Livestock Electronic Identification Tag Reader Synchronization

Abstract

Method for synchronizing a livestock electronic identification tag reader to read livestock electronic identification tags attached to livestock. Embodiments include using pulses from a global navigation satellite system (GNSS) receiver, adjusting for errors between a reference beat signal and a local beat signal, and using a synchronization signal.

Description

Technical Field

[0001] The present invention relates to the synchronization of livestock electronic identification tag readers for reading livestock electronic identification tags attached to livestock. Background Art

[0002] Livestock electronic identification tags can be used for livestock identification. The tag is securely attached to the livestock, usually on the livestock's ear. The livestock can be uniquely identified by reading the tag. Readers are located in certain areas to read the livestock's tags. Summary of the invention

[0003] In a first embodiment, a method is provided, comprising: receiving pulses from a global navigation satellite system (GNSS) receiver; calculating a transmission period and a reception period based on the pulses; during the transmission period, sending a signal to an electronic tag attached to livestock; and during the reception period, monitoring a signal received from the electronic tag attached to livestock; wherein the method is performed by a livestock electronic identification tag reader, the livestock electronic identification tag reader being configured to read a livestock electronic identification tag attached to livestock.

[0004] In a second exemplary embodiment, a livestock electronic identification tag reader is provided, comprising: a GNSS receiver configured to generate pulses; a beat calculation module configured to calculate a sending period and a receiving period based on the pulses; a signal transmitter module configured to send a signal to an electronic tag attached to the livestock during the sending period; and a signal receiver module configured to monitor a signal received from the electronic tag attached to the livestock during the receiving period.

[0005] In a third exemplary embodiment, a method is provided, comprising: receiving a reference beat signal; generating a local beat signal in a local beat signal generator, the local beat signal corresponding to a sending period and a receiving period, during the sending period, sending a signal to a livestock electronic identification tag, and during the receiving period, monitoring a signal from the livestock electronic identification tag; determining an error between the reference beat signal and the local beat signal; and adjusting the local beat signal generator based on the error to minimize the difference between the reference beat signal and the local beat signal; wherein the method is performed by a livestock electronic identification tag reader configured to read a livestock electronic identification tag attached to livestock.

[0006] In a fourth exemplary embodiment, a livestock electronic identification tag reader is provided, comprising: a beat signal receiver configured to receive a reference beat signal; a local beat signal generator configured to generate a local beat signal, the local beat signal corresponding to a sending period and a receiving period, during which a signal is sent to the livestock electronic identification tag and during which a signal from the livestock electronic identification tag is monitored; an error calculation module configured to determine an error between the reference beat signal and the local beat signal; and an error adjustment module configured to adjust the local beat signal generator based on the error to minimize the difference between the reference beat signal and the local beat signal.

[0007] In a fifth exemplary embodiment, a method for reading an electronic tag attached to livestock is provided, comprising: generating a synchronization signal; encoding the synchronization signal to generate an encoded synchronization signal; and sending the encoded synchronization signal to one or more slave readers; wherein the method is performed by a master reader that communicates with one or more slave readers, each slave reader being a livestock electronic identification tag reader configured to read a livestock electronic identification tag attached to the livestock.

[0008] In a sixth exemplary embodiment, a reader is provided, comprising: a synchronization signal generator configured to generate a synchronization signal; a synchronization signal encoder module configured to encode the synchronization signal to generate an encoded synchronization signal; and a synchronization signal transmission module configured to send the encoded synchronization signal to one or more slave readers; wherein the reader is a master reader that communicates with one or more slave readers, each slave reader being a livestock electronic identification tag reader configured to read a livestock electronic identification tag attached to livestock.

[0009] In a seventh exemplary embodiment, a method is provided, comprising: receiving an encoded synchronization signal from a master reader; decoding the encoded synchronization signal to obtain a decoded synchronization signal; synchronizing a cadence based on the decoded synchronization signal; and operating according to the cadence; wherein the method is performed by a slave reader, the slave reader communicates with the master reader, the slave reader being a livestock electronic identification tag reader configured to read a livestock electronic identification tag attached to livestock.

[0010] In an eighth exemplary embodiment, a livestock electronic identification tag reader is provided, comprising: a synchronization signal receiver module configured to receive an encoded synchronization signal from a main reader; a synchronization signal decoding module configured to decode the encoded synchronization signal to obtain a decoded synchronization signal; and a beat synchronization module configured to synchronize the beat based on the decoded synchronization signal; wherein the reader is configured to read the livestock electronic identification tag attached to the livestock according to the beat. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention is described below by way of example with reference to the accompanying drawings, in which only some embodiments of the present invention are shown. However, these embodiments are for illustration purposes only. The present invention is not limited to the specific details in the accompanying drawings and the corresponding description.

