System for monitoring inventory location in warehouse

Abstract

A system for monitoring inventory location in a warehouse is provided. The system includes a movement sensor system for attachment to a vehicle moving around the warehouse. In one embodiment, the mobile sensor system includes an RFID antenna configured to provide RFID signaling representative of one or more RFID tag signals received from one or more RFID tags. The system for monitoring the inventory location in the warehouse further includes a controller configured to: process the RFID signaling to determine one or more infrastructure RFID tag identifiers associated with an RFID tag, the RFID tag associated with a static infrastructure item in the warehouse; determining an antenna location based on the determined one or more infrastructure RFID tag identifiers; processing the RFID signaling to determine one or more inventory RFID tag identifiers associated with an RFID tag, the RFID tag associated with a removable inventory item in the warehouse; associating the inventory RFID tag identifier with the determined antenna location; and providing inventory location signaling based on an association between the inventory RFID tag identifier and the antenna location.

Description

Technical Field

[0001] This disclosure relates to systems and methods for monitoring the location of inventory in a warehouse, and more particularly to systems and methods using RFID antennas. Summary of the Invention

[0002] According to a first aspect of this disclosure, a system for monitoring the location of inventory in a warehouse is provided, the system comprising:

[0003] A mobile sensor system for attaching to vehicles moving around the warehouse, the mobile sensor system comprising:

[0004] The RFID antenna is configured as follows:

[0005] Transmit an RFID scanning signal to excite one or more RFID tags near the RFID antenna; and

[0006] Provides RFID signaling indicating one or more RFID tag signals received from one or more RFID tags;

[0007] The system for monitoring this inventory location in the warehouse further includes a controller configured to:

[0008] The RFID signaling is processed to determine one or more infrastructure RFID tag identifiers associated with the RFID tag, which is associated with a static infrastructure item in the warehouse;

[0009] Antenna location is determined based on one or more infrastructure RFID tag identifiers, wherein the antenna location indicates the location of the RFID antenna in the warehouse when the RFID signal is received;

[0010] The RFID signaling is processed to determine one or more inventory RFID tag identifiers associated with an RFID tag that is linked to a movable inventory item in the warehouse;

[0011] Associate the inventory RFID tag identifier with the determined antenna location for substantially simultaneous RFID signaling; and

[0012] Inventory location signaling is provided based on the association between the inventory RFID tag identifier and the antenna location.

[0013] Advantageously, such systems can provide a convenient and effective way to monitor the location of inventory in a warehouse.

[0014] The inventory location signaling can include the location of each detected inventory item, so that the location of those inventory items can be visually represented on a map of the warehouse.

[0015] The static infrastructure items in the warehouse may include one or more of columns, partitions, shelf legs, column caps, doorposts, and shelves.

[0016] The controller can be configured to:

[0017] The RFID signaling is processed to determine a first infrastructure RFID tag identifier and a second infrastructure RFID tag identifier, which are associated with an RFID tag that is associated with a different static infrastructure item in the warehouse.

[0018] The signal strength of the RFID tag signal for the first infrastructure RFID tag identifier is compared with the signal strength of the RFID tag signal for the second infrastructure RFID tag identifier to determine whether the RFID antenna is closer to the RFID tag associated with the first infrastructure RFID tag identifier or the RFID tag associated with the second infrastructure RFID tag identifier; and

[0019] The inventory location signal is provided based on the comparison of the signal strength.

[0020] The system may further include:

[0021] A static sensor system, attached to any static infrastructure item in the warehouse, wherein the static sensor system includes:

[0022] A static RFID antenna at a known location within the warehouse, wherein the RFID antenna is configured to:

[0023] Transmit an RFID scanning signal to excite one or more RFID tags near the RFID antenna; and

[0024] Provides RFID signaling indicating one or more RFID tag signals received from one or more RFID tags; and

[0025] The controller is configured as follows:

[0026] The RFID signaling from the static RFID antenna is processed to determine one or more inventory RFID tag identifiers associated with the RFID tag, which is associated with a movable inventory item;

[0027] The inventory RFID tag identifier determined from the RFID signaling provided by the static RFID antenna is associated with the known location of the static RFID antenna; and

[0028] The inventory location signaling is provided based on the association between the inventory RFID tag identifier determined from the RFID signaling provided by the static RFID antenna and the known location of the static RFID antenna.

