Abstract:
The invention generally relates to an airborne deployed passive radio frequency identification system and a method to identify an analyte and then to communicate a result of the analyte identification to a receiving station for an analysis and generation of a set of recommended actions. The invention will enhance the situational awareness and preparedness of forward deployed combat troops or security forces by assessing the presence of benign substances or hazardous substances as they advance and enter an area.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     The invention described herein may be manufactured and used by or for the government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention generally relates to an airborne deployed passive radio frequency identification system and a method to identify an analyte and then to communicate a result of the analyte identification to a receiving station for an analysis and generation of a set of recommended actions. The invention will enhance the situational awareness and preparedness of forward deployed combat troops or security forces by assessing the presence of hazards as they advance and enter a hazardous zone. 
     2. Description of Related Art 
     Historically, exploitation of passive radio frequency identification (RFID) tag technology to track items of manufacture is known. A typical commercial RFID system is composed of an electronic device capable of rendering a response containing encoded information when interrogated. The encoded information is transmitted via a wireless link to the interrogating unit and processed either by a software algorithm executing on a computer or viewed by a user on a display. 
     An advanced type of RFID system renders upon interrogation a particular encoded piece of information. The particular information rendered by advanced RFID systems is dynamically ascertained as a result of exposing a sensing element to a substance that the sensing element is designed to detect. Sensing and then rendering the presence or absence of a specific substance is accomplished by integrating an RFID electronic device with a sensing element. 
     What is lacking in the area of RFID systems is an RFID system deployable ahead of an advancing military unit or security force that automatically identifies a hazardous analyte, upon interrogation autonomously transmits to a receiving station the identity of the hazardous analyte, locates with GPS precision a position of the hazardous analyte, then develops a set of recommended precautions specific to the hazardous analyte and then conveys the set of recommended precautions to a user. 
     Information relevant to attempts to address these problems can be found in U.S. Pat. No. 7,040,139 which is titled a Sensor Arrangement. However, this reference suffers from one or more of the following disadvantages: it is commercial in nature, it does not lend itself to be exploited in a forward deployed manner and is not described as operating outside of a container. 
     Additional information relevant to attempts to address these problems can be found in a Patent Application Publication No. 2006/60181414, titled as Radio Frequency Identification (RFID) Based Sensor Networks. However, this reference suffers from one or more of the following disadvantages: it is commercial in nature, it does not lend itself to be exploited in a forward deployed manner and it does not develop a set of recommended actions based upon the presence of a particular analyte. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an apparatus and method that satisfies the need for an RFID system which is deployable ahead of an advancing military unit or security force that automatically identifies a hazardous analyte, upon interrogation autonomously transmits to a receiving station the identity of the hazardous analyte, locates with GPS precision a position of the hazardous analyte, then develops a set of recommended precautions specific to the hazardous analyte and then conveys the set of recommended precautions to a user for the purpose of increasing the probability of mission success. The apparatus and method is a system that includes a delivery vehicle and a canister containing a plurality of RFID devices. Each one of the individual RFID devices is comprised of electronic circuitry integrated with a sensing array. A sensing array is comprised of multiple detectors, where each detector is sensitive to a single analyte or is sensitive to a different analyte. In either configuration, all of the detectors in the array are integrated with a single set of electronics. 
     An interrogator is integrated with the delivery vehicle for sending an interrogation signal to the RFID device wherein the interrogation signal also powers the RFID electronic circuitry. Once the RFID electronic circuitry is powered the RFID device transmits the status of the sensor portion of the RFID device to a receiver, which is integrated with the delivery vehicle. The interrogator then repeats the interrogation for each RFID device. The response to each interrogation is processed by an interrogation and response processor and assembled into a message that is transmitted via telemetry to a receiving station. The transmitted telemetry message is decoded by computer operated software contained within the receiving station. The computer operated software converts the contents of the transmitted telemetry message into a series of alerts and recommended measures. A user then incorporates the information conveyed in the series of alerts and recommended measures into a strategy to minimize the effect of any hazardous material. 
     Generally, the method comprises seeding a geographic area with a plurality of RFID devices for the purpose of creating a monitored area, then sweeping an interrogator over the monitored area, then interrogating the plurality of RFID devices seeding the geographic area for the purpose of ascertaining a detection result as determined by the plurality of RFID devices, then compiling the detection results reported by the RFID devices, then marking a position of the responding RFID device, then transmitting a telemetry formatted message containing the compilation of detection results with the position data to a ground receiving station and then processing the compilation results at the ground station for the purpose of presenting a set of recommendations to a user. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features described above, other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: 
         FIG. 1  is a high level functional block diagram of the preferred embodiment showing the major functions of the airborne deployed radio frequency identification system. 
