Abstract:
A method for collecting and sensing a column of air in near real-time to detect one or more agents dispersed within the air column is described. The method includes passing the column of air through a port in a parafoil, the parafoil configured with a flow-through sensor suite located in the port and operable such that the column of air passes through the sensor suite, operating the sensor suite to test the column of air for the one or more agents, and receiving test results from the sensor suite.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to agent and contaminant detection and identification, and more specifically, to an integrated parafoil threat agent sensor system and the methods associated therewith. 
         [0002]    While detection and identification of agents and contaminants in ground-based situations is a fairly mature science, detection and identification of airborne agents and contaminants is not as mature. Particularly, there have been no systems promulgated that solve the problem of collecting and detection of agents and contaminants in a column of air, in real time. More particularly, some of these agents/contaminants may have the potential to contain threatening or contaminating materials such as aerosol or particulate chemicals or biological agents or other contaminants. The detection and identification problem is especially challenging when persistent measurements across a large column of air are attempted. This is in part due to the transient and vaporous nature of aerosols and particulates in free space. Sensors to detect such agents have response time constraints, sensitivity to various interferences and concentration threshold sensitivities. 
         [0003]    Previous efforts to sense, identify, and discriminate on a standoff basis have had a limitation in their overall effectiveness in one or both of size and range, false alarms, specificity, sensitivity and persistence. Such problems limit the effectiveness of free space discriminating and sensing of threat agents across the spectrum of their characteristic behaviors in free space. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0004]    In one aspect, a method for collecting and sensing a column of air in near real-time to detect one or more agents dispersed within the air column is provided. The method includes passing the column of air through a port in a parafoil, the parafoil configured with a flow-through sensor suite located in the port and operable such that the column of air passes through the sensor suite, operating the sensor suite to test the column of air for the one or more agents, and receiving test results from the sensor suite. 
         [0005]    In another aspect, a system for airborne detection of one or more agents dispersed within the atmosphere is provided. The system includes a parafoil operable to pass through a portion of the atmosphere, a sensor suite attached to the parafoil that is operable to determine if one or more agents are in the atmosphere portion, and a processing device configured to receive data from the sensor suite and utilize the received data to discriminate from multiple received signatures to establish the presence or absence of at least one specific agent type. 
         [0006]    The features, functions, and advantages that have been discussed can be achieved independently in various embodiments of the present invention or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an illustration of a passive parafoil having a flow through center port, a sensor head mounted in the center port. 
           [0008]      FIG. 2  is a schematic diagram of one embodiment of a sensor head 
           [0009]      FIG. 3  is a detailed schematic diagram of a portion of a sensor head. 
           [0010]      FIG. 4A  is an exploded view of the components for one embodiment of a sensor head. 
           [0011]      FIG. 4B  is an assembled view of the sensor head of  FIG. 4A . 
           [0012]      FIG. 5  is an illustration of a sensing device, suspended from a parafoil, configured to characterize airborne contaminants. 
           [0013]      FIG. 6  is an illustration of another sensing device, suspended from a parafoil, configured to characterize airborne contaminants, and illustrating distribution of agent responsive sensors which subsequently flow through the space in proximity to the sensors that read the sensors in addition to the agents. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    The embodiments described herein can be generally described as one or more sensors embedded in an expandable funnel whereby one or more sensing devices per sensor are deployed. Specifically, and referring now to  FIG. 1 , which illustrates a deployed parachute, or parafoil  10 , which operates as an expandable funnel during deployment and subsequent utilization. While illustrated as a parachute, parafoil  10  in other embodiments, is configured as one of a square chute, a funnel shaped expandable collector, or any other device capable of funneling air to, and through, a sensing unit such as sensor head  12 . 
         [0015]    Parafoil  10  includes, at its center, a sensor head  12  which receives a directed airflow based on the operation of the parafoil  10 . Communicatively coupled to sensor head  12 , and utilized as the load for parafoil  10 , is a processing module  20  that includes, at least in the embodiment illustrated, a communications module  22 , a processor module  24 , and a battery  26 . As illustrated, the processing module  20  is suspended from lines  30  that extend from a perimeter of parafoil  10  to a harness  32  that connects the lines  30  to the processing module  20 . 
