ANTI-THEFT SYSTEM AND METHOD
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to anti-theft systems and, more particularly, to a system and method for inhibiting the theft of baggage at travel terminals such as airports.
The commonly used system for checking baggage on an airline flight is to provide each bag with an identification tag and to provide each passenger with a stub from each of the tags of his or her bags. The purpose of the tag is twofold: to make it easier for the passenger to identify his or her bags at the end of the flight, and to inhibit deliberate or accidental theft of baggage. In many airports, guards are stationed at the exit gates of baggage pickup areas to verify that the exiting passengers have in their possession stubs corresponding to the tags on their baggage. This manual system often causes delays in leaving the airport, and also imposes on the airport authorities the expense of hiring the guards. Therefore, at many other airports, particularly outside the United States, arriving passengers and their baggage are not checked to verify that each passenger has in his or her possession only his or her own baggage. It thus would be highly advantageous to have an automated system for verifying that someone leaving an airport is not walking off with someone else's baggage.
There are two prior art anti-theft systems for related applications. Neither, however, is directly applicable to the problem at hand. The first anti-theft system is used by couriers carrying valuable items such as diamonds. Two short range (order of one meter) transceivers are provided that continuously transmit radio signals to each other. The courier keeps one transceiver
in his or her pocket and puts the other transceiver in the bag with the valuable items. If the bag is taken out of range of the first transceiver, the first transceiver signals the courier that an attempted theft is in progress. This system is unsuitable for the problem at hand because a passenger and his or her checked baggage must be separated during the flight; their presence together is possible, and required, only after the flight, on the way out of the airport.
The second anti-theft system is the one commonly used by retail stores to inhibit shoplifting. Every item in the store is provided with a tag whose presence is sensed by a gate at the store exit. When an item is purchased, the clerk removes the tag. Any item transiting the gate without being paid for sets off an alarm at the gate. This system, too, is unsuitable for the problem at hand, because it associates the store's merchandise with a particular location (the store), not a particular person.
SUMMARY OF THE INVENTION According to the present invention there is provided a system for verifying the mutual association of a plurality of items belonging to a common set, at least one of the items being a primary item and at least one other of the items being a secondary item, the system comprising: (a) a plurality of identification devices, each of the identification devices being associated uniquely with one of the items, each of the identification devices having an identity; and (b) an electronic monitor capable of establishing the identities and querying the association of each of the at least one secondary item with each of the at least one primary item.
According to the present invention there is provided a method of verifying the mutual association of a plurality of items belonging to a common set, at least one of the items being a primary item and at least one other of the items being a secondary
item, comprising the steps of: (a) providing each of the items with an identification device having an identity; (b) providing an electronic monitor capable of establishing the identities; and (c) establishing the identity of the identification device provided to at least one of the items, by the monitor, the establishing being done substantially simultaneously for all items whose identity is established in the case that the identity of at least two of the items is established.
According to the present invention, each passenger and his or her baggage are provided with devices that associate that passenger with that baggage. So far, the system of the present invention is identical to the prior art system that relies on identification tags and their stubs. The point of innovation of the present invention is to replace the guards at the airport exits with machines, located at transit control devices such as exit gates, that are capable of establishing the identities of the devices and verifying, based on those identities, that the baggage belongs to the passenger.
One system, within the scope of the present invention, is a direct extension of the prior art system. In one prior art system, the tag provided to each bag is a sticker bearing a bar code. According to the present invention, the tag provided to the passenger is a second sticker bearing the same bar code, or a related bar code. The passenger applies the second sticker to the bag before leaving the baggage pickup area. Each exit gate is provided with a monitor including a bar code reader. Each exiting passenger is required to pass his baggage past the bar code reader. If the monitor detects only one bar code, or two bar codes that differ in a way indicative of separate ownership, on a bag, the monitor indicates a possible theft attempt, for example by emitting an audible alarm.