         FIG. 2A  is a drawing showing an overview of deploying an RFID sensor canister and its contents. 
         FIG. 2B  is a drawing showing the different types of RFID sensors in a field of scattered sensors. 
         FIG. 3  is a drawing showing an internal and external view of an RFID sensor canister. 
         FIG. 4  is a drawing describing the power supply, electromechanical and electronic components internal to the RFID canister. 
         FIG. 5  is a flowchart describing the software processing and operational functionality that takes place onboard the UAV interrogator. 
         FIG. 6  is a drawing showing the RFID sensor system. The monitored area is overflown in a predetermined flight path by a UAV which interrogates and collects responses from the RFID sensors and communicates the collected responses to a ground receiving station. 
         FIG. 7  is a drawing describing the hardware components comprising the RFID sensor system which are integrated with the UAV. 
         FIG. 8  is a lower level software flowchart describing the software processing that takes place within the ground receiving station which culminates in a set of recommendations consistent with the hazardous analyte detected. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , shown is a high level functional block diagram  100  generally describing the major functions of an airborne passive radio frequency identification system (RFID). The passive RFID system is used to identify an analyte that is present in a forward area slated for occupation by combat or security forces. The operation of the passive RFID system begins with the deployment of a canister (step  105 ) filled with a plurality of RFID sensors set to sense an analyte. The RFID sensors are scattered throughout the area to be monitored (step  110 ) during the final stages of the canister deployment. Once the RFID sensors are scattered throughout the area to be monitored, an interrogator is deployed in a spiral pattern (step  115 ). 
     An analyte is any substance detectable by any of the scattered RFID sensors. Examples of hazardous substances are explosive agents, chemical agents, biological agents or nuclear radiation. An example of a non-hazardous substances are known chemical taggants. The RFID sensor is an electronic device having an antenna for both receiving an interrogation signal and transmitting a reply signal, a computer memory for storing programming information and data, electronic circuitry for coupling the computer memory to the antenna and an interface coupling an analyte sensor to the computer memory. One skilled in the art of RFID devices is familiar with RFID sensors of this type. One suitable example of an RFID device integrated with a sensing element can be found in United States Patent Application Publication numbered US 2005/0263790A1 having a publication date of Dec. 1, 2005 and titled GAN-BASED SENSOR NODES FOR IN SITU DETECTION OF GASES, which is herein incorporated by reference. 
     As the RFID sensor interrogation responses are collected by the interrogator the location of a responding RFID sensor is marked with a Global Positioning Satellite system coordinate (step  125 ). Software processing of the collected RFID sensor responses are performed onboard the interrogator resulting in a telemetry formatted message containing the analyte type and location (step  130 ). The telemetry formatted message is then transmitted (step  135 ) to a receiving station. Upon receipt of the telemetry formatted message (step  140 ) at the receiving station hardware and software components are used to perform signal processing to unpack the data contained in the telemetry formatted message (step  145 ). The unpacked data is then further processed resulting in a set of alerts and recommendations (step  150 ) consistent with the presence of the detected analyte. 
     Referring to  FIG. 2A , the phases of RFID sensor deployment are depicted. First, an unmanned air vehicle (UAV)  205  flies at an altitude of H 1  over an area to be monitored  210  and drops an RFID filled canister  215 . Second, a closed parachute  220  deploys to an altitude of H 2  at which point a canister battery  347  ( FIG. 3 ) provides power in the form of a battery voltage and a current flow to the canister electrical and electronics  345  ( FIG. 3 ). Third, an open parachute  220  then serves as a means to control a canister orientation and a descent rate at altitude H 3 . Canister orientation is crucial in that the RFID sensors are deployed from the end of the canister  215  facing the geographic area to be monitored  210 . At an altitude of H 3  the canister electrical and electronic components  345  ( FIG. 3 ) begin to monitor the altitude of the descending RFID filled canister  215 . Fourth, when a preset altitude of H 4  is reached an output of the canister electrical and electronic components  345  ( FIG. 3 ) trigger a deployment mechanism  340  ( FIG. 3 ) to eject and scatter the contents of the RFID canister  215  about the area to be monitored  210 . The deployment mechanism  340  ( FIG. 3 ) utilizes a force created by releasing compressed air into a compartment  310  ( FIG. 3 ) resulting in an ejection of the RFID sensors from the RFID canister  215 . The RFID sensors ( 230 ,  235 ,  240 , and  245 ) initially depart the RFID canister  215  with the force imparted by the compressed air and attain a terminal velocity wherein the terminal velocity is a function of gravity, the mass of the RFID sensor and an ambient air flow. The negligible mass of the RFID sensors ensures that an impact force with the ground does not interfere with RFID sensor ( 230 ,  235 ,  240 , and  245 ) operation. 
