KR102308601B1 - Method And System for Positioning based on Reverse Time Difference Of Arrival - Google Patents

Abstract

Disclosed are a reverse TDoA-based positioning method and system. The embodiment of the present invention provides the reverse TDoA-based positioning method and system, which locally synchronizes clock information with a master anchor based on a master synchronization signal at each multiple slave anchors communicating with the master anchor configured per single cell for wired/wireless synchronization for Ultra-Wideband (UWB) based Real-Time Locating System (RTLS), and calculates a position of a tag based on time difference between synchronization signals received from a plurality of master anchors and slave anchors in the tag.

Description

Reverse TDoA-based positioning method and system {Method And System for Positioning based on Reverse Time Difference Of Arrival}

One embodiment of the present invention relates to a reverse TDoA-based positioning method and system.

The content described below merely provides background information related to the present embodiment and does not constitute the prior art.

RTLS (Real-Time Locating System) is a real-time location tracking system and refers to a system that checks the location of a person or thing in real time based on a specific technology. RTLS is applied using RFID (Radio Frequency Identification) technology or wireless LAN technology, and can be applied to various fields according to the purpose or method used.

In order to apply RTLS, an RTLS transmitter (eg, an RFID tag) is attached to each thing. The RTLS receiver (eg, RFID reader) wirelessly recognizes the unique identifier (ID) of the thing to which the RTLS transmitter is attached. RTLS provides a location service for things by collecting, storing, processing, and tracking unique identifiers after being collected by the RTLS receiver. Here, the RTLS receiver recognizes the location of the RTLS transmitter by using location information including the signal strength and signal arrival time and signal reception direction according to the radio wave reception of the RTLS transmitter in order to determine the location of the RTLS transmitter.

In order to locate the RTLS transmitter, the RTLS receiver is required to be synchronized to a precise standard time, but there is a problem with a nanoscale error range so far.

In this embodiment, for wired/wireless synchronization for UWB (Ultra-Wideband)-based Real-Time Locating System (RTLS), each of a plurality of slave anchors communicating with a master anchor configured for each single cell locally clocks itself based on the master synchronization signal. An object of the present invention is to provide a reverse TDoA-based positioning method and system that synchronizes information with a master anchor and calculates a position of a tag based on a time difference between synchronization signals received from a plurality of master anchors and slave anchors in the tag.

According to one aspect of the present embodiment, a master anchor for wirelessly broadcasting a clock synchronization signal (Clock Sync Signal) to the periphery in units of cells (Master Anchor); a slave anchor receiving the clock synchronization signal from the master anchor and locally synchronizing clock information with the master anchor based on the clock synchronization signal; Calculate a temporal difference value of the reception time of the clock synchronization signal received from the plurality of master anchors and the slave anchors, extract coordinate information included in the clock synchronization signal, and combine the difference value and the coordinate information a tag that calculates a location based on it; and a location engine that converts the difference value into an offset value and then synchronizes the difference value between master anchors of different cells based on the offset value.

According to another aspect of the present embodiment, the process of wirelessly broadcasting a clock synchronization signal (Clock Sync Signal) from the master anchor (Master Anchor) to the surrounding cell unit; receiving the clock synchronization signal from the master anchor at a slave anchor, and locally synchronizing clock information with the master anchor based on the clock synchronization signal; A tag calculates a temporal difference in reception time of the clock synchronization signals received from the plurality of master anchors and the slave anchors, extracts coordinate information included in the clock synchronization signal, and the difference value and calculating a location based on the coordinate information; The process of converting the difference value into an offset value in a location engine and then synchronizing the difference value between master anchors of different cells based on the offset value; Reverse TDoA-based positioning method comprising: provides

As described above, according to this embodiment, for each of a plurality of slave anchors communicating with the master anchor configured for each single cell for wired/wireless synchronization for an Ultra-Wideband (UWB)-based Real-Time Locating System (RTLS), local master synchronization It has the effect of synchronizing the clock information with the master anchor by itself based on the signal, and calculating the position of the tag based on the time difference between the synchronization signals received from the plurality of master anchors and the slave anchors in the tag.

1 is a diagram illustrating wireless synchronization between a master and a slave according to the present embodiment.
2 is a diagram illustrating the calculation of coordinates of a tag by performing a TDoA operation according to the present embodiment.
3 is a diagram illustrating the calculation of coordinates of a tag by performing a reverse TDoA operation according to the present embodiment.
4 is a flowchart illustrating a reverse TDoA-based positioning method according to the present embodiment.
5 is a diagram illustrating a wireless synchronization system according to the present embodiment.
6 is a flowchart for explaining the operations of the master anchor, the slave anchor, and the multi-slave anchor according to the present embodiment.
7 is a flowchart illustrating a wireless synchronization method according to the present embodiment.
8 is a diagram illustrating a wired synchronization concept according to the present embodiment.
9 is a diagram illustrating a wired/wireless hybrid synchronization system according to the present embodiment.

Hereinafter, this embodiment will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating wireless synchronization between a master and a slave according to the present embodiment.

