Abstract:
A method and apparatus for detecting and tracking an object within a defined area, and determining its position, status, movement and identity therein, includes interrogating the defined area to communicate with an information device associated with an object and transmit information received to a master controller unit, which determines the object&#39;s presence, position, status, movement and identity within the defined area. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to the non-provisional patent application having Ser. No. 11/040,137 filed on Jan. 21, 2005, which is hereby incorporated by reference in its entirety as if fully set forth herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to the detection of objects. Specifically, the present invention relates to systems and methods that track and detect position, status, movement and identity of objects within a defined area. 
       BACKGROUND OF THE INVENTION 
       [0003]    Systems that identify and track objects within a particular area include security systems used to identify unauthorized access to restricted areas and set off alarms when someone enters an unauthorized area. Conventional security systems control entry access to an enclosed structure. Typically, the enclosed structures have secured doors and windows that prevent anyone without a key from entering the building. Many commercially available systems require anyone entering an enclosure to confirm their access authorization by first entering a code at a keypad at the entrance to the enclosure, or swipe a card or similar device past an access reader near the entry point. The security confirms the identity of the person based on the access code or encoded information on the card and unlocks the door for entry. 
         [0004]    These systems require access authorization at each point of entry. In addition, these systems do not have an economic way of monitoring people as they move within or leave an enclosure. As a result, it is possible for people to remain in a building intentionally or accidentally without detection. In emergency situations it can be critical to know if everyone has been evacuated to know when to initiate search and rescue procedures. Also, individuals may need to enter a building late at or on holidays to complete a work assignment. If they become ill or injured, this problem goes undetected since systems such as those described in the above examples cannot detect when someone leaves a building or if they remain in the building. 
         [0005]    Additionally, if someone is in an enclosure, the only methods to control access from one area of an enclosure to another area are to install doors with access authorization hardware, to install video security cameras to monitor movement, or to employ security guards at checkpoints to control access. Any of these solutions is complex and costly. 
         [0006]    Access control systems also limit flexibility to readily change the configuration of the work space or use a common space for workers with different levels of authorization. For example, manufacturers who have several contract manufacturers may use the same space for manufacturing different processes. Since the contract groups operating in this space are employees of different companies, it is desirable for these workers to have access only to the floor space reserved for their activities. It is also, desirable not to build enclosures and install security systems to control access since the manufacturing needs of the company and the space required for these changes may change quickly over time depending on business opportunities or economic conditions. 
         [0007]    Other conventional tracking systems include package tracking and warehousing. Tracking of packages includes affixing bar codes to letters and packages and scanning the labels at pickup and delivery points. The identity of the letter or package retrieved from the barcode label might be combined with positional information based on global positioning or more simply based on a known route or reported location of the delivery person. In each case a delivery person must scan the barcode attached to the letter or package. Also, the spatial location, presence or identity of the package within a delivery vehicle or warehouse is not known continuously in real time because bar code readers used to establish identity and location required close proximity of the bar code reader to the bar code. 
         [0008]    In warehousing, which involves assigning items numbers to inventory, if someone fails to place an item in the correct location in the warehouse the item may be lost. Warehousing does not provide security features to insure that items really enter and leave the warehouse when management thinks they are entering or leaving the warehouse, and efficient use of the warehouse depends on accurate prediction of the space requirement for an inventory supply and requires reorganizing the warehouse space in case inventory levels of particular items change in response to business conditions. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention provides a method of locating an object within a defined area, comprising interrogating the defined area to determine the presence of an object within the defined area, wherein the at least one interrogation device is within communication range of at least one master controller unit and transmits a signal within the defined area and receives data relating to the object if the object is within the defined area, transmitting the data from the at least one interrogation device to the at least one master controller unit and storing the data received in a memory therein, compiling the data received from the at least one interrogation device at the at least one master controller unit, and interpreting the data compiled by at the least one master controller unit to determine characteristic information of the object within the defined area. 
         [0010]    In another embodiment, the present invention provides an object detection apparatus comprising a low frequency information device positioned on an object within a defined area, at least one high frequency interrogation device, the at least one interrogation device within a transmission and detection range of the defined area, a passive repeater powered by the at least one interrogation device, the passive repeater receiving a high frequency signal transmitted by the least one interrogation device and converting to a low frequency signal for communication with the information device to determine the presence of an object, and receiving a low frequency signal from the information device and converting to a high frequency signal for transmission to the at least one interrogation device, and a master controller unit within a transmission and detection range of the at least one interrogation device and capable of receiving information transmitted from the at least one interrogation device, wherein the passive repeater provides an interface to communicate information over a distance. 
         [0011]    The foregoing and other aspects of the present invention will be apparent from the following detailed description of the embodiments, which makes reference to the several figures of the drawings as listed below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  shows an object tracking system and method within a defined area according to one embodiment of the present invention; 
           [0013]      FIG. 2  shows components of an object tracking system and method according to one embodiment of the present invention; 
           [0014]      FIG. 3  is another view of components of an object tracking system and method according to one embodiment of the present invention; 
           [0015]      FIG. 4  is a three dimensional view of one type of information device for use with the present invention; and 
           [0016]      FIG. 5  is a three dimensional view of another type of information device for use with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0017]    In the following description of the present invention reference is made to the accompanying drawings which form a part thereof, and in which is shown, by way of illustration, exemplary embodiments illustrating the principles of the present invention and how it may be practiced. It is to be understood that other embodiments may be utilized to practice the present invention and structural and functional changes may be made thereto without departing from the scope of the present invention. 