[0012] Figure 1 is a diagram of an exemplary reader system in which livestock electronic tag readers are synchronized;

[0013] Figure 2 is a diagram of an exemplary method for generating a synchronization signal;

[0014] Figure 3 is a diagram of an exemplary method for synchronizing readers based on a synchronization signal;

[0015] Figure 4 An exemplary method diagram based on GNSS synchronous reader

[0016] Figure 5 is a diagram showing an exemplary method of how to improve the accuracy of a beat signal generator; and

[0017] Figure 6 is a diagram of an exemplary reader. DETAILED DESCRIPTION

[0018] In some embodiments, a method is provided to synchronize readers with each other. Synchronization means that each reader enters a transmit mode at about the same time and enters a receive mode at about the same time.

[0019] system

[0020] Figure 1 An exemplary reader system is shown in which livestock electronic tag readers are synchronized.

[0021] The system has a plurality of livestock electronic tag readers 110, which are distributed around areas such as livestock farms. Each livestock electronic tag reader is associated with a race 120 through which livestock can pass. The race 120 can be located at the entrance and exit between the same areas to increase the throughput of livestock passing through these areas.

[0022] In some cases, readers 110 may be spaced hundreds of meters apart and widely distributed over an area. For example, in a series of fences, one or more readers may be located at each entrance and exit.

[0023] In use, livestock 130 passes by one or more of the readers 110. The livestock electronic identification tags 131 attached to each livestock (e.g., each livestock's ears) are read by one or more readers 110. This allows the reader system to identify and monitor the identity and location of livestock throughout an area.

[0024] The tag 131 is read by the reader 110 which sends an excitation signal during the transmit mode. Upon receiving the excitation signal, the tag powers up and sends an identifier. The identifier is a 96-bit unique code for the animal. If there are multiple tags 131 attached to the same animal, each tag 131 uses the same identifier. The identifier is received by one or more readers 110 during the reader receive mode.

[0025] The transmission power of the excitation signal is relatively high compared to the identifier. In fact, it is impossible for a reader 110 (the same reader or a different reader) to receive the identifier if the reader 110 is generating the excitation signal. To avoid this, the readers 110 are synchronized so that they enter the transmission mode and the reception mode at approximately the same time.

[0026] One of the readers is designated as a master reader 111, and the remaining readers 110 are designated as slave readers. The master reader 111 is configured to set a clock for each reader 110. That is, the master reader 111 determines when the reader 110 enters a transmit mode and when the reader 110 enters a receive mode. This is achieved in part by the master reader 111 sending a wireless synchronization signal to the slave readers. A reader that is approximately in the middle of the readers 110 or a reader that has a good wireless communication link to minimize transmission time may be selected as the master reader 111. The master reader 111 may operate in the same manner as the other readers 110.

[0027] Additionally, each reader 110 may maintain a local clock generator. This may be used to clock in between synchronization signals, or when the master reader 111 is unable to send a synchronization signal.

[0028] Due to the synchronization signal, the readers 110 enter the transmission mode and the reception mode at approximately the same time. For example, the range for each reader 110 to enter the transmission mode or each reader 110 to enter the reception mode is about 250 ps.

[0029] In some cases, one or more of the readers 110 may be repeaters that transmit synchronization signals from the master reader 111 to other slave readers 110 that are not within the communication range of the master reader 111 .

[0030] Synchronize using sync signal

[0031] Figure 2 An exemplary method for generating a synchronization signal is shown.

[0032] In step 201, an analog beat signal is generated. This is usually implemented in the master reader. The analog beat signal is generated to determine when the livestock electronic tag reader enters the sending mode or the receiving mode.

[0033] The analog beat signal has a predetermined period. For example, the period is about 60ms or 100ms. Therefore, the period is mapped to the time required for the reader to complete a transmission mode and a reception mode. The high part of the analog beat signal corresponds to the transmission mode, and the low part of the analog beat signal corresponds to the reception mode. The ratio of these modes can be selected from a group of predetermined beats. For example, the ratio of reception to transmission can be one of 80:20, 50:50 or 40:20.

[0034] This analog beat signal can be directly used by the master reader to control its own transmit mode and receive mode.

[0035] The analog beat signal can be generated in a beat signal generator of the master reader. For example, the beat signal generator can be an oscillator, such as a voltage-controlled oscillator.

[0036] In step 202, the analog beat signal is digitized to generate a digital synchronization signal.

[0037] This can be performed by an analog-to-digital converter of the master reader, which can be implemented as an integrated circuit. The sampling frequency can be set based on the required accuracy and / or period of the analog beat signal. For a 100ms beat signal, a sampling frequency of 1kHz is sufficient.

[0038] In some embodiments, the digital synchronization signal can be generated directly without first generating an analog beat signal. For example, it can be generated in the processor of the master reader based on a hardware beat signal generator (such as a local oscillator). When the beat signal generator runs at a higher frequency than the digital synchronization signal, the digital synchronization signal can be generated by dividing the signal of the local oscillator.

[0039] In step 203, the digital synchronization signal is encoded to generate an encoded synchronization signal.