[0029] The mobile sensor system may further include a second RFID antenna, which is configured to:

[0030] Transmit a second RFID scanning signal to activate one or more RFID tags near the RFID antenna; and

[0031] Provide a second RFID signaling that represents one or more RFID tag signals received from one or more RFID tags.

[0032] The controller can be further configured to:

[0033] The second RFID signaling is processed to determine one or more infrastructure RFID tag identifiers associated with an RFID tag that is associated with a static infrastructure item in the warehouse;

[0034] The location of the second antenna is determined based on one or more infrastructure RFID tag identifiers, wherein the location of the second antenna in the warehouse indicates the position of the second RFID antenna when the second RFID signal is received;

[0035] The second RFID signaling is processed to determine one or more inventory RFID tag identifiers associated with an RFID tag that is associated with a movable inventory item in the warehouse;

[0036] Associate the inventory RFID tag identifier with the determined second antenna location for a second RFID signal acquired substantially simultaneously; and

[0037] The inventory location signaling is provided based on the association between the inventory RFID tag identifier and the second terrestrial location.

[0038] The RFID antenna can be configured to provide subsequent RFID signaling in response to a subsequent transmission of an RFID scan signal. The controller is configured to:

[0039] The subsequent RFID signaling is processed to determine one or more subsequent infrastructure RFID tag identifiers associated with the RFID tag, which is associated with a static infrastructure item in the warehouse;

[0040] The location of the subsequent antenna is determined based on one or more subsequent infrastructure RFID tag identifiers, wherein the location of the RFID antenna in the warehouse is indicated when the subsequent RFID signaling is received;

[0041] The subsequent RFID signaling is processed to determine one or more subsequent inventory RFID tag identifiers associated with the RFID tag, which is associated with a movable inventory item in the warehouse;

[0042] Associate the subsequent inventory RFID tag identifier with the subsequent antenna location for the subsequent RFID signaling acquired substantially simultaneously; and

[0043] Determine whether the inventory RFID tag identifier and the subsequent inventory RFID tag identifier are associated with the same RFID tag but with different antenna locations, and if so, provide an output signal indicating that the movable inventory item associated with the RFID tag is transported together with the vehicle to which the mobile sensor system is attached.

[0044] The controller can be further configured to:

[0045] Control the RFID antenna to periodically emit RFID scanning signals.

[0046] The controller can be configured to set the period at which the RFID antenna transmits RFID scan signals based on the speed of the vehicle to which the mobile sensor system is attached.

[0047] The RFID tag can be passive.

[0048] The controller can be configured to:

[0049] The presence of an RFID tag signal in the RFID signaling is determined only if the RFID tag signal has a signal strength greater than a threshold.

[0050] According to another aspect of this disclosure, a method for monitoring the location of inventory in a warehouse is provided, the method comprising:

[0051] An RFID antenna attached to a vehicle moving around the warehouse transmits an RFID scan signal to excite one or more RFID tags near the RFID antenna and provides RFID signaling indicating one or more RFID tag signals received from one or more RFID tags.

[0052] The RFID signaling is processed to determine one or more infrastructure RFID tag identifiers associated with the RFID tag, which is associated with a static infrastructure item in the warehouse;

[0053] Antenna location is determined based on one or more infrastructure RFID tag identifiers, wherein the antenna location indicates the location of the RFID antenna in the warehouse when the RFID signal is received;

[0054] The RFID signaling is processed to determine one or more inventory RFID tag identifiers associated with an RFID tag that is linked to a movable inventory item in the warehouse;

[0055] Associate the inventory RFID tag identifier with the determined antenna location for substantially simultaneous RFID signaling; and

[0056] Inventory location signaling is provided based on the association between the inventory RFID tag identifier and the antenna location.

[0057] This document may provide a computer program that, when run on a computer, causes the computer to configure any device, including the controllers, systems, or apparatuses disclosed herein, or to perform any of the methods disclosed herein. As a non-limiting example, the computer program may be a software implementation, and the computer may be considered any suitable hardware, including digital signal processors, microcontrollers, and implementations in read-only memory (ROM), erasable programmable read-only memory (EPROM), or electrically erasable programmable read-only memory (EEPROM). The software may be an assembler.

[0058] Computer programs may be provided on computer-readable media or implemented as transient signals, such as physical computer-readable media, like optical discs or storage devices. This transient signal may be a network download, including an internet download. One or more non-transitory computer-readable storage media may be provided storing computer-executable instructions that, when executed by a computing system, cause the computing system to perform any of the methods disclosed herein. Attached Figure Description

[0059] One or more embodiments will now be described by way of example only with reference to the accompanying drawings, in which:

[0060] Figure 1 A schematic floor plan of a portion of the warehouse's interior is shown.