1, the master anchor 110 and the slave anchors 120 and 130 perform synchronization. The master anchor 110 transmits a clock synchronization signal to the slave anchors 120 and 130 . The slave anchors 120 and 130 are synchronized based on the clock synchronization signal received from the master anchor 110 , and the slave anchors 120 and 130 have the same time information as the master anchor 110 .

2 is a diagram illustrating the calculation of coordinates of a tag by performing a TDoA operation according to the present embodiment.

As shown in FIG. 2 , the master anchor 110 and the slave anchors 120 and 130 perform synchronization. The master anchor 110 transmits a clock synchronization signal to the slave anchors 120 and 130 . The slave anchors 120 and 130 are synchronized based on the clock synchronization signal received from the master anchor 110 , and the slave anchors 120 and 130 have the same time information as the master anchor 110 .

The master anchor 110 transmits a clock synchronization signal to the tag 210 . The slave anchors 120 and 130 transmit the clock synchronization signal to the tag 210 after performing synchronization based on the clock synchronization signal received from the master anchor 110 . The tag 210 calculates a difference in reception times of clock synchronization signals respectively received from the plurality of master anchors 110 and the slave anchors 120 and 130 using a Time Difference Of Arrival (TDOA) algorithm.

When the master anchor 110 transmits the clock synchronization signal to the slave anchors 120 and 130 and the tag 210, a sequence is included in the packet. The master anchor 110 transmits the clock synchronization signal including the sequence in the packet to the slave anchors 120 and 130 and the tag 210 every 100 ms.

After receiving the clock synchronization signal including the sequence from the master anchor 110, the slave anchor A 120 synchronizes its own time with the master anchor 110, and then synchronizes the clock including the TDoA packet with the plurality of tags 210. transmit a signal

After receiving the clock synchronization signal including the sequence from the master anchor 110, the slave anchor B 130 synchronizes its own time with the master anchor 110, and then synchronizes the clock including the TDoA packet with a plurality of tags 210. transmit a signal

When the slave anchor A 120 and the slave anchor B 130 transmit the clock synchronization signal to the tag 210, the time information transmitted by each slave anchor is also included in the packet based on the time information received from the master anchor 110. make it When the slave anchor A 120 and the slave anchor B 130 transmit the clock synchronization signal to the tag 210, GPS information of the corresponding anchor is also included.

The tag 210 receives the TDoA packet included in the three or more clock synchronization signals received from the plurality of master anchors 110 and the slave anchors 120 and 130 . The tag 210 calculates the coordinates of the tag by applying an Offset value to the time information of the same sequence in the TDoA packet based on the master, and performing a TDoA operation using the arrival time difference in the tag 210 .

The tag 210 performs a reverse TDoA by receiving signals received from the synchronized master anchor 110 and the slave anchors 120 and 130 . The tag 210 synchronizes with the master anchor 110 and the slave anchors 120 and 130 using wired/wireless synchronization technology. The master anchor 110 transmits the clock synchronization signal to the slave anchors 120 and 130 and the tag 210 by including a sequence in the clock synchronization signal. The slave anchors 120 and 130 transmit (Tx) the UWB signal in the same sequence received from the master anchor 110 . When the slave anchors 120 and 130 transmit the reference clock synchronization signal, the synchronized time is included in a transmission packet and transmitted.

The slave anchors 120 and 130 are included in the transmission packet as reference coordinates of the anchor based on GPS location information. After receiving the clock synchronization signal from the slave anchors 120 and 130, the tag 210 receives the clock synchronization signals respectively from the plurality of master anchors 110 and the slave anchors 120 and 130 using a TDOA (Time Difference Of Arrival) algorithm. Calculate the difference in reception time. The tag 210 positions the tag 210 by performing triangulation using the reference coordinates of each anchor mapped to the clock synchronization signal.

3 is a diagram illustrating the calculation of coordinates of a tag by performing a reverse TDoA operation according to the present embodiment.

The master anchor 110 and the slave anchors 120 and 130 map the clock synchronization information and the GPS information to the tag 210 . The tag 210 calculates the location of the tag 210 by inversely calculating the GPS after receiving the GPS information together with the corresponding protocol.

The tag 210 synchronizes with the master anchor 110 and the slave anchors 120 and 130, and uses a TDOA (Time Difference Of Arrival) algorithm to synchronize the clocks received from the plurality of master anchors 110 and the slave anchors 120 and 130, respectively. Calculate the difference between the signal reception times.

The tag 210 receives three or more TDoA packets of the same sequence. In other words, the tag 210 receives TDoA packets from three or more master anchors 110 and slave anchors 120 and 130 .

The tag 210 positions the tag 210 based on Equation 1 based on three or more clock synchronization signals received from the plurality of master anchors 110 and the slave anchors 120 and 130 .

는 앵커 i로부터 태그 A까지의 의사거리(m)를 의미한다.

is the pseudo-distance (m) from anchor i to tag A.

는 진공속에서 빛의 속도 × (GPS 신호의 수신시간 - GPS 신호의 송신 시간)을 의미한다.

is the speed of light in vacuum × (reception time of GPS signal - transmission time of GPS signal).

c is the speed of light in vacuum (m/sec).