[0040] The encoding may include determining the period and / or beat based on the digital synchronization signal and encoding these periods and / or beats into bytes representing the signal. Therefore, the amount of data of the encoded synchronization signal is significantly lower than that of the digital synchronization signal.

[0041] The coded synchronization signal may be a sequence of bytes (i.e., a sequence of 8-bit bytes). The first part of the coded synchronization signal may be a predetermined synchronization sequence to indicate the start of the coded synchronization signal so that the start time of the beat is synchronized. The predetermined sequence may be a sequence associated with the reader system. This allows two master readers operating in the same geographical area to set the beat of their slave reader systems separately: each slave reader can only operate according to a synchronization signal having a specific synchronization sequence.

[0042] The second part of the coded synchronization signal may be a beat sequence. The beat sequence may be a byte sequence indicating a beat ratio and / or a beat period.

[0043] In some cases, the beat sequence is an index into a beat dictionary. The beat dictionary is a mapping of indices to specific beat ratios and / or beat periods. For example, a first index in the beat dictionary may correspond to a 100 ms period with a transmit-receive ratio of 80:20, while a second index in the beat dictionary may correspond to a 60 ms period with a transmit-receive ratio of 40:20. The beat dictionary may be pre-stored in the master reader and each slave reader.

[0044] In other cases, the beat sequence directly encodes the beat ratio and / or the beat period. For example, the first byte sequence of the beat sequence may be associated with an integer number of milliseconds of the period, the second byte sequence of the beat sequence may be associated with the period of the receive mode, and the third byte sequence of the beat sequence may be associated with the period of the transmit mode.

[0045] The encoding may also include checking information or redundant information as part to ensure that a receiver correctly receives the encoded synchronization signal and the information it contains.

[0046] The coded synchronization signal also includes other information related to the master reader. For example, it includes the mode of the master reader or the synchronization method of the original analog beat signal. If the master reader has a GNSS lock so that the analog beat signal is synchronized via GNSS, it can be indicated in the coded synchronization signal.

[0047] The encoding may be performed in a signal encoding module of the master reader. The signal encoding module may be a hardware circuit configured to perform the encoding. Alternatively, the signal encoding module may be a series of instructions that may be executed by a processor of the master reader to perform the encoding.

[0048] In step 204, the encoded synchronization signal is sent to one or more slave readers.

[0049] This may be achieved by appropriate technology, such as appropriately configured IEEE 802.11 or other suitable transmission protocols.The transmission range may be configured to be received by a slave reader within a predetermined range (eg 1 km) of the master reader.

[0050] This can be achieved by a synchronization signal transmission module of the master reader. The transmission module can be a hardware circuit configured to implement transmission via an antenna. Alternatively, the transmission module can be a series of instructions that can be executed by a processor of the master reader to transmit data via an antenna.

[0051] Figure 3 An exemplary method of synchronizing readers based on a synchronization signal is shown.

[0052] In step 301, a coded synchronization signal is received by a reader.

[0053] This can be implemented in a synchronization signal receiver module of the reader. The synchronization signal receiver module can be a hardware circuit configured to perform reception via an antenna. Alternatively, the synchronization signal receiver module can be a series of instructions that can be executed by a processor of the slave reader to receive data via an antenna.

[0054] Receiving the digitally encoded synchronization signal may also include verifying whether the digitally encoded synchronization signal is correctly received.

[0055] In step 302, the digital encoded synchronization signal is decoded to generate a digital decoded synchronization signal.

[0056] This can be accomplished by identifying the beat start time. The start time is the time when the digital decode synchronization signal is available. Alternatively, the start time may be an estimated time when the analog beat signal is generated in step 201, and thus may be calculated based on the time when the digital decode synchronization signal is available to calculate the processing and transmission delays.

[0057] Furthermore, decoding may also include extracting a beat ratio and / or period from a digitally encoded synchronization signal, in particular a beat sequence.

[0058] In the case where the master reader uses a unique synchronization sequence, the slave reader can determine whether the synchronization sequence of the digitally encoded synchronization signal matches the predetermined synchronization sequence. If it does not match, the slave reader can omit other steps.

[0059] The decoding may be performed in a signal decoding module of the slave reader. The signal decoding module may be a hardware circuit configured to perform the decoding. Alternatively, the signal decoding module may be a series of instructions that may be executed by a processor of the slave reader to perform the decoding.

[0060] In step 303, the beats are synchronized based on the digitally decoded synchronization signal.

[0061] In this context, the beat includes a transmission period and a reception period corresponding to the time when the reader enters a transmission mode and a reception mode, respectively.

[0062] Synchronizing the beats may include determining the transmit period and receive period based on the beat ratio and period. For example, a 100 ms beat period and a 80:20 beat ratio indicate that the reader should have a transmit period of 20 ms and a receive period of 80 ms. These periods may be measured from the beat start time.