         [0018]    The present invention is embodied in a system comprising one or more of the elements shown in  FIG. 1  and described in the following specification. 
         [0019]      FIG. 1  represents a system and associated methods to detect position, status, movement and identity of objects entering, leaving and residing within defined spaces, areas, or volumes.  FIG. 1  shows a defined area  10 , within which there are objects  20  which are capable of entering, exiting, and residing within the defined area  10 .  FIG. 1  shows that the objects  20  may or may not include an information device  30  positioned thereon. Interrogation devices  40  are shown in  FIG. 1  placed within the defined area  10 ; however, it is to be understood that any number of interrogation devices  40  may be placed within the defined area  10 , outside the defined area  10 , or both. Also,  FIG. 1  shows master controller units  50  placed within the defined area  10 . However, as with the interrogation devices  40 , any number of master controller units  50  may be placed within the defined area  10 , outside the defined area  10 , or both. 
         [0020]    The objects  20  may be animate (for example, people) or inanimate (for example, packages). The system and methods may employ one or more information devices  30 , one or more interrogation devices  40 , and one or more master controller units  50 . The information devices  30  are either passive or active. An information device  30  may be any type of device which is capable of identifying or providing characteristic information for an object  20  on which it resides, including, for example, Radio Frequency Identification (RFID) tags. Inanimate objects  20  may include sensors or controllers that the system may query for additional information or control. One or more interrogation devices  40  are positioned within a transmission and detection range of the defined area  10  (an the information devices  20  located therein) and within a transmission and detection range of another interrogation device  40 , if more than one interrogation device  40  is utilized. The interrogation devices  40  receive signals reflected from objects  20  or information devices  30 , or signals generated by information devices  30  up to 100 meters in a narrow aperture. The signals received contain directional field strength information as well as information about the identity of the object  20 . 
         [0021]    The present invention also contemplates that one or more master controller units  50  are placed within a transmission and detection range of one or more of the interrogation devices  40 . The interrogation devices  40  may interrogate an information device  30  or object  20  simultaneously and communicate with each other and with the master controller unit  50  as a network. The master controller units  50  receive information from one or more interrogation devices  40 , and compile this information for human review or automatic response to the information. The master controller unit  50  can interpret directional field strength information from two or more interrogation devices  40  to define spatial coordinates over time of information devices  30  or objects  20 . The master controller unit  50  combines this spatial coordinate information with the identity information retrieved by interrogation devices  40  to locate objects  20 . Using this coordinate information it is possible to track objects  20  of known identity within a defined area  10  that is not necessarily confined by walls. 
         [0022]    The defined area  10  may be an area, volume or space of any size and may be single or multi-dimensional. The perimeter of the defined area  10  need not necessarily be the enclosure of a room or building. The area or volume of the defined area  10  is only limited by the transmission and reception range of the interrogation devices  40  placed near, around or within the defined area  10 . The defined area  10  can have any number of objects  20  with or without information devices  30  therein. The objects  20  may be animate or inanimate, and the animate objects  20  may include people  60 . The defined area  10  can also have inanimate objects  20  such as packages  110  with or without information devices  30 . The defined area  10  has one or more interrogation devices  40  each one of which is placed close enough to its nearest neighboring interrogation device  40  so that it can communicate with it. All interrogation devices  40  are able to communicate with one another and with the master controller units  50  directly or through other interrogation devices  40 . 
         [0023]    An interrogation device  40  interrogates the defined area  10  to obtain characteristic information associated with an object  20 . In one embodiment, interrogation of the defined area  10  includes communication with an information device  30 . Communication with the information device  30  provides a signal which represents data having characteristic information about the object  20 . The data is compiled by the master controller unit  50  to determine the characteristic information, which may include at least one of identity, presence, status, and position of the object  20  within the defined area  10 . 
         [0024]    The information device  30  may store characteristic information that identifies the animate and inanimate objects  20  associated with the information device  30 . For both animate and inanimate objects  20 , the information device  30  may have preprogrammed authorization levels or may receive authorization levels dynamically from the master controller units  50  via the interrogation device  40 . 
         [0025]    For animate objects  20 , the information device  30  may contain additional information specific for the animate object  20 , including but not limited to (i) biometric information, (ii) physiological information for animate objects, and/or (iii) legal, financial or health information. For animate objects  20  without an information device  30 , identity may be determined using biometric information independent of the information device  30  and is obtained by scanning the person  60 . 
         [0026]    For inanimate objects  20 , the information device  30  may contain information in addition to the identity and authorization level of the inanimate objects  20 , including but not limited to (i) chemical and physical properties of the inanimate object, (ii) preferred storage conditions and shelf life, (iii) date of manufacture, (iv) shipping information, (v) safety and handling information. For inanimate objects  20  without an information device  30 , the interrogation device  40  may scan the object  20  to determine its position, change in position, radio frequency signature and other information that may assist in identifying the object  20 . 