^{Δδ means the time deviation (δ i} ) of the anchor from the GPS standard time = the time of the receiver from the GPS standard time.

The tag 210 implements the TDoA method in the reverse direction to perform wireless synchronization with the master anchor 110 and the slave anchors 120 and 130 . After receiving clock synchronization information from the master anchor 110 and the slave anchors 120 and 130 , the tag 210 calculates the position of the tag 210 using the clock synchronization information.

4 is a flowchart illustrating a reverse TDoA-based positioning method according to the present embodiment.

The tag 210 performs synchronization with the master anchor 110 and the slave anchors 120 and 130 to perform the reverse TDoA (S410). When synchronization with the master anchor 110 and the slave anchors 120 and 130 is completed, the tag 210 starts TDoA Blink transmission (Tx) (S420).

The tag 210 checks whether three or more TDoA signals are received (S430). As a result of checking in step S430 , when three or more TDoA signals are received, the tag 210 performs a TDoA operation. As a result of checking in step S430 , when three or more TDoA signals are not received, the tag 210 waits for the TDoA signal.

Although it is described that steps S410 to S430 are sequentially executed in FIG. 4 , the present invention is not limited thereto. In other words, since it may be applicable to changing and executing the steps described in FIG. 4 or executing one or more steps in parallel, FIG. 4 is not limited to a time-series order.

As described above, the reverse TDoA-based positioning method according to the present embodiment described in FIG. 4 may be implemented as a program and recorded in a computer-readable recording medium. The program for implementing the reverse TDoA-based positioning method according to the present embodiment is recorded and the computer-readable recording medium includes all types of recording devices in which data readable by the computer system is stored.

5 is a diagram illustrating a wireless synchronization system according to the present embodiment.

The wireless synchronization system according to the present embodiment includes a clock generator 510 , a multi-cell synchronization setting device 520 , a location engine 530 , a master anchor, a slave anchor, and a multi-slave anchor. Components included in the wireless synchronization system are not necessarily limited thereto.

Master anchor, slave anchor, and multi-slave anchor are receivers that precisely synchronize the clocks via wired or wireless. The master anchor, the slave anchor, and the multi-slave anchor perform synchronization precisely in pico units using the clock information and the synchronization signal received from the clock generator 510 .

In the case of a single cell, n master anchors are required for each cell. On a cell-by-cell basis, a master anchor is configured together with a multi-slave anchor.

The clock generator 510 generates clock information and a synchronization signal of a wireless ultra-wideband (UWB) band. The clock generator 510 transmits clock information and a sync signal to the master anchor connected by a LAN cable.

The location engine 530 has a wireless synchronization method that accurately calculates the generated delay and reflects it to the offset. The location engine 530 collects the time difference of the multi-slave anchors and generates an offset value to synchronize all the master anchors.

The location engine 530 converts the difference values received from the master anchors of different cells from the multi-slave anchors into an offset value form, and then synchronizes the deviation values between the master anchors of different cells to the same value. The location engine 530 synchronizes the clocks of the other master anchors based on the reference master anchor among the master anchors of different cells by using the offset value. That is, the location engine 530 equally synchronizes the deviations of the master anchors of different cells based on the difference values received from the multi-slave anchors.

The location engine 530 synchronizes the clocks of the other master anchors based on the reference master anchor among the difference values received from the plurality of multi-slave anchors.

When the location engine 530 receives the difference value between the master anchors of different cells from the multi-slave anchors and generates an offset value, the offset value is generated by cumulatively reflecting the difference value between the master anchors of different cells received thereafter. . In other words, the location engine 530 synchronizes the deviation values of the master anchors of different cells that are not adjacent to the reference master anchor to the same value. Since the location engine 530 accumulates and generates offset values, all master anchors have the same clock.

The location engine 530 creates a Time Sync Tree Map. The location engine 530 configures a separate tab next to the anchor list on the time synchronization tree map to express only the master in a tree form.

For example, the location engine 530 may be set in the order of master anchor B → master anchor C → master anchor A in the time synchronization tree map, and calculates in the final pico unit by summing the differences at the final end.

The location engine 530 manages the cell time difference between the master anchor A and the master anchor B, and calculates the time difference of the tag reception time as a single time zone. The location engine 530 applies standard time information for positioning a tag in one same time zone in the case of a multi-cell (multi-master).

The location engine 530 calculates the standard time by adding up all the time differences from the upper-connected master anchors in the case of a multi-cell of two or more stages, and managing the time difference. For example, the location engine 530 calculates a value obtained by adding the difference value between the master anchor A and the master anchor C and the difference value between the master anchor C and the master anchor B as the standard time of the area B.

The location engine 530 converts the difference value into an offset value and then synchronizes the deviation value between the master anchors of different cells based on the offset value. The location engine 530 synchronizes the clocks of the other master anchors based on a master source anchor serving as a reference among master anchors of different cells by using the offset value.