[0061] Figure 2 An example embodiment of a system for monitoring the location of inventory in a warehouse is shown;

[0062] Figure 3 Another example embodiment of a system for monitoring the location of inventory in a warehouse is shown.

[0063] Figure 4 A further example embodiment of a system for monitoring the location of inventory in a warehouse is shown;

[0064] Figure 5a and Figure 5b An example embodiment of a system is illustrated, which can identify inventory transported together with a forklift to which a motion sensor system is attached; and

[0065] Figure 6 An example embodiment of a method for monitoring the location of inventory in a warehouse is illustrated. Detailed Implementation

[0066] Tracking inventory in warehouses, especially very large ones, is difficult. Furthermore, in some cases, containers storing multiple inventory items (such as cartons, boxes, or pallets) may accumulate in certain areas of the warehouse. Identifying when this is happening and where it is happening can be challenging.

[0067] Figure 1 A schematic floor plan of a portion of the warehouse interior is shown, which is the suitable environment for the systems and methods described herein. Figure 1 Six rows of shelves 101 are shown, with aisles 102 between each row 101. Figure 1 As shown, a forklift (FLT) 108 can travel along the aisle to retrieve inventory stored in different rack rows 101. Each rack row 101 has multiple rack legs 103. Rack legs 103 are vertical supports for supporting shelves or pallets. The rack row 101 may also include beams (typically horizontal) and / or supports (typically extending diagonally relative to the ground).

[0068] Figure 1 A portion of the warehouse is designated as walkway 104. Walkway 104 is separated from the end aisles of the shelving by barriers 105. In this example, barriers 105 are shown as comprising a plurality of spaced-apart posts 106, with tracks 107 connecting most adjacent posts 106. Pedestrian entry points 109 are shown as gaps in the barriers through which pedestrians can move between walkway 104 and a portion of the warehouse through which FLT 108 operates.

[0069] Each of column 106, barrier 105, shelf leg 103, and shelf row 101 is an example of a static warehouse infrastructure item according to this disclosure. Additionally, one or more of the following may also be considered as static warehouse infrastructure items: column caps (i.e., caps on columns), doorposts, shelves, and any other barriers or partitions between different areas in the warehouse (including barriers between different inventory storage areas).

[0070] Figure 2 An example embodiment of a system 209 for monitoring the location of inventory 215 in a warehouse is shown. System 209 includes a motion sensor system 212 attached to a vehicle moving around the warehouse. In this example, the vehicle is a forklift (FLT) 210. The motion sensor system 212 may be powered by a battery located on the FLT 210. System 209 also includes a controller 213 (which will no longer be used below) that processes signaling received from the motion sensor system 212 to determine the location of inventory 215 in the warehouse. It should be understood that some or all of the functionality of the controller 213 may be implemented by one or more devices located on the FLT 210, and / or some or all of the functionality of the controller 213 may be implemented by one or more devices located remotely from the FLT 210.

[0071] The mobile sensor system 212 includes an RFID antenna 211, shown emitting an RFID scan signal 216 to activate one or more RFID tags in the vicinity of the RFID antenna 211. This can also be referred to as the RFID antenna 211 performing an RFID scan. In this example, the RFID antenna 211 is directional because it emits the RFID scan signal 216 in a specific direction relative to the FLT 210. In other examples, the RFID antenna 211 may not be directional.

[0072] As is known in the art, any RFID tag 219, 220 excited by RFID scan signal 216 transmits RFID tag signal 217, 218 in response to the excitation. Figure 2 The diagram illustrates two types of RFID tags: RFID tag 220 associated with mobile warehouse inventory item 215; and RFID tag 219 associated with static infrastructure item 221 in the warehouse. Mobile warehouse inventory item 215 can be a single inventory item, a package of multiple inventory items, and / or inventory containers such as cartons or pallets. Figure 2 The static infrastructure item in the warehouse shown is column 221. As will be discussed below, two different types of RFID tags 219 and 220 can be provided with different identifiers, which are provided as part of RFID tag signals 217 and 218, so that they can be distinguished from each other.

