This invention relates in general to techniques for tracking and monitoring and, more particularly, to techniques for tracking and monitoring assets such as shipping containers.
A variety of different products are transported in shipping containers. Products are packed into a container by a shipper, and then the container doors are closed and secured with some type of lock. The locked container is then transported to a destination, where a recipient removes the lock and unloads the container.
It is often advantageous to the shipper if some form of monitoring can be carried out while the container is being transported. As one example, the cargo in the container may be relatively valuable products such as computers or other electronic devices, and thieves may attempt to break into the container to steal these products while the container is in transport. As a different example, the cargo in the container may include products such as fresh fruit, for which it is advantageous to continuously monitor temperature, humidity and/or other environmental conditions, in order to avoid or minimize spoilage. Another consideration is that it may be beneficial to the shipper and/or the recipient to be able to accurately track the current location of the container as it travels from the shipper to the recipient.
It is not cost-feasible to have a person watch a container at all times in order to provide security and/or monitoring. Accordingly, electronic systems have previously been developed to provide a degree of automated security and/or monitoring. For example, one existing approach is to attach a radio frequency identification (RFID) tag to a container. The tag then provides monitoring as to both security and environmental conditions, and can send wireless signals that contain status information, including warnings about alarm conditions. Pre-existing systems of this type have been generally adequate for their intended purposes, but they have not been satisfactory in all respects. As one example, tags are typically battery operated, and there is always a need to find new ways to minimize power consumption, while maximizing the “visibility” of the tag to a central system, and minimizing service costs.
A better understanding of the present invention will be realized from the detailed description that follows, taken in conjunction with the accompanying drawings, in which:
The container 11 is made almost entirely of steel or aluminum, except that a not-illustrated floor within the container may be made of either wood or metal. The container 11 has at one end a large opening 14 with an approximately square shape. The container has hinges that support two rectangular doors 16 and 17 for pivotal movement about respective spaced vertical axes 18 and 19. The axes 18 and 19 are located near respective side edges of the opening 14. The doors 16 and 17 are each shown in a closed position in
The doors 16 and 17 each have a respective vertical outer edge 21 or 22, which is disposed adjacent the associated pivot axis 18 or 19. In addition, the doors 16 and 17 each have a respective vertical inner edge 23 or 24. When the doors 16 and 17 are in the closed position of
When the container 11 has been packed with items or products that are to be shipped, various considerations come into play. As a first example, there are situations in which it is desirable to be able to monitor environmental conditions within the container. For example, products such as fresh fruit may keep better if environmental conditions within the container 11 remain within certain acceptable limits. Thus, it may be desirable to monitor relevant environmental conditions such as temperature or humidity. As a second example, after the doors 16 and 17 have been closed and secured at the point of shipment, it may be desirable to have some form of security and monitoring in order to verify that the doors are not opened again until the container arrives at its destination. For example, while the container is in transit, thieves may attempt to break into the container 11 in order to steal valuable cargo therein, such as computers or other electronic devices. As a third example, the shipper may wish to have accurate information about the current location of the container as it progresses along its journey from the shipper to the recipient. The tracking and monitoring system 10 of
The modules 56 and 57 contain most but not all of the circuitry of the tag 12. The circuitry is discussed in more detail later, but one part of the circuitry is a flat, flexible door sensor 58 that is fixedly secured to the outer side of the bight 54 of the clip 51. In the disclosed embodiment, the door sensor 58 is a capacitive proximity sensor that is responsive to the presence or absence of the metal door 16 in the vicinity of the sensor 58. It is not necessary for the metal door 16 to physically touch the door sensor 58.
Although the door sensor 58 is a capacitive proximity sensor, it would alternatively be possible to use some other type of sensor, such as a pressure sensor that is engaged by door 16, and actuated by physical pressure exerted on it by the door 16. The interior module 56, door sensor 58 and exterior module 57 are electrically coupled by a ribbon cable that is not visible in the drawings. The ribbon cable extends along the outer side of the clip 51, from the interior module 56 to the door sensor 58, and then on to the exterior module 57. The physical configuration of the tag 12 shown in
Referring again to
The system 10 includes a computer-based central system 81 that communicates with the tag 12 in order to facilitate tracking and monitoring of the container 11. As one aspect of this, the central system 81 is coupled to a stationary RFID reader 83. A typical system might include a plurality of readers 83 but, for clarity, only one reader 83 is shown in
The system 10 also includes a stationary signpost 87 of a known type, and the signpost 87 is electrically coupled to the central system 81. A typical system would include a plurality of the signposts 87 but, for clarity, only one signpost 87 is shown in
The signpost signal 88 also includes a field that contains a command 92. The command 92 is a command sent by the central system 81 to the tag 12, and can affect the operation of the tag 12. Some types of commands 92 do not require any associated parameter, but other types of commands do require a parameter. As to the types of commands that require a parameter, the parameter for the command is provided in a field 93. Since the purpose of the command 92 is to affect the operation of the tag 12, a discussion of specific commands will be deferred until after the tag 12 has been described in more detail.