         [0027]    The interrogation device  40  interrogates an object  20  by transmitting a signal into the defined area  10 . In one embodiment, the interrogation device  40  sends radio frequency transmissions to a person  60  or package  110  having an information device  30  position thereon. The interrogation device  40  then detects a signal sent back from the information device  30 . The returned signal contains information stored in the information device  30 . The interrogation device  40  may be a fixed device or a wireless or mobile device, such as a handheld device. 
         [0028]    The master controller unit  50  receives, compiles, and decodes information from one or more interrogation devices  40 . The master controller unit  50  can also transmit information to other master controller units  50 . The master controller unit  50  determines the identity of the object  20  by comparing the information obtained from the information device  30  and comparing it to reference data associated with the object  20  previously stored in the master controller unit  50  or accessed by the master controller unit  50  from another storage medium. 
         [0029]    The master controller unit  50  determines the spatial coordinates of the object  20  by comparing the angle of maximum field strength during transmission and reception and the time required for transmission from one or more interrogation devices  40 . The master controller unit  50  may also determine motion by comparing spatial coordinates determined over time. In another embodiment, the master controller unit  50  determines motion by analyzing Doppler shift, in which waves propagated by an object are analyzed for frequency changes to determine if the object is in motion over a given period of time. The master controller unit  50  is capable of determining if a person  60  or object  20  is authorized to be within a defined area  10  by comparing authorization information with pre-approved authorization information for the defined area  10  stored in a memory in the master controller unit  50  and determining based on spatial coordinates of the object  20  if it is within the defined area  10 . The master controller unit  50  can then create and transmit an alarm  70  to any one of several alarming devices  80  (not shown). Examples of alarming devices  80  might be (1) a CRT display of the alarm status for human review, (2) wireless transmission to an audible (for example, a siren or horn) or visual (for example flashing lights) alarm visible to people within or external to the defined area or (3) to an alarming device  80  on the information device  30  itself. The master controller unit  50  can also transmit preprogrammed responses to other devices. 
         [0030]      FIG. 2  shows components of an object tracking system and method according to one embodiment of the present invention. In this embodiment, the master controller unit  50  is a computer or other similar device in a network that communicates with wireless interrogation devices  40 . The interrogation devices  40  are within a transmission and detection range of the master controller unit  50  and are within a transmission and detection range of objects  20  that reside within a defined area  10  with or without information devices  30 . Additionally, the information devices  30  may be active or passive. Active information devices  30  are powered and capable of transmission to and from an interrogation device  40 . Passive information devices  30  are not powered, but instead may derive power from the signal transmitted by the interrogation device  40  itself, or may be reflective devices, or both. 
         [0031]      FIG. 3  is another view of components of an object tracking system and method according to one embodiment of the present invention.  FIG. 3  shows the master controller unit  50  is a computer or other similar device in a network that communicates with wireless interrogation devices  40 . The interrogation devices  40  are within a transmission and detection range of the master controller unit  50  and are within a transmission and detection range of objects  20  that reside within a defined area  10  with or without information devices  30 . In  FIG. 3 , the interrogation device  40  communicates with the information devices  30  via a passive repeater  120 . In this embodiment, the interrogation devices  40  communicate using microwave frequencies with small antennas. The passive repeater  120  allows microwave communication with low frequency information devices  30  placed on objects  20  by relaying the signals back and forth between the interrogation device  40  and the information device  30 . The passive repeater  120  also allows communication by inductive coupling. This embodiment also allows for the use of either of active or passive information devices  30  as described herein. 
         [0032]      FIG. 1 ,  FIG. 2  and  FIG. 3  generally describe systems and methods which may be used in many different embodiments of the present invention. 
         [0033]    One such embodiment provides a system and method that permits tracking objects  20  entering, exiting, residing within, and moving within defined areas  10 . One aspect of this embodiment is monitoring objects  20  entering and leaving a defined area  10 . Security systems in use today often only provide an automatic method of monitoring entry into an area; exiting a space is either not automatic or is not monitored at all. The present invention provides a means of monitoring not only entry but also exit from a defined area  10  since it is possible to determine if an animate or inanimate object  20  has moved outside of defined coordinates. This capability is helpful to determine if animate or inanimate objects  20  remain within a secured area once they have entered. 
         [0034]    Another embodiment of the present invention involves automatic real-time surveillance of an object  20  within a defined area  10 . Defined areas  10  may be buildings or areas in which a high level of security is needed. In this embodiment, automatic real-time surveillance is conducted by interrogating objects  20  continuously or periodically in real time to determine identity, spatial coordinates, change in spatial coordinates and change in status. In one aspect of this embodiment, interrogating is performed by communicating with an information device  30  positioned on the object  20 . In another embodiment, interrogation of the object  20  includes performing a biometric scan of the object  20 . 
         [0035]    In a further embodiment, objects  20  in an ensemble configuration are monitored to determine if the objects  20  stay together or are separated. For example a guard and a group of prisoners may be monitored to determine if they all stay together within a defined area  10 . If the guard or one of the prisoners is missing an alarm  70  is created. 