[0073] In this example, RFID tags 219 and 220 are passive, which is advantageous because it is not necessary to provide batteries for RFID tags 219 and 220, and therefore there is no need to periodically charge or replace any such batteries. Furthermore, in this example, RFID tags 219 and 220 are ultra-high frequency (UHF) tags.

[0074] The RFID antenna 211 then provides RFID signaling 214 to the controller 213. RFID signaling 214 indicates one or more RFID tag signals 217, 218 received from one or more RFID tags 219, 220.

[0075] Controller 213 processes RFID signaling 214 to determine one or more infrastructure RFID tag identifiers associated with RFID tag 219, which is associated with static infrastructure item 221 in the warehouse. In one example, this can be done by controller 213 using a lookup table or database to look up RFID tag identifiers received as part of RFID tag signals 217, 218 to determine whether they are associated with static infrastructure item 221 in the warehouse. If so, the RFID tag identifier is considered an infrastructure RFID tag identifier.

[0076] The controller 213 can then determine the antenna location based on one or more infrastructure RFID tag identifiers. The antenna location represents the position of the RFID antenna 211 in the warehouse when RFID signaling is received. In one example, this can be achieved by the controller accessing a lookup table or database stored in its computer memory. This lookup table or database includes the location of each static infrastructure item 221 in the warehouse and its associated infrastructure RFID tag identifier. This location can be provided as a set of coordinates or in any suitable manner. If only a single infrastructure RFID tag identifier is identified in RFID signaling 214, the antenna location can simply be set to be the same as the location of the associated static infrastructure item 221. If multiple infrastructure RFID tag identifiers are identified in RFID signaling 214, the antenna location can be set based on a combination of the locations of the associated static infrastructure items 221. For example, the controller 213 can calculate a mathematical average of multiple locations of the static infrastructure item 221.

[0077] When identifying multiple infrastructure RFID tag identifiers, one way the controller 213 determines its antenna position is by using the signal strength / power of the received RFID tag signal 217 associated with each infrastructure RFID tag identifier. An example of how signal strength can be represented is the Received Signal Strength Indicator (RSSI) for the received RFID tag signal 217. The controller 213 can compare the signal strength of the RFID tag signal 217 for the first infrastructure RFID tag identifier with the signal strength of the RFID tag signal 217 for the second infrastructure RFID tag identifier to determine whether the RFID antenna 211 is closer to the RFID tag 219 associated with the first infrastructure RFID tag identifier or the RFID tag 219 associated with the second infrastructure RFID tag identifier. By comparing signal strengths in this way, the controller 213 can determine the relative position of the RFID antenna 211. For example, if the positions associated with the first and second infrastructure RFID tag identifiers are offset along a first dimension, the controller 213 can determine that the RFID antenna is closer to the one of the first and second infrastructure RFID tag identifiers that has the strongest RFID tag signal 217.

[0078] The controller 213 can also process RFID signaling 214 received from the RFID antenna 211 to determine one or more inventory RFID tag identifiers associated with RFID tag 220, which is associated with movable inventory item 215 in the warehouse. In the same manner as described above, the controller 213 can use a lookup table or database to look up RFID tag identifiers received as part of RFID tag signals 217, 218 to determine whether they are associated with movable inventory item 215. If so, the RFID tag identifier is considered an inventory RFID tag identifier.

[0079] Once the controller 213 has distinguished between the infrastructure RFID tag identifier (associated with static infrastructure item 221) and the inventory RFID tag identifier (associated with movable inventory item 215), it can determine the location of the inventory in the warehouse. To do this, the controller 213 associates the inventory RFID tag identifier with the determined antenna location for RFID signaling 214 acquired substantially simultaneously. This can include RFID signaling 214 acquired at exactly the same time (e.g., as part of the same RFID scan) or at least at least a minimum time interval (such as less than 1 second, 5 seconds, or 10 seconds).

[0080] The controller 213 can then provide inventory location signaling 222 based on the association between the inventory RFID tag identifier and the antenna location. Inventory location signaling 222 can be implemented in any of a variety of ways, representing the location of inventory 215 in the warehouse. For example, inventory location signaling 222 can include the location for each detected inventory item 215, such that the location of those inventory items can be visually represented on a map of the warehouse or in a list with inventory locations. In this way, a graphical representation of the location of the detected inventory in the warehouse can be provided.

[0081] In the example of associating inventory RFID tag identifiers with movable boxes / pallets in a warehouse, the provision of inventory location signaling 222 is particularly useful for identifying any areas with unintended stacking of boxes / pallets that already exist (potentially empty). Otherwise, identifying the location of such stackings in a large, highly automated warehouse can be particularly difficult.