         [0016]      FIG. 2  is a schematic diagram of one embodiment of a sensor head  12 . In the illustrated embodiment, sensor head  12  includes an optional fan  40  for pulling an airflow through the sensor head  12 . Sensor head  12  further includes sensor targets  42 , which in alternative embodiments includes a plurality of sensing elements and/or sensing taggants (not shown in  FIG. 2 ) coated or embedded thereon. Liquid-based sensors may be hosted on porous substrates or otherwise configured for interaction with an air flow  43  through the sensor head  12 . Sensors may be mounted on vanes (not shown in  FIG. 2 ) within the sensor head  12  or may even be mounted on the blades or mounting structure associated with the fan  40 . Signatures of the integrated suite of sensors are used to discriminate signals using a variety of sensor modalities, providing the capabilities described herein. The air flow path  43 , in one embodiment is directional, as illustrated by the arrow in  FIG. 2 . In other embodiments, the airflow path  43  incorporates an open air configuration, with illumination and sensing elements disbursed within the sensor head  12 . 
         [0017]    As further described below, to determine a composition of particles passing along the air flow path  43 , the sensor head  12  may incorporate one or more of an optical illuminator  50 , an infrared illuminator  52 , a video or other spectrally appropriate sensor  54 , an ultraviolet illuminator  56 , or other sensors  58  as appropriate. As particles pass through the air flow path  43 , they are illuminated by one or more of the various illuminators described above and the sensors are utilized to determine particulate composition based on the reaction of the particles to illumination. 
         [0018]      FIG. 3  is a detailed schematic diagram of one portion of the sensor head  12 , further illustrating illumination and spectral sensing. In the illustrated embodiment, sensor head  12  includes a flow-through threat agent and/or contaminant sensor suite embedded in or on a flow collector. The sensor head  12  includes an air inlet  70  where an airflow passes through a recently opened membrane closure  72 . The airflow exits through a second recently opened membrane closure  73 . Throughout the length of the sensor head  12  there are turbulence generating elements to direct flow onto sensing surfaces and create enhanced interactions with said surfaces  74 . Adjacent each of the vanes  74  are a sensor appliqué  76  and a return lens  78 . Other embodiments include sensors that are not optical, but electrical in their external interface. One or more lasers  80  and modulators  82  are directed at the sensor where the reading is reflected to the return lens  78  via fiber optic lines  86 . The multiple lasers  80  and modulators  82  operate at different frequencies for different modes of sensing thereby providing detection of a number of different substances encountered in the air flow path through sensor head  12 . The network of fiber optic lines  86  passes the returned laser light that has been transmitted into the air flow path of sensor head  12  and subsequently reflected by sensors appliqués interacting with agents and/or contaminants. 
         [0019]    The path of the fiber optics  86  includes one or more detectors  90  and optionally one or more spectral filters  92 . Through the operation of filters  92  and detectors  90 , sensed reflections that impinge lenses  78  can be analyzed to determine a makeup-up or configuration of any of a number of threatening substances flowing through the sensor head  12 . 
         [0020]      FIGS. 4A and 4B  are illustrations of the various components of one embodiment for a sensor head  12 , where  FIG. 4A  is an exploded view and  FIG. 4B  is an assembled view. The illustrated embodiment includes a sensor housing  100 , a movable inner housing  102  into which multiple multi-sensor cells  104  are inserted. During operation, a progressive opener  106  works in conjunction with a cutter  110  that operates with the progressive opener  106  and the inner housing  102  to expose one multi-sensor cell  104  to the above described airflow, through a flow through cell  112 , for a prescribed period of time. By serially exposing the sensor cells, the sensor head  12  is operational over a longer duration of time. The sensor cells  104  each may include a flow-through membrane  120 , that in one embodiment is twisted to enhance flow interaction. The progressive opener  106  and cutter  100  combination is attached to a moving end plate  122 , enabling sensing over a period of time. In a specific embodiment, a motor is included within the sensor head  12  to rotate the end plates  122 , thereby exposing each sensor cell  104  to the air stream at a prescribed time during the deployment. Other embodiments are envisioned that might include a needle cutter to open a stretched rubber membrane at the proper time. 
         [0021]    The characteristics of a parafoil  10  allow for the concentration and mixing of a large volume of air, that is condensed into a column to pass into and through the sensor head  12  for real-time or near real-time analysis. Such a process is herein sometimes referred to as adaptive air column sampling. 