     Referring to  FIG. 2A , in one embodiment the UAV  205  altitude H 1  is in the range of one thousand five hundred feet to three hundred feet, H 2  is in the range of seventy -five feet to fifty feet below the UAV  205  altitude H 1 , and H 3  is in the range of twenty feet to ten feet below the altitude of H 2  and altitude H 4  is in the range of one thousand feet to one hundred feet. Altitude H 1  range is expandable beyond that listed provided the size of the UAV  205  is increased. Increasing altitude H 4  results in a proportional increase in the size of the monitored area  210 . 
     The preferred embodiment utilizes a Predator drone as the UAV  205 . The Predator drone has the characteristics of long range, ability to deliver a payload, adequate flight time, flight path programmability, sufficient power to operate an electronic suite of receivers and transmitters, is able to mark the GPS location coordinates and associate the GPS mark with a drop event, operates at speeds slow enough to perform interrogations and collect responses, and has hard points to mount RFID sensor canisters  215  for dropping. In the preferred embodiment, marking the GPS location coordinate and associating the GPS mark with the drop event for the RFID canister  215  is performed in order to designate a search pattern starting point “P” ( FIG. 6 ). The search pattern  610  ( FIG. 6 ) is necessary to ensure that the UAV  205  can return to the area to be monitored  210  and collect RFID sensor ( 230 ,  235 ,  240  and  245 ) responses. 
     Referring to  FIG. 3 , a detailed description of the RFID canister  215  construction and internal components follows. In the preferred embodiment a shell  305  for the RFID canister  215  is composed of a lightweight plastic material. The shell  305  houses and protects an RFID sensor compartment  310 , provides an anchor point  315  for a parachute connection and contains an opening  320  for routing a firing pin lanyard  325 . The shell  305  also houses and protects a deployment system compartment  330  for protecting a compressed air cylinder  360 , a two way valve  340 , the battery  347 , an electronics circuit board  345 , a firing pin  350  and a pressure released bottom plate  335 . The opening  320  also serves as a pressure equalization port to equalize the air pressure within the deployment system compartment with the external atmospheric pressure. 
     Referring to  FIG. 4 , a detailed description of the components of an RFID sensor deployment system  400  contained within the deployment system compartment  330  ( FIG. 3 ) follows. The operation of the RFID sensor deployment system  400  begins with the pulling of the firing pin  350  by a pulling force imparted on the firing pin lanyard  325  exerted by the deployment of the parachute  220  ( FIG. 2A ). The absence of the firing pin  350  allows a spring  410  to decompress and push a plate  415  onto a piezoelectric switch  420 . 
     The piezoelectric switch  420  senses the pressure applied by the plate  415  and closes its normally open contacts, allowing the battery  347  to supply power to several electrical devices and electronic devices mounted to the electronics circuit board  345 . The piezoelectric switch  420  in the preferred embodiment is manufactured by Apem Components Incorporated and is available in their PBA product line. The preferred piezoelectric switch  420  has no moving parts, is small, completely sealed for harsh environments and can switch a maximum of 24 Volts DC at 1 ampere. This is well below the 12 Volts DC and 0.5 amperes of current supplied by the battery  347 . 
