GB2306736A

GB2306736A - Method and apparatus to provide security for a movable article

Info

Publication number: GB2306736A
Application number: GB9522797A
Authority: GB
Inventors: Trevor John Pullen; Den Heuvel Anthony Van
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1995-11-03
Filing date: 1995-11-03
Publication date: 1997-05-07
Also published as: GB9522797D0

Abstract

A security device (15) is associated with the movable article (12), and enabled to provide protection for the movable article (12). The security device (15) determines relative distance information corresponding to the difference between an initial position of the article when security is enabled, and the current position of the article (51, 52). This relative distance information is compared with range limit information designated for the movable article, such as by configuration of the security device (53). When the comparison indicates that the relative distance information exceeds a designated range limit, the security device initiates a particular response (54). Distance information is obtained from a satellite positioning system or from an internal accelerometer.

Description

METHOD AND APPARATUS TO PROVIDE SECURITY FOR A MOVABLE ARTICLE Technical Field This invention relates in general to security devices, such as security devices attached to articles to protect against unauthorized movement.

Badund of the Invention Security devices are often attached to movable articles to guard against theft or other unauthorized movement. These devices vary in complexity, cost, effectiveness, and suitability for a particular application. In one example, a motion detector and alarm device is associated with a protected article. When the article is moved, motion is detected and the alarm enabled.

Such devices are suitable for protecting articles intended to remain at a fixed location.

In a second example, merchandise available for sale in a store may have a security tag securely attached. It is expected that the merchandise will remain within a restricted egress area until removal is authorized.

Ordinarily, the restricted egress area includes a detection system that has detectors installed at various egress locations. The detector alerts when unauthorized removal of a protected item is attempted. In such instances, protection is disabled by removal of the tag, or by registration of the tag with the detection system. This approach requires the establishment of a controlled access environment, and the installation of detectors.

A third example involves a theft recovery device located within a protected article. When activated, the device transmits a signal that is used to locate the article. The theft recovery device may include a location determining system, such as a global positioning satellite (GPS) receiver, to determine absolute position. This positioning information can be incorporated into the signal. A theft recovery system employing this technique requires a separate receiver system located outside the device at a location likely to intercept the transmitted signal. Moreover, this type of protection generally require knowledge of unauthorized movement of the protected article, and activation of the theft recovery device.

The prior art security devices described do not fully address the protection of movable articles, particularly, when an additional setup of an externally enforced secure environment is impractical or undesirable. Yet in many such situations, protection is needed for an article for which permissible movement within a particular area is desired. Therefore, a need exists for a security device which allows for limited movement of a protected article without the need to establish a secure environment.

Summary of Invention These needs and others are substantially met through the provision of a method and apparatus to implement security for a movable article. A security device is associated with the movable article, and enabled to provide protection for the movable article. Pursuant to the present invention, the security device determines relative distance information corresponding to the difference between an initial position of the article when security is enabled, and the current position of the article. This relative distance information is compared with range limit information designated for the movable article, such as by configuration of the security device. When the comparison indicates that the relative distance information exceeds a designated range limit, the security device initiates a particular response.

In a first embodiment, the security device incorporates a receiver for obtaining positioning information from an external source. First location information is obtained for the initial position of the security device when armed, and second location information obtained for the current position of the security device. The security device determines relative distance by comparing the first and second location information.

In a second embodiment, the security device incorporates a timer and at least one accelerometer. The security device combines information derived from the accelerometer and timer to determine the relative distance moved.

Brief Description of the I)rawings FIG. 1 is a block diagram representing a protected movable article that incorporates a security device, in accordance with the present invention.

FIG. 2 is a block diagram of the security device of FIG. 1, in accordance with the present invention.

FIG. 3 is a block diagram of a first embodiment of the security device having a relocation range determiner based on externally sourced positioning information, such as provided by a global positioning satellite receiver, in accordance with the present invention.

FIG. 4 is a block diagram of a second embodiment of the security device having a relocation range determiner based on information derived from an accelerometer, in accordance with the present invention.

FIG. 5 is a flowchart of procedures for operation of the security device, in accordance with the present invention.

FIG. 6 is a flowchart of procedures used by the security device of FIG. 3, in accordance with the present invention.

FIG. 7 is a flowchart of procedures used by the security device of FIG. 4, in accordance with the present invention.

Detailed Description of the Preferred Enibodiment While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward.

Generally, the present invention provides a method and apparatus to implement security for a movable article. A security device is associated with the movable article, such as by attachment, or such as by embedding the security device within the movable article. The security device is enabled to provide protection for the movable article. According to the present invention, the security device determines relative distance information corresponding to the difference between an initial position of the article when security is enabled, and the current position of the article. This relative distance information is compared with range limit information designated for the movable article, such as by configuration of the security device. When the comparison indicates that the relative distance information exceeds a designated range limit, the security device initiates a particular response.In a first embodiment, the security device uses positioning information derived from an external source, such as a global positioning system (GPS), to determine relative distance from the current position of the article to its initial position. In a second embodiment, the security device derives information from an accelerometer to determine the relative distance moved.