This simple embodiment of the system of the present invention suffers from the disability that each bag must be scanned separately. A passenger with several
bags on a baggage cart must unload the bags for scanning, and then reload the cart after scanning. This tends to create a bottleneck at the exit gates Therefore, the preferred embodiments of the system of the present invention are based on active electronic devices: the identification devices provided to the passengers and their baggage include short range transmitters that transmit signals corresponding to their identities, and each exit gate is provided with a monitor that includes a receiver for receiving the signals, a processor for processing the signals, and an alarm system that indicates a possible theft attempt if the identities corresponding to the signals show that one or more bags are present without a person authorized to have them in his or her possession. Most preferably, the alarm system also indicates the presence of an unaccompanied primary identification device, to remind an absent minded passenger that he or she has forgotten to retrieve the baggage that he or she had checked onto the flight prior to boarding.
Although the description herein focuses on associating a passenger with the proper baggage, the scope of the present invention includes all applications in which it is necessary to verify the mutual association of a plurality of items located together at one time at a particular point. The only restriction on the kinds of items that are within the scope of the present invention is that some of the items are primary, in the sense that, like a passenger or other authorized possessor of baggage, these items must be present when mutual association is verified, and the other items are secondary. Nevertheless, the primary application of the present invention is to verifying the mutual association of a passenger and his or her baggage, and the description herein is phrased in terms of this application.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
FIG. 1 is a general portrayal of the components of the embodiments of the present invention that are based on wireless communications;
FIG. 2 is a block diagram of the identification devices;
FIG. 3 is a block diagram of the monitor;
FIG. 4 is a flow diagram for the present invention;
FIG. 5 is a general portrayal of the components of the embodiment of the present invention that is based on bar code stickers.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is of an anti-theft system that verifies the mutual association of a plurality of items, and a method for its use. Specifically, the present invention can be used to deter the theft of baggage at airports.
The principles and operation of an anti-theft system according to the present invention may be better understood with reference to the drawings and the accompanying description.
Referring now to the drawings, Figure 1 is an overview of the components of the present invention. A traveler 10 carries a suitcase 20. Traveler 10 carries on his or her person (for example, in a shirt pocket, as shown) a primary identification device
30. Inside, or integrally formed with, suitcase 20 is a secondary identification device
32. On an exit gate 40 is mounted a monitor 42.
Figure 2 is a simplified block diagram of each of the identification devices. When a wake-up signal from monitor 42 is received by a receiver 52, a
processing/control unit 54 turns on a transmitter 50. Transmitter 50, receiver 52 and processing/control unit 54 receive electrical power from a power supply 56. The medium of transmission and reception may be any suitable wireless communications medium, for example, radio communications, ultrasound communications or infrared communications. The transmission range of devices 30 and 32 is short, on the order of a few meter, to make sure that monitor 42 processes, at one time, only those travelers 10 and associated baggage that pass through gate 40. Therefore, the required power level of the device is very low. Because the most prolific consumer of power in devices 30 and 32 is transmitter 50, the fact that transmitter 50 is turned on only in response to a wake-up signal make the energy requirements of devices 30 and 32 extremely low: an ordinary watch battery is more than adequate as power supply 56. A mechanism 58, connected to battery 56, is provided to sense the power level of battery 56 and indicate when that power level falls below a preset threshold, to warn the user that battery 56 must be replaced. This indication may take the form of a suitable signal to monitor 42. Note that primary device 30 and secondary device 32 are substantially identical, except in their external form (device 30 being adapted to being carried on the person of traveler 10; device 32 being adapted to suitcase 20) and in the identification signals they transmit.
Figure 3 is a simplified block diagram of monitor 42. A processing/control unit 64 analyzes the signals received by a receiver 62 and, depending on the nature of the signals received, activates an alarm system 66. Monitor 42 also includes a transmitter 60, controlled by processing/control unit 64, whose function is described below, and a device such as a video camera/video recorder 68 for recording images of the passengers and baggage transiting gate 40, to enable the identification of thieves who evade other apprehension procedures that rely on alarm system 66. Transmitter
60 and receiver 62 are structurally similar (but not identical) to transmitter 50 and receiver 52, respectively. It will be clear to one ordinarily skilled in the art how the functional differences described below between devices 30 and 32 and monitor 42 are reflected in structural differences between transmitters 50 and 60, and between receivers 52 and 62. (For example, in one embodiment of the system of the present invention, described below, receiver 62 must be capable of receiving transmissions at several frequencies, whereas receiver 52 receives transmissions at only a single frequency.)
