to satellite-based navigation. In some examples, as shown, the mobile device is further configured to receive radio signals <NUM> at the mobile device from satellites <NUM> of a satellite navigation system <NUM> (e.g., GPS, GLONASS). In these examples, the mobile device is configured to determine a geographic location of the mobile device from the radio signals, and the second radio signal <NUM> and the data are transmitted further with and including the geographic location of the mobile device. In these examples, the system may be as in <FIG>, <FIG> or <FIG>, with or without the fixed radio beacons <NUM>.

<FIG> illustrates the mobile device <NUM> according to some examples in which the mobile device further includes a sensor <NUM> configured to measure and produce measurements of a condition of an environment of the confined space or a worker equipped with the mobile device. This may include measuremens of an amount of a chemical that comes into contact with the sensor. In other examples, the sensor may be a sensor to measure a condition of the environment and/or worker that may provide some situational awareness, or a sensor to measure condition of the worker, such as a health condition like heart rate, oxygen saturation or the like. In some of these examples, the mobile device is configured to transmit the second radio signal <NUM> further with the measurements. Also in these examples, the base station <NUM> is configured to transmit the data further including the measurements, causing the computer <NUM> in receipt of the data to further determine or monitor the condition of the environment or the worker from the measurements.

In <FIG>, <FIG> and <FIG>, the system <NUM> for tracking entry to and exit from a confined space <NUM> is shown as including a portable radio beacon <NUM> and a mobile device <NUM>, where a worker may be equipped with the mobile device, and a structure <NUM> in an area <NUM> defines the confined space. It should be understood, however, that the system may be equally useful for tracking entry to and exit from a plurality of confined spaces defined by the same stucture and/or a plurality of structures in the area. In these examples, the system may include a plurality of portable radio beacons and a plurality of mobile devices for a plurality of workers. Even further, in some examples, the system may include a plurality of base stations <NUM> with respective base station identifiers.

In some examples in which the system <NUM> is configured to track entry to and exit from a plurality of confined spaces <NUM>, the plurality of portable radio beacons <NUM> have portable radio beacon identifiers associated with respective ones of the plurality of confined spaces <NUM>. The plurality of workers are equipped with respective ones of the plurality of mobile devices <NUM>, and associated with the mobile device identifiers. The system operates in a manner similar to that described above, and the computer <NUM> distinguishes the confined spaces by the portable radio beacon identifiers associated with respective ones of the confined spaces. Likewise, the computer distinguishes workers by the mobile device identifiers of the mobile devices with which the workers are equipped (and that are associated with the workers). Additionally or alternatively, the system may track a mobile device moving between confined spaces distinguishable by portable radio beacon identifiers of portable radio beacons placed proximate to but outside the confined spaces. Even further, the system may track a mobile device moving between coverage of base stations <NUM> distinguishable by base station identifiers placed around the area <NUM>.

<FIG>, <FIG> are flowcharts illustrating various steps in a method of tracking entry to and exit from a confined space <NUM>. As shown at block <NUM> in <FIG>, the method includes equipping a worker with the mobile device <NUM> for use in an area <NUM> including a structure <NUM> that defines the confined space. In some examples, the mobile device has a mobile device identifier that is associated with the worker.

The method <NUM> includes transmitting a first radio signal <NUM> with a portable radio beacon identifier that is associated with the confined space <NUM>. The first radio signal is transmitted from a portable radio beacon <NUM> placed proximate to but outside the confined space, and received at a mobile device <NUM>, as shown at block <NUM>. The method includes measuring a first real-time value of a first measure of received signal strength or quality from the portable radio beacon at the mobile device, and transmitting a second radio signal <NUM> with the portable radio beacon identifier and the first real-time value from the mobile device, and receiving the second radio signal at a base station <NUM>, as shown at blocks <NUM> and <NUM>. In some examples in which the mobile device has a mobile device identifier that is associated with the worker, the the second radio signal is transmitted further with the mobile device identifier.

As shown at block <NUM>, the method <NUM> includes measuring a second real-time value of a second measure of received signal strength or quality from the mobile device <NUM> at the base station <NUM>. This second measure of received signal strength or quality is the same as or different from the first measure of received signal strength or quality. The method includes transmitting data including the portable radio beacon identifier, and real-time values including the first real-time value and the second real-time value, from the base station, and receiving the data at a computer <NUM>, as shown at block <NUM>. And in some examples including the second radio signal <NUM> with the mobile device identifier, the data is transmitted further including the mobile device identifier.