     The output of the piezoelectric switch  420  is connected to a collector lead  430  of a transistor  435  and is also connected to a voltage regulator  440 . The voltage regulator  440  accepts as input 12 Volts DC and outputs a regulated 3.0 Volts for powering an altitude sensor  445  and a microcontroller  450 , all of which are mounted to the electronics circuit board  345 . The altitude sensor  445  in the preferred embodiment is manufactured by Intersema Corporation and carries part number MS5534. The altitude sensor  445  in the preferred embodiment is accurate to one meter of altitude resolution, provides a digital output signal compatible with the input of the microcontroller  450 , consumes power in the 200 micro-ampere range and has an altitude response ranging from a high of fifty thousand feet to a low of two thousand feet below sea level. The microcontroller  450  in the preferred embodiment is manufactured by EM Microelectronics Corporation and carries part number EM6626. The EM6626 is an all-in-one unit providing, a processor, a clock output, internal memory, random access memory, an instruction set, configurable input ports and configurable output ports. Application notes and technical data sheets for the preferred altitude sensor  445  and the preferred microcontroller  450  are available from the manufacturers. 
     The altitude sensor  445  and the microcontroller  450  communicate via a set of electrical interfaces. A portion of the electrical interfaces are labeled as CLOCK  465 , DIN  460  (data in) and DOUT  455  (data out). The CLOCK  465  interface connects a clock output from the microcontroller  450  to the altitude sensor  445  for synchronizing the operation of the two devices (items  445  and  450 ). The DIN  460  interface couples control signals from the microcontroller  450  to influence the operation of the altitude sensor relative to sending altitude data. The DOUT  455  interface couples digital altitude data from the altitude sensor  445  to the internal input circuitry of the microcontroller  450 . The microcontroller  450  is programmed in software utilizing the instruction set to process the altitude sensor data and to specifically detect a preset altitude point H 4  ( FIG. 2A ). 
     Upon the detection of the preset altitude point H 4  ( FIG. 2A ) the output circuitry of the microcontroller  450  outputs a base current to a base lead  432  of a transistor  435  causing the battery  347  voltage and current available at the collector lead  430  to flow to the emitter lead  470 . The presence of battery  347  voltage and current at the emitter lead  470  actuates a two-way valve  340  allowing compressed oxygen that is stored in a cylinder  360  to escape through an output port  355 . 
     Referring to  FIG. 3 , the escaping oxygen at the output port  355  pressurizes the RFID sensor compartment  310  of the RFID canister  305 . The pressurization of the RFID sensor compartment  310  continues until the bottom plate  335  separates from the RFID canister  305 . In the preferred embodiment the separation pressure force required to separate the bottom plate  335  from the RFID canister  305  is in the range of thirty to forty pounds per square inch. Significantly increasing the separation pressure force will result in damage to the RFID sensors ( 230 ,  235 ,  240 , and  245 ). 
     The sudden separation of the bottom plate  335  and the pressure build up within the RFID sensor compartment  310  results in the ejection of all the RFID sensors ( 230 ,  235 ,  240 , and  245 ) into the atmosphere. As the RFID sensors ( 230 ,  235 ,  240 , and  245 ) descend they begin to detect the analyte for which they are sensitive. Detection arrays for detecting chemical agents, explosive material, biological agents and radiological agents using high electron mobility transistor (HMET) technology are known in the art. HMET based detection arrays integrated with electronic RFID circuitry are also known in the art. In the preferred embodiment the RFID sensor ( 230 ,  235 ,  240 , and  245 ) is composed of an HMET detection array integrated with electronic RFID circuitry. The preferred embodiment uses electronic RFID circuitry comprising an antenna for receiving interrogation signals from an interrogator and for transmitting a response, a transceiver coupled to the antenna for communicating the responses of the HMET detector array, a unique identification code stored in internal memory and an interface coupling the HMET detection array to the transceiver. In one embodiment the electronic RFID circuitry and integrated HMET detection array is sensitive to one type of analyte. In another embodiment the electronic RFID circuitry and integrated HMET detection array is sensitive to multiple types of analyte. In yet another embodiment, the RFID sensors ( 230 ,  235 ,  240 , and  245 ) are chemiresistors. Chemiresistors are fully described in U.S. Pat. No. 6,359,444 and are suitable for detecting a wide variety of analytes. 
     Referring to  FIGS. 2A and 2B , the descending RFID sensors settle on the earth in a random pattern  250  about the area to be monitored  210 . The separation between the individual RFID sensors ( 230 ,  235 ,  240 , and  245 ) within the random pattern  250  is a function of the release altitude H 4 , the pressure that separates the pressure released bottom plate ( FIG. 3 , item  335 ) from the RFID canister shell  305  ( FIG. 3 ) and the prevailing wind speed and wind direction. In the preferred embodiment RFID sensor  230  detects an explosive agent, sensor  235  detects a biological agent, sensor  240  detects a radiological agent, and sensor  245  detects a chemical agent. 