[0082] Figure 3 and Figure 4 Further examples of sample embodiments of a system for monitoring the location of inventory in a warehouse are provided.

[0083] exist Figure 3 In the example, FLT 310 is shown within the warehouse. Inventory 315 is shown as an area within the warehouse defined by various static infrastructure items, one or more of which may be equipped with RFID tags (not shown). In this example, the static infrastructure items shown include pillars 321, barriers 324, and pillar caps (i.e., caps on the top of the pillars) 323. In other examples, one or more of the following static infrastructure items in the warehouse, along with associated RFID tags, may also be provided: doorposts, shelves, and rack legs.

[0084] The FLT 310 includes an RFID antenna 311, which is designed to work with... Figure 2 The same manner described is used to transmit RFID scanning signals 316 in order to activate RFID tags associated with inventory 315 and static infrastructure items 321, 323, 324 in the warehouse.

[0085] Also in Figure 3 The system for monitoring the location of inventory 315 in a warehouse includes a static sensor system 340. The static sensor system 340 can be attached to a wall of the warehouse (as shown) or to any static infrastructure item within the warehouse. The static sensor system 340 also includes RFID antennas (not shown) at locations known to the system. For example, when installing the static sensor system 340, the location of each static RFID antenna can be stored in a memory. The static sensor system 340 can be powered by mains electricity.

[0086] In the same manner as the RFID antenna 311 of the mobile sensor system, the RFID antenna of the static sensor system transmits an RFID scan signal to excite one or more RFID tags near the RFID antenna and provides RFID signaling indicating one or more RFID tag signals received from one or more RFID tags. The controller of the system for monitoring inventory locations in a warehouse can then process the RFID signaling from the static RFID antenna to determine one or more inventory RFID tag identifiers associated with RFID tags associated with movable inventory items 315. Since the location of the static RFID antenna is already known to the system, the controller can then associate the inventory RFID tag identifiers with the known static RFID antenna location; and provide inventory location signaling based on: i) information received from the static RFID antenna, i.e., the inventory RFID tag identifiers determined from the RFID signaling provided by the static RFID antenna and the associated static RFID antenna location; and ii) information received from the mobile RFID antenna 311, i.e., the association between the inventory RFID tag identifiers determined from the RFID signaling provided by the mobile RFID antenna and the determined antenna location.

[0087] In this way, the controller can provide information from the static RFID antenna, which can be used to verify the location of inventory 315 determined by the mobile sensor system. If the controller identifies a discrepancy between the location of any inventory 315 item determined from the signals provided by the mobile RFID antenna and the static RFID antenna, the controller can provide an alarm to the user to indicate a system malfunction.

[0088] exist Figure 4 In the diagram, FLT 410 is shown as having a first RFID antenna 411a and a controller housed within a forklift top box 413. The first RFID antenna 411a transmits a first RFID scan signal 416a, which activates RFID tags 420 associated with inventory / boxes 415, and also activates RFID tags associated with static infrastructure items (such as...). Figure 4 The barrier (or column) shown is equipped with a column cap 425 and associated with an RFID tag. The first RFID antenna 411a can therefore provide first RFID signaling.

[0089] exist Figure 4In addition, the FLT 410 also features a second RFID antenna 411b. The second RFID antenna 411b transmits a second RFID scan signal 416b, which can also activate RFID tags associated with inventory / boxes and RFID tags associated with static infrastructure items. The second RFID antenna 411b can thus provide second RFID signaling. The system controller can process each of the second RFID signaling to determine inventory location in the same manner as discussed above.

[0090] exist Figure 4 In this configuration, the first RFID antenna 411a and the second RFID antenna 411b are oriented and point in the opposite direction from FLT 410. In this way, the system used to identify inventory 415 can perform RFID scanning covering a large area.

[0091] In another embodiment, the first RFID antenna 411a and the second RFID antenna 411b can be oriented and point in the same direction. Figure 4 As shown, they are still spaced apart from each other in the first dimension. In this example, the controller can compare the signal strength of the RFID tag signal in the first RFID signaling with the signal strength of the RFID tag signal in the second RFID signaling to determine the position of the associated tag relative to the FLT 410 in the first dimension. By comparing the signal strength in this way, the controller can determine whether the associated RFID tag is closer to the first RFID antenna 411a or the second RFID antenna 411b, and therefore it can determine the relative position of the associated RFID tag in the first dimension (which is offset along with the first RFID antenna 411a and the second RFID antenna 411b). This can improve the accuracy of determining the inventory location.