Referring to FIG. 1, a block diagram 10 shows a movable article 12 that incorporates a security device 15, in accordance with the present invention.

The movable article 12 may be any item that needs protection, such as electronic equipment, luggage, or other item that can support attachment of the security device 15. The security device 15 may be attached externally or internally with respect to the movable article.

Referring to FIG. 2, a block diagram of the security device 15 is shown, in accordance with the present invention. The security device 15 includes a security enabler 21, a security breach detector 23, a response initiator 27, and an alarm generator 28. The security enabler 21 is operable to arm and disarm the security device, and thus provides a mechanism for enabling and disabling the security device 15. Accordingly, the security enabler 21 incorporates an input device 22 which may be in the form of a simple ON/OFF switch. However, inputs to the security device 15 may be accomplished through a more sophisticated input device 22, such as a keypad. Moreover, the input device may be a receiver, such as an infrared receiver, a radio frequency receiver, or the like, which can receive external inputs for configuration purposes.

In the preferred embodiment, the input device 22 comprises a keypad or other input means for configuring additional information used by the security device 15. Configuration information may include one or more range limit parameters that define the boundaries of permissible movement for the security device, and thus the movable article, before a security breach response is initiated.

The response initiator 27 provides an appropriate response to a security breach. The response initiated may be fixed, such as the generation of an alarm, or in a more sophisticated application, may vary based on the severity of the security breach, as determined by the security breach detector 23.

Preferably, the initiated response varies based on the distance relocated from the initial position. The alarm generator generates an audible or visual signal when a range limit is exceeded. Further, the alarm generator may incorporate a transmitter, for transmitting signals containing information useful in locating the movable object. The transmitter may be enabled for particular egregious security breaches, such as after the movable article is relocated a large distance from its initial position.

According to the present invention, the security device 15 incorporates a security breach detector 23 that uses relative positioning information to determine when the movable article is relocated from an initial location that corresponds to the position of the security device when security is enabled.

The security breach detector 23 is coupled to the security enabler 21 and the response initiator 27. In the preferred embodiment, the security breach detector 23 includes a range limit memory 24, a controller 25, and a relocation range determiner 26. The range limit memory 24 is a storage area for one or more parameters, specified as a default, or derived from information configured at the security enabler 21 via the input device 22. The relocation range determiner 26 ascertains distance information corresponding to the current location of the security device with respect to its initial position at the time security is enabled. The controller 25 is coupled to the range limit memory 24 and the relocation range determiner 26, and provides operational control of the security breach detector 23.Preferably, a power source 29, such as a battery, provides operating power to the security breach detector 23 for constant operation after security is enabled. This is particularly useful in the accelerometer based embodiment of the security breach detector 23 described below.

Referring to FIG. 3, a portion of the security breach detector is shown, in which the relocation range determiner 26 is based on externally sourced information, in accordance with the present invention. Generally, the external source comprises strategically located transmitters that transmit location signals. In this embodiment, the external source is a global positioning satellite (GPS) system. The relocation range determiner 26 includes a GPS receiver 31, an initial location memory 32, a current location memory 33, and a comparator 34. As is well known in the art, the GPS receiver 31 gets information signals from orbiting satellites via an antenna 36, which is used to provide current location information.One benefit of determining location based on an external source that provides absolute positioning information, such as a GPS system, is that the security breach detector 23 need not be constantly powered. A temporary disruption of power may delay a security breach response but still permits the security breach detector 23 to function as described.

The receiver 31 receives location information when the security device is armed to determine initial position. Additionally, location information is received periodically, that corresponds to the current position of the security device. When an initial location is determined, this information is stored in an initial location memory 32. Similarly, current location information is stored in memory 33. The comparator 34 compares the information stored in the location memories 32, 33 and determines the difference between the initial and current location information, preferably along a vector extending between the initial and current locations.

Referring to FIG. 4, an alternative embodiment of the present invention is shown, in which a relocation range determiner 46 is based on information derived from an accelerometer. The relocation range determiner 46 includes a timer 41, an accelerometer 42, and a current location memory 43. The controller 25 is coupled to the accelerometer 42 and the timer 41. When the security enabler 21 sends an arming signal to the security breach detector 23, the controller 25 repeatedly samples information from the accelerometer 43 and combines the sampled information with related elapse time information from the timer 41 to derive range of movement information. As frequent sampling of information from the accelerometer 42 is desirable, it is important to maintain power to the security breach detector 46 while the security breach detector 23 is armed.

In the preferred embodiment, information, such as a voltage signal, from the accelerometer is integrated twice to determine distance information.

Generally, it is assumed that the protected article is initially at rest with respect to its immediate environment when the security device is armed.