     Referring to  FIGS. 5 and 6 , presented are a UAV software processing flowchart  500  describing the software processing steps performed onboard the UAV  205 , and a graphical depiction  600  of the RFID system components. The UAV  205  returns to point P, which is coincident with the GPS mark for the dropped canister event, and begins to fly a spiral flight pattern  610  at an altitude of H 5 . In the preferred embodiment the altitude of H 5  is in the range of fifty feet to two hundred feet. The altitude H 5  is limited by the aerodynamic capabilities of the UAV  205  and the efficiency of the interrogation response cycle. The UAV  205  initiates interrogations (step  505  and item  615 ) and collects RFID sensor responses (step  510  and item  620 ) for detection report processing. In the preferred embodiment the interrogation signal  615  is transmitted in an RF beam having a narrow RF beamwidth. The narrow RF beamwidth of the interrogation signal  615  is necessary to control the number of RFID sensor responses  620 . Increasing the altitude H 5  for the UAV  205  leads to an increase in the number of RFID sensor responses  620  due to spreading of the effective area of the RF beamwidth that illuminates the monitored area  210 . Decreasing the altitude H 5  for the UAV  205  leads to a decrease in the number of RFID sensor responses  620  due to a reduction of the effective area of the RF beamwidth that illuminates the monitored area  210 . The GPS location coordinate of the interrogation is marked (step  505 ) and stored in a data structure. The RFID sensor responses  620  are collected during step  510 . The RFID sensor responses  520  are also GPS marked (step  515 ) and stored in another data structure as a part of a detection report. Contained in the RFID sensor responses  620  are the type of analyte detected which is stored in yet another data structure (step  520 ) as part of the detection report. Software processing then links the GPS location coordinate with the type of analyte (step  525 ) and stores the linked results in yet another data structure. Software processing then invokes a correlation scheme to merge (step  530 ) the RFID sensor responses  620  that are alike and are located close together. 
     In one embodiment, the correlation scheme of step  530  invokes a simple square root of the sum of the squares using the GPS latitude and longitude coordinates for pairs of like RFID responses and compares them to a square correlation window having a dimension of one hundred feet per side. All like responses that fit within the square correlation window are merged as a single response with a single GPS location coordinate at the center of the window which are then stored in yet another data structure (step  530 ) as a merged detection report. Each set of merged responses are written into a telemetry (TM) formatted message (step  535 ). At the end of the interrogation response cycle the TM formatted message (step  535 ) contains header information describing the source and size of the TM message, as well as a data record for each set of merged responses. Each data record in the TM message is composed of a time stamp, a GPS location coordinate, an identification of the analyte, the sequence number for the interrogation cycle and the number of correlated responses that define the merged response. In the preferred embodiment the TM formatted message (step  535 ) contains the results of more than one interrogation response cycle. When the TM formatted message (step  535 ) has reached a maximum size the TM formatted message is sent to a TM processor (step  540 ). The interrogations  615 , collection of responses  620  and transmission of the TM formatted message to the TM processor (step  540 ) continues until the area to be monitored  210  is no longer overflown by the UAV  205 . 
     The widening of the spiral flight pattern  610  continues until the number of RFID responses  620  peak and then drop to near zero, which is an indication that the area to be monitored  210  is no longer being overflown (step  545 ). The spiral flight pattern  610  is a predetermined flight path configurable by the user prior to UAV takeoff. 
     Referring to  FIG. 7 , we now turn to a description of the components located onboard the UAV  205  ( FIG. 6 ) that implement the operational steps depicted in the UAV software processing flowchart  500  ( FIG. 5 ). One skilled in the art of UAV system engineering will recognize and be able to carryout an implementation for each of the following described components in the novel manner in which they are assembled and used. 
     At the core of the RFID sensor system is an interrogation response processor  705  executing the steps described in the UAV software processing flowchart  500  ( FIG. 5 ). The interrogation response processor  705  accepts as input a GPS signal  710  provided by a GPS system  715 , an event marker signal  720  provided by an event marker system  725 , and an amplified signal  730  output by a low noise amplifier  735 . The interrogation response processor  705  sends a digital TM data stream  740  containing the TM formatted message  540  ( FIG. 5 ) to a TM processor  745 . The interrogation response processor  705  also provides an interrogation command signal  750  to an RFID sensor interrogator  755 . The interrogation response processor  705  includes a central processing unit, internal read only memory to store a coded software program, random access memory to store data, input and output buffers for data manipulation, and multiple electrical interface circuits for communicating with these and other devices. 