[0092] Figure 5a and Figure 5b An example embodiment of the system is illustrated, which can identify inventory 515 transported together with FLT 510 attached to the mobile sensor system 512. Figure 5a The FLT 510 at the first moment is shown, when it is close to the first column 526. Figure 5b The FLT 510 is shown at a second moment after the first moment, when it is close to the second post 528. In the same manner as described above, the mobile sensor system 512 includes an RFID antenna 511 and a controller 513.

[0093] First reference Figure 5aThe RFID antenna 511 transmits an RFID scanning signal 516a at the first moment. In response to receiving RFID tag signals 518a and 530 from any RFID tag 520 or 527 near the RFID antenna 511, the controller 513 provides RFID signaling 514a to the controller 513.

[0094] Controller 513 then processes RFID signaling 514a to determine one or more infrastructure RFID tag identifiers associated with RFID tag 527, which are related to static infrastructure items in the warehouse (in... Figure 5a In the middle, it is related to the first column (526). See above for reference. Figure 2 In the same manner described, controller 513 can determine the antenna location based on one or more infrastructure RFID tag identifiers, where the antenna location indicates the location of RFID antenna 511 in the warehouse when RFID signaling 514a is received (i.e., at the first moment).

[0095] Similarly, controller 513 can process RFID signaling 514a to determine one or more inventory RFID tag identifiers associated with RFID tag 520, which is associated with movable inventory 515 items in the warehouse. Figure 5a As shown, inventory item 515 with RFID tag 520 is located on the fork of FLT 510, so that inventory 515 is transported together with FLT 510. Controller 513 can then associate the inventory RFID tag identifier with the determined antenna location for RFID signaling 514a acquired in the first moment.

[0096] Now go to Figure 5b At the second moment, the RFID antenna 511 transmits a subsequent RFID scan signal 516b. In response to receiving subsequent RFID tag signals 518b and 531 from any RFID tag 520 or 529 near the RFID antenna 511, the controller 513 provides subsequent RFID signaling 514b to the controller 513.

[0097] Controller 513 then processes subsequent RFID signaling 514b to determine one or more subsequent infrastructure RFID tag identifiers associated with RFID tag 529, which are related to static infrastructure items in the warehouse (in Figure 5b In the middle, it is related to the second column (528). (This is in conjunction with the reference.) Figure 2In the same manner described, controller 513 can then determine the location of the subsequent antenna based on one or more determined subsequent infrastructure RFID tag identifiers, wherein the location of the RFID antenna 511 in the warehouse when subsequent RFID signaling 514b is received (i.e., at the second moment).

[0098] The controller 513 can also process subsequent RFID signaling 514b to determine one or more subsequent inventory RFID tag identifiers associated with RFID tag 520, which is associated with movable inventory item 515 in the warehouse. Figure 5b As shown, Figure 5a The same inventory item 515 shown (with the same RFID tag 520) remains on the fork of the FLT 510. The controller 513 can then associate the subsequent inventory RFID tag identifier with the subsequent antenna location for subsequent RFID signaling acquired substantially simultaneously (i.e., at a second moment).

[0099] The controller 513 can then determine the inventory RFID tag identifier (from...) Figure 5a The initial RFID signaling 514a and subsequent inventory RFID tag identifiers shown in the figure (from Figure 5b The subsequent RFID signaling 514b) shown is associated with the same RFID tag 520 but with a different antenna location. If so, the controller can provide an output signal indicating that the movable inventory item 515 associated with the RFID tag 520 is transported with the FLT 510. Optionally, the controller 513 may only provide such an output signal if there is at least a minimum distance between the antenna location determined for the initial RFID signaling 514a and the antenna location determined for the subsequent RFID signaling 514b. This minimum distance can be at least the range of the RFID antenna 511. In this way, the likelihood of identifying the stationary inventory item 515 during transport can be reduced.

[0100] In some examples, controller 513 can control RFID antenna 511 to perform RFID scans periodically. Controller 513 can optionally set the period between consecutive RFID scans based on the speed of FLT 510. For example, controller 513 can receive a vehicle speed signal representing the speed of FLT 510. A speed sensor associated with FLT 510 can provide the vehicle speed signal. Controller 513 can then set the time interval between consecutive RFID scans based on the vehicle speed signal, such that RFID scans are performed more frequently at relatively fast speeds than at relatively slow speeds. In this way, RFID scanning can be performed such that most (if not all) of the inventory 515 is identified, but an unnecessary large number of RFID scans are not required. This effectively controls the energy consumption required for RFID scanning. Furthermore, RFID scanning can be temporarily paused when FLT 510 is stationary.

