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EP-4740159-A1 - ROTARY ANTENNA ASSEMBLY FOR INVENTORY TAKING

EP4740159A1EP 4740159 A1EP4740159 A1EP 4740159A1EP-4740159-A1

Abstract

A method comprising: commanding rotation of at least one antenna of each antenna assembly of at least one antenna assembly around at least one rotation axis so as to capture radio waves with radio-frequency identification, RFID, data reaching the respective antenna assembly from several directions; processing, for each RFID data of the captured radio waves, each of: the RFID data to identify a transmitter tag thereof; an RSSI and/or a received signal phase and/or a read count included in a data packet that comprises the RFID data; and an angle or a set of angles of the antenna or antennas of the at least one antenna when capturing the radio waves with the RFID data; based on the processing, estimating a location or updating an estimated location of each transmitter tag whose RFID data has been processed; and updating an inventory of the transmitter tags based on the processing and the estimating steps.

Inventors

  • JUEZ DUESO, Alejandro
  • VIVES PRAT, Ausias
  • POUS ANDRÉS, Rafael
  • DE PORRATA-DORIA I YAGÜE, Ramir

Assignees

  • Keonn Technologies S.L.

Dates

Publication Date
20260513
Application Date
20240703

Claims (15)

  1. 1. A method (100) comprising: commanding (110) rotation (16a-16c) of at least one antenna (15) of each antenna assembly of at least one antenna assembly (10) around at least one rotation axis (17a, 17b) so as to capture radio waves with radio-frequency identification, RFID, data reaching the respective antenna assembly from several directions, wherein each assembly of the at least one antenna assembly comprises the at least one antenna and is configured for rotation of the respective at least one antenna; processing (120), for each RFID data of the captured radio waves, each of: the RFID data to identify a transmitter tag (50a, 50b) thereof; a received signal strength indicator and/or a received signal phase and/or a read count included in a data packet that comprises the RFID data; and an angle or a set of angles (32a, 34a, 34b) of the antenna or antennas of the at least one antenna when capturing the radio waves with the RFID data; based on the processing, estimating (130) a location (32a, 32b) or updating an estimated location of each transmitter tag whose RFID data has been processed, wherein the location at least comprises data indicative of a portion of a cell (30a, 30b) of the respective assembly or assemblies of the at least one antenna assembly, wherein the cell is that covered by the respective at least one antenna with the rotation thereof around the at least one rotation axis; and updating (140) an inventory of the transmitter tags based on the processing and the estimating steps.
  2. 2. The method (100) of claim 1 , wherein the at least one antenna assembly (10) comprises two or more antenna assemblies with adjacent or partially overlapping cells (30a, 30b); and wherein the location (32a, 32b) of each transmitter tag (50a, 50b) whose RFID data has been processed following capturing of radio waves by the two or more antenna assemblies is estimated such that the portion of the cell is that partially overlapping or in adjacency between the cells of the two or more antenna assemblies, or by processing all the information obtained by all or some of the antennas of all or some of the antenna assemblies with a triangulation algorithm that estimates the position of the tag.
  3. 3. The method (100) of any one of the preceding claims, further comprising commanding oscillation of one or more antennas (15) of the at least one antenna assembly (10) around a given direction.
  4. 4. The method (100) of any one of the preceding claims, further comprising commanding rotation (16a-16c) of one or more particular antennas (15) of the at least one antenna assembly (10) according to one or more given angular values, the one or more particular antennas being the antenna or antennas of the at least one antenna that are closest to a given transmitter tag (50a, 50b), the one or more given angular values being computed for the one or more particular antennas to have them rotated such that they are substantially directed to the given transmitter tag, and the computation of the one or more given angular value being at least based on the estimated location (32a, 32b) of the given transmitter tag resulting from the estimating (130) step.
  5. 5. The method (100) of any one of the preceding claims, wherein the commanded (110) rotation (16a-16c) is stepped with a plurality of steps per full rotation, thereby making the respective at least one antenna (15) stay, for a period of time, between each pair of consecutive steps of the plurality of steps, wherein each step of the plurality of steps corresponds to a different angle of the at least one antenna relative to the at least one rotation axis (17a, 17b).