The tag 12 has a unique identification code, and the container 11 has a unique identification code. If the tag 12 sends the central system 81 a communication containing the unique tag identification code, the unique signpost code most recently received from any signpost, and the unique container identification code for the container 11 on which the tag is currently mounted, the central system can determine the approximate current location of the container and tag. In particular, the signpost code uniquely identifies the particular signpost that sent it, and the central system knows where that signpost is located. Further, as explained above, if the tag 12 has received signpost signals from that signpost, then the tag and the container must have passed within a radius of about 12 feet from that signpost. The unique tag code and the unique container code tell the central system 81 exactly which tag and container passed near the particular signpost.
Referring again to
The system 10 includes a Global Positioning System (GPS) satellite 101. The satellite 101 is an existing device that is in orbit about the earth. There are actually a plurality of satellites 101 but, for clarity, only one satellite 101 is shown in
The system 10 further includes a portable handheld unit 106 with a display 107, a manually operable keypad 108, and a cable 111. The cable 111 has at its outer end an electrical connector that can be releasably electrically coupled to a connector on the tag 12. In addition, the tag 12 and the handheld unit 106 can exchange wireless signals, as indicated diagrammatically at 112. In the disclosed embodiment, the wireless signals 112 are UHF signals at the above-mentioned frequency of 433.92 MHz, but they could alternatively use any other suitable frequency.
The system 10 has an antenna 116 that is coupled to the central system 81, in order to permit the central system 81 to exchange wireless signals 117 with a communication satellite 118. In turn, the communication satellite 118 can exchange wireless signals 119 with the tag 12. In the disclosed embodiment, the wireless signals 117 and 119 conform to a known satellite communication protocol, which is the IEEE L-band protocol. However, it would alternatively be possible for the wireless signals 117 and 119 to conform to some other communication protocol. The link between the central system 81 and the antenna 116 can optionally include a conventional Internet protocol (IP) network, such as a portion of the Internet.
For purposes of this disclosure, when a communication path uses long-range wireless transmissions, for example transmissions capable of traveling distances of about 1 Km or more, that communication path is considered to be a wide area network (WAN). The communication path 99 between the tag 12 and the cell tower 97 is one example of a WAN. The communication path 119 between the tag 12 and the satellite 118 is another example of a WAN. In contrast, for purposes of this disclosure, when a communication path uses short-range wireless transmissions, for example transmissions capable of traveling distances of about 500 m or less, that communication path is considered to be a local area network (LAN). The communication paths 84 and 88 between the tag 12 and the RFID reader 83 and signpost 87 are examples of LANs.
As another example of a LAN, the system 10 could optionally include a LAN 126 in the form of a wireless computer network, which is electrically coupled to the central system 81, and which can communicate with the tag 12 through the transmission and reception of wireless signals 127. The LAN 126 is shown in broken lines in
The memory 144 stores GPS data 163. In this regard, each time the tag 12 takes a “GPS fix” (by recording positioning information currently being received from GPS satellites), the positioning information is saved at 163. The data saved for each GPS fix includes a time stamp specifying the time and date that the GPS fix was obtained. The memory 144 also stores location information 165, representing the current location of the tag 12 on the surface of the earth. The tag 12 can derive the location information from the GPS positioning information stored at 163.