The location engine 530 generates an offset value based on the difference value received from the multi-slave anchors, and then updates the offset value by cumulatively reflecting the difference value newly received from the multi-slave anchors of other cells. The location engine 530 synchronizes the deviation values of the master anchors of different cells that are not adjacent to the same value based on the accumulated offset values. The location engine 530 generates a time sync tree map including a master anchor, a slave anchor, and a multi-slave anchor, and configures a separate tab next to the anchor list on the time synchronization tree map to tree only the master anchor. expressed in the form

The multi-cell synchronization setting apparatus 520 configures any one of a plurality of slave anchors as a multi-slave anchor on a cell-by-cell basis.

The multi-cell synchronization setting device 520 sets the master anchor to at least two or more communicating with the multi-slave anchor. The multi-cell synchronization setting device 520 determines a master source anchor as a reference among at least two or more master anchors communicating with the multi-slave anchors.

The multi-cell synchronization setting device 520 determines the communication order of the master anchor for each single cell. Thereafter, the multi-cell synchronization setting device 520 may automatically set according to the communication order of the master anchors at the moment when the multi-slave anchors set at least two or more master anchors to communicate with. The multi-cell synchronization setting device 520 sets at least two or more master anchors that communicate with the multi-slave anchors, and when determining a master source anchor as a reference, the master source anchor is reversed in the order of the master source anchor. After calculating the communication sequence of the anchor, it is confirmed to the user.

Configure a master anchor and a slave anchor for each single cell.

The master anchor includes a master anchor A 610 , a master anchor B 620 , and a master anchor C 630 . The master anchor wirelessly broadcasts a clock sync signal to the surroundings on a cell-by-cell basis.

The master anchor transmits clock information and synchronization signals to a plurality of slave anchors existing in a single cell. A plurality of master anchors within a single cell establish a communication multi-slave anchor.

The slave anchor is output by synchronizing the time stamp with the clock of the master anchor.

The slave anchors are: Slave Anchor A1 (612), Slave Anchor A2 (614), Slave Anchor A3 (616), Slave Anchor B1 (622), Slave Anchor B2 (624), Slave Anchor B3 (626), Slave Anchor C1 (632) ), including a slave anchor C2 (634), a slave anchor C3 (636), and a slave anchor C4 (638).

When a specific slave anchor has a synchronization error, it can be transmitted to the corresponding master anchor and server. The slave anchors time series receive synchronization signals from the master anchor in a preset time period (eg, 200 ms). When a deviation occurs in the received signal by more than a preset threshold, it recognizes that an error has occurred, and may cause an error notification.

Wirelessly synchronize multicells to synchronize the entire UWB anchor with an accuracy of less than 1 nanosecond. For single cells, use the method on page 2 to synchronize.

The slave anchor calculates the time difference in hardware using the time it receives clock information from the master anchor for each single cell, and calculates the arrival time for the TDOA operation received from the transmitter (tag) to the location engine 530 based on the master anchor. send.

In the case of multi-cell, the multi-slave anchor receives clock information from at least two or more master anchors, and transmits a time difference between clock information received from the two master anchors to the location engine 530 .

The slave anchor receives the clock synchronization signal from the master anchor and synchronizes the clock information with the master anchor locally based on the clock synchronization signal. The slave anchor generates local time sync data based on the clock sync signal and then applies the local time sync data to match the clock to the master anchor's clock.

When the slave anchor receives the tag event from the tag, it applies the local time synchronization data to match the clock to the master anchor's clock, and then transmits the tag event received from the tag to the location engine 530 . The slave anchor receives the clock synchronization signal from the master anchor at a preset time period, and when the time period is more than a preset threshold, it recognizes that an error has occurred and generates an error alarm to the location engine.

The multi-slave anchor includes a multi-slave anchor A (618) and a multi-slave anchor B (628). Multi-slave anchors may receive synchronization signals from master anchors of different cells. That is, the multi-slave anchors process synchronization by receiving signals from two or more master anchors.

The multi-slave anchor transmits the difference between the synchronization signals received from the master anchors of different cells to the server. In other words, the multi-slave anchors calculate a temporal difference between clock synchronization signals received from the master anchors of different cells and transmit them to the location engine 530 . A multi-slave anchor does not necessarily exist between a single cell and different single cells, and may not exist when seamless operation is required.

The multi-slave anchor calculates a temporal difference in reception time of each clock synchronization signal received from a plurality of master anchors on a cell-by-cell basis and transmits them. The multi-slave anchor calculates a difference in reception time of each clock synchronization signal received from a plurality of master anchors by using a Time Difference Of Arrival (TDOA) algorithm.

A multi-slave anchor communicates with at least two or more master anchors, and registers a master anchor MAC address for the communicating master anchor. The multi-slave anchor automatically determines the communication order with a plurality of communicating master anchors according to the communication order of the master anchor for each single cell. The multi-slave anchor determines the communication order of the master anchor in reverse according to the communication order with a master source anchor serving as a reference among a plurality of master anchors that communicate.

6 is a flowchart for explaining the operations of the master anchor, the slave anchor, and the multi-slave anchor according to the present embodiment.

The master anchor A 610 transmits the clock synchronization signal to the slave anchor A1 (612), the slave anchor A2 (614), the slave anchor A3 (616), and the multi-slave anchor A (618).

