Electromagnetic navigation system and data synchronization method, device and electronic equipment thereof

Abstract

The application relates to an electromagnetic navigation system and a data synchronization method and device thereof and electronic equipment, wherein the electromagnetic navigation system comprises a field transmitter and a magnetic sensor, the field transmitter comprises a first transmitting unit and a second transmitting unit; the first transmitting unit is used for generating a working magnetic field, and the working magnetic field is used for positioning the magnetic sensor; the second transmitting unit is used for generating a reference signal, and the reference signal is used for synchronizing magnetic field detection data of the working magnetic field and magnetic field working data; wherein the magnetic field detection data is obtained by detecting the working magnetic field through the magnetic sensor, and the magnetic field working data is provided by the field transmitter; the first transmitting unit and the second transmitting unit are configured to share a working clock of the field transmitter. Through the application, the problem that there is a time difference between time information of the magnetic field working data and the magnetic field detection data corresponding to the same physical moment in the existing electromagnetic navigation system, and the positioning error of the magnetic sensor is increased, is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electromagnetic navigation, and in particular to an electromagnetic navigation system, a data synchronization method and device thereof, and an electronic device. BACKGROUND

[0002] An electro-magnetic transient simulator (EMTS) is one of the mainstream surgical navigation system technical solutions. The most typical EMTS basic principle is to generate a time-varying magnetic field through a field transmitter, and then to detect the time-varying magnetic field through a magnetic sensor, and to perform pose calculation of the magnetic sensor. The phase method is a commonly used positioning calculation method, which needs to obtain the magnetic field working state (such as phase, intensity) and the magnetic field detection data at the same physical time. The magnetic field working state is determined according to the magnetic field working data of the field transmitter, and the magnetic field working data refers to the angular position data of the rotating shaft of each motor in the field transmitter; the magnetic field detection data is obtained by detecting the time-varying magnetic field by the magnetic sensor.

[0003] Due to the fact that the device clocks of the field transmitter and the magnetic sensor are not synchronized, and in the magnetic sensor, the collection time of the magnetic field detection data and the generation time of the time stamp are also not synchronized, there is a time difference between the time information of the magnetic field working data and the magnetic field detection data corresponding to the same physical time. Further, in the pose calculator, there is a phase difference between the measured value and the model value of the time-varying magnetic field, which will cause the positioning error of the magnetic sensor to increase. The model value of the time-varying magnetic field is the theoretical magnetic field signal in the time-varying magnetic field model of the field transmitter.

[0004] At present, there is no effective solution to the problem that in the electromagnetic navigation system, the time information of the magnetic field working data and the magnetic field detection data corresponding to the same physical time has a time difference, resulting in an increase in the positioning error of the magnetic sensor. SUMMARY

[0005] In the present application, an electromagnetic navigation system and a data synchronization method and device thereof, and an electronic device are provided to solve the problem that in the related electromagnetic navigation system, the time information of the magnetic field working data and the magnetic field detection data corresponding to the same physical time has a time difference, resulting in an increase in the positioning error of the magnetic sensor.

[0006] In a first aspect, an electromagnetic navigation system is provided in the present application, and the electromagnetic navigation system comprises a field transmitter and a magnetic sensor, the field transmitter comprises a first transmitting unit and a second transmitting unit;

[0007] The first transmitting unit is configured to generate a working magnetic field, and the working magnetic field is configured to position the magnetic sensor.

[0008] The second transmitting unit is configured to generate a reference signal, the reference signal being used to synchronize magnetic field detection data of the working magnetic field and magnetic field working data; wherein the magnetic field detection data is obtained by detecting the working magnetic field by the magnetic sensor, and the magnetic field working data is provided by the field transmitter.

[0009] The first transmitting unit and the second transmitting unit are configured to share a working clock of the field transmitter.

[0010] In some embodiments, the second transmitting unit comprises a square wave transmitter or a pulse transmitter.

[0011] In some embodiments, the second transmitting unit comprises an electromagnetic coil.

[0012] In some embodiments, the first transmitting unit and the second transmitting unit are configured to work synchronously.

[0013] The first transmitting unit and the second transmitting unit have different working frequencies.

[0014] In a second aspect, a data synchronization method of an electromagnetic navigation system is provided in the present application, the data synchronization method being applied to the electromagnetic navigation system of the first aspect.

[0015] The data synchronization method of the electromagnetic navigation system comprises:

[0016] Obtaining magnetic field detection data of a working magnetic field; wherein the magnetic field detection data is obtained by detecting the working magnetic field by a magnetic sensor, and the working magnetic field is generated by a first transmitting unit;

[0017] Obtaining signal detection data of a reference signal; wherein the signal detection data is obtained by detecting the reference signal by the magnetic sensor, and the reference signal is generated by a second transmitting unit;

[0018] Obtaining magnetic field working data of the working magnetic field; wherein the magnetic field working data is provided by a field transmitter.

[0019] Determining a reference time difference between the signal detection data and the reference signal, and synchronizing the magnetic field detection data and the magnetic field working data according to the reference time difference.

[0020] In some embodiments, the determining of the reference time difference between the signal detection data and the reference signal comprises:

[0021] Determining target signal data in the signal detection data, and determining a target position corresponding to the target signal data in the reference signal.

[0022] determine the reference time difference according to the time information of the target position and the time information of the target signal data.

[0023] In some embodiments, the reference signal comprises a periodic square wave signal, and a half period of the periodic square wave signal is greater than a sampling interval of the magnetic sensor.

[0024] The determining of the target signal data in the signal detection data and the target position corresponding to the target signal data in the reference signal comprises:

[0025] In the signal detection data, two signal data that are the same and adjacent are determined as reference signal data, and one of the reference signal data is determined as the target signal data.

[0026] In the periodic square wave signal, a signal edge closest to the target signal data is determined as a target signal edge, and a position of the target signal edge is the target position.

[0027] In some embodiments, the determining of the reference time difference according to the time information of the target position and the time information of the target signal data comprises:

[0028] The reference time difference is determined according to a time difference between the time information of the target signal edge and the time information of the target signal data.

[0029] In some embodiments, the determining of the reference time difference according to the time information of the target position and the time information of the target signal data comprises:

[0030] The reference time difference is determined according to a time difference between the time information of the target signal edge and the time information of the target signal data, and a physical time interval between the target signal edge and a sampling point corresponding to the target signal data, wherein the physical time interval is obtained by pre-simulation.

[0031] In some embodiments, the time information of the target signal edge comprises trigger time information of the target signal edge.

[0032] The data synchronization method of the electromagnetic navigation system further comprises, before determining the reference time difference between the signal detection data and the reference signal:

[0033] The signal detection data is binarized by using a preset threshold.

[0034] The determining of the reference time difference according to the time information of the target position and the time information of the target signal data comprises:

[0035] The reference time difference is determined according to a time difference between a trigger time information of the target signal edge and a time information of the target signal data, and a change time required for the target signal edge to change from a trigger value to the preset threshold value, wherein the change time is determined according to an operating characteristic of the second transmitting unit.

[0036] In some embodiments, the reference signal comprises a periodic pulse signal.