     The GPS system  715  is coupled to a UAV flight control computer  760  by an electrical interface  765 . The UAV flight control computer  760  is responsive to navigational data sent from the GPS system  715 , where the navigational data from GPS system  715  is used to direct the UAV flight path, directs operating altitudes and provides GPS time for coordinating tasks. 
     The TM processor  745  communicates with a TM transmitter  770  via an electrical interface  775 . The TM processor  745  accepts the digital TM data stream  740  containing the TM formatted message  540  ( FIG. 5 ) and reformats the digital TM data stream  740  into a format suitable for transmission by the TM transmitter  770 . The TM transmitter is coupled to a TM antenna  797  that is mounted onto the UAV  205  ( FIG. 6 ). The TM antenna  797  provides a radio frequency downlink  625  directed towards a ground receiving station ( FIG. 6  item  630 ). 
     An RFID transceiver  780  has an output line  785  connected to the low noise amplifier  735  and has an input line  790  connected to the interrogator  755 . The low noise amplifier  735  filters and amplifies an output on the output line  785  of the RFID transceiver  780  where the output of the RFID transceiver  780  contains the RFID sensor responses  620 . The interrogator  755  accepts commands to perform and cease interrogator operations as directed by the interrogation response processor  705 . The RFID transceiver  780  is coupled to a combined transmit receive antenna  795  providing a means to transmit an interrogation RF link  615  and to receive a response RF link  620  necessary for communication with the RFID sensors ( FIG. 6  item  605 ) scattered over the area to be monitored  210  ( FIG. 6 ). 
     Referring to  FIG. 6 , the ground based receiving station  630  is now described. The ground based receiving station  630  includes a receive antenna  635  connected to an RF receiver  640 . The output of the RF receiver  640  is connected to the input of a bit synchronizer and decommutation unit  645 . The output of the bit synchronizer and decommutation unit  645  is connected to a telemetry processor  650  having an output connected to a computer station  655 . 
     Referring to  FIGS. 6 and 8 , item  800  is a software flowchart describing the processing steps performed by the ground based receiving station  630 . The ground based receiving station  630  receives the UAV transmitted RF  625  at the receive antenna  635 . In step  805  the UAV transmitted RF  625  is down converted in frequency and filtered for further processing by the bit synchronizer and decommucation unit  645 . In step  810  the TM processor  650  unpacks the contents of the TM formatted message ( FIG. 5  item  540 ) into a plurality of data records composed of the time stamp, the GPS location coordinate, the identification of the analyte, the sequence number for the interrogation cycle and the number of correlated responses that define the merged responses prepared by the interrogation response processor  705  ( FIG. 7 ). The unpacked contents of the TM formatted message of step  810  are sent to the ground station computer  655  for further processing. The ground station computer  655  executes an analysis and recommendation algorithm which implements steps  815  through  855 . 
     The analysis and recommendation algorithm begins by reading (step  815 ) from computer memory the time stamp, the GPS location coordinate, the identification of the analyte, the sequence number for the interrogation cycle and the number of correlated responses that define the merged responses unpacked (step  810 ) by the TM processor  650 . A check (step  820 ) is made to determine whether an analyte is in the category of an explosive. If the analyte is in the category of an explosive then the corresponding GPS coordinate, an alert message, and a recommended action is output by the algorithm (step  825 ). The alert message is defined by a computer programmer based upon user requirements and includes graphics, text or an audible conveyance of the alert. The recommended action is defined by the computer programmer based upon user requirements and includes graphics, text or an audible conveyance of the recommended action. In the preferred embodiment an alert is a color coded textual message comprised of textual symbols that reads “EXPLOSIVE LAT coordinate LON coordinate”. In the preferred embodiment a recommended action ranges from complete avoidance of the entire area to be monitored  210 , avoidance of a circular area surrounding the coordinates of the explosives, or other precautions as determined by the type of explosive and the mission of the advancing force. Whether an explosive is detected or not a second check is made (step  830 ). 