         [0036]    Another embodiment of the present invention is a system and method of controlling and confirming evacuation from a defined area  10 . When a defined area  10  is evacuated during an emergency it is important to determine if every person  60  or object  20  has left the defined area  10 . If the defined area  10  remains intact following an emergency, interrogation devices  40  installed in the defined area  10  can determine if objects  20  with or without information devices  30  still remain in the defined area  10 . One can also use a handheld interrogation device  40  to determine if any people  60  or objects  20  remain in the defined area  10  in the event that the interrogation devices  40  that normally service the defined area  10  have been destroyed during the emergency. In another aspect of this embodiment, an interrogation device  40  can also be used to quickly count all the people  60  evacuated and held in a defined area  10  following evacuation. 
         [0037]    Yet another embodiment of the present invention provides a system and method for authorization level control for a defined area  10 . The authorization level for a person  60  or object  20  depicted in  FIG. 1  may be preprogrammed in an information device  30  carried by a person  60  or object  20 . It may be dynamically assigned by determining the identity of the object  20  by interrogating the information device  30  positioned on the object  20  (or some other means of identifying the object  20  as described herein). The object identity is compared to authorization levels stored in the master controller unit  50  or access authorization rules based on such variables as time and location. Authorization is granted if the object&#39;s identity meets stored criteria or meets predetermined rules. If the system does not authorize access, the system creates an alarm  70 . 
         [0038]    Another embodiment of the present invention includes a system and method for information device-identity pair confirmation. With most security or tracking systems, it is assumed that a person using an information device  30  such as a security access card is the person in possession of the identity card. This may not be the case. Identity cards are sometimes lost, loaned to another for unauthorized use or stolen or recovered by unauthorized personnel. When this happens, someone without authorization may enter restricted areas without detection. The present invention provides a system and method of determining the identity of an individual by independent biometric measurements and comparing measured biometric data to stored biometric information specific for the individual. If measured biometric information is identical to stored biometric information, this confirms that the person  60  in possession of an information device  30  is the person  60  who should properly possess the information device  30 . If the person  60  in possession of the information device  30  should not have the information device  30 , the present invention is capable of triggering an alarm  70 . 
         [0039]    This system and method of information device-identity pair confirmation uses identity and biometric information obtained by scanning the person  60 . One example of obtaining biometric information is to design an information device  30  that can detect and record fingerprint patterns. An interrogation device  40  retrieves both the biometric fingerprint information and identity information stored in the information device  30 . Another example of obtaining biometric information is to scan individuals  60  with radio frequencies and detect reflected radio frequency patterns that identify the individual  60 . These scanned radio frequency patterns can be compared to stored patterns known to identify the individual  60 . Another example of this embodiment is to attach a physiologic sensor  90  (not shown) to an information device  30 . One example of such a physiologic sensor  90  is one capable of detecting skin characteristics using optical means to uniquely identify an individual  60 . The sensor information may be transferred to the information device  30  so that an interrogation device  40  can scan it. Other types of physiologic sensors  90  could detect ECG, EKG, blood pressure, pulse, galvanic skin response, skin color, oxygen tension, or blood glucose level. Many other types of physiologic sensors  90  may be employed within the scope of the present invention. Another example of this embodiment is an information device  30  that permits the person  60  wearing the information device  30  to manually enter a password. The interrogation device  40  can retrieve the entered password as well as identification information on the information device  30 . 
         [0040]    Physiologic and biometric characteristics of a person  60  may be determined by different sensors or by the same sensor, and may also be determined by scanning the person  60 . For example, a camera is an example of sensor which can be used to take a picture to record a person&#39;s appearance such as skin color, and which can also be used to record a person&#39;s iris pattern. It should be noted that physiologic characteristics generally relate to characteristics that are not unique to one person  60 , such as a breathing pattern, and that biometric characteristics relate to characteristics which are unique to a particular individual, such as a fingerprint. 
         [0041]    In another embodiment, the physiologic sensor  90  is used to determine whether a person  60  is in danger within the defined area  10 . In this embodiment, the physiologic sensor  90  is coupled to the information device  30 . The sensor  90  detects a physiologic state with the physiologic sensor. Physiologic information related to the physiologic state is stored in the information device  30 , and is transmitted to the interrogation device  40 , and from there is transmitted to the master controller unit  50 . The master controller unit  50  determines whether the physiologic information for a person  60  obtained from the physiologic sensor represents an abnormal condition, and creates and transmits an alarm  70  of unauthorized presence or access if an abnormal condition is found. The abnormal condition exists if the physiologic information is outside a range of normal values for the physiologic state. 
         [0042]    Another embodiment of the present invention provides a system and method of detecting and alarming unauthorized removal or utilization of an information device  30  by an individual  60 . In this embodiment, real time identity information  100  (not shown) associated with a person  60  must be obtained. This real time information  100  may include dental records, fingerprints, body weight, body dimensions, skin color, hair color, identifying marks, racial characteristics, blood type, DNA sequence, or other confidential information known only to the individual  60 , such as mother&#39;s maiden name, social security number or place of birth. Real time identity information  100  for a person  60  may be obtained by automatic passive or active scanning of biometric data with or without the aid of an information device  30 . Real time identity information  100  for inanimate objects  20  such as packages might include contents, labeling, chemical compositions, physical dimensions, physical properties, shipping date, attached work orders or descriptive information, or electronic identifiers. Real time identity information  100  for inanimate objects  20  may also be obtained by automatic passive or active scanning of additional electronic identifiers such as RFID tags with or without the aid of information device  30 . By comparing real time identity information  100  with identity information stored on the information device  30 , one can create an alarm  70  if real time identity information does not agree with stored identity. The alarm  70  indicates that an unauthorized person has possession of the information device  30 . 