[0037] The target signal data is determined in the signal detection data, and a target position corresponding to the target signal data is determined in the reference signal.

[0038] In the signal detection data, high signal data is determined as the target signal data.

[0039] In the periodic pulse signal, a pulse corresponding to the target signal data is determined as a target pulse, wherein a position of the target pulse is the target position.

[0040] In some embodiments, the reference time difference is determined according to a time information of the target position and a time information of the target signal data.

[0041] The reference time difference is determined according to a time difference between a time information of the target pulse and a time information of the target signal data.

[0042] In some embodiments, the reference signal is superimposed on the working magnetic field, and a frequency of the reference signal is different from a frequency of the working magnetic field.

[0043] In a third aspect, the present application provides a data synchronization device of an electromagnetic navigation system, which is applied to the electromagnetic navigation system of the first aspect.

[0044] The data synchronization device of the electromagnetic navigation system comprises:

[0045] A first data acquisition module is configured to acquire magnetic field detection data of a working magnetic field, wherein the magnetic field detection data is obtained by detecting the working magnetic field by a magnetic sensor, and the working magnetic field is generated by a first transmitting unit.

[0046] A second data acquisition module is configured to acquire signal detection data of a reference signal, wherein the signal detection data is obtained by detecting the reference signal by the magnetic sensor, and the reference signal is generated by a second transmitting unit.

[0047] A third data acquisition module is configured to acquire magnetic field operating data of the working magnetic field, wherein the magnetic field operating data is provided by a field transmitter.

[0048] a data synchronization module, configured to determine a reference time difference between the signal detection data and the reference signal, and synchronize the magnetic field detection data and the magnetic field operation data according to the reference time difference.

[0049] In a fourth aspect, the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the data synchronization method of the electromagnetic navigation system according to the second aspect when executing the computer program.

[0050] In a fifth aspect, the present application provides a storage medium, which stores a computer program executable on a processor to implement the data synchronization method of the electromagnetic navigation system according to the second aspect.

[0051] Compared with the related art, the electromagnetic navigation system and the data synchronization method, device and electronic device thereof provided by the present application can eliminate the time difference between the magnetic field operation data and the magnetic field detection data of the working magnetic field, and further eliminate the positioning error and the mispositioning of the magnetic sensor, and finally improve the positioning accuracy of the magnetic sensor, by setting the second transmitting unit capable of generating the reference signal in the field transmitter, and synchronizing the time measurement between the field transmitter and the magnetic sensor through the reference signal. The problem that the time difference exists between the time information of the magnetic field operation data and the magnetic field detection data corresponding to the same physical time in the existing electromagnetic navigation system, and the positioning error of the magnetic sensor is increased, is solved.

[0052] The details of one or more embodiments of the present application are presented in the following drawings and description to make other features, objects and advantages of the present application more apparent. BRIEF DESCRIPTION OF DRAWINGS

[0053] The accompanying drawings, which are included to provide a further understanding of the present application, constitute a part of the present application and illustrate embodiments of the present application and the description thereof, which serve to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0054] Figure 1 is a hardware structure block diagram of a terminal for implementing the data synchronization method of the electromagnetic navigation system provided by the present application;

[0055] Figure 2 is a structural schematic diagram of the electromagnetic navigation system provided by the present application;

[0056] Figure 3 is a flowchart of the data synchronization method of the electromagnetic navigation system provided by the present application;

[0057] Figure 4 is a sampling schematic diagram of a periodic square wave signal in some embodiments of the present application;

[0058] Figure 5 This is a schematic diagram of the binarized waveform of a periodic square wave signal in some embodiments of the present invention;

[0059] Figure 6 This is a waveform diagram of the reference signal in some embodiments of the present invention;

[0060] Figure 7 This is a structural block diagram of the data synchronization device for the electromagnetic navigation system provided by the present invention. Detailed Implementation

[0061] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0062] Unless otherwise defined, the technical or scientific terms used in this application shall have the general meaning as understood by one of ordinary skill in the art to which this application pertains. Words such as “a,” “an,” “an,” “the,” “the,” and “these,” used in this application, do not indicate quantitative limitation and may be singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or modules (units) is not limited to the listed steps or modules (units) but may include steps or modules (units) not listed, or may include other steps or modules (units) inherent to such processes, methods, products, or devices. The terms “connected,” “linked,” and “coupled,” used in this application, are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. The term “multiple” used in this application refers to two or more. The "and / or" operator describes the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: A alone, A and B simultaneously, and B alone. Typically, the character " / " indicates that the objects before and after it are in an "or" relationship. The terms "first," "second," and "third," etc., used in this application are merely for distinguishing similar objects and do not represent a specific ordering of the objects.

[0063] The method embodiments provided in this example can be executed on a terminal, computer, or similar computing device. For example, it can run on a terminal. Figure 1 This is a hardware structure block diagram of a terminal that executes the data synchronization method of the electromagnetic navigation system provided by this invention. For example... Figure 1 As shown, a terminal may include one or more ( Figure 1The terminal shown in FIG. 1 includes only one processor 102 and a memory 104 for storing data, wherein the processor 102 can include, but is not limited to, a processing device such as a microprocessor (MCU) or a programmable logic device (FPGA). The terminal can also include a transmission device 106 for communication function and an input / output device 108. Those skilled in the art can understand that Figure 1 The structure shown is only schematic, which does not limit the structure of the terminal. For example, the terminal can include more or less components than those shown, or have a different configuration of components than those shown. Figure 1 The terminal shown in FIG. 1 includes only one processor 102 and a memory 104 for storing data, wherein the processor 102 can include, but is not limited to, a processing device such as a microprocessor (MCU) or a programmable logic device (FPGA). The terminal can also include a transmission device 106 for communication function and an input / output device 108. Those skilled in the art can understand that Figure 1 The structure shown is only schematic, which does not limit the structure of the terminal. For example, the terminal can include more or less components than those shown, or have a different configuration of components than those shown.

[0064] The memory 104 can be used to store computer programs, such as software programs of application software and modules, such as the computer program corresponding to the data synchronization method of the electromagnetic navigation system provided in the present application. The processor 102 can execute various functional applications and data processing by running the computer programs stored in the memory 104, i.e. implement the method described above. The memory 104 can include a high-speed random access memory, and can also include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some examples, the memory 104 can further include a memory remotely arranged with respect to the processor 102, which can be connected to the terminal through a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0065] The transmission device 106 is used to receive or send data via a network. The network includes a wireless network provided by a communication provider of the terminal. In one example, the transmission device 106 includes a network adapter (NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet in a wireless manner.

[0066] In the present application, an electromagnetic navigation system is provided, Figure 2 is a schematic diagram of the electromagnetic navigation system provided in the present application. Referring to Figure 2The electromagnetic navigation system comprises a field transmitter 100 and a magnetic sensor 200, the field transmitter 100 comprises a first transmitting unit 110 and a second transmitting unit 120; the first transmitting unit 110 is used to generate a working magnetic field, the working magnetic field is used to position the magnetic sensor 200; the second transmitting unit 120 is used to generate a reference signal, the reference signal is used to synchronize magnetic field detection data of the working magnetic field and magnetic field working data; wherein the magnetic field detection data is obtained by detecting the working magnetic field through the magnetic sensor 200, and the magnetic field working data is provided by the field transmitter 100; the first transmitting unit and the second transmitting unit are configured to share a working clock of the field transmitter 100.