[0063] This also includes updating the beat signal generator of the slave reader based on the beat period of the digital decoded synchronization signal. For example, the beat signal generator can be an oscillator, such as a voltage controlled oscillator.

[0064] This may be performed in a beat synchronization module of the slave reader. The beat synchronization module may be a hardware circuit configured to perform synchronization (e.g., by interacting with a beat signal generator). Alternatively, the beat synchronization module may be a series of instructions that may be executed by a processor of the slave reader to implement synchronization.

[0065] In step 304, the reader operates according to the beat.

[0066] In this way, the reader can enter the sending mode according to the sending cycle and enter the receiving mode according to the receiving cycle.

[0067] Since the reader is synchronized with the master reader, the timing of the reader's transmission cycle and reception cycle is substantially the same as that of each of the other readers synchronized with the master reader.

[0068] This reduces the possibility of interference from one reader's transmission when it is received by another reader.

[0069] In some cases, the reader may determine that it is not synchronized with the beat based on the digital decoded synchronization signal. This determination may be based on other information provided in the digital encoded synchronization signal. If the information indicates that the master reader does not have a GNSS lock and the slave reader also does not have a GNSS lock, the slave reader determines that it can use GNSS to synchronize the beat.

[0070] Figure 2 and Figure 3 The method shown in provides a robust method for synchronizing the beat of one or more slave readers with a master reader. The method reduces interference and improves the reliability and accuracy of reading. In addition, because the synchronization signal is a digitally encoded signal, it has been shown in practice that the synchronization signal can be received by the slave reader even in the presence of significant interference from other signals. This allows the synchronization signal to be used for readers that are farther away.

[0071] GNSS synchronization

[0072] Some readers have a beat signal generator configured to maintain a beat. For example, an oscillator (e.g., a voltage-controlled oscillator) can be used to maintain the beat period. By setting the oscillator to have a predetermined beat, the reader has a fixed transmission period and reception period. Therefore, it is very important to synchronize the beat of the beat signal generator to avoid the transmission mode of one reader interfering with the reception mode of another reader.

[0073] As described above, a slave reader can be synchronized with a master reader. However, in the event that the master reader's synchronization signal is not available, it is necessary to incorporate an alternative method. For example, due to atmospheric conditions, the signal transmission distance may be lower than expected, making it impossible for the slave reader to receive the master reader's synchronization signal.

[0074] In addition, it is necessary to synchronize the master reader's clock according to an external source. This allows multiple master readers to be synchronized, allowing for a wider geographical distribution of the reader system.

[0075] One method is to use pulses generated by a GNSS receiver. A GNSS receiver is configured to receive readings from a global navigation satellite system (GNSS), such as GPS, GLONASS, BeiDou, or Galileo. Each GNSS system has multiple satellites that transmit signals at fixed intervals under the control of highly accurate atomic clocks. Users can determine their position based on the signals received from multiple satellites. However, due to the precise timing of the signal, it can be used to generate pulses at fixed intervals. Such pulses are highly accurate because they are synchronized with the satellites.

[0076] Therefore, a GNSS receiver can generate pulses that are synchronized with any other GNSS receiver. By synchronizing the reader's tick with the pulses generated by the GNSS receiver, the ticks of each reader can be synchronized with each other.

[0077] This can be used in the master to synchronize its tick signal generator and / or generate an analog tick signal. Since the slave can use the analog tick signal to eventually synchronize with the master, the slave can use the pulses from the GNSS receiver to synchronize indirectly.

[0078] In other cases, the method can be used in a slave reader as a backup or replacement for the synchronization signal from the master reader. This can improve the accuracy and resilience of the reader system because the master reader is no longer a single point of failure.

[0079] This method can also be used with readers that are not in a master-slave configuration. Multiple readers can operate synchronously without direct communication, relying on pulses from the GNSS receiver.

[0080] Figure 4 An exemplary method of synchronizing readers based on GNSS is shown.

[0081] In step 401 , a pulse is received from a GNSS receiver.

[0082] The pulse is output by the GNSS receiver at a fixed period (eg, every second). The pulse may be transmitted to the reader, for example, via a connection between the pulse output of the GNSS receiver and the input of the reader. The pulse may have a predetermined duration, for example, 100 ms.

[0083] In step 402, the beats are synchronized based on the pulses.

[0084] In this context, the beat includes a transmission period and a reception period corresponding to the time when the reader enters a transmission mode and a reception mode, respectively.

[0085] Synchronizing the beat may include setting the start point of the beat (or the start point of the transmission cycle) based on the start point of the pulse. This also includes updating the beat signal generator of the reader based on the beat period of the digital decoded synchronization signal. For example, the beat signal generator can be an oscillator, such as a voltage controlled oscillator.

[0086] This may be performed in a beat synchronization module of the reader. The beat synchronization module may be a hardware circuit configured to perform synchronization (e.g., by interacting with a beat signal generator and a GNSS receiver). Alternatively, the beat synchronization module may be a series of instructions that may be executed by a processor of the reader to perform synchronization.