         [0043]    In another embodiment, a system and method of detecting and alarming unauthorized removal or utilization of a information device  30  includes placing a plurality of information devices  30  on a single animate or inanimate object  20 . To detect unauthorized removal or utilization, one compares real time identity information  100  stored on one information device  30  associated with a single animate or inanimate object  20  with the identify information stored on a second information device  30 . If the identify information on the two information devices  30  does not agree, then the system creates an alarm  70  that can warn system users of unauthorized removal or utilization. 
         [0044]    Another embodiment of the present invention provides a system and method for controlling an environment based on information contained within an information device  30  associated with an object  20 . Information devices  30  may be attached to sensors to gather environmental information such as illumination level, temperature, pressure, humidity, gas composition, particle counts, presence of biological or chemical agents, or physiologic information. The interrogation device  40  collects this environmental information by interrogating the information device  30  as described previously. The master controller unit  50  evaluates the environmental status and transmit control signals via the interrogation device  40  to controllers to control the environment. In addition, the interrogation device  40  may scan an object  20  within a defined area  10  to determine identity, physiologic status or preprogrammed environmental preferences or requirements. This information may be stored on an information device  30  associated with the object  20  or in some other memory device in communication with the present invention. Based on environmental preferences of the object  20 , the master controller unit  50  can change the environmental conditions in the defined area  10 . For example, the master controller unit  50  may have stored therein rules that a defined area should be maintained at a particular temperature if an object  20  is present, but be otherwise maintained at another temperature. The interrogation device  40  determines if a person  60  or object  20  enters the defined area  10  and adjusts the temperature according to the object&#39;s presence in the defined area  10 . 
         [0045]    A package  110  might also have an information device  30 , such as a RFID device, that controls warehouse storage conditions. An interrogation device  40  may determine package storage conditions when a package  110  enters a warehouse and creates an alarm  70  if environmental conditions exceed predetermined limits or adjust temperature and humidity to required limits. 
         [0046]    Another embodiment of the present invention provides the ability to communicate with a person  60  through an information device  30 . For example, if a person  60  enters an unauthorized defined area  10 , the location of the person  60  can be determined by interrogating the information device  30  worn by the person  60 . The interrogation device  40  interrogates the defined area  10  and communicates with the master controller unit  50 . The master controller unit  50  determines that the person  60  is not authorized in the defined area  10 . In one aspect of this embodiment, the master controller unit  50  directs the interrogation device  40  to transmit a signal to the information device  30  for notification of unauthorized access. The information device  30  may include an alarming device  80  such as a visual or auditory alarm  70  that will notify the person  60  or surrounding people that the person  60  should not be in the restricted defined area  10 . 
         [0047]    Yet another embodiment of the present invention involves monitoring and controlling a mixed identity environment, in which objects  20  with and without information devices  30  may be found. For example, a person  60  may carry an information device  30  for identification purposes, or a person  60  may be identified by biometric scanning, or simply by monitoring movement. A person  60  may be detected within a defined area  10  by a unique pattern of reflected radio waves and tracked by the movement of that unique pattern. By incorporating the dual capability of information device  30  tracking and biometric scanning, people  60  and objects  20  can be tracked within the defined area  10 , whether they have an information device  30  or not, and an authorization of their presence within the defined area  10  can be determined. 
         [0048]    The following examples illustrate this embodiment. One such example involves monitoring mixed identities for school security. Each student in a school has an information device  30  that permits entry, exit or passage between various points within the school perimeter. In another example, the present invention detects and monitors people without information devices  30  entering, leaving and moving within the school perimeter. People  60  without information devices  30  would not go undetected using the present invention. 
         [0049]    Another example of the present invention involves controlling access to commercial buildings. Security systems used for commercial buildings monitor entry into buildings of personnel with information devices  30 . However, someone without an information device  30  may enter a building undetected if accompanied by someone who does have an information device  30 . The unauthorized person can only be detected if surveillance cameras or security guards are also employed. This, of course, is more costly and complex to implement. 
         [0050]    Still another embodiment of the present invention includes a method of package  110  identification and tracking within defined areas  10 . A package  110  or other inanimate object  20  includes an information device  30  that has information stored thereon that identifies the package  110  associated with the information device  30 . The information device  30  may include additional information including but not limited to (i) preprogrammed authorization levels, (ii) content information, (iii) disposition information, (iv) storage and stability information, (v) safety information and (v) memory for receiving information dynamically from the interrogation device  40 . Alternatively, packages may not have an information device  30 . In this case it may be possible to determine the identity of the package using physical, chemical or biologic sensors  90 . For example, volatile organic component sensors can detect the presence of many explosives. 
         [0051]    Alternatively, one may be able to identify a package  110  by determining its position or change in position. If a package  110  or object  20  has a unique radio frequency signature (for example a gun or explosive), the object  20  may be detected directly. The present invention may also be used to detect an unattended package  110  by associating the package  110  with another object and determining of the package  110  and the associated object have been separated. 