[0067] Specifically, the first transmitting unit 110 is a transmitting unit of the working magnetic field of the field transmitter 100, and the working magnetic field is a time-varying magnetic field used to position the magnetic sensor 200. The magnetic field detection data obtained by detecting the working magnetic field through the magnetic sensor 200 and the magnetic field working data of the working magnetic field output by the field transmitter 100 can determine the pose of the magnetic sensor 200 in the working magnetic field. Wherein, the first transmitting unit 110 mainly comprises a motor, an absolute position encoder and a permanent magnet and the like. The permanent magnet generates a time-varying magnetic field when being driven to rotate by the motor, and the absolute position encoder records the rotation state of the permanent magnet, i.e. the angular position at each moment. And the magnetic field working data includes the angular position information of each permanent magnet at each moment.

[0068] As introduced above, the above-mentioned components are the main components of the current electromagnetic navigation system. The electromagnetic navigation system provided by the present application mainly improves the second transmitting unit 120 compared with the existing electromagnetic navigation system.

[0069] In an embodiment, the first transmitting unit 110 and the second transmitting unit 120 are configured to work synchronously, and the working frequencies of the first transmitting unit 110 and the second transmitting unit 120 are different. The first transmitting unit 110 and the second transmitting unit 120 can work simultaneously, and the simultaneous working means that both of them are turned on at the same time and turned off at the same time. In this embodiment, the second transmitting unit 120 can generate a reference signal which can be superimposed on the working magnetic field. The reference signal can be significantly distinguished from the working magnetic field in frequency, so that the data of the magnetic sensor 200 can be decoupled to obtain signal detection data corresponding to the reference signal and magnetic field detection data corresponding to the working magnetic field, respectively. The magnetic field detection data is used for positioning the magnetic sensor 200, and the signal detection data is not used for positioning the magnetic sensor 200, but is used for synchronizing the time measurement between the magnetic sensor 200 and the field transmitter 100, so that the positioning of the magnetic sensor 200 is more accurate.

[0070] In another embodiment, the second transmitting unit 120 can work prior to the first transmitting unit 110, and the magnetic sensor 200 detects the reference signal to obtain signal detection data, at this time, the electromagnetic navigation has not started, and the magnetic sensor 200 can be in a relatively static state. After the second transmitting unit 120 stops working, the electromagnetic navigation is performed, that is, the first transmitting unit 110 starts working, and the magnetic sensor 200 detects the working magnetic field to obtain magnetic field detection data. Since the signal detection data can be used to synchronize the time measurement between the magnetic sensor 200 and the field transmitter 100 before the electromagnetic navigation, the time measurement between the magnetic sensor 200 and the field transmitter 100 is synchronized during the entire electromagnetic navigation process.

[0071] Specifically, the reference signal having a preset time-varying characteristic can be set, that is, the waveform of the reference signal is preset and known. At this time, the waveform of the reference signal can be designed to have uniqueness at some positions, that is, the signal strength at some positions is unique, and the corresponding signal detection data has identification. That is to say, when the magnetic sensor 200 outputs the signal detection data having identification, the positions of the data in the reference signal can be reversely inferred. Further, the signal detection data having identification and the corresponding positions in the reference signal constitute the reference physical quantity. At this time, the time difference of the time measurement between the field transmitter 100 and the magnetic sensor 200 can be determined according to the time measurement of the same reference physical quantity. For example, it is assumed that there is signal detection data A and the corresponding position B in the reference signal. Since the signal detection data A and the position B correspond to the same physical time, if the time measurement between the magnetic sensor 200 and the field transmitter 100 is synchronized, the time measurement of the signal detection data A by the magnetic sensor 200 and the time measurement of the position B by the field transmitter 100 are the same. If the time measurement of the signal detection data A and the position B by the magnetic sensor 200 and the field transmitter 100 respectively has a deviation, the deviation is the time difference of the time measurement between the magnetic sensor 200 and the field transmitter 100. Further, the time difference can be used to synchronize the magnetic field detection data and the magnetic field working data.

[0072] As can be seen from the above description, the electromagnetic navigation system provided in the present application can generate the reference signal by setting the second transmitting unit 120 in the field transmitter 100, and the time measurement between the field transmitter 100 and the magnetic sensor 200 can be synchronized by the reference signal, the time difference between the magnetic field working data and the magnetic field detection data of the working magnetic field can be eliminated, the positioning error of the magnetic sensor 200 can be eliminated, and the positioning accuracy of the magnetic sensor 200 can be improved. The problem that the time information of the magnetic field working data and the magnetic field detection data corresponding to the same physical time has a time difference in the existing electromagnetic navigation system, resulting in an increased positioning error of the magnetic sensor 200, is solved.

[0073] In some embodiments, the second transmitting unit 120 comprises a square wave transmitter or a pulse transmitter. The square wave transmitter can generate a square wave signal, such as a periodic square wave signal, or a partially periodic square wave signal. The pulse transmitter can generate a pulse signal, such as a periodic pulse signal, or a partially periodic pulse signal. The specific way of synchronizing the time measurement between the field transmitter 100 and the magnetic sensor 200 through the square wave signal or the pulse signal can refer to the related embodiments of the data synchronization method of the electromagnetic navigation system provided by the present application.

[0074] In some embodiments, the second transmitting unit 120 comprises an electromagnetic coil. The electromagnetic coil can generate a magnetic field signal when energized, and then the electromagnetic coil can generate a reference signal with a preset time-varying characteristic by modulating the current of the electromagnetic coil. Further, the time measurement of each position in the reference signal by the field transmitter 100 can be determined by the time measurement of the current data of the electromagnetic coil by the field transmitter 100.

[0075] Based on the electromagnetic navigation system provided by the present application, an electromagnetic navigation system data synchronization method is also provided in the present application. The electromagnetic navigation system data synchronization method is applied to the electromagnetic navigation system provided by the present application, and is used to synchronize the magnetic field detection data and the magnetic field operation data of the working magnetic field in the electromagnetic navigation system.

[0076] Figure 3 is a flowchart of the electromagnetic navigation system data synchronization method provided by the present application. Referring to Figure 3 , the electromagnetic navigation system data synchronization method comprises steps S310 to S340. Wherein:

[0077] Step S310, obtaining magnetic field detection data of the working magnetic field; wherein the magnetic field detection data is obtained by detecting the working magnetic field by the magnetic sensor, and the working magnetic field is generated by the first transmitting unit.

[0078] Step S320, obtaining signal detection data of the reference signal; wherein the signal detection data is obtained by detecting the reference signal by the magnetic sensor, and the reference signal is generated by the second transmitting unit.

[0079] Step S330, obtaining magnetic field operation data of the working magnetic field; wherein the magnetic field operation data is provided by the field transmitter.

[0080] Step S340, determining the reference time difference between the signal detection data and the reference signal, and synchronizing the magnetic field detection data and the magnetic field operation data according to the reference time difference.