[0087] In some cases, the beat period is an integer multiple of the pulse period. This allows the beat period to be synchronized after the integer multiple period.

[0088] In the case where the beat cycle is not an integer multiple of the pulse cycle, the pulse can be offset to adapt to this situation. For example, an integer multiple of a 60ms beat cycle is not suitable for a 1s pulse cycle. Therefore, the first beat cycle can be synchronized with the first pulse because both occur at the target start time (e.g., midnight). The sixteenth beat should occur 960ms after the start time, and the seventeenth cycle should occur 1020ms after the start time. These are not consistent with the second pulse, which occurs 1000ms after the start time. Therefore, synchronization can be performed using the second pulse based on the sixteenth beat plus a 40ms offset. Similarly, synchronization using the third pulse can be performed based on the thirty-third beat plus a 20ms offset. Then, the fiftieth beat and the fourth pulse occur simultaneously.

[0089] Using the offset in this way allows the pulse to be synchronized with any beat period, even if the beat does not always start at the same time as the pulse.

[0090] In step 403, the sending period and the receiving period are calculated based on the beat.

[0091] The transmit cycle corresponds to the period when the reader is in the transmit mode, and the receive cycle corresponds to the period when the reader is in the receive mode. The duration and relative timing of these cycles can be preset according to the beat cycle and the beat ratio.

[0092] Because the beat is set based on the pulse, the sending cycle and receiving cycle can be indirectly calculated based on the pulse.

[0093] This can be implemented in a beat calculation module of the reader. The beat calculation module can be a hardware circuit configured to perform calculations. Alternatively, the beat calculation module can be a series of instructions that can be executed by a processor of the reader to perform the calculations.

[0094] In step 404, the reader operates according to the sending cycle and the receiving cycle.

[0095] During the transmit cycle, the reader is in transmit mode. The reader transmits an excitation signal. The signal may be sent to an electronic livestock identification tag attached to the livestock to power the tag.

[0096] During the receive cycle, the reader is in receive mode. The reader monitors for signals from tags. In this mode, the reader can receive signals from powered tags attached to livestock.

[0097] In this way, multiple readers can rely on GNSS receivers to synchronize (ie, enter their transmit and receive modes in a synchronized manner). This reduces the chance that one reader's transmit mode will interfere with another reader's receive mode and can provide a more reliable reader system.

[0098] In some embodiments, the slave reader can selectively synchronize its beat based on a synchronization signal from the master reader or a GNSS receiver. In some cases, the synchronization beat is primarily based on the GNSS receiver. The synchronization signal from the master reader is used only when the GNSS receiver cannot output a signal (for example, due to atmospheric conditions). In other cases, the synchronization signal from the master reader is used primarily for synchronization. However, if the master reader synchronization signal is not synchronized with the GNSS receiver (or in other words, the master reader does not have a GNSS lock), the slave reader switches to synchronizing with the GNSS receiver.

[0099] This increases the resiliency of the slave reader. By setting up redundant synchronization methods, the slave reader can continue to operate even if some part of the system fails.

[0100] Error Correction

[0101] In the above method, the reader's beat may be synchronized from time to time. For example, when using a GNSS receiver, the reader's beat may be synchronized once per second.

[0102] However, the clock cycle is usually significantly shorter than this, for example, 100ms or 60ms. The clock is controlled by a clock signal generator, for example, a voltage-controlled oscillator of the reader.

[0103] It is common for a beat generator to drift over time. For example, every beat cycle. The beat cycle often grows or shrinks depending on the characteristics of the beat generator. For example, in some cases, the beat cycle can grow by 10ms per second.

[0104] This drift is different for each reader. As drift accumulates over time, readers tend to lose synchronization. This may eventually cause the reader system to fail to operate due to excessive interference between readers.

[0105] Frequent synchronization of the reader signal can prevent excessive accumulation of drift. However, if such synchronization is not possible (e.g., due to atmospheric conditions rendering the GNSS signal unusable for synchronization), this may prevent the reader system from operating.

[0106] One way to mitigate this is drift correction, which keeps the local clock signal (i.e., the clock signal from the clock signal generator) relatively close to the reference signal (i.e., the clock of the synchronization signal from the master reader or the clock of the pulse from the GNSS receiver) for a longer period of time.

[0107] Figure 5 An exemplary method of how to improve the accuracy of a beat signal generator is shown.

[0108] In step 501, a reference beat signal is received.

[0109] In case the method is performed by a master reader or a standalone reader (ie a reader not operating in a master-slave configuration), the reference beat signal may correspond to a pulse generated by a GNSS receiver.

[0110] In the case where the method is performed by a slave reader, the reference beat signal may correspond to a pulse generated by a GNSS receiver or a synchronization signal sent by a master reader.

[0111] This can be done during normal operation of the reader, for example, by receiving a reference clock signal for synchronization.