         [0052]    In another embodiment of the present invention, automatic warehousing of packages  110  within a defined area  10  includes package  110  identification and tracking. If a package  110  has an information device  30  attached thereto, an interrogation device  40  can determine the identity of the package  110 , its spatial coordinates and its movement within a warehouse. The information device  30  may also include (i) preprogrammed authorization levels, (ii) content information, (iii) disposition information, (iv) storage and stability information, (v) safety information and (v) memory for receiving information dynamically from the interrogation device  40 . Using the interrogation device  40 , one can determine in real time when packages  110  enter or leave a warehouse and where they are located within the warehouse. A package  110  can be stored almost anywhere without fear of losing the package  110  since one can easily determine its coordinates within the warehouse using an appropriately positioned interrogation device  40 . 
         [0053]    Another embodiment of the present invention provides an automated filing system. Files with information devices  30  can be stored randomly and retrieved after the location is determined with an interrogation device  40 . This approach reduces the chance of misplacing or losing important documents. It also reduces the time required to retrieve documents or files. Additional information stored in the information device  30  can help determine whether a file is relevant without retrieving and reviewing the complete file. 
         [0054]    Another embodiment of the present invention relates to baggage handling for airline, bus or train or other means of travel. By attaching information devices  30  to bags and passengers, interrogating the defined area  10  (the airport perimeter or other location), and communicating with the a master controller unit  50 , the present invention determines where a person&#39;s bags are after the person  60  enters the defined area  10  in relationship to the owner. 
         [0055]    In yet another embodiment, the present invention also provides a method of information transfer from an information device  30  positioned on an object  20  within a defined area  10 . The method includes transmitting data from the information device  30  to at least one interrogation device  40 . Data is then transmitted from the at least one interrogation device  40  to a master controller unit  50 . The data is compiled at the master controller unit  50  to determine characteristic information associated with the object  20 . In this embodiment, the method may also include transmitting data from the information device  30  to at least one passive repeater  120 , and relaying the data from the at least one passive repeater  120  to the at least one interrogation device  40 . The method may also include relaying the data from the at least one information device  30  to the at least one interrogation device  40  through a plurality of passive repeaters  120 . A transmission path for transmitting data is bi-directional, such that data flows from the at least one information device to the interrogation device to the master controller along the transmission path, and such that data flows from the master controller unit to the at least one interrogation device to the at least one information device along the transmission path. It is noted that in all embodiments of this invention, the path of transmission of information, including signals and data may include bi-directional or multi-directional paths. 
         [0056]    An information device  30  as contemplated by the present invention may be any device that is capable of active or passive communications and stores information regarding the object  20  on which it is placed. As discussed above, an example of an information device  30  according to the present invention is a standard RFID tag, drawings of which are shown in  FIG. 4  and  FIG. 5 . Standard RFID tags include a front-end that converts radio frequency or inductively coupled energy to the DC power required to operate the tag, and demodulates or detects the information signal. The RFID tags also include circuitry, often comprising a single chip, which contains the identification information and the capability to perform additional functions when the RFID tag is powered. 
         [0057]    RFID tags have different frequencies and come in many different shapes and with different functions. Unlike inductive RFID tags which require substantial surface area, many turns of wire, or magnetic core material to collect the magnetic field, UHF and microwave tags can be very small requiring length in only one dimension. Thus, in addition to longer range over the inductive systems, the UHF and microwave tags are easier to package and come in a wider variety of configurations. Tag lengths of 2 to 10 cm are typical. The tag&#39;s thickness is limited only by the thickness of the chip as the antenna can be fabricated on thin flexible materials. Since tags operating in the E field do not require antennas with extremely low impedances, inexpensive flexible antennas able to withstand considerable bending are achievable. 
         [0058]    RFID systems operate in both low (less than 100 MHz) and high frequency (greater than 100 MHz) modes. Unlike their low-frequency counterparts, high-frequency tags can have their data read at distances of greater than one meter, even while closely spaced together. New data can also be transmitted to the tags. 
         [0059]      FIG. 4  is a view of a low frequency information device  30 , such as an RFID tag. Information devices  30  such as those shown in  FIG. 4  and  FIG. 5  include a reader portion  130  and a tag portion  140 . In low-frequency systems such as those shown in  FIG. 4 , an integrated circuit  150  in the reader portion  130  sends a signal to an oscillator  160 , which creates an alternating current in the reader portion&#39;s coil  170 . That current, in turn, generates an alternating magnetic field that serves as a power source for the tag portion  140 . The field interacts with the tag portion&#39;s coil  180  in the tag, which induces a current that causes charge to flow into a capacitor, where it is trapped by the diode. As charge accumulates in the capacitor, the voltage across it also increases and activates the tag portion&#39;s integrated circuit  190 , which then transmits its identifier code. High and low levels of a digital signal, corresponding to the ones and zeros encoding the identifier number, turn a transistor on and off. Variations in the resistance of the integrated circuit  190 , a result of the transistor turning on and off, cause the tag portion  140  to generate its own varying magnetic field, which interacts with the reader portion&#39;s magnetic field. In this technique, called lead modulation, magnetic fluctuations cause changes in current flow from the reader portion  130  to its coil  170  in the same pattern as the ones and zeros transmitted by the tag portion  140 . The variations in current flow in the reader portion&#39;s coil  170  are sensed by a device that converts this pattern to a digital signal. The reader portion&#39;s integrated circuit  150  then discerns the tag&#39;s identifier code. 