Transmitters 50 transmit signals identifying their respective devices 30 and 32. Each identification signal includes an indication of the identities of the set to which it belongs, and an indication of whether it is transmitted by a primary device 30 or a secondary device 32. Illustrative formats for these identification signals are described below. Monitor 42 receives these signals and processes them in accordance with the flow diagram of Figure 4. When signals are received (block 70), monitor 42 first counts the number of sets indicated by the incoming signals (block 72). The presence of a large number (more than a reasonable threshold number of passengers that can pass through exit gate 40 simultaneously) of sets (block 74) suggests the presence of a sophisticated thief equipped with a transmitter that transmits all possible primary signals, so alarm system 66 alerts the airport authorities to the presence of a thief who is trying to deceive the system using jamming techniques (block 76). If a reasonable number of sets are present, monitor 42 loops over the sets (block 78). If one of the sets lacks primary signals (block 80), alarm system 66 alerts the airport authorities to the presence of a thief (block 82). If one of the sets lacks secondary signals (block 84), alarm system 66 issues a warning that one or more of travelers 10 has forgotten to
retrieve his or her baggage (block 86). When all sets have been checked (block 88), monitor 42 returns to block 70 to wait for more signals.
There are several possible methods for distinguishing sets of items from one another, and for distinguishing the primary identification device from the secondary identification devices within the same set, based on the identification signals transmitted by the identification devices. The simplest, particularly if the communications medium used is radio or ultrasound, is to assign each set a pair of frequencies chosen at random from a large number (for example, 500) of available pairs of frequencies, one frequency for primary device 30 and the other frequency for secondary device 32. Under this scheme, devices 30 and 32 transmit continuous waves (sinusoids) of their respective frequencies. Another is to transmit at a single frequency, but to time-share the transmissions by assigning each device 30 or 32 a particular transmission time slot. Under this scheme, time is divided into a sequence of successive time frames of equal length, for example 0.5 seconds each. Each device 30 or 32 transmits only during a defined time slot within each frame. These time slots all have a duration equal to a common base time, for example 1 millisecond, and all start at some integral multiple of that base time relative to the start of their time frame. All primary devices 30 which belong to the same set are assigned a time slot which starts at an even multiple of the base time. Secondary devices 32 of that set all are assigned the following time slot. The specific even integer assigned to the primary devices of a particular set is selected at random from a large set of even numbers that is compatible with the durations of the time frames and the base time. In the case of 0.5 second time frames and a base time of 1 millisecond, a suitable set of integers is the set of even integers from 0 to 498. Under this scheme, monitor 42 continuously transmits a synchronization signal that indicates the start of each time frame, and that
is received by identification devices 30 and 32 while they are within range of monitor
42, to guarantee that each device 30 or 32 transmits its identification signal only in its assigned time slot.
As noted above, processing/control unit 54 is configured to turn device 30 or 32 only on receipt of a wake-up signal from transmitter 60 of monitor 42, via receiver 52, and to turn off device 30 or 32 when the wake-up signal is no longer received. In this way, devices 30 and 32 are turned on only when traveler 10 or suitcase 20 pass through gate 40. This greatly extends the life of power supply 56. The wake-up signal from monitor 32 may be as simple as a continuous wave signal that is received by devices 30 and 32 only when they are within the transmitting range of monitor 42. Alternatively, the same signal from monitor 42 is used as both a synchronization signal and a wake-up signal.
Figure 5 shows the components of a system of the present invention base on bar code stickers 34 and 36, encoded with identification numbers encoded as bar codes 38. At check-in, the clerk at the check-in counter applies secondary sticker 36 to suitcase 20, and gives primary sticker 34 to traveler 10. When traveler 10 retrieves suitcase 20 at the baggage pickup area, traveler 10 applies primary sticker 34 to suitcase 20 and proceeds to gate 40'. Gate 40' includes an egress 41 for passengers and a conveyor belt 44 for baggage. Alongside conveyor belt 44 is a monitor 42', similar to monitor 42 but lacking transmitter 60 and including, instead of receiver 62, a bar code reader 46. Traveler 10 places suitcase 20 onto conveyor belt 44, oriented so that conveyor belt 44 carries stickers 34 and 36 past bar code reader 46. As suitcase 20 passes bar code reader 46, monitor 42' reads bar codes 38. In all other respects, the operation of this embodiment is identical to the operation of the embodiments based on wireless communications media.
While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.