In some examples, the method <NUM> includes, at the computer <NUM>, identifying the worker from the mobile device identifier, as shown at block <NUM>. The method includes, at the computer, determining proximity of the mobile device <NUM> to the confined space <NUM> from the portable radio beacon identifier, and determining whether the mobile device is outside or inside the confined space from the real-time values, as shown at blocks <NUM> and <NUM>. In some examples, the method includes measuring the real-time values including the first real-time value and the second real-time value, and determining whether the mobile device is outside or inside the confined space from the real-time values, repeatedly while the worker is within the area <NUM>. Here, changes in the real-time values while the worker is within the area may indicate movement of the mobile device entering or exiting the confined space.

In some examples, the method <NUM> further includes transmitting radio signals <NUM> with respective fixed radio beacon identifiers from fixed radio beacons <NUM> at fixed locations in or around an area <NUM> including a structure <NUM> that defines the confined space <NUM>, and receiving the radio signals at the mobile device <NUM>, as shown at block <NUM> in <FIG>. In some of these examples, the method also includes measuring third real-time values of a third measure of received signal strength or quality from the fixed radio beacons at the mobile device, as shown at block <NUM>. The third measure of received signal strength or quality is the same as or different from either or both the first measure of received signal strength or quality, or the second measure of received signal strength or quality. The second radio signal <NUM> and the data are transmitted further with and including the respective fixed radio beacon identifiers and the third real-time values. And at the computer <NUM>, the method includes determining a location of the mobile device in the area from the respective fixed radio beacon identifiers and the third real-time values, as shown at block <NUM>.

The method <NUM> further includes receiving radio signals <NUM> at the mobile device <NUM> from satellites <NUM> of a satellite navigation system <NUM>, and determining a geographic location of the mobile device from the radio signals, as shown at blocks <NUM> and <NUM> in <FIG>. The second radio signal <NUM> and the data are transmitted further with and including the geographic location of the mobile device.

The method <NUM> further includes measuring and producing measurements of a condition of an environment of the confined space or a worker equipped with the mobile device, using a sensor <NUM> on the mobile device <NUM>, and determining or monitoring the condition of the environment or the worker from the measurements, as shown at blocks <NUM> and <NUM> in <FIG>. Similar to before, the second radio signal <NUM> and the data are transmitted further with and including the measurements; and at the computer <NUM>.

According to example implementations of the present disclosure, the system <NUM> and its components, including in various example implementations, the portable radio beacon <NUM>, mobile device <NUM>, base station <NUM>, computer <NUM>, database <NUM>, fixed and radio beacons <NUM>, may be implemented or otherwise executed by various means. These means may include hardware, alone or under direction of one or more computer programs from a computer-readable storage medium. In some examples, one or more apparatuses may be configured to function as or otherwise implement one or more of the components shown and described herein.

<FIG> illustrates an apparatus <NUM> according to some example implementations of the present disclosure. Generally, an apparatus of example implementations of the present disclosure may comprise, include or be embodied in one or more fixed, portable or mobile electronic devices. The apparatus may include one or more of each of a number of components such as, for example, processing circuitry <NUM> (e.g., processor unit) connected to a memory <NUM> (e.g., storage device).

The processing circuitry <NUM> may be composed of one or more processors alone or in combination with one or more memories. The processing circuitry is generally any piece of computer hardware that is capable of processing information such as, for example, data, computer programs and/or other suitable electronic information. The processing circuitry is composed of a collection of electronic circuits some of which may be packaged as an integrated circuit or multiple interconnected integrated circuits (an integrated circuit at times more commonly referred to as a "chip"). The processing circuitry may be configured to execute computer programs, which may be stored onboard the processing circuitry or otherwise stored in the memory <NUM> (of the same or another apparatus).

The processing circuitry <NUM> may be a number of processors, a multi-core processor or some other type of processor, depending on the particular implementation. Further, the processing circuitry may be implemented using a number of heterogeneous processor systems in which a main processor is present with one or more secondary processors on a single chip. As another illustrative example, the processing circuitry may be a symmetric multi-processor system containing multiple processors of the same type. In yet another example, the processing circuitry may be embodied as or otherwise include one or more ASICs, FPGAs or the like. Thus, although the processing circuitry may be capable of executing a computer program to perform one or more functions, the processing circuitry of various examples may be capable of performing one or more functions without the aid of a computer program. In either instance, the processing circuitry may be appropriately programmed to perform functions or operations according to example implementations of the present disclosure.