The central system 81 can provide the tag 12 with some information that can help the tag obtain a GPS fix. For example, with reference to
As discussed above in association with
The tag 12 includes a UHF transceiver 171 that is coupled to the control circuit 141, and the transceiver includes a transmitter 172 and a receiver 173. As mentioned earlier, the disclosed tag 12 happens to include the UHF transmitter 172, but this transmitter is optional, and could be omitted for some applications, although the receiver 173 would typically still be present. The control circuit 141 can selectively turn the transmitter 172 on and off, and can selectively turn the receiver 173 on and off, in order to reduce overall power consumption. As discussed above, the transmitter 172 and the receiver 173 each operate at 433.92 MHz. The transceiver 171 is coupled to two antennas 176 and 177. The antenna 176 is located in the interior module 56 (
The tag 12 has an electrical connector 181 that is part of the exterior module 57 (
The tag 12 includes a low-frequency (LF) receiver 186 that is coupled to the control circuit 141, and to an antenna 187. The antenna 187 is located in the exterior module 57 (
The tag 12 could optionally have a cellular transceiver 191 that includes a transmitter 192 and a receiver 193, and that is coupled to the control circuit 141. The transceiver 191 is coupled to an optional antenna 196, where the antenna 196 is located in the exterior module 57 (
The tag 12 has a GPS circuit 201 that includes a receiver 202, and that is coupled to the control circuit 141, and. The GPS circuit 201 is coupled to an antenna 203, and the antenna 203 is located in the exterior module 57 (
The tag 12 includes a sensor section 207 having several outputs that are each electrically coupled to a respective input of the control circuit 141. The sensor section 207 includes several sensors, one of which is the door sensor 58 that was discussed earlier in association with
The temperature sensor 211, the humidity sensor 212, and the light sensor 215 are all provided in the interior module 56 (
As explained earlier, the memory 144 stores sensor configuration information 157. This configuration information includes an indication of whether each of the sensors in the sensor section 207 is currently enabled or disabled, or in other words whether the control circuit 141 should currently accept or discard data from that sensor. For example, if the container 11 is loaded with fruit, the temperature within the container is likely important, and thus the temperature sensor 211 will probably be enabled. In contrast, if the container 11 is loaded with lumber, temperature may not be an issue, and the temperature sensor 211 may therefore be disabled. The sensor section 207 can be configured so that, when a sensor is disabled, that sensor is powered off in order to conserve battery power.
The sensor configuration information 157 also includes thresholds for some or all of the sensors. For example, if the container 11 is loaded with fruit, the temperature within the container should preferably not be allowed to get too high or too low. A high temperature may cause the fruit to ripen too rapidly and thus spoil, whereas a low temperature may injure the fruit by causing it to freeze. Consequently, the sensor configuration information 157 may include an upper limit value and a lower limit value for the temperature sensor 211. If the actual temperature detected by the temperature sensor 211 goes above the upper limit or below the lower limit, the control circuit 141 would designate this condition as an environmental event that justifies the transmission of a wireless signal containing an alarm.
The sensor configuration information 157 could also optionally include other configuration information relating to the sensors 207. As one example, the sensor configuration information could specify that the door sensor 58 can trigger a tamper event by itself, or alternatively that the door sensor 58 and the light sensor 215 must both detect a problem in order to trigger a tamper event.
If the tag 12 includes the optional cellular transceiver 191, then the tag 12 also includes an optional removable Subscriber Identity Module (SIM) card 217. The SIM card 217 is electrically coupled to the control circuit 141, and is a component of a known type that is commonly used in existing cellular telephones. Within the tag 12, the SIM card 217 facilitates communication between the tag 12 and the cellular network 98 (
The SIM card 217, if present, is located in the interior module 56 (
The tag 12 includes a battery 218 that provides operating power to all of the electrical components within the tag 12. In the disclosed embodiment, the battery 218 is a replaceable lithium battery that is a commercially-available part. However, it would alternatively be possible to use any of a variety of other commercially-available batteries, or a custom battery.
The tag 12 includes a satellite transceiver circuit 221 that is electrically coupled to the control circuit 141 and also to an antenna 224. The transceiver 221 includes a transmitter 222 and a receiver 223. The tag 12 uses the transceiver 221 and the antenna 224 to communicate via the wireless signals 119 with the communication satellite 118 (
In
Referring again to
The tag 12 could include each of the satellite transceiver 221, the cellular network transceiver 191, the wireless LAN transceiver 231 and the UHF transceiver 171. However, for reasons for practicality and economy, the tag 12 of
In addition to or in place of the UHF transceiver 171 and antenna 177, the tag 12 could have not-illustrated passive or semi-passive circuitry of a type known in the art. In response to an incoming UHF signal 84, the passive or semi-passive circuitry would use a portion of the energy of that signal to provide itself with operating power. Remaining energy from the signal would be reflected or re-transmitted, and the passive or semi-passive circuitry would modulate that reflected or retransmitted energy so as to add information, such as the unique identification code of the tag 12.