[0081] Specifically, the first transmitting unit is a transmitting unit of a working magnetic field of the field transmitter, and the working magnetic field is a time-varying magnetic field used for positioning the magnetic sensor. The magnetic field detection data obtained by detecting the working magnetic field by the magnetic sensor and the magnetic field working data of the working magnetic field output by the field transmitter can determine the pose of the magnetic sensor in the working magnetic field.

[0082] The second transmitting unit can generate a reference signal with a preset time-varying characteristic, that is, the waveform of the reference signal is preset and known. At this time, the waveform of the reference signal can be designed to have uniqueness at some positions, that is, the signal strength at some positions is unique, and the corresponding signal detection data has identification. That is, when the magnetic sensor outputs signal detection data with identification, the position of these data in the reference signal can be reversely inferred. Further, the signal detection data with identification and its corresponding position in the reference signal constitute a reference physical quantity.

[0083] Further, the timestamp information of the signal detection data reflects the time measurement of the magnetic sensor on the signal detection data, that is, the generation time of the signal detection data in the working clock of the magnetic sensor. The timestamp information of the signal working data of the second transmitting unit output by the field transmitter reflects the time measurement of the field transmitter on each position of the reference signal. For example, when the second transmitting unit adopts an electromagnetic coil, the current data of the electromagnetic coil is the signal working data of the second transmitting unit. Since each current data of the electromagnetic coil corresponds to each signal position of the reference signal one by one, the time measurement of the current data by the field transmitter is the time measurement of each signal position. At this time, according to the time measurement of the same reference physical quantity (the same physical moment) by the field transmitter and the magnetic sensor, the time measurement deviation between the two can be determined. The reference time difference between the signal detection data and the reference signal is equal to the time measurement deviation between the field transmitter and the magnetic sensor. Similarly, the time difference between the magnetic field detection data and the magnetic field working data is also equal to the time measurement deviation between the field transmitter and the magnetic sensor. Therefore, the magnetic field detection data and the magnetic field working data can be synchronized through the reference time difference between the signal detection data and the reference signal.

[0084] Specifically, in step S340, determining the reference time difference between the signal detection data and the reference signal includes: step S341, determining target signal data in the signal detection data and determining a target position corresponding to the target signal data in the reference signal; and step S342, determining the reference time difference according to the time information of the target position and the time information of the target signal data.

[0085] The target signal data is signal detection data with identification, and the target position corresponding to the target signal data can be determined in the reference signal. The correspondence between the target signal data and the target position is determined according to the time-varying characteristics of the reference signal. Exemplarily, when the reference signal is a periodic pulse signal, the pulse peak detection data and the pulse peak position constitute the target signal data and the target position respectively, and the two correspond to the same physical time. If the target signal data and the target position correspond to the same physical time, the time information deviation between the two is the time measurement deviation between the field emitter and the magnetic sensor.

[0086] It should be noted that the target signal data and the target position do not necessarily correspond to the same physical time, but can also correspond to two different physical times, but the time interval between the two physical times needs to be known. At this time, the time information deviation between the target signal data and the target position includes two parts, one is the time measurement deviation between the field emitter and the magnetic sensor, and the other is the physical time interval between the target signal data and the target position. Therefore, only the physical time interval needs to be deducted from the time signal deviation to obtain the time measurement deviation.

[0087] The data synchronization method of the electromagnetic navigation system provided by the application mainly comprises the following steps: acquiring, by a data calculation processing device, magnetic field detection data and signal detection data of a working magnetic field from a magnetic sensor, and acquiring magnetic field working data of the working magnetic field from a field emitter, and finally synchronizing the magnetic field detection data and the magnetic field working data of the working magnetic field based on the signal detection data.

[0088] Through the above steps, the time measurement deviation between the field emitter and the magnetic sensor can be determined. Through the time measurement deviation, the time difference between the magnetic field working data and the magnetic field detection data of the working magnetic field can be eliminated, and then the positioning result displacement and the positioning error of the magnetic sensor can be eliminated, and finally the positioning accuracy of the magnetic sensor is improved. The problem that the time information between the magnetic field working data and the magnetic field detection data corresponding to the same physical time exists in the existing electromagnetic navigation method, which leads to the increase of the positioning error of the magnetic sensor, is solved.

[0089] It should be noted that although the steps are described in a certain order in the above process or the flowchart of the accompanying drawings, the step number only has the function of distinguishing the steps, and does not represent the execution order of the steps. The execution order of the steps can be determined according to the actual use requirements and the technical correlation between the steps. Specifically, step S320 can be executed before step S310, or step S320 can be executed simultaneously with step S310.

[0090] In the embodiment where step S310 is performed prior to step S320, the reference signal can be generated by the second transmitting unit first, and the reference signal is detected by the magnetic sensor to obtain signal detection data of the reference signal, and then the working magnetic field is generated by the first transmitting unit, and the working magnetic field is detected by the magnetic sensor to obtain magnetic field detection data of the working magnetic field. Therefore, in this embodiment, the data processing and computing device can first obtain the signal detection data of the reference signal, and then obtain the magnetic field detection data and the magnetic field working data of the working magnetic field. The reference time difference between the signal detection data and the reference signal is finally determined, and the magnetic field detection data and the magnetic field working data are synchronized based on the determined reference time difference.

[0091] In the embodiment where step S320 and step S310 are performed simultaneously, the first transmitting unit and the second transmitting unit work simultaneously, and the reference signal is superimposed on the working magnetic field. At this time, the detection data output by the magnetic sensor is the combined magnetic field data. In order to be able to decouple the magnetic field data, the frequency of the reference signal transmitted by the second transmitting unit needs to be different from the frequency of the working magnetic field transmitted by the field transmitter. Preferably, the frequency of the reference signal is higher than the frequency of the working magnetic field. At this time, the combined magnetic field signal can be decoupled by a digital filter to obtain the magnetic field detection data and the signal detection data. Exemplarily, the frequency of the working magnetic field is relatively low, usually lower than 100 Hz, and the reference signal can be set to a higher frequency, such as 400 Hz. Therefore, in this embodiment, the data processing and computing device can simultaneously obtain the signal detection data of the reference signal and the magnetic field detection data and the magnetic field working data of the working magnetic field. And in the process of continuous data acquisition, with the continuous accumulation or update of data, the reference time difference between the signal detection data and the reference signal can be updated in real time, and the current magnetic field detection data and the magnetic field working data are synchronized in real time based on the latest reference time difference.

[0092] In some embodiments, the reference signal includes a periodic square wave signal, and a half period of the periodic square wave signal is greater than a sampling interval of the magnetic sensor, usually with a certain margin.

[0093] Step S341, determining target signal data in the signal detection data and determining a target position corresponding to the target signal data in the reference signal, specifically including: step S3411, determining two signal data that are the same and adjacent as reference signal data in the signal detection data, and determining one of the reference signal data as the target signal data; step S3412, determining a signal direction closest to the target signal data as a target signal direction in the periodic square wave signal; wherein the position of the target signal direction is the target position.