[0101] In any of the examples disclosed herein, the controller can only determine that an RFID tag signal is present in the RFID signaling if the RFID tag signal has a signal strength greater than a threshold. One example of how signal strength can be represented is a Received Signal Strength Indicator (RSSI) for received RFID tag signals. In this way, weak RFID tag signals can be excluded from further processing, possibly because they are too far away to be considered near the RFID antenna.

[0102] Figure 6 An example embodiment of a method for monitoring the location of inventory in a warehouse is illustrated.

[0103] At step 650, the method includes transmitting an RFID scan signal from an RFID antenna attached to a vehicle moving around the warehouse. The RFID scan signal is used to activate one or more RFID tags near the RFID antenna. Also at step 650, the method involves providing RFID signaling indicating one or more RFID tag signals received from one or more RFID tags.

[0104] At step 651, the method includes processing RFID signaling to determine one or more infrastructure RFID tag identifiers associated with an RFID tag that is associated with a static infrastructure item in the warehouse. An example of how to distinguish infrastructure RFID tag identifiers from RFID tag identifiers not associated with static infrastructure items in the warehouse has been described above.

[0105] At step 652, the method includes determining the antenna location based on one or more infrastructure RFID tag identifiers. The antenna location indicates the position of the RFID antenna in the warehouse when RFID signaling is received.

[0106] At step 653, the method includes processing RFID signaling to determine one or more inventory RFID tag identifiers associated with an RFID tag linked to a movable inventory item in the warehouse. It should be understood that steps 651 and 653 can be performed in any order, or even simultaneously.

[0107] At step 654, the method includes associating an inventory RFID tag identifier with a determined antenna location for substantially simultaneously acquired RFID signaling. Then, at step 655, the method involves providing inventory location signaling based on the association between the inventory RFID tag identifier and the antenna location.

Claims

1. A system for monitoring the location of inventory in a warehouse, the system comprising: A mobile sensor system for attaching to a vehicle moving around the warehouse, the mobile sensor system comprising: The RFID antenna is configured as follows: Transmit an RFID scanning signal to excite one or more RFID tags near the RFID antenna; and Provides RFID signaling indicating one or more RFID tag signals received from one or more RFID tags; The system for monitoring the location of the inventory in the warehouse further includes a controller configured to: The RFID signaling is processed to determine one or more infrastructure RFID tag identifiers associated with RFID tags, which are associated with static infrastructure items in the warehouse; Antenna location is determined based on one or more infrastructure RFID tag identifiers, wherein the antenna location indicates the position of the RFID antenna in the warehouse when the RFID signaling is received; The RFID signaling is processed to determine one or more inventory RFID tag identifiers associated with RFID tags, which are associated with movable inventory items in the warehouse; Associate the inventory RFID tag identifier with the determined antenna location for substantially simultaneous RFID signaling; and Inventory location signaling is provided based on the association between the inventory RFID tag identifier and the antenna location.

2. The system of claim 1, wherein the inventory location signaling includes the location for each detected inventory item, such that the location of those inventory items can be visually represented on a map of the warehouse.

3. The system according to claim 1 or claim 2, wherein the static infrastructure items in the warehouse include one or more of columns, barriers, shelf legs, column caps, doorposts, and shelves.

4. The system according to any of the preceding claims, wherein the controller is configured to: The RFID signaling is processed to determine a first infrastructure RFID tag identifier and a second infrastructure RFID tag identifier, which are associated with RFID tags that are associated with different static infrastructure items in the warehouse. The signal strength of the RFID tag signal for the first infrastructure RFID tag identifier is compared with the signal strength of the RFID tag signal for the second infrastructure RFID tag identifier in order to determine whether the RFID antenna is closer to the RFID tag associated with the first infrastructure RFID tag identifier or the RFID tag associated with the second infrastructure RFID tag identifier. as well as The inventory location signaling is provided based on the comparison of the signal strength.