         [0022]      FIG. 5  is an illustration of an alternative embodiment for a sensing device  150  configured to characterize airborne contaminants. Specifically, a delivery platform  152  is launched or dropped, for example from a aircraft or other air vehicle. At an appropriate time, a parachute  154  is deployed when a canister  156  of the delivery platform  152  opens. Rather than a parafoil with a flow through center port as in the embodiments described above, a payload  160  is attached to the parachute  154 . The payload  160  includes, in the illustrated embodiment, a sensor cartridge  162 , a network interface  164 , and a bank  166  of illuminators and sensors, for example, infrared LEDs and infrared sensors. 
         [0023]      FIG. 6  illustrates another embodiment of a payload  180 . In addition to sensor cartridge  182 , a network interface  184 , and a bank  186  of infrared LEDs and infrared sensors, payload  180  includes a bank  188  of ultraviolet LEDs and ultraviolet sensors.  FIG. 4  also illustrates dispersion of dispersed nano-sensors  190  released from a nano-sensor cartridge  182 . In one embodiment, these sensors  190  are spectrally interrogated materials that are treated, or coated, to react when exposed to one or more airborne agents or contaminants. 
         [0024]    In other embodiments, such as within sensor head  12 , sensors can be attached to a surface using adhesives, applied as appliqués within sensor head  12 , or painted on in an appropriately configured paint that causes the surface of the material to be exposed as required for the application. In these embodiments, the sensors can be deployed on the surfaces of the parachute or other funneling device or integrated into the materials from which the parachutes are fabricated. In these configurations, the sensors may be exposed to the agents over a broader surface, and therefore allows a greater sensitivity through integration of a broader sensed surface area. 
         [0025]    All of the above described embodiments include sensor target areas, which spatially separate the sensing modalities, and in certain embodiments, spectral separation is leveraged to achieve discrimination of threat agents of various types. This spatial separation enables concurrent sensing and electronic signal processing to provide faster response, greater sensitivity, or higher resistance to false alarm. Proper configuration can achieve all of these goals. 
         [0026]    Various sensor types may be utilized. In one embodiment, the target sensors are coated with optically interrogated chemical and/or biological sensor appliqués. Optical illuminators or electronic excitation are utilized in conjunction with optical sensors, for example, one or more of a photodiode, video camera or other appropriate optical/RF sensor, or electronic signal converter to receive the optical, spectral or electrical data which is then processed to indicate the presence of agents and their specific types. 
         [0027]    Additionally, the sensing devices may be deployed in a number of ways. For example, the nano-sensors can be distributed (released) into the atmosphere using one delivery platform (the devices of  FIGS. 3 and 4 ), ahead of a second platform such as the device of  FIGS. 1 and 2 . Once deployed, these nano-sensors pass, for example, through the air stream associated with sensing head  12 . The nano-sensor elements are interrogated as they pass each individual section within the sensor head  12 . 
         [0028]    As those skilled in the art will understand, there are a variety of implementations of the above described airborne sensor and/or sensors, and it easily understandable that these can be mounted in many ways and in many configurations: 
         [0029]    In addition to the above described passive parafoil  10  with flow through center port and sensor head  12 , other embodiments have been contemplated which are described above. Specifically, sensors embedded or coated onto a passive parafoil, nano-sensors that are distributed into an air column and locally illuminatedor energized for interrogation as it passes into the funnel effect associated with, for example, a flow through port, and flow through chambers acting as ducts or vents to funnel air for concentrated sample management. 
         [0030]    The variously described sensor systems incorporate one or more high specificity sensing modalities to characterize the contaminants in a column of air. The sensors utilized afford an adaptive nature that is realized due to the parafoil inflation or extension process. In certain embodiments, to concentrate and assure a broad area is swept in the direction of travel the extension of the parafoil can be fixed or variable in geometry (i.e., the parafoil may only be partially opened if speed dictates lesser area to induce equivalent flows). Passive or active platforms are practical to implement the system, and deployment constraints are based on the characteristic speed and air column size through which the sensors pass. Combinations of mixing elements, reed vanes, and driven fans are utilized in certain applications. 
         [0031]    Still other applications incorporate a powered parafoil that is configured with a multiple cell sensor mounted in the air flow. 
         [0032]    While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.