[0094] Specifically, the reference signal can directly adopt a periodic square wave signal, or can be an interval of periodic square wave signal, that is, other signals or no signal can be set between two periodic square wave signals. The sampling interval of the magnetic sensor can be set to a certain value between 1ms-10ms. The half period T of the periodic square wave signal p = T s + δT s , wherein 0 < δT s < T s , that is, longer than the sampling interval of the magnetic sensor by a certain value. Therefore, the half period of the periodic square wave signal is usually the sampling interval of the magnetic sensor plus a certain margin, that is, slightly larger than the sampling interval of the magnetic sensor. For example, the difference between the half period of the periodic square wave signal and the sampling interval of the magnetic sensor can not exceed 10% of the sampling interval of the magnetic sensor. According to the characteristics of the square wave periodic signal, there are high signal data and low signal data in the signal detection data, the high signal data corresponds to the high level signal segment in the square wave signal, and the low signal data corresponds to the low level signal in the square wave signal. Since the half period of the periodic square wave signal is slightly larger than the sampling interval, under normal circumstances, the high signal data and the low signal data in the signal detection data are alternately present, but as the difference between the half period of the periodic square wave signal and the sampling interval of the magnetic sensor accumulates, two consecutive same signal data, both high signal data or both low signal data, will appear. At this time, the two consecutive same signal data can be determined as reference signal data. If the reference signal data is high signal data, the two reference signal data are in the same high level signal segment, and if the reference signal data is low signal data, the two reference signal data are in the same low level signal segment.

[0095] Figure 4 is a sampling schematic diagram of the periodic square wave signal in some embodiments of the present application. In Figure 4 , the black dots represent the sampling points of the periodic square wave signal, that is, the corresponding positions of each signal detection data in the periodic square wave signal; the x-axis represents the time axis of the working clock of the field emitter, and the r-axis represents the time axis of the working clock of the magnetic sensor. For example, as shown in Figure 4 , in the area shown by the dashed line box in the figure, there are two high signal sampling points, corresponding to two reference signal data. As shown in Figure 4 , the present embodiment is described more specifically.

[0096] After determining two continuous high signal data as reference signal data, it is needed to determine the high level signal segment where the two reference signal data are located in the periodic square wave signal. Specifically, before the two reference signal data, high signal data and low signal data appear alternately, which correspond to different high level signal segments and low level signal segments respectively. Therefore, the high level signal segment where the two reference signal data are located can be determined according to the number of high signal data before the two reference signal data. For example, if 10 high signal data (alternating with low signal data) have appeared before the two reference signal data, it indicates that the two reference signal data are located in the 11th high level signal segment in the periodic square wave signal. At this time, the first reference signal data can be determined as the target signal data, and the rising edge of the high level signal segment where the target signal data is located is determined as the target signal edge.

[0097] Further, referring to Figure 4 , the time measurement of the target signal edge by the field emitter is t1, and the sampling point corresponding to the target signal data is not exactly at the target signal edge, and there is a physical time interval Δt1 between them. The time measurement of the target signal data by the magnetic sensor is t3. Both t1 and t3 are represented by data time stamps. t2 represents the actual collection time of the corresponding high signal data in the working clock of the magnetic sensor. Since there is a time interval between the collection time and the time stamp marking time of the same data in the magnetic sensor, t2 and t3 are not the same time, and there is a physical time interval Δt2 between them. Δt2 is the time interval between the collection time and the time stamp marking time of the same data in the magnetic sensor, which is mainly related to the specific magnetic sensor chip.

[0098] Since the half period of the periodic square wave signal is slightly larger than the sampling interval of the magnetic sensor, the physical time interval Δt1 is relatively small, which is smaller than the difference between the half period of the periodic square wave signal and the sampling interval of the magnetic sensor, and is usually much smaller than the time measurement deviation between the magnetic sensor and the field emitter. Therefore, when calculating the above-mentioned time measurement deviation, the physical time interval Δt1 can be ignored. At the same time, it can be known from the above description that the closer the half period of the periodic square wave signal and the sampling interval of the magnetic sensor, the smaller the physical time interval Δt1, and the smaller the synchronization error between the magnetic field working data and the magnetic field detection data of the working magnetic field.

[0099] Therefore, in one embodiment, step S342, determining the reference time difference according to the time information of the target position and the time information of the target signal data, specifically comprising: step S3421, determining the reference time difference according to the time difference between the time information of the target signal edge and the time information of the target signal data.

[0100] Specifically, the time information of the target signal edge is the time measurement of the field transmitter, and the time information of the target signal data is the time measurement of the magnetic sensor. Therefore, the time difference between the time information of the target signal edge and the time information of the target signal data mainly includes three parts: one is the time difference between the working clock of the field transmitter and the working clock of the magnetic sensor (the initial time difference of the two clocks), the second is the physical time interval (△t1) between the corresponding sampling points of the target signal edge and the target signal data, and the third is the physical time interval (△t2) between the collection time of the same data in the magnetic sensor and the time stamp marking time. Among them, the first part error and the second part error together constitute the time measurement deviation between the field transmitter and the magnetic sensor. In the embodiment, the physical time interval (△t1) between the corresponding sampling points of the target signal edge and the target signal data is ignored, and the time difference between the time information of the target signal edge and the time information of the target signal data is directly determined as the time measurement deviation between the field transmitter and the magnetic sensor, that is, the reference time difference between the signal detection data and the reference signal, which is the time synchronization parameter that needs to be solved finally.

[0101] Correspondingly, in another embodiment, step S342, the reference time difference is determined according to the time information of the target position and the time information of the target signal data, specifically including: step S3422, determining the reference time difference according to the time difference between the time information of the target signal edge and the time information of the target signal data, and the physical time interval (△t1) between the corresponding sampling points of the target signal edge and the target signal data; wherein the physical time interval (△t1) is obtained by simulation in advance.

[0102] Different from the last embodiment, in the embodiment, in order to more accurately determine the time measurement deviation between the field transmitter and the magnetic sensor, the physical time interval (△t1) between the corresponding sampling points of the target signal edge and the target signal data will be considered. Specifically, in the time difference between the time information of the target signal edge and the time information of the target signal data, the physical time interval (△t1) between the corresponding sampling points of the target signal edge and the target signal data is deducted, and finally the more accurate time measurement deviation (time synchronization parameter) between the field transmitter and the magnetic sensor is obtained.

[0103] Wherein, since the physical time interval (△t1) between the target signal edge and the corresponding sampling point of the target signal data is irrelevant to the time measurement deviation between the field emitter and the magnetic sensor, and only related to the half cycle of the periodic square wave signal and the collection cycle of the magnetic sensor, the expected value can be obtained by simulation in advance. The actual periodic square wave signal and the collection action of the actual magnetic sensor can be simulated in a simulation environment, so as to obtain the average physical time interval (△t1) between the target signal edge and the corresponding sampling point of the target signal data. Then, the average physical time interval (△t1) obtained by simulation is deducted from the time difference between the time information of the target signal edge and the time information of the target signal data, and finally the time measurement deviation between the field emitter and the magnetic sensor is obtained more accurately.