The slave anchor A1 (612), the slave anchor A2 (614), the slave anchor A3 (616), and the multi-slave anchor A (618) receive the clock synchronization signal from the master anchor A (610) to the location engine 530. It is not transmitted directly, but is synchronized with the clock of the master anchor A 610 based on its own clock synchronization information. In other words, the slave anchor A1 (612), the slave anchor A2 (614), the slave anchor A3 (616), and the multi-slave anchor A (618) are the master anchor A based on the clock synchronization information received from the master anchor A (610). Synchronize the clock with 610.

Each of the slave anchors A1 ( 612 ), the slave anchors A2 ( 614 ), and the slave anchors A3 ( 616 ) applies their own synchronized clocks. In other words, the slave anchor A1 (612), the slave anchor A2 (614), and the slave anchor A3 (616) do not need to send the time difference received from the master anchor A (610) to the location engine 530, so the location engine 530 ) can be reduced, and even if the network is cut, synchronization can be performed stably locally.

Multi-slave anchor A (618) calculates a temporal difference between the clock synchronization signals received from the master anchor A (610) and the master anchor C (630), respectively, and transmits it to the location engine (530).

The multi-slave anchor A 618 calculates a reception time difference between the clock synchronization signals respectively received from the master anchor A 610 and the master anchor C 630 using a Time Difference Of Arrival (TDOA) algorithm.

The master anchor B (620) transmits the clock synchronization signal to the slave anchor B1 (622), the slave anchor B2 (624), the slave anchor B3 (626), and the multi-slave anchor B (628).

The slave anchor B1 (622), the slave anchor B2 (624), the slave anchor B3 (626), and the multi-slave anchor B (628) receive the clock synchronization signal from the master anchor B (620) to the location engine (530). It is not transmitted directly, but is synchronized with the clock of the master anchor B 620 based on its own clock synchronization information. In other words, the slave anchor B1 (622), the slave anchor B2 (624), the slave anchor B3 (626), and the multi-slave anchor B (628) are the master anchor B based on the clock synchronization information received from the master anchor B (620). Synchronize the clock with 620.

The slave anchor B1 (622), the slave anchor B2 (624), and the slave anchor B3 (626) each apply their own synchronized clocks. In other words, the slave anchor B1 (622), the slave anchor B2 (624), and the slave anchor B3 (626) do not need to send the time difference received from the master anchor B 620 to the location engine 530, so the location engine 530 ) can be reduced, and even if the network is cut, synchronization can be performed stably locally.

The multi-slave anchor B 628 calculates a temporal difference between the clock synchronization signals received from the master anchor A 610 and the master anchor C 630 , respectively, and transmits it to the location engine 530 .

The multi-slave anchor B 628 calculates a reception time difference of the clock synchronization signals respectively received from the master anchor B 620 and the master anchor C 630 using a Time Difference Of Arrival (TDOA) algorithm.

The master anchor C (630) transmits the clock synchronization signal to the slave anchors C1 (632), the slave anchors C2 (634), the slave anchors C3 (636), and the slave anchors C4 (638).

The slave anchor C1 (632), the slave anchor C2 (634), the slave anchor C3 (636), and the slave anchor C4 (638) receive the clock synchronization signal from the master anchor C (630) directly to the location engine 530. Without transmission, it synchronizes with the clock of the master anchor C 630 based on its own clock synchronization information. In other words, the slave anchor C1 (632), the slave anchor C2 (634), the slave anchor C3 (636), and the slave anchor C4 (638) are based on the clock synchronization information received from the master anchor C (630), the master anchor B ( 620) and the clock.

Each of the slave anchor C1 ( 632 ), the slave anchor C2 ( 634 ), the slave anchor C3 ( 636 ), and the slave anchor C4 ( 638 ) applies a self-synchronized clock to itself. In other words, the slave anchor C1 (632), the slave anchor C2 (634), the slave anchor C3 (636), and the slave anchor C4 (638) need to send the time difference received from the master anchor C (630) to the location engine (530). Since there is no , the load on the location engine 530 can be reduced, and even if the network is cut off, synchronization can be stably performed locally.

7 is a flowchart illustrating a wireless synchronization method according to the present embodiment.

The multi-cell synchronization setting device 520 checks whether the anchor is set as the master anchor (S710). As a result of checking in step S710, if the anchor is set as the master anchor, the multi-cell synchronization setting apparatus 520 sets the master anchor to generate a clock synchronization signal (S712). The master anchor broadcasts the clock synchronization signal to the slave anchors existing in the vicinity (S714).

As a result of checking in step S710, if the anchor is not set as the master anchor, the multi-cell synchronization setting apparatus 520 checks whether the anchor is set as the multi-slave anchor (S720). As a result of checking in step S720, if the anchor is set as a multi-slave anchor, the multi-cell synchronization setting device 520 registers master anchor MAC addresses for a plurality of master anchors with which the multi-slave anchors communicate (S722). ). The multi-slave anchors wait for reception of clock synchronization signals from a plurality of master anchors (S724). The multi-slave anchor calculates the time difference of the clock synchronization signal from the plurality of master anchors and transmits it to the location engine 530 (S726).