The memory <NUM> is generally any piece of computer hardware that is capable of storing information such as, for example, data, computer programs (e.g., computer-readable program code <NUM>) and/or other suitable information either on a temporary basis and/or a permanent basis. The memory may include volatile and/or non-volatile memory, and may be fixed or removable. Examples of suitable memory include random access memory (RAM), read-only memory (ROM), a hard drive, a flash memory, a thumb drive, a removable computer diskette, an optical disk, a magnetic tape or some combination of the above. Optical disks may include compact disk - read only memory (CD-ROM), compact disk - read/write (CD-R/W), DVD or the like. In various instances, the memory may be referred to as a computer-readable storage medium. The computer-readable storage medium is a non-transitory device capable of storing information, and is distinguishable from computer-readable transmission media such as electronic transitory signals capable of carrying information from one location to another. Computer-readable medium as described herein may generally refer to a computer-readable storage medium or computer-readable transmission medium.

In addition to the memory <NUM>, the processing circuitry <NUM> may also be connected to one or more interfaces for displaying, transmitting and/or receiving information. The interfaces may include communications interface(s) <NUM> (e.g., communications unit) and/or one or more user interfaces. The communications interface may be configured to transmit and/or receive information, such as to and/or from other apparatus(es), network(s) or the like. The communications interface may be configured to transmit and/or receive information by physical (wired) and/or wireless communications links. Examples of suitable communication interfaces include a network interface controller (NIC), wireless NIC (WNIC) or the like.

The user interfaces may include a display <NUM> and/or user input interface(s) <NUM> (e.g., input/output unit). The display may be configured to present or otherwise display information to a user, suitable examples of which include a liquid crystal display (LCD), light-emitting diode display (LED), plasma display panel (PDP) or the like. The user input interfaces may be wired or wireless, and may be configured to receive information from a user into the apparatus, such as for processing, storage and/or display. Suitable examples of user input interfaces include a microphone, image or video capture device, keyboard or keypad, joystick, touch-sensitive surface (separate from or integrated into a touchscreen), biometric sensor or the like. The user interfaces may further include one or more interfaces for communicating with peripherals such as printers, scanners or the like.

As indicated above, program code instructions may be stored in memory, and executed by processing circuitry that is thereby programmed, to implement functions of the systems, subsystems, tools and their respective elements described herein. As will be appreciated, any suitable program code instructions may be loaded onto a computer or other programmable apparatus from a computer-readable storage medium to produce a particular machine, such that the particular machine becomes a means for implementing the functions specified herein. These program code instructions may also be stored in a computer-readable storage medium that can direct a computer, a processing circuitry or other programmable apparatus to function in a particular manner to thereby generate a particular machine or particular article of manufacture. The instructions stored in the computer-readable storage medium may produce an article of manufacture, where the article of manufacture becomes a means for implementing functions described herein. The program code instructions may be retrieved from a computer-readable storage medium and loaded into a computer, processing circuitry or other programmable apparatus to configure the computer, processing circuitry or other programmable apparatus to execute operations to be performed on or by the computer, processing circuitry or other programmable apparatus.

Retrieval, loading and execution of the program code instructions may be performed sequentially such that one instruction is retrieved, loaded and executed at a time. In some example implementations, retrieval, loading and/or execution may be performed in parallel such that multiple instructions are retrieved, loaded, and/or executed together. Execution of the program code instructions may produce a computer-implemented process such that the instructions executed by the computer, processing circuitry or other programmable apparatus provide operations for implementing functions described herein.

Claim 1:
A system (<NUM>) for tracking entry to and exit from a confined space (<NUM>), the system comprising:
a portable radio beacon (<NUM>) placed proximate to but outside the confined space, and configured to transmit a first radio signal (<NUM>) with a portable radio beacon identifier that is associated with the confined space;
a mobile device (<NUM>) configured to receive the first radio signal (<NUM>), measure a first real-time value of a first measure of received signal strength or quality from the portable radio beacon, and transmit a second radio signal (<NUM>) with the portable radio beacon identifier and the first real-time value; and
a base station (<NUM>) configured to receive the second radio signal (<NUM>), measure a second real-time value of a second measure of received signal strength or quality from the mobile device (<NUM>), the second measure of received signal strength or quality being the same as or different from the first measure of received signal strength or quality, and transmit data including the portable radio beacon identifier, and real-time values including the first real-time value and the second real-time value, the base station (<NUM>) being configured to transmit the data to cause a computer (<NUM>) in receipt of the data to determine, from the portable radio beacon identifier, proximity of the mobile device (<NUM>) to the confined space, and wherein the real-time values are described by a real-time value vector, and the base station (<NUM>) is configured to transmit the data to cause the computer (<NUM>) in receipt of the data to perform a similarity match between the real-time value vector and a database (<NUM>) of feature vectors that describe corresponding values of the mobile device (<NUM>) outside and inside the confined space (<NUM>), the computer thereby caused to determine whether the mobile device (<NUM>) is outside or inside the confined space from the real-time values.