     The second check (step  830 ) is made to determine whether an analyte is in the category of a biological material. If the analyte is in the category of a biological material then the corresponding GPS coordinate, an alert message, and a recommended action is output by the algorithm (step  835 ). The alert message is defined by a computer programmer based upon user requirements and includes graphics, text or an audible conveyance of the alert. The recommended action is defined by the computer programmer based upon user requirements and includes graphical symbols, textual symbols, any combination of graphical and textual symbols or an audible conveyance of the recommended action. In the preferred embodiment an alert is a color coded text message that reads “BIOLOGICAL LAT coordinate LON coordinate”. In the preferred embodiment a recommended action ranges from complete avoidance of the entire area to be monitored  210 , avoidance of a circular area surrounding the coordinates of the biological material, or other precautions as determined by the type of biological material and the mission of the advancing force. Whether a biological material is detected or not a third check is made (step  840 ). 
     The third check (step  840 ) is made to determine whether an analyte is in the category of a radioactive material. If the analyte is in the category of a radioactive material then the corresponding GPS coordinate, an alert message, and a recommended action is output by the algorithm (step  845 ). The alert message is defined by a computer programmer based upon user requirements and includes graphics, text or an audible conveyance of the alert. The recommended action is defined by the computer programmer based upon user requirements and includes graphics, text or an audible conveyance of the recommended action. In the preferred embodiment an alert is a color coded text message that reads “RADIATION LAT coordinate LON coordinate”. In the preferred embodiment a recommended action ranges from complete avoidance of the entire area to be monitored  210 , avoidance of a circular area surrounding the coordinates of the radioactive material, or other precautions as determined by the type of radioactive material and the mission of the advancing force. Whether a radioactive material is detected or not a fourth check is made (step  850 ). 
     The fourth check (step  850 ) is made to determine whether an analyte is in the category of a chemical agent. If the analyte is in the category of a chemical agent then the corresponding GPS coordinate, an alert message, and a recommended action is output by the algorithm (step  855 ). The alert message is defined by a computer programmer based upon user requirements and includes graphics, text or an audible conveyance of the alert. The recommended action is defined by the computer programmer based upon user requirements and includes graphics, text or an audible conveyance of the recommended action. In the preferred embodiment an alert is a color coded text message that reads “CHEMICAL LAT coordinate LON coordinate”. In the preferred embodiment a recommended action ranges from complete avoidance of the entire area to be monitored  210 , avoidance of a circular area surrounding the coordinates of the a chemical agent, or other precautions as determined by the type of a chemical agent and the mission of the advancing force. 
     The algorithms described herein may be programmed in any suitable programming language for operation on compatible computer processors and computer processing hardware. The computer language for the preferred embodiment is an object oriented language with error recovery features to allow algorithm execution in the presence of data or computer errors. The preferred embodiment is loaded onto a computer readable medium which may include, but are not limited to, memory disks, flash memory devices, optically read media, and mass storage devices. 
     One skilled in the art may adapt the applicant&#39;s invention to any platform that operates in any area for which there is a need to provide an assessment of the presence of hazardous material and such adaptation is within the scope of the present invention. It is necessary for the platform that is used for operating the algorithms described herein to have a power supply for supplying power to the computers, computer processors, memory storage devices, display heads, electrical interfaces and other associated hardware. 
     Although the present invention has been described in considerable detail with references to certain preferred versions thereof, other versions are possible. For example, RFID sensors of a type not described herein may be used. A series of deployed RFID canisters may be used to significantly increase the number and size of the area to be monitored. The UAV interrogator may climb to a higher altitude prior to transmitting the TM formatted message to the ground station in order to increase the overall effective distance of system operation. A TM relay in the form of an additional UAV or intermediate ground receiving station may be used to increase the overall effective distance of system operation. Another example of other embodiments includes permutations of described text and graphics are as numerous as there are fonts, colors, textures and user preferences. A suitable set of accepted graphical warning symbols for hazardous material are drawn from the symbols and signage adopted by the Occupational Safety and Health Administration and those adopted by the European Agency for Safety and Health at Work. Yet another example of alternative embodiments lies in the substitution of the plurality of records with an array of data structures, or with databases having data stored in retrievable datasets, or with matrices having data stored in retrievable data cells, or with other types of data structures that can store and access data. 
     It is necessary for the airborne platform that is used for operating delivering the RFID canister and operating the algorithms described herein to have a power supply for powering the navigation computers, the computer processors, the memory storage devices, the electrical interfaces, telemetry components and other associated hardware. 
     Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.