         [0060]      FIG. 5  is a view of a high frequency information device  30 , such as an RFID tag. In a high-frequency system, the reader portion&#39;s integrated circuit  150  sends a digital signal to a transceiver  200 , which generates a radio-frequency signal that is transmitted by a dipole antenna  210  in the reader portion  130 . The electric field of the propagating signal gives rise to a potential difference across a dipole antenna  220  in the tag portion  140 , which causes current to flow into the capacitor, the resulting charge is trapped there by the diode. The voltage across the capacitor turns on the tag portion&#39;s integrated circuit  190 , which sends out its unique identifier code as a series of digital high and low voltage levels, corresponding to ones and zeros. The transistor gets turned on or off by the highs and lows of the digital signal, alternately causing the dipole antenna  220  to reflect back or absorb some of the incident radio-frequency energy from the reader portion  130 . The variation in the amplitude of the reflected signal, in what is called backscatter modulation, correspond to the pattern of the transistor turning on and off. The reader portion&#39;s transceiver  200  detects the reflected signals and converts them to a digital signal that is relayed to the reader portion&#39;s integrated circuit  150 , where the tag portion&#39;s unique identifier is determined. 
         [0061]    Typical memory size for information devices  30  such as RFID tags ranges from 64 bits for simple device to several Kbytes for devices used in data rich logistic applications. Memory types include factory-programmed “read only” for identification purposes with small memory size requirements, one time field programmable devices (OTP), and read/write tags which permit data to be changed. 
         [0062]    Passive information devices  30  store information in memory therein but do not have a source of power other than that provided by a signal from an external source, such as an interrogation device  40 . One type of information device  30  capable of use with the present invention is a preprogrammed information device  30 . This type of information device  30  may not be programmed by an interrogation device  40 . Still another type of information device  30  may be powered by interrogation device  40  at which time it performs specified functions in addition to reporting stored information. 
         [0063]    An active information device  30  is powered from a source other than the interrogation device  40 . For example, if the information device  30  is to be mobile it may have battery-supplied power. A cell phone and keyless entry system in a car and the hand-held controller for such a keyless entry system are examples of active information devices  30 . 
         [0064]    One example of an active information device  30  is one which is capable of identifying the object  20  on which it resides. For animate objects  20 , identification of the object  20  may include active biometric signature determination, which requires the identity to participate directly in the biometric determination by positioning itself or part of itself with respect to the sensor, such as fingerprint, iris pattern or hand or other blood vessel pattern. Identification may also include passive biometric identification, which does not require active participation of the identity in order to measure or sense the identity&#39;s biometric property. Identification may further include proximity to another information device  30  to confirm the identity. For example two information devices  30  can be positioned on an object  20 , where one is obvious and the other is hidden, that must have a prescribed relationship with respect to each other. Identification may also performed by an information device  30  that must be re-authenticated each time it is moved. An example of this is an information device  30  worn on the wrist for which a password must be entered each time the wristband is opened and closed. 
         [0065]    Information devices  30  capable of identifying the object  20  on which it resides by actively taking biometric or physiologic information may include additional modules for capturing specific biometric information. For example, a fingerprint module is a sensor which may be coupled to an information device  30  for use with the present invention. Other examples include image sensors that may be used to capture the image of the eye for a retinal scan or detection of an iris pattern. Another example is a sensor capable of detecting vascular patterns, such as the vein pattern on the back of a hand, or skin surface proximate capillary patterns. An information device  30  or sensor worn on the wrist may measure other characteristics such as wrist size, skin temperature and skin resistance. 
         [0066]    In one embodiment, an information device  30  identifying the object  20  on which it resides may also signal that it has been moved from the object  20  on which it belongs. In one aspect of this embodiment, the information device  30  sends a signal when it can no longer confirm the identity of the object  20  on which it is or was placed. Another aspect of this embodiment includes an information device  30  comprised of two parts that must both be moved/removed according to a specific protocol to avoid a signal that the information device  30  has been improperly removed. Such a two-part information device  30  may confirm identity by being positioned within a specific distance from each other, such that at some time prior to interrogation, this proximity is valid only for a given time period. For example, a user must set/reset encryption key periodically by bringing one part of the device to a “recharge station.” 
         [0067]    Another example of an information device  30  contemplated by the present invention is one which must be re-authenticated each time it is moved from an object  20 . Such an information device  30  may be one that is worn on the wrist and for which a password must be entered each time the wristband is opened and closed. 
         [0068]    Yet another example of an information device  30  according to this embodiment of the present invention is one which opening a wristband cuts an electrical connection for proper operation of the information device  30 . This connection is completed when a tool is used to affix the wristband. Such an information device  30  may be embodied, for example, on a single use identification bracelet. 
         [0069]    The present invention determines the presence of objects  20  and communicates with information devices  30  by spatially and temporally surveying the defined area  10 . Interrogation devices  40  contemplated by the present invention perform this spatial and temporal survey of the defined area  10 . In the present invention, therefore, at least one interrogation device  40  is within a transmission and detection range of a defined area  10 . One example of an interrogation device  40  contemplated by this invention is one that typically relies on low cost implementation technology, operating in the microwave range to enable radar-like operation for identifying and tracking objects  20  with or without information devices  30 . One or more interrogation devices  40  each with scanning capability are used to localize the position and interrogate each information device  30  within its range. Information from all interrogation devices  40  are combined to locate and identify objects  20  within a defined area  10 . 