As a result of checking in step S720, if the anchor is not set as a multi-slave anchor, the slave anchor waits for reception of a clock synchronization signal from the master anchor (S730). The slave anchor receives a clock synchronization signal from the master anchor (S732). The slave anchor calculates Local Timesync Data based on the clock synchronization signal received from the master anchor (S734). The slave anchor applies the local time synchronization data by itself to match the clock with the clock of the master anchor (S736).

The slave anchor receives the tag event from the tag (S742). The slave anchor applies the local time synchronization data by itself to match the clock with the clock of the master anchor, and then transmits the tag event received from the tag to the location engine 530 (S744).

Although it is described that steps S710 to S744 are sequentially executed in FIG. 7 , the present invention is not limited thereto. In other words, since it may be applicable by changing and executing the steps described in FIG. 7 or executing one or more steps in parallel, FIG. 7 is not limited to a time-series order.

As described above, the wireless synchronization method according to the present embodiment illustrated in FIG. 7 may be implemented as a program and recorded in a computer-readable recording medium. The computer-readable recording medium in which the program for implementing the wireless synchronization method according to the present embodiment is recorded includes all types of recording devices in which data readable by the computer system is stored.

8 is a diagram illustrating a wired synchronization concept according to the present embodiment.

In case of wired synchronization between master anchors, they have the same clock in terms of hardware. If the master anchor is bent in a curved or L-shape between cells, only the relevant area is connected by wire to have the same clock. When connecting master anchors by wire, even if separate synchronization is not performed, the same offset value is obtained with the same hardware.

The clock generator 510 generates a clock at a preset period and transmits it to the master anchor B 620 . The master anchor B 620 periodically transmits a clock signal for synchronization to the master anchor C 630 . The master anchor C 630 sets the offset value to 0 while resetting the timer while receiving the clock signal.

The multi-cell synchronization setting device 520 provides a synchronization function with one cable rather than a separate cable for wired synchronization by mounting a communication function and a starter function together on one CAT5E cable.

The multi-cell synchronization setting device 520 uses the CAT5E international standard standard 1, 2, 3, and 6 preferred lines for communication. The multi-cell synchronization setting device 520 synchronizes the anchors in pico units accurately by providing synchronization signals to No. 4 and 5, which are spare signal lines in the CAT5E cable, and clock information to No. 7 and 8. The master anchor and slave anchor are also equipped with a clock generator function to provide clock information and synchronization signals to other slave anchors to enable self-wired synchronization.

9 is a diagram illustrating a wired/wireless hybrid synchronization system according to the present embodiment.

The multi-cell synchronization setting device 520 provides hybrid synchronization in which wired and wireless synchronization functions are integrated. In the case of wireless synchronization, Line of Sight (LOS) must be guaranteed. There is a limitation in radio capacity as much as the corresponding UWB channel for radio synchronization is used. When synchronizing by wire, there is no need to calculate the time difference in the location engine 530, so the precision is high and the operation load of the engine is reduced.

According to the configuration of a single cell, each of the plurality of single cells wirelessly synchronizes the clocks of the slave anchors locally, respectively, but the curves between cells or the section bent in the L-shape are wired between the master anchors.

The master anchor A 610 transmits the clock synchronization signal to the slave anchor A1 (612), the slave anchor A2 (614), the slave anchor A3 (616), and the multi-slave anchor A (618).

The slave anchor A1 (612), the slave anchor A2 (614), the slave anchor A3 (616), and the multi-slave anchor A (618) receive the clock synchronization signal from the master anchor A (610) to the location engine 530. It is not transmitted directly, but is synchronized with the clock of the master anchor A 610 based on its own clock synchronization information. In other words, the slave anchor A1 (612), the slave anchor A2 (614), the slave anchor A3 (616), and the multi-slave anchor A (618) are the master anchor A based on the clock synchronization information received from the master anchor A (610). Synchronize the clock with 610.

Each of the slave anchors A1 ( 612 ), the slave anchors A2 ( 614 ), and the slave anchors A3 ( 616 ) applies their own synchronized clocks. In other words, the slave anchor A1 (612), the slave anchor A2 (614), and the slave anchor A3 (616) do not need to send the time difference received from the master anchor A (610) to the location engine 530, so the location engine 530 ) can be reduced, and even if the network is cut, synchronization can be performed stably locally.

Multi-slave anchor A (618) calculates a temporal difference between the clock synchronization signals received from the master anchor A (610) and the master anchor C (630), respectively, and transmits it to the location engine (530).

The multi-slave anchor A 618 calculates a reception time difference between the clock synchronization signals respectively received from the master anchor A 610 and the master anchor C 630 using a Time Difference Of Arrival (TDOA) algorithm.

The master anchor B (620) transmits the clock synchronization signal to the slave anchor B1 (622), the slave anchor B2 (624), the slave anchor B3 (626), and the multi-slave anchor B (628).

The slave anchor B1 (622), the slave anchor B2 (624), the slave anchor B3 (626), and the multi-slave anchor B (628) receive the clock synchronization signal from the master anchor B (620) to the location engine (530). It is not transmitted directly, but is synchronized with the clock of the master anchor B 620 based on its own clock synchronization information. In other words, the slave anchor B1 (622), the slave anchor B2 (624), the slave anchor B3 (626), and the multi-slave anchor B (628) are the master anchor B based on the clock synchronization information received from the master anchor B (620). Synchronize the clock with 620.