[0104] It should be noted that the time measurement deviation between the field emitter and the magnetic sensor obtained by the above steps includes two parts: one is the time difference between the working clock of the field emitter and the working clock of the magnetic sensor, that is, the initial time of the two working clocks has a time difference, and the other is the physical time interval (△t2) between the collection time and the time stamp marking time of the same data in the magnetic sensor. Since the above two parts will cause the misalignment of the magnetic field detection data and the magnetic field working data, the time measurement deviation between the field emitter and the magnetic sensor can be directly used to synchronize the magnetic field detection data and the magnetic field working data, without the need to specifically solve the above two parts. It is also illustrated that the data synchronization method in the present application not only eliminates the time difference between the working clock of the field emitter and the working clock of the magnetic sensor, but also eliminates the physical time interval (△t2) between the collection time and the time stamp marking time of the same data in the magnetic sensor, so as to more accurately synchronize the magnetic field detection data and the magnetic field working data.

[0105] It should also be noted that, Figure 4 It should also be noted that,

[0106] Figure 5 is a binarization processing schematic diagram of the periodic square wave signal in some embodiments of the present application. Referring to Figure 5 In some embodiments, the time information of the target signal edge includes trigger time information of the target signal edge; the data synchronization method of the electromagnetic navigation system further includes, before step S340, step S331, binarizing the signal detection data using a preset threshold.

[0107] Step S342, determining the reference time difference according to the time information of the target position and the time information of the target signal data, includes: step S3423, determining the reference time difference according to the time difference between the trigger time information of the target signal edge and the time information of the target signal data, and the change time required for the target signal edge to change from the trigger value to the preset threshold; wherein the change time is determined according to the working characteristics of the second transmitting unit.

[0108] In this embodiment, considering that the second transmitting unit uses an electromagnetic coil, it is difficult to emit a standard periodic square wave signal in the actual working process, mainly because the conversion of the high signal and the low signal in the reference signal requires a certain time, and the actual waveform is as shown in waveform a in Figure 5 In order to equivalent to detect the standard periodic square wave signal, after obtaining the signal detection data through the magnetic sensor, a preset threshold (corresponding to the position of the dashed line c in Figure 5 ) is used to binarize the signal detection data, and the binarized signal detection data can be equivalent to the data obtained by detecting the standard periodic square wave signal, that is, the binarized periodic square wave signal, as shown in waveform b in Figure 5 At this time, the signal edge position in the binarized periodic square wave signal is equal to the position of the corresponding signal edge in the actual periodic square wave signal at the preset threshold. That is, the signal edge trigger time of the binarized periodic square wave signal has a delay compared with the signal edge trigger time of the actual periodic square wave signal.

[0109] Therefore in actual process, the time difference between the time information of the target signal edge and the time information of the target signal data mainly includes the following three parts, one is the time difference between the working clock of the field emitter and the working clock of the magnetic sensor (the initial time difference of the two clocks), the second is the physical time interval between the trigger point of the target signal edge and the corresponding sampling point of the target signal data, and the third is the physical time interval between the collection time of the same data in the magnetic sensor and the time stamp marking time. Among them, the first part error and the second part error together constitute the time measurement deviation between the field emitter and the magnetic sensor. The physical time interval between the trigger point of the target signal edge and the corresponding sampling point of the target signal data includes the change time required for the target signal edge to change from the trigger value to the preset threshold, and the physical time interval between the corresponding point of the preset threshold in the target signal edge and the corresponding sampling point of the target signal data (the physical time interval between the target signal edge and the corresponding sampling point of the target signal data in the binary periodic square wave signal). Therefore, in the time difference between the time information of the target signal edge and the time information of the target signal data, the change time required for the target signal edge to change from the trigger value to the preset threshold is removed, and the time measurement deviation between the field emitter and the magnetic sensor can be more accurately obtained.

[0110] Reference Figure 4 Correspondingly, in the above embodiment, the physical time interval (△t1) between the target signal edge and the corresponding sampling point of the target signal data will also be obtained by simulation. In the actual simulation process, in order to more accurately obtain the above physical time interval (△t1), the standard periodic square wave signal is usually simulated. Therefore, the physical time interval (△t1) between the target signal edge and the corresponding sampling point of the target signal data obtained by simulation is the physical time interval between the target signal edge and the corresponding sampling point of the target signal data in the binary periodic square wave signal, that is, the physical time interval between the corresponding point of the preset threshold in the target signal edge of the actual signal and the corresponding sampling point of the target signal data. Therefore, in some embodiments, the change time required for the target signal edge of the actual signal to change from the trigger value to the preset threshold and the physical time interval between the corresponding point of the preset threshold in the target signal edge of the actual signal and the corresponding sampling point of the target signal data can be calculated at the same time, and the above change time and physical time interval are removed at the same time in the time difference between the time information of the target signal edge and the time information of the target signal data, so that the time measurement deviation between the field emitter and the magnetic sensor can be more accurately obtained.

[0111] Generally, the preset threshold can be set as the middle value of the high signal and the low signal, and the change time Δt lag = τln(2), where τ is the relaxation time constant of the coil, which can be determined by the inductance and resistance of the electromagnetic coil.

[0112] Therefore, the trigger time information of the signal edge in the periodic square wave signal is still used to determine the time information of the signal edge. In order to obtain a more accurate time measurement deviation result between the field emitter and the magnetic sensor, the variation time required for the target signal edge to change from the trigger value to the preset threshold can be further removed from the time measurement deviation obtained in the foregoing embodiment, so that the time measurement deviation between the field emitter and the magnetic sensor is more accurately obtained.

[0113] The foregoing mainly introduces the technical solution for data synchronization through a periodic square wave signal. In addition, data synchronization can also be performed through a periodic pulse signal.

[0114] In some embodiments, the reference signal includes a periodic pulse signal; and step S341 of determining target signal data in the signal detection data and determining a target position corresponding to the target signal data in the reference signal includes: step S3413 of determining high signal data in the signal detection data as the target signal data; and step S3414 of determining a pulse corresponding to the target signal data in the periodic pulse signal as a target pulse; wherein the position of the target pulse is the target position.

[0115] Specifically, the signal detection data includes high signal data and low signal data, wherein the high signal data is obtained by sampling the pulse top position by the magnetic sensor. Therefore, when the high signal data appears in the signal detection data, it must correspond to a pulse. At this time, the high signal data can be determined as the target signal data, and then the target pulse corresponding to the high signal data in the periodic pulse signal is determined.

[0116] Further, in order to more accurately determine the target pulse, the period of the periodic pulse signal can be set to be higher than twice the maximum time measurement deviation between the field emitter and the magnetic sensor. For example, assuming that the maximum time measurement deviation between the field emitter and the magnetic sensor is 1s, the period of the periodic pulse signal is at least 2s. When the period of the periodic pulse signal is set to 3s, assuming that the time measurement of the target signal data by the magnetic sensor is the 10th second, the time measurement of the target pulse corresponding to the target signal data by the field emitter is between the 9th second and the 11th second. The time interval is smaller than the period of the periodic pulse signal, and there is only one pulse in the time interval, that is, the pulse generated at the 9th second in the time measurement of the field emitter, which is the target pulse.