Consequently, an initial position of zero (0), and an initial velocity of zero (0) can be assumed. When the information from the accelerometer is integrated twice with respect to time, distance information is generated. The controller 25 resolves the various movement of the article to determine a distance along a vector from the initial location to the current location. For improved vector distance resolution, the relocation range determiner 46 may include multiple accelerometers. For example, samples from three properly oriented accelerometers can provide movement information along three axes. The current relative location information with respect to the initial position is updated and maintained in memory 43. Additional memories (not shown) may also be incorporated to facilitate calculations.

FIG. 5 shows a flowchart of procedures used to establish security for a movable article, in accordance with the present invention. FIG. 6 is a flowchart of procedures used for a relocation range determiner based on externally sourced positioning information. FIG. 7 is a flowchart of procedures in the alternative embodiment, in which the relocation determiner is based on information derived from an accelerometer. With reference to FIGs 5, 6, and 7, the operation of the security device will now be described.

It is assumed that the security device is embedded in, or attached to, the movable object to be protected. When protection of the movable article is desired, security is enabled by arming the security device, step 51. The security device determines relative distance information corresponding to a difference between an initial position of the article when security is enabled, and a current position of the article. In other words, the security device determines the relative distance moved, preferably, according to a vector, with respect to the initial position of the article.

In the first embodiment, the security device receives first location information from an external source when security is enabled, step 61. This location information may be sourced from a satellite positioning system. The security device also receives, from the same or other external source, second location information corresponding to the current location of the article, step 62. The security device then compares the first and second location information to determine a difference corresponding to the net distance moved, step 63. In the second embodiment, the security device samples signals from an accelerometer, step 71, and in conjunction, also gets related elapsed time information, step 72. Acceleration information is integrated twice with respect to the time information to determine the distance moved between the current location and an initial location, step 73.

The security device then compares the relative distance information, according to distance moved, with range limit information designated for the movable article, step 53. This may be a single parameter defaulted for the security device, or the information may comprise several configurable parameters. When the security device determines that the movable article has been relocated with respect to its initial position, outside a predefined permissible range or boundary, the security device then initiates a response such as an alarm to alert the user of unauthorized movement of the article, step 54. The initiated response may be fixed or may vary depending on the distance relocated.

The present invention offers significant benefits over security devices of the prior art. For example, a range of permissible movement can be defined for a protected article, and be enforced without having to setup an external secure environment. This represents an advance over the art for security devices depending, for example, on simple motion detection for alarm purposes, as some movement of the protected article is permitted. By establishing relative boundaries, with respect to the movable article, a security device, according to the present invention, affords a wide variety of applications.

While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.

What is claimed is:

Claims

Claims 1. A method for providing security for a movable article, comprising the steps of: enabling security for the movable article; determining relative distance information corresponding to a difference between an initial position of the movable article when security is enabled to a current position of the movable article; comparing the relative distance inforination with range limit information designated for the movable article; and initiating a response when the relative distance information indicates an exceeded range limit.
2. I'he method of claim 1, wherein the step of determining relative distance information comprises the steps of: receiving first location information from an external source when security is enabled; receiving second location information from an external source when article at the current position; and determining a difference between the first and second location information.
3. The method of claim 2, wherein the steps of receiving first location information and receiving second location information comprises the step of receiving location information from a satellite positioning system.
4. The method of claim 1, wherein the step of determining relative distance information comprises the steps of: repeatedly sampling information from an accelerometer; and combing information derived from the accelerometer with related elapse time information.
5. The method of claim 2, 3 or 4, further comprising the step of configuring range limit information for the movable article.
6. The method of claim 2, 3, 4, or 5, wherein the step of initiating a response, comprises the step of enabling an alarm.
7. A security device for a movable article, comprising: a security enabler operable to arm the security device; a response initiator for activation in response to a security breach; a security breach detector coupled to the security enabler and response initiator, characterized by: a relocation determiner that determines a range of movement between an initial position of the security device when armed, and a current position of the security device; wherein the response initiator is activated when the range of movement is beyond a particular range limit.
8. The security device of claim 7, wherein the relocation determiner comprises: a receiver for receiving present location information, wherein the receiver receives first location information when the security device is armed, and second location information corresponding to the current position of the security device; and a comparator that determines a difference between the first and second location information.
9. The security device of claim 8, wherein the receiver comprises a global positioning satellite receiver.
10. The security device of claim 7, wherein the relocation determiner comprises: an accelerometer; a timer; and a controller coupled to the accelerometer and timer, the controller being responsive to an arming signal from the security enabler to repeatedly sample information from the accelerometer, and combine sampled accelerometer information with related time elapse information from the timer to derive range of movement information.
11. The security device of claim 7, 8, 9, or 10, wherein the security breach detector is further characterized by a memory having a configurable range limit parameter.
12. The security device of claim 7, 8, 9, 10, or 11 wherein the security device is attached to a movable article.
13. The security device of claim 7, 8, 9, 10, or 11 further comprising an alert generator coupled to the response initiator.