         [0070]    Several different types of interrogation devices  40  are contemplated for use with the present invention. In one embodiment, an interrogation device  40  locates objects  20  within a defined area  10  without information devices  30  positioned thereon. An interrogation device  40  according to this embodiment emits a signal and analyzes the return signal to determine the presence of objects  20  within its scan range. The interrogation device  40  may operate at different frequencies and at different distances depending on a variety of factors, including the aperture and antenna configuration and the type of application for which transmission is being used. In one embodiment, the interrogation devices  40  may transmit 10 to 30 GHz signals focused in a narrow aperture using a phased array antenna for distances up to 100 meters. In another embodiment, the interrogation device  40  operates with a spatial resolution of less than a meter at distances up to 100 meters; in the embodiment where the frequency is 10 GHz, the wavelength is 3 cm. In another embodiment, the interrogation device  40  performs a mapping function using electromagnetic radiation in any band providing desired resolution, such as RF with a frequency of 984 MHz for distances of 1 foot, RF with a frequency between 30 and 15 GHz for distances of 1 or 2 cm. This technology is well known and is widely used for applications such as radar systems. 
         [0071]    Other interrogation devices  40  according to this embodiment operate over a large range at relatively low power, such as a wireless device. Such interrogation devices  40  may have a range of several miles or larger. These long-range interrogation devices  40  employ a narrow directed beam from the interrogation device  40 . Use of the narrow beam delivers more power and more signal strength to the information device  30 . Use of this technology also allows greater sensitivity in receiving a response from the information device  30 . 
         [0072]    In another embodiment of the present invention, a plurality of interrogation devices  40  are employed, each of which is capable of communicating with other at least one other interrogation device  40 . Such interrogation devices  40  are configured to operate in a relay format, in which one or more interrogation devices  40  interrogate a defined area  10 , and communicate received data to and from another interrogation device  40  in the plurality of interrogation devices  40  as part of the overall system of communication with a master controller unit  50 . This type of communication technology is widely known in the art and is commonly used in systems such as mobile telephone networks, in which devices communicate with one another either directly or through a base station. 
         [0073]    Another embodiment of an interrogation device  40  capable of operating in synchrony with other such interrogation devices  40  is one which creates a “large aperture” device for fine resolution. Examples of such devices include synthetic aperture radar. A spatial array of interrogation devices  40  operating in appropriate synchrony can duplicate a moving antenna configuration, such as in radio telescopes and phased array devices. 
         [0074]    An interrogation device  40  according to the present invention communicates data to and from a master controller unit  50 , which is located within a transmission and detection range of at least one interrogation device  40 . A master controller unit  50  according to the present invention may be a single device or a distributed group of devices. A master controller unit  50  may include a computer or a computer network that receives information from one or more interrogation devices  40 . Examples of a master controller unit  50  include cell phone networks, in which a base station acts as the master controller unit  50 , and the Internet, in which with various servers acts as network of distributed master controller units  50 . 
         [0075]    One function of a master controller unit  50  of the present invention is compiling information received from an interrogation device  40 . The master controller unit  50  compiles such information to perform a variety of other functions, such as resolving the location of an object  20  within the defined area  10 , determining its identity, and defining access and presence conditions. The master controller unit  50  may accomplish this by performing algorithmic functions to determine the position of the object  20 . One example of an algorithm applied by a master controller unit  50  is one for which the intersection of every possible pair of interrogator direction lines is determined. The centroid of the points is computed as the estimate of the object&#39;s location. 
         [0076]    Information processed by a master controller unit  50  may also be transmitted to another master controller unit  50 , or displayed for human review. The location of objects can be displayed graphically for a human observer to review and act upon. The master controller unit  50  may also control an environment within the defined area  10  in accordance with information received from the interrogation device  40 . Environmental control may include limiting ingress to the defined area  10  if the capacity of the defined area  10  has been reached or if other conditions such as a dangerous object or classified material are present. Environmental control may also include adapting an environment to a specific object  20  or a group of objects  20 . For example, if inanimate objects  20  requiring specific temperature or humidity control are found, the appropriate conditions can be imposed. If certain human identities are sensed that are for example visually impaired, then audible environmental warnings stating the dangers explicitly can be announced as opposed to say the normal light indicators. 
         [0077]    It is to be understood that other embodiments may be utilized and structural and functional changes may be made without departing from the scope of the present invention. The foregoing descriptions of embodiments of the invention have been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Accordingly, many modifications and variations are possible in light of the above teachings. For example, multiple information devices  30 , and many different types of passive and active information devices  30  in different combinations may be used in accordance with the present invention. Additionally, the information device  30  may be of any size, including nano-scale devices, and may be embedded in another device or some other vehicle on the object  20 , including human skin or blood. An object  20  may therefore have any number of nano-scale information devices positioned thereon, each capable of indicating characteristic information associated with the object  20 , and each capable of communicating with another such device and/or with an interrogation device  40 . It is therefore intended that the scope of the invention be limited not by this detailed description.