[0112] In the case of receiving a synchronization signal from a master reader, this may occur in a synchronization signal receiver module of the reader. The synchronization signal receiver module may be a hardware circuit configured to perform reception via an antenna. Alternatively, the synchronization signal receiver module may be a series of instructions executable by a processor of the reader to receive data via an antenna.

[0113] In step 502, a local beat signal is generated.

[0114] The signal is generated by a clock signal generator (eg, a voltage controlled oscillator) of the reader. This can be done during normal operation of the reader. For example, a local clock signal can be generated to determine the transmission cycle and the reception cycle of the reader.

[0115] This is usually done before the beat signal generator is synchronized. This is because the reference beat signal and the local beat signal are essentially the same after synchronization.

[0116] In step 503, the error between the reference beat signal and the local beat signal is calculated, which can be achieved by calculating the absolute time difference between the cycle start point of the local beat signal and the cycle start point of the reference beat signal.

[0117] The periods of the local beat signal and the reference beat signal may be different. For example, the local beat signal corresponds to a 100ms beat, while the reference beat signal corresponds to a 1s pulse. In this case, the error is calculated based on the time point when each signal starts at the same time (for example, after 10 beats).

[0118] This can be implemented in an error calculation module of the reader. The error calculation module can be a hardware circuit configured to perform the calculation. Alternatively, the error calculation module can be a series of instructions that can be executed by a processor of the reader to perform the calculation.

[0119] In step 504, the local beat signal generator is adjusted based on the error. This is to minimize the difference between the reference beat signal and the local beat signal (or in other words, to minimize the error that can be calculated in the subsequent execution of step 503). In this case, minimization means reducing the error below an acceptable error threshold. For a 100ms beat period, the acceptable error is 250ps, so the adjustment is to reduce the error below 250ps.

[0120] In some cases, the local beat signal generator is adjusted to generate the local beat signal earlier or later based on the error. This may be a small fraction of the error (e.g., 50% of the error) to allow for incremental changes. For example, if the calculated error is 10ms per beat cycle (i.e., the local beat signal is 10ms later than the reference beat signal), the local beat signal generator may be adjusted so that subsequent local beat signals are generated 5ms earlier. This is expected to reduce the next calculated error to 5ms.

[0121] In some cases, adjustments may be made only when the calculated error is above a threshold. This avoids making minimal adjustments to the local beat signal and the reference beat signal that remain consistent in practical applications. For example, adjustments may be made only when the error is greater than 150ps.

[0122] This can be implemented in an error adjustment module of the reader. The error adjustment module can be a hardware circuit configured to perform the adjustment. Alternatively, the error adjustment module can be a series of instructions that can be executed by a processor of the reader to implement the adjustment.

[0123] In this way, the amount of drift accumulated over time can be minimized by adjusting the beat signal generator based on the error.

[0124] When this method is used in a master or standalone reader, the reader can rely on a reference tick signal that corresponds to the GNSS receiver pulses. This method allows the local tick signal from the tick generator to more closely match the reference tick signal for a longer period of time. Since this signal is propagated to the slave readers, this allows the system as a whole to operate more flexibly.

[0125] In the case of using this method in a slave reader, the slave reader can rely on a reference tick signal corresponding to the master reader's sync signal and / or a reference tick signal corresponding to the GNSS receiver pulse. This method allows the local tick signal from the tick signal generator to more closely match the reference tick signal for a longer period of time. This avoids one reader transmitting for a long time during another reader's receive cycle, allowing the system as a whole to operate more flexibly.

[0126] Reader

[0127] The above method can be implemented in a reader system including a plurality of readers.

[0128] Figure 6 An exemplary reader of this type is shown. The reader has a signal transmitter module 601 and a signal receiver module 602, wherein the signal transmitter module 601 is used to send signals to livestock electronic identification tags and the signal receiver module 602 is used to receive signals from livestock electronic identification tags. These modules can use an antenna 603 (or each uses a separate antenna). The reader has a beat signal generator 604 (e.g., a voltage-controlled oscillator) configured to generate a beat signal; and a beat calculation module 605, which is used to calculate a sending period and a receiving period based on the beat signal.

[0129] The reader also has an analog-to-digital converter 611 for converting the analog beat signal into a digital synchronization signal; a signal encoding module 612 for generating the encoded synchronization signal; and a synchronization signal transmission module 613 for transmitting the encoded synchronization signal to the slave reader. The synchronization signal transmission module 613 can communicate with an antenna 614 (although it is also the same as antenna 603). In some cases, the analog-to-digital converter 611, signal encoding module 612, synchronization signal transmission module 613 and antenna 614 are only provided on a reader intended to operate as a master reader.

[0130] The reader may also have a synchronization signal receiver module 621 configured to receive a digitally encoded synchronization signal, a signal decoding module 622 configured to generate a digitally decoded synchronization signal, and a beat synchronization module 623 configured to synchronize the beat signal generator 604. The synchronization signal receiver module 621 may communicate with an antenna 624 (although it may also communicate with antenna 603 or antenna 614).