5. The system according to any of the preceding claims, wherein the system further comprises: A static sensor system, attached to any static infrastructure item in the warehouse, wherein the static sensor system includes: A static RFID antenna at a known location within the warehouse, wherein the RFID antenna is configured to: Transmit an RFID scanning signal to excite one or more RFID tags near the RFID antenna; and Provides RFID signaling indicating one or more RFID tag signals received from one or more RFID tags; and The controller is configured to: The RFID signaling from the static RFID antenna is processed to determine one or more inventory RFID tag identifiers associated with RFID tags, which are associated with movable inventory items; The inventory RFID tag identifier determined from the RFID signaling provided by the static RFID antenna is associated with the known location of the static RFID antenna; and The inventory location signaling is provided based on the association between the inventory RFID tag identifier determined from the RFID signaling provided by the static RFID antenna and the known location of the static RFID antenna.

6. The system according to any preceding claim, wherein the mobile sensor system further comprises a second RFID antenna, the second RFID antenna being configured to: Transmit a second RFID scanning signal to activate one or more RFID tags near the RFID antenna; and Provide a second RFID signaling indicating one or more RFID tag signals received from one or more RFID tags; and The controller is further configured to: The second RFID signaling is processed to determine one or more infrastructure RFID tag identifiers associated with RFID tags, which are associated with static infrastructure items in the warehouse; The location of the second antenna is determined based on one or more infrastructure RFID tag identifiers, wherein the location of the second antenna in the warehouse indicates the position of the second RFID antenna when the second RFID signaling is received; The second RFID signaling is processed to determine one or more inventory RFID tag identifiers associated with RFID tags, which are associated with movable inventory items in the warehouse; The inventory RFID tag identifier is associated with the determined second antenna location for the second RFID signaling acquired substantially simultaneously; as well as The inventory location signaling is provided based on the association between the inventory RFID tag identifier and the location of the second antenna.

7. The system according to any of the preceding claims, wherein: The RFID antenna is configured to: In response to subsequent transmissions of RFID scan signals, it provides subsequent RFID signaling; and The controller is configured to: The subsequent RFID signaling is processed to determine one or more subsequent infrastructure RFID tag identifiers associated with RFID tags, which are associated with static infrastructure items in the warehouse; The location of the subsequent antenna is determined based on one or more identified subsequent infrastructure RFID tag identifiers, wherein the location of the RFID antenna in the warehouse is indicated when the subsequent RFID signaling is received; The subsequent RFID signaling is processed to determine one or more subsequent inventory RFID tag identifiers associated with RFID tags, which are associated with movable inventory items in the warehouse; The subsequent inventory RFID tag identifier is associated with the subsequent antenna location for the subsequent RFID signaling acquired substantially simultaneously; as well as Determine whether the inventory RFID tag identifier and the subsequent inventory RFID tag identifier are associated with the same RFID tag but with different antenna locations, and if so, provide an output signal indicating that the movable inventory item associated with the RFID tag is transported together with the vehicle to which the mobile sensor system is attached.

8. The system according to any of the preceding claims, wherein the controller is further configured to: Control the RFID antenna so that it periodically transmits RFID scanning signals.

9. The system of claim 8, wherein the controller is configured to set the period at which the RFID antenna transmits RFID scan signals based on the speed of the vehicle to which the mobile sensor system is attached.

10. The system according to any of the preceding claims, wherein the RFID tag is passive.

11. The system according to any of the preceding claims, wherein the controller is configured to: The presence of an RFID tag signal in the RFID signaling is determined only if the RFID tag signal has a signal strength greater than a threshold.

12. A method for monitoring the location of inventory in a warehouse, the method comprising: An RFID antenna attached to a vehicle moving around the warehouse transmits an RFID scan signal to excite one or more RFID tags near the RFID antenna and provides RFID signaling indicating one or more RFID tag signals received from one or more RFID tags. The RFID signaling is processed to determine one or more infrastructure RFID tag identifiers associated with RFID tags, which are associated with static infrastructure items in the warehouse; Antenna location is determined based on one or more infrastructure RFID tag identifiers, wherein the antenna location indicates the position of the RFID antenna in the warehouse when the RFID signaling is received; The RFID signaling is processed to determine one or more inventory RFID tag identifiers associated with RFID tags, which are associated with movable inventory items in the warehouse; The inventory RFID tag identifier is associated with the determined antenna location for RFID signaling acquired substantially simultaneously. as well as Inventory location signaling is provided based on the association between the inventory RFID tag identifier and the antenna location.

13. A computer program configured to perform the method according to claim 12.

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