Due to the fact that the GPS receiver 202 and the satellite transceiver 221 each transmit and/or receive long-range signals, they consume substantially more power from the battery 218 than short-range transmitters and receivers such as the transceiver 171 (
As discussed above in association with
Another example is that the command 92 can instruct the tag 12 to change the rate at which the tag takes periodic GPS fixes. In other words, the tag would increase or decrease the time interval between successive GPS fixes. The parameter 93 would specify the new time interval. Still another example is that the command 92 can instruct the tag 12 to change the rate at which the tag makes WAN transmissions using the satellite transceiver 221 or the cellular transceiver 191. In other words, the tag would increase or decrease the time interval between successive WAN transmissions. The parameter 93 would specify the new time interval.
Yet another example is that the command 92 (
Another example is that the command 92 can instruct the tag to use a different data template for the information that the tag transmits to the central system 81 (
For purposes of this discussion, assume that the container 11 and tag 12 follow a path of travel indicated diagrammatically by a broken line 311. More specifically, the container 11 and tag 12 approach and pass through the entry doorway 302, then spend a period of time stored within the warehouse 301, and then exit the warehouse through the exit doorway 303. As the container and tag are moving along the path of travel 311, before they reach the doorway 302, the tag 12 will typically be using its GPS receiver 202 (
When the container 11 and tag 12 are inside the warehouse 301, the GPS receiver 202 and satellite transceiver 221 may be ineffective, or at least exhibit degraded performance. For example, if the warehouse is a steel-frame building, it may act as an electromagnetic shield that blocks or degrades most or all wireless WAN transmissions to or from the tag. Further, if the warehouse 301 has a security system, and/or the interior of the warehouse is climate controlled, then while the tag is within the warehouse, the tag may not need to use all of the sensors in its sensor section 207 to carry out monitoring directed to environmental conditions and security considerations. Accordingly, the GPS receiver 202, the satellite transceiver 221 and/or some or all of the sensors can essentially be disabled while the container 11 and tag 12 are within the warehouse 301, thereby achieving a significant reduction in power consumption that helps to avoid unnecessarily rapid discharging of the battery 218.
With this goal in mind, as the container 11 and tag 12 pass through the entry doorway 302, the tag will receive one or more signpost signals 88A from the signpost 87A. The command or commands 92 (
When the container 11 and tag 12 later leave the warehouse 301 through the exit doorway 303, the tag will receive one or more signpost signals 88B from the signpost 87B, thereby restoring the tag 12 to the operational state that it had when it arrived. For example, the tag will be instructed to enable its normal use of the GPS receiver 202, satellite transceiver 221, and sensor section 207. As part of this, the sensor configuration information 157 may be restored to the state that it had when the tag arrived at the warehouse 301.
In effect, as the tag 12 enters and exits the warehouse 301, short-range LAN components such as the signposts 87A and 87B reconfigure the tag in regard to its use of long-range WAN components such as the GPS receiver 202 and the satellite transceiver 221. One benefit is reduced power consumption, and thus reduced discharge of the battery 218. This can also reduce service costs associated with WAN components. For example, each transmission from the tag 12 through the satellite 118 (
Summarizing, the operation of the tag 12 is dynamically configured in a manner that is intended to minimize power consumption and service charges, while maximizing “visibility” of the tag to the central system 81. Reducing power consumption from the battery 218 can permit use of a smaller battery, thereby reducing the size, cost and weight of the battery 218 and also the tag 12. Further, reducing the size of the battery 218 serves to reduce the volume of chemicals or other hazardous substances that are present in the battery and thus in the tag.
Although
Although selected embodiments have been illustrated and described in detail, it should be understood that a variety of substitutions and alterations are possible without departing from the spirit and scope of the present invention, as defined by the claims that follow.
This application claims the priority under 35 U.S.C. §119 of provisional application No. 61/034,764 filed Mar. 7, 2008, the disclosure of which is hereby incorporated herein by reference.
Number | Date | Country | |
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61034764 | Mar 2008 | US |