  6. 6. The method (100) of claim 5, further comprising performing computer vision by processing one or more images of at least one optical sensor (90), and adjusting the period of time, based on the number of objects detected in the processed one or more images, detecting people in the processed one or more images, and detecting interactions between the people and the objects.
  7. 7. The method (100) of any one of claims 5-6, further comprising adjusting the rotation (16a- 16c) to be commanded (110) such that: in a first set of full rotations, steps of the plurality of steps have a first angle difference between each pair of consecutive steps and/or the period of time between each pair of consecutive steps has a first time duration; and in a second set of full rotations, steps of the plurality of steps have a second angle difference between each pair of consecutive steps and/or the period of time between each pair of consecutive steps has a second time duration; wherein the first angle difference is smaller than the second angle difference, and the first time duration is longer than the second time duration.
  8. 8. The method (100) of claim 7, wherein: the commanding (110), processing (120), estimating (130), and updating (140) steps are conducted a plurality of times such that, a plurality of first commanded full rotations is according to the first set of full rotations, and a plurality of second commanded full rotations is according to the second set of full rotations, wherein at least one or more second commanded full rotations are subsequent to one or more first commanded full rotations; and the updating step comprises removing the transmitter tags (50a, 50b) from the inventory whose RFID data has been processed in the one or more first commanded full rotations but not in the one or more second commanded full rotations.
  9. 9. The method (100) of any one of the preceding claims, further comprising classifying or updating a classification of the transmitter tags (50a, 50b) in a first category or a second category depending on whether: a time difference between two radio waves with the RFID data of the respective transmitter tag being consecutively captured is greater than a predetermined time threshold or not; and/or a number of times that radio waves with the RFID tags of the respective transmitter tag are captured is less than a predetermined read count or read rate threshold or not; wherein the transmitter tags are classified in the first category when the time difference is greater than the predetermined time threshold and/or the number of times is less than the predetermined read count or read rate threshold, and in the second category otherwise.
  10. 10. The method (100) of claim 9 when depending upon claim 8, wherein the commanding (110), processing (120), estimating (130), and updating (140) steps are conducted according to the one or more first commanded full rotations when a number of transmitter tags (50a, 50b) classified in the first category exceeds a predetermined tag threshold in a given observation period.
  11. 11. The method (100) of any one of claims 8-10, wherein the commanding (110), processing (120), estimating (130), and updating (140) steps are conducted according to the one or more second commanded full rotations such that two or more second commanded full rotations are performed back-to-back when a time of day is within a predetermined hour range.
  12. 12. The method (100) of any one of claims 8-11 , wherein the commanding (110), processing (120), estimating (130), and updating (140) steps are conducted according to the one or more first commanded full rotations when a difference between a number of transmitter tags (50a, 50b) whose radio waves have been captured in one or more most recent second commanded full rotations and a number of transmitter tags whose radio waves have been captured in one or more most recent first commanded full rotations exceeds a predetermined tag difference.
  13. 13. A computing device or system (80) comprising means adapted to execute the steps of a method (100) according to any one of the preceding claims.
  14. 14. An antenna assembly (10a, 10b) comprising: at least one antenna (15a-15c); and at least one motor (12) for rotation of the at least one antenna around at least one rotation axis (17a, 17b); wherein each antenna of the at least one antenna is at least linearly polarized, dual- linearly polarized or circularly polarized; wherein the antenna assembly preferably has at least four different linear polarizations, with first and second linear polarizations thereof being perpendicular one another, and third and fourth linear polarizations thereof being perpendicular one another.
  15. 15. A system comprising: at least one antenna assembly (10a, 10b) according to claim 14; and a computing device or system (80) according to claim 13 communicatively coupled with each antenna assembly of the at least one antenna assembly.