[0117] Correspondingly, step S342 of determining the reference time difference according to the time information of the target position and the time information of the target signal data includes: step S345 of determining the reference time difference according to the time difference between the time information of the target pulse and the time information of the target signal data.

[0118] Between the target signal data and the target pulse, a time difference between the time information of the target pulse and the time information of the target signal data can be calculated, and the time difference represents a time measurement deviation between the field transmitter and the magnetic sensor, i.e., a reference time difference between the signal detection data and the reference signal.

[0119] As described above, two technical solutions for data synchronization through a periodic pulse signal and a periodic square wave signal are introduced. It should be noted that the specific waveform of the reference signal is not limited to the above two signal waveforms. The design requirement for the waveform of the reference signal is that there are some signal positions with identification in the waveform, and correspondingly, the signal detection data corresponding to the signal positions also have identification. Therefore, when the signal detection data with identification appears, the corresponding position of the signal detection data in the reference signal can be determined reversely. It should be understood that any reference signal meeting the above design requirement can realize the data synchronization method of the electromagnetic navigation system provided by the application.

[0120] The technical solutions in the application will be described in detail through some specific embodiments as follows.

[0121] In the data synchronization method of the electromagnetic navigation system provided by the application, an electromagnetic coil for synchronization is additionally arranged in the field transmitter, and a reference signal for time synchronization, such as a periodic square wave signal, can be superimposed on the time-varying working magnetic field for positioning.

[0122] In the technical solution, the time-varying working magnetic field for positioning can be generated by a coil or a rotating magnet, and the frequency is relatively low, such as less than 100 Hz. The reference signal for time synchronization is a periodic square wave signal with a relatively high frequency, such as 400 Hz, which is about 50% of the sampling rate of the magnetic sensor, and is generated by the electromagnetic coil. The frequency difference between the two signals is large (several hundred Hz), and the two signals can be separated through a digital filter, and the positioning and time synchronization processing can be performed simultaneously. The magnetic sensor end only needs to collect the magnetic field data in real time and stamp the local time stamp, and then send it to the processing unit at a certain frequency (the transmission frequency is less than the sampling rate). The magnetic sensor end does not distinguish between "positioning mode" or "synchronization mode", i.e., it does not need to distinguish between the magnetic field detection data and the signal detection data, thereby reducing the complexity of the magnetic sensor end and making the whole system work more simply. Since the time synchronization can be continuously performed, the synchronization performance will not significantly degrade over time.

[0123] Reference Figure 4 , it is assumed that the sampling interval of the magnetic sensor is T s , and the mean value is between 1 ms and 10 ms. At the magnetic sensor end, there is a certain interval Δt1 between the time when the magnetic sensor actually samples the data and the time when the MCU (micro control unit) gets the data and stamps the time stamp, and the interval is related to the specific sensor chip.

[0124] In order to synchronize the magnetic field data collected by the magnetic sensor, the half period of the synchronization reference signal generated by the magnetic field transmitter is:

[0125] T p = T s + δT s

[0126] Wherein 0 < δT s < T s , that is, it can be ensured that the magnetic sensor can always collect high magnetic field signals (corresponding to high signal data), but because the sensor sampling rate is limited, it cannot be guaranteed to capture the signal rising edge. Because the period of the square wave signal is not equal to an integer multiple of the sampling interval, and accumulates over time, the relative position of the sampling point on the square wave signal will shift. Because T p > T s , with the continuous accumulation of the above displacement, there will be two consecutive high magnetic field signals (one high and one low at other times). At this time, the interval between the sampling time of the first of the two consecutive high magnetic field signals and the magnetic field rising edge is:

[0127] Δt1 = (t2 - T r0 ) - (t1 - T x0 )

[0128] Wherein, T x0 is the initial time of the working clock of the field transmitter, and T r0 is the corresponding time of the initial time of the field transmitter in the working clock of the magnetic sensor. That is, T x0 and T r0 are the time measurements of the two device working clocks for the same physical time (transmitter initial time), and determining the time difference between them is one of the purposes of the data synchronization method in the present application. t1 is the logical time of the actual data sampling time of the magnetic sensor on the magnetic sensor side, and t2 is the logical time of the rising edge of the square wave signal on the field transmitter.

[0129] The occurrence of two consecutive high magnetic field signals has a certain randomness, and Δt1 is a random variable, and the mean E(Δt) = kδT s , such as k < 1, the specific parameters can be simulated and counted in advance. At this point, the synchronization reference point (a certain rising edge of the square wave signal) and the time measurement of the field transmitter and the magnetic sensor for this synchronization reference point have been determined, and the time synchronization is performed through the time measurement deviation between them, and the synchronization error can be controlled in the order of δT s , and with the increase of the statistical amount, the error can be further reduced and controlled, such as < 10 μs. The specific calculation process is as follows:

[0130] t3 - t1

[0131] = (T r0 -T x0 + Δt2 t2 ) + Δt1 t1

[0132] Thus, the time synchronization parameter is obtained:

[0133] T r0 -T x0 + Δt2

[0134] = t3-t1-Δt1

[0135] ≈ t3-t1-E(Δt)

[0136] From the above formula, it can be seen that the data synchronization method in the embodiment also considers Δt2, so that the above interval is automatically corrected when the local logical time of the magnetic sensor is calibrated:

[0137] t syn

[0138] = t3-(T r0 -T x0 + Δt2)

[0139] = (t3-Δt2)-(T r0 -T x0 )

[0140] = t2-(T r0 -T x0 )

[0141] The correction result t syn is the corresponding time of the actual sampling time in the working clock of the magnetic sensor in the working clock of the field transmitter, which facilitates accurate searching and interpolation of the corresponding magnetic field working data of the time-varying working magnetic field.

[0142] Referring to Figure 5 , in addition, it needs to be considered that the electromagnetic coil has inductance, so the reference signal is not an ideal square wave signal. The reference signal has a rise and fall time. Assuming that the relaxation time constant of the electromagnetic coil is τ, from the start of the trigger signal to the time when the signal (current) rises to half the height, Δt lag = τ In(2) is needed. At the same time, the program sets the 50% peak value as the binary threshold, and the signal data of the square wave signal with a strength lower than the 50% peak value is set to 0, and higher than 1, so that the rising edge of the binary square wave signal obtained will be delayed by Δt lag relative to the actual square wave signal, so the time synchronization parameter needs to be corrected:

[0143] T r0 -T x0+ Δt2

[0144] = t3-t1-(Δt1+Δt lag )

[0145] ≈ t3-t1-(E(Δt)+Δt lag )

[0146] Since Δt lag = τIn(2) can be estimated according to the inductance, resistance of the electromagnetic coil, τ = L / R, so this delay can be eliminated.

[0147] Finally, it needs to be pointed out that the reference signal can also be intermittent. Figure 6 is the waveform diagram of the reference signal in some embodiments of the application. As Figure 6 shown, the reference signal lasts T1 time each time, and is intermittent for T2 time, and the specific length can be adjusted.

[0148] In each T1 time, the number of double high magnetic field signals that appear may be more than once, at which time the average of multiple time synchronization parameters can be calculated.