The slave anchor B1 (622), the slave anchor B2 (624), and the slave anchor B3 (626) each apply their own synchronized clocks. In other words, the slave anchor B1 (622), the slave anchor B2 (624), and the slave anchor B3 (626) do not need to send the time difference received from the master anchor B 620 to the location engine 530, so the location engine 530 ) can be reduced, and even if the network is cut, synchronization can be performed stably locally.

The multi-slave anchor B 628 calculates a temporal difference between the clock synchronization signals received from the master anchor A 610 and the master anchor C 630 , respectively, and transmits it to the location engine 530 .

The multi-slave anchor B 628 calculates a reception time difference of the clock synchronization signals respectively received from the master anchor B 620 and the master anchor C 630 using a Time Difference Of Arrival (TDOA) algorithm.

The master anchor C (630) transmits the clock synchronization signal to the slave anchors C1 (632), the slave anchors C2 (634), the slave anchors C3 (636), and the slave anchors C4 (638).

The slave anchor C1 (632), the slave anchor C2 (634), the slave anchor C3 (636), and the slave anchor C4 (638) receive the clock synchronization signal from the master anchor C (630) directly to the location engine 530. Without transmission, it synchronizes with the clock of the master anchor C 630 based on its own clock synchronization information. In other words, the slave anchor C1 (632), the slave anchor C2 (634), the slave anchor C3 (636), and the slave anchor C4 (638) are based on the clock synchronization information received from the master anchor C (630), the master anchor B ( 620) and the clock.

Each of the slave anchor C1 ( 632 ), the slave anchor C2 ( 634 ), the slave anchor C3 ( 636 ), and the slave anchor C4 ( 638 ) applies a self-synchronized clock to itself. In other words, the slave anchor C1 (632), the slave anchor C2 (634), the slave anchor C3 (636), and the slave anchor C4 (638) need to send the time difference received from the master anchor C (630) to the location engine (530). Since there is no , the load on the location engine 530 can be reduced, and even if the network is cut off, synchronization can be stably performed locally.

The clock generator 510 generates a clock synchronization signal at a preset period.

The master anchor B 620 is connected to the clock generator 510 by wire to receive a clock synchronization signal. The master anchor B 620 synchronizes clock information based on the clock synchronization signal. The master anchor B 620 wirelessly broadcasts a clock synchronization signal to the periphery on a cell-by-cell basis.

The slave anchor B1 (622), the slave anchor B2 (624), and the slave anchor B3 (626) receive a clock synchronization signal from the master anchor B (620). The slave anchor B1 622 , the slave anchor B2 624 , and the slave anchor B3 626 locally synchronize clock information with the master anchor B 620 based on the clock synchronization signal.

Multi-slave anchor B (628) calculates a first temporal difference value of the reception time of each clock synchronization signal received from the master anchor B (620) and the master anchor C (630) and transmits.

The master anchor D (610) is connected to the master anchor A (610) by wire to receive the clock synchronization signal, then synchronizes clock information based on the clock synchronization signal, and wirelessly broadcasts the clock synchronization signal around the cell unit. do.

The master anchor E (620) is connected to the master anchor D (610) by wire to receive the clock synchronization signal, then synchronizes clock information based on the clock synchronization signal, and wirelessly broadcasts the clock synchronization signal around the cell unit. do.

The slave anchor E1 , the slave anchor E2 , and the slave anchor E3 receive a clock synchronization signal from the master anchor E 620 . The slave anchor E1, the slave anchor E2, and the slave anchor E3 locally synchronize clock information with the master anchor E 620 based on the clock synchronization signal.

The multi-slave anchor E 622 calculates and transmits a second temporal difference value of the reception time of the clock synchronization signals respectively received from the master anchor E 620 and the master anchor F 630 .

The location engine 530 converts the first difference value and the second difference value into an offset value, and then synchronizes the deviation values between the master anchors of different cells based on the offset value.

The clock generator 510 transmits a communication signal using some (No. 1, 2, 3, 6) of the signal lines in the LAN cable connected to the master anchor B 620 . The clock generator 510 transmits a synchronization pulse using some of the remaining spare signal lines (No. 4 and 5) except for the signal lines for transmitting communication signals among the signal lines in the LAN cable. The clock generator 510 transmits clock information using spare signal lines other than a signal line transmitting a communication signal and a signal line transmitting a synchronization pulse among signal lines in the LAN cable. The clock generator 510 transmits all communication signals, synchronization pulses, and clock information through a single LAN cable.

The master anchor B 620 and the master anchor D 610 are connected by wire to a section bent at a right angle or a curve between cells. The master anchor D (610) and the master anchor E (620) are connected by wire to a section bent at a right angle or a curve between cells. The master anchor D (610) is connected to the master anchor B (620) by wire to receive a clock synchronization signal, reset a timer, and initialize an offset value to synchronize clock information.