Description

ROTARY ANTENNA ASSEMBLY FOR INVENTORY TAKING TECHNICAL FIELD The present disclosure relates to inventory taking, i.e., stock-taking. More particularly, the present disclosure relates to the controlled use of one or more rotary antennas for detection and estimation of position of RFI D tags associated with objects within a given space. BACKGROUND Keeping track of objects, especially in large facilities like warehouses, has always been a cumbersome and time-consuming task. The resources required for inventory taking become larger the larger the facilities are. On top of that, the complexity of keeping track of the objects within a given space increases whenever not only the number of units of each object is registered, but the position thereof is also to be registered so that retrieval of the object when desired is carried out quickly. Even when there is a good organization within the facilities for placing the objects in one location or another, it can happen that objects get misplaced. The use of RFID tags has simplified inventory taking owing to the possibility of interrogating, with short-range wireless communications, the tags associated with objects to get to know if the objects are within the facilities. Notwithstanding, existing limitations of RFID tags in terms of both the range of their radiated electromagnetic waves, and the propagation issues of electromagnetic waves that cause the interrogation not to reach the RFID tag or the response of the latter not to reach an RFID reader, are still problematic for inventory taking. Besides, when the position of the RFID tag is to be estimated, the accuracy in the estimated position has room for improvement. Nowadays, antenna systems formed by multiple antennas interrogating and detecting RFID tags are typically used within facilities where inventory of objects is to be taken and kept updated. Although there have been improvements in the antennas used and the positioning thereof within the facilities to make the systems capable of detecting most RFID tags and estimating positions thereof, the systems feature several limitations when it comes to number of RFID tags within the facilities that are hard to detect, or the number of antennas necessary to cover a given space is high. There is an interest in improving inventory taking so that at least some of the aforesaid shortcomings are overcome. DESCRIPTION A first aspect relates to a method comprising: commanding rotation of at least one antenna of each antenna assembly of at least one antenna assembly around at least one rotation axis so as to capture radio waves with radio-frequency identification, RFID, data reaching the respective antenna assembly from several directions; processing, for each RFID data of the captured radio waves, each of: the RFID data to identify a transmitter tag thereof; a received signal strength indicator, i.e., RSSI, and/or a received signal phase and/or a read count included in a data packet that comprises the RFID data; and an angle or a set of angles of the antenna or antennas of the at least one antenna when capturing the radio waves with the RFID data; based on the processing, estimating a location or updating an estimated location of each transmitter tag whose RFID data has been processed; and updating an inventory of the transmitter tags based on the processing and the estimating steps. The rotation of the antenna(s) enables to scan a given space, thereby reducing the number of antennas used for tracking objects in the space and increasing the accuracy of the location estimation. The angle or set of angles of the antenna(s) is a piece of data relevant for the estimation of the location as it shows under which angular conditions there has been reception of radio waves corresponding to a given transmitter tag. The accuracy that the angle or set of angles adds to the location estimation is increased by additionally considering at least one further piece of data from the transmitter tag, which is the RSSI, the signal phase and/or the read count. Any of these data is indicative, to a greater or lesser extent, of the distance that the transmitter tag is from the respective antenna(s) as known in the art. Hence, by combining the reception of radio waves for a given angle or set of angles with such distance-related data, which is applicable to each angle of the set of angles or the only angle (depending on whether the antenna(s) received the radio waves for the transmitter tag in just one angle or in several angles), location may be estimated. To this end, each of said pieces of data that are available for a given transmitter tag are processed to perform the estimation or update an existing estimation. The latter, takes place, for example, when a location has been estimated following a first rotation of one or more antennas, and then the location for the same transmitter tag has been estimated again following a second rotation of the one or more antennas, or a rotation of one or mo