[0149] As above is the detailed description of the data synchronization method of the electromagnetic navigation system in this specific embodiment. The summary of the data synchronization method is as follows:

[0150] 1. The data synchronization method is suitable for time synchronization of magnetic sensors in electromagnetic navigation systems based on low-frequency time-varying working magnetic fields. The frequency of the time-varying working magnetic field is usually lower than 100 Hz.

[0151] 2. The data synchronization method requires adding an electromagnetic coil (or sharing) in the field transmitter to generate a periodic square wave signal. The duty cycle of the periodic square wave signal is 50%, and the period is slightly larger than the average sampling interval of the magnetic sensor, and the frequency is usually several hundred hertz.

[0152] 3. The magnetic sensor measures the combined magnetic field of the time-varying working magnetic field and the synchronous reference signal in real time, and decouples the two signals through a low-pass, band-pass filter to achieve synchronous positioning.

[0153] 4. When processing the synchronization signal, first, it is binarized; then find the position of the two consecutive high magnetic field strength sampling points, record the time stamp of the first sampling point and the number N of high magnetic field waves captured; then find the trigger time stamp of the field transmitter according to N; finally, calculate t3-t1, then deduct E(Δt) and the delay Δt lag caused by the electromagnetic coil, that is, the time synchronization parameter T r0 -T x0 + Δt2.

[0154] This invention also provides a data synchronization device for an electromagnetic navigation system, which is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. The terms "module," "unit," "subunit," etc., used below refer to combinations of software and / or hardware that implement a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0155] Figure 7 This is a structural block diagram of the data synchronization device for the electromagnetic navigation system provided by the present invention, as shown below. Figure 7 As shown, the device includes:

[0156] The first data acquisition module 710 is used to acquire magnetic field detection data of the working magnetic field; wherein, the magnetic field detection data is obtained by a magnetic sensor detecting the working magnetic field, and the working magnetic field is generated by the first transmitting unit;

[0157] The second data acquisition module 720 is used to acquire signal detection data of the reference signal; wherein, the signal detection data is obtained by the magnetic sensor detecting the reference signal, and the reference signal is generated by the second transmitting unit;

[0158] The third data acquisition module 730 is used to acquire the magnetic field operating data of the working magnetic field; wherein, the magnetic field operating data is provided by the field emitter;

[0159] The data synchronization module 740 is used to determine the reference time difference between the signal detection data and the reference signal, and to synchronize the magnetic field detection data and the magnetic field working data according to the reference time difference.

[0160] The aforementioned device can determine the time measurement deviation between the field transmitter and the magnetic sensor. This time measurement deviation can eliminate the time difference between the working magnetic field data and the detected magnetic field data, thereby eliminating misalignment and positioning errors in the magnetic sensor's positioning results, ultimately improving the positioning accuracy of the magnetic sensor. This solves the problem in existing electromagnetic navigation methods where a time difference exists between the working magnetic field data and the detected magnetic field data corresponding to the same physical moment, leading to increased positioning errors in the magnetic sensor.

[0161] It should be noted that the above modules can be functional modules or program modules, and can be implemented through software or hardware. For modules implemented through hardware, the above modules can reside in the same processor; or the above modules can be located in different processors in any combination.

[0162] In the present application, an electronic device is also provided, comprising a memory and a processor, the memory stores a computer program, and the processor is configured to run the computer program to perform the steps in any of the above method embodiments.

[0163] It should be noted that the specific examples in the present embodiment can refer to the examples described in the above embodiments and optional implementation manners, which will not be repeated in the present embodiment.

[0164] In addition, in combination with the data synchronization method of the electromagnetic navigation system provided in the above application, a storage medium can also be provided in the present application to achieve the same. The storage medium stores a computer program; the computer program is executed by a processor to implement any of the data synchronization methods of the electromagnetic navigation system in the above embodiments.

[0165] It should be noted that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties.

[0166] It should be understood that the specific embodiments described herein are only used to explain the application, but not to limit it. According to the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0167] Obviously, the drawings are only some examples or embodiments of the present application, and those of ordinary skill in the art can also apply the present application to other similar situations without creative labor. In addition, it can be understood that although the work done in the development process may be complex and long, some design, manufacture or production changes made by those of ordinary skill in the art according to the technical content disclosed in the present application are only routine technical means and should not be regarded as insufficient disclosure of the present application.

[0168] The term "embodiment" in the present application means that the specific features, structures or characteristics described in combination with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor does it mean independence or alternative to other embodiments. Those of ordinary skill in the art can clearly or implicitly understand that the embodiments described in the present application can be combined with other embodiments without conflict.

[0169] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific manner, but should not be construed as limiting the scope of patent protection. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. An electromagnetic navigation system characterized by, The electromagnetic navigation system comprises a field transmitter (100) and a magnetic sensor (200), the field transmitter (100) comprises a first transmitting unit (110) and a second transmitting unit (120); The first transmitting unit (110) is configured to generate a working magnetic field, and the working magnetic field is used for positioning the magnetic sensor (200); The second transmitting unit (120) is configured to generate a reference signal, and the reference signal is used for synchronizing magnetic field detection data of the working magnetic field and magnetic field working data; wherein the magnetic field detection data is obtained by detecting the working magnetic field by the magnetic sensor (200), and the magnetic field working data is provided by the field transmitter (100); The first transmitting unit (110) and the second transmitting unit (120) are configured to share a working clock of the field transmitter (100); The data synchronization method of the electromagnetic navigation system comprises: Obtaining signal detection data of the reference signal; wherein the signal detection data is obtained by detecting the reference signal by the magnetic sensor; the reference signal comprises a periodic square wave signal, and a half period of the periodic square wave signal is greater than a sampling interval of the magnetic sensor; In the signal detection data, two signal data that are the same and adjacent are determined as reference signal data, and one of the reference signal data is determined as target signal data; In the periodic square wave signal, a signal edge closest to the target signal data is determined as a target signal edge; wherein a position of the target signal edge is a target position; According to time information of the target position and time information of the target signal data, a reference time difference between the signal detection data and the reference signal is determined; According to the reference time difference, the magnetic field detection data and the magnetic field working data are synchronized.

2. The electromagnetic navigation system of claim 1, wherein, The second transmitting unit (120) comprises a square wave transmitter or a pulse transmitter.

3. The electromagnetic navigation system of claim 1, wherein, The second transmitting unit (120) comprises an electromagnetic coil.

4. The electromagnetic navigation system of claim 1, wherein, The first transmitting unit (110) and the second transmitting unit (120) are configured to work synchronously; The working frequencies of the first transmitting unit (110) and the second transmitting unit (120) are different.

5. A method of data synchronization for an electromagnetic navigation system, the method comprising: The data synchronization method is applied to the electromagnetic navigation system according to any one of claims 1-4; The data synchronization method of the electromagnetic navigation system comprises: Obtaining magnetic field detection data of a working magnetic field; wherein the magnetic field detection data is obtained by detecting the working magnetic field by a magnetic sensor, and the working magnetic field is generated by a first transmitting unit; Obtaining signal detection data of a reference signal; wherein the signal detection data is obtained by detecting the reference signal