[0131] The reader may also have a GNSS receiver 631 for receiving GNSS signals. The GNSS receiver 631 may communicate with an antenna 632 (although the same may be true for antenna 603, antenna 614, or antenna 624).

[0132] The reader may also include an error calculation module 641 and an error adjustment module 642 . The error calculation module 641 is used to calculate the error between the local beat signal and the reference beat signal. The error calculation module 641 is used to adjust the beat signal generator 604 based on the error.

[0133] In certain embodiments, one or more of the above modules may be omitted.

[0134] Although these modules are shown as separate components, in some embodiments, these modules are implemented in software. That is, computer executable instructions corresponding to the functions performed by one of the multiple modules are stored in a computer readable medium, such as the reader's memory 652. These instructions for performing the corresponding functions can then be executed by one or more processors 651 in the memory.

[0135] illustrate

[0136] Although a series of steps are described, they do not necessarily have to be performed in the order specified (unless the context requires otherwise). That is, in different embodiments, the steps may be performed out of order or in parallel.

[0137] Unless otherwise stated, the terms "include" and other grammatical forms have an inclusive meaning. That is, these terms and grammatical forms should be deemed to include the listed components and may also include other components or elements that are not listed.

[0138] The invention has been illustrated by describing certain embodiments. Although these embodiments have been described in detail, the scope of the claims should not be construed as being restricted or limited by these detailed descriptions. Additional advantages and modifications will be more readily apparent to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details shown or described. Therefore, these details may be modified without departing from the spirit or scope of the general concept of the invention.

Claims

1. A method for synchronizing livestock electronic identification tag readers, comprising: wirelessly receiving a synchronization signal from a master reader; In case the synchronization signal of the master reader is unavailable: Determine the use of pulses to synchronize beats; Receive pulses from a GNSS receiver; Calculating a sending period and a receiving period based on the pulses; During the transmission period, transmitting a signal to a livestock electronic identification tag attached to the livestock; as well as During a receiving period, monitoring signals received from livestock electronic identification tags attached to livestock; The method is performed by a livestock electronic identification tag reader, which is configured to read the livestock electronic identification tag attached to the livestock.

2. The method according to claim 1, wherein: Calculating the sending period and the receiving period based on the pulse includes: The beats are synchronized based on the pulses, wherein a first portion of the beats corresponds to the transmission period and a second portion of the beats corresponds to the reception period.

3. The method according to claim 2, wherein: The synchronization occurs in response to each pulse.

4. The method according to claim 1, wherein: Determining the use of the pulse to synchronize the beat includes: It is determined that the synchronization signal from the master reader is not locked by GNSS.

5. The method according to any one of claims 1 to 4, wherein: The period of the beat is an integer multiple of the period of the pulse.

6. The method according to any one of claims 1 to 4, wherein: The period of the beat is 100 ms or 60 ms.

7. The method according to any one of claims 1 to 4, wherein: The period of the pulse is 1 s.

8. The method according to any one of claims 1 to 4, wherein: The ratio of the duration of the receiving period to the duration of the sending period is 80:20, 50:50 or 40:

20.

9. A livestock electronic identification tag reader, comprising: a GNSS receiver configured to generate pulses; a synchronization signal receiver module configured to wirelessly receive a synchronization signal from a master reader; The processor is configured to: when the synchronization signal of the master reader is unavailable, determining to use the pulse to synchronize the beat; A beat calculation module, configured to calculate a sending period and a receiving period based on the pulse; a signal transmitter module configured to transmit a signal to a livestock electronic identification tag attached to the livestock during the transmission period; and A signal receiver module is configured to monitor, during the reception period, a signal received from a livestock electronic identification tag attached to the livestock.

10. The reader according to claim 9, wherein: The reader is configured to execute the method according to any one of claims 1-8.

11. A computer-readable medium comprising instructions which, when executed by a processor of a livestock electronic identification tag reader, cause the livestock electronic identification tag reader to perform the method of any one of claims 1-8.

12. A method for synchronizing livestock electronic identification tag readers, comprising: receiving a reference beat signal; generating a local beat signal at a local beat signal generator, the local beat signal corresponding to a sending period and a receiving period, during which a signal is sent to a livestock electronic identification tag, and during which a signal from the livestock electronic identification tag is monitored; Determining an error between the reference beat signal and the local beat signal; as well as adjusting the local beat signal generator based on the error to minimize the difference between the reference beat signal and the local beat signal; The method is performed by a livestock electronic identification tag reader, which is configured to read a livestock electronic identification tag attached to the livestock.

13. The method according to claim 12, wherein: The reference beat signal is based on pulses received from a GNSS receiver.

14. The method according to claim 12, wherein: The reference beat signal is a synchronization signal received from a master reader.

15. The method according to any one of claims 12 to 14, wherein: The method is repeatedly executed each time the reference beat signal is received.