The master anchor D 610 is connected to the master anchor B 620 by wire to receive the clock synchronization signal, and then synchronizes clock information based on the clock synchronization signal. The master anchor E 620 is connected to the master anchor D 610 by wire to receive a clock synchronization signal and then synchronizes clock information based on the clock synchronization signal. The master anchor E 620 wirelessly broadcasts a clock synchronization signal to the periphery on a cell-by-cell basis.

Multi-slave anchor E 622 calculates a temporal difference between the clock synchronization signals received from the master anchor E 620 and the master anchor F 630, respectively, and transmits it to the location engine 530. The multi-slave anchor G 642 calculates a temporal difference between the clock synchronization signals received from the master anchor E 620 and the master anchor G 640 , respectively, and transmits it to the location engine 530 .

The above description is merely illustrative of the technical idea of this embodiment, and various modifications and variations will be possible by those skilled in the art to which this embodiment belongs without departing from the essential characteristics of the present embodiment. Accordingly, the present embodiments are intended to explain rather than limit the technical spirit of the present embodiment, and the scope of the technical spirit of the present embodiment is not limited by these embodiments. The protection scope of this embodiment should be interpreted by the following claims, and all technical ideas within the equivalent range should be interpreted as being included in the scope of the present embodiment.

110: master anchor
120, 130: slave anchor
140: tag
510: clock generator
520: multi-cell synchronization setting device
530: location engine

Claims (11)

A master anchor (Master Anchor) for wirelessly broadcasting a clock synchronization signal (Clock Sync Signal) around the cell unit;
a slave anchor receiving the clock synchronization signal from the master anchor and locally synchronizing clock information with the master anchor based on the clock synchronization signal;
Calculate a temporal difference value of the reception time of the clock synchronization signal received from the plurality of master anchors and the slave anchors, extract coordinate information included in the clock synchronization signal, and combine the difference value and the coordinate information a tag that calculates a location based on it; and
After converting the difference value into an offset value, a location engine (Location Engine) for synchronizing the deviation values between master anchors of different cells based on the offset value;
The slave anchor is
After generating local time sync data based on the clock sync signal, the local time sync data is applied to match the clock to the clock of the master anchor,
The reverse TDOA system according to claim 1, wherein the GPS location information of the anchor is mapped to the same sequence information as the sequence information included in the clock synchronization signal received from the master anchor and transmitted to the tag. According to claim 1,
The tag is
When there are three or more clock synchronization signals received from the plurality of master anchors and the slave anchors, the position is calculated based on triangulation based on the coordinate information, and the offset value is reflected in the position A reverse TDOA system. According to claim 1,
The master anchor is
A reverse TDOA system, characterized in that when the clock synchronization signal is transmitted, sequence information and GPS location information of the anchor itself are mapped in a packet and transmitted to the slave anchor and the tag. delete According to claim 1,
The slave anchor is
Reverse TDOA, characterized in that when a tag event is received from the tag, the local time synchronization data is applied to match the clock to the clock of the master anchor, and then the tag event received from the tag is transmitted to the location engine. system. 6. The method of claim 5,
The slave anchor is
Receives the clock synchronization signal from the master anchor in a preset time period, and when the time period is more than a preset threshold, recognizes that an error has occurred and generates an error alarm to the location engine Reverse TDOA system. According to claim 1,
The clock synchronization signal received from a plurality of master anchors is transmitted by calculating a temporal difference in reception time for each cell, and the clock synchronization signal received from the plurality of master anchors is respectively received by using the TDOA algorithm at the reception time Multi-slave anchor for calculating the difference value of (Multi Slave Anchor);
Reverse TDOA system, characterized in that it further comprises. 8. The method of claim 7,
The location engine is
Reverse TDOA system, characterized in that by using the offset value to synchronize the clocks of the other master anchors based on a master source anchor serving as a reference among master anchors of different cells. 9. The method of claim 8,
The location engine is
Reverse TDOA system, characterized in that after generating the offset value based on the difference value received from the multi-slave anchor, the offset value is updated by cumulatively reflecting the difference value newly received from the multi-slave anchor of another cell. 10. The method of claim 9,
The location engine is
A reverse TDOA system, characterized in that the deviation values of the master anchors of different cells that are not adjacent are synchronized to the same value based on the accumulated offset value. A process of wirelessly broadcasting a clock synchronization signal (Clock Sync Signal) from the master anchor (Master Anchor) to the surrounding cell unit;
receiving the clock synchronization signal from the master anchor at a slave anchor, and locally synchronizing clock information with the master anchor based on the clock synchronization signal;
A tag calculates a temporal difference in reception time of the clock synchronization signals received from the plurality of master anchors and the slave anchors, extracts coordinate information included in the clock synchronization signal, and the difference value and calculating a location based on the coordinate information;
The process of converting the difference value into an offset value in a location engine and then synchronizing the difference value between master anchors of different cells based on the offset value;
The process of synchronizing with the master anchor is,
generating local time synchronization data based on the clock synchronization signal in the slave anchor and then applying the local time synchronization data to match the clock to the clock of the master anchor; and
The method further comprising the step of mapping the GPS location information of the anchor to the same sequence information as the sequence information included in the clock synchronization signal received from the master anchor, and transmitting to the tag,
Reverse TDoA-based positioning method.

Images