16. The method according to any one of claims 13-14, wherein: Adjusting the local beat signal generator includes adjusting the beat signal generated by the local beat signal generator based on the error to cause it to occur earlier or later.

17. The method according to any one of claims 12 to 14, further comprising: It is determined whether the error is above a threshold.

18. The method according to claim 17, wherein: The threshold is 150ps.

19. The method according to any one of claims 12 to 14, wherein: Minimizing the difference includes reducing the difference to below an acceptable error threshold.

20. The method according to claim 19, wherein: The acceptable error threshold is 250ps.

21. The method according to any one of claims 12 to 14, wherein: The local beat signal generator is a voltage-controlled oscillator.

22. A livestock electronic identification tag reader, comprising: A beat signal receiver configured to receive a reference beat signal; A local beat signal generator configured to generate a local beat signal, wherein the local beat signal corresponds to a sending period and a receiving period, during which a signal is sent to the livestock electronic identification tag, and during which a signal from the livestock electronic identification tag is monitored; an error calculation module, configured to determine an error between the reference beat signal and the local beat signal; as well as An error adjustment module is configured to adjust the local beat signal generator based on the error to minimize the difference between the reference beat signal and the local beat signal.

23. The reader according to claim 22, wherein: The reader is configured to execute the method according to any one of claims 12-21.

24. A computer-readable medium comprising instructions which, when executed by a processor of a livestock electronic identification tag reader, cause the livestock electronic identification tag reader to perform the method of any one of claims 12-21.

25. A method for reading an electronic tag attached to livestock, comprising: generating a synchronization signal; encoding the synchronization signal to generate an encoded synchronization signal; as well as wirelessly transmitting the encoded synchronization signal to one or more slave readers; The method is performed by a master reader communicating with the one or more slave readers, each of which is a livestock electronic identification tag reader configured to read a livestock electronic identification tag attached to livestock.

26. The method according to claim 25, wherein: Generating a synchronization signal comprises: generating an analog beat signal; and The analog beat signal is simulated to generate a digital synchronization signal.

27. The method according to claim 25 or 26, wherein: The encoded synchronization signal comprises a sequence of bytes.

28. The method according to claim 27, wherein: The byte sequence includes a sequence for identifying the master reader.

29. The method according to claim 27, wherein: The byte sequence includes a sequence for identifying the start time of a beat.

30. The method of claim 27, wherein: The byte sequence includes a beat sequence for determining a ratio of a transmission cycle to a reception cycle and / or a beat cycle.

31. The method according to claim 30, wherein: The beat sequence is one of a set of predetermined values.

32. The method according to any one of claims 25-26, wherein: The encoded synchronization signal indicates a mode of the master reader.

33. A reader, comprising: A synchronization signal generator, used for generating a synchronization signal; a synchronization signal encoder module configured to encode the synchronization signal to generate an encoded synchronization signal; and A synchronization signal transmission module, configured to send the coded synchronization signal to one or more slave readers; The reader is a master reader that communicates with the one or more slave readers, and each of the slave readers is a livestock electronic identification tag reader configured to read a livestock electronic identification tag attached to the livestock.

34. The reader according to claim 22 or 33, wherein: The reader is configured to perform the method according to any one of claims 25-32.

35. A computer readable medium comprising instructions which, when executed by a processor of a livestock electronic identification tag reader, cause the livestock electronic identification tag reader to perform the method of any one of claims 25-32.

36. A method for synchronizing livestock electronic identification tag readers, comprising: Receive the encoding synchronization signal from the main reader; decoding the encoded synchronization signal to obtain a decoded synchronization signal; synchronizing the beats based on the decoded synchronization signal; as well as Operate according to said beat; The method is performed by a slave reader, the slave reader communicates with a master reader, and the slave reader is a livestock electronic identification tag reader configured to read a livestock electronic identification tag attached to the livestock.

37. The method of claim 36, wherein: The operations include: Calculate the sending cycle and the receiving cycle based on the beat; During the transmission period, transmitting a signal to a livestock electronic identification tag attached to the livestock; and During the receive cycle, signals received from livestock electronic identification tags attached to livestock are monitored.

38. The method according to claim 36 or 37, wherein: Synchronizing the beats includes adjusting a beat signal generated by a beat signal generator.

39. A livestock electronic identification tag reader, comprising: a synchronization signal receiver module configured to receive a coded synchronization signal from a master reader; a synchronization signal decoding module, configured to decode the encoded synchronization signal to obtain a decoded synchronization signal; and a beat synchronization module configured to synchronize the beats based on the decoded synchronization signal; Wherein, the reader is configured to read the livestock electronic identification tag attached to the livestock according to the beat.

40. The reader according to claim 22, wherein: The reader is configured to perform the method of any one of claims 36-38.

41. A computer readable medium comprising instructions which, when executed by a processor of a livestock electronic identification tag reader, cause the livestock electronic identification tag reader to perform the method of any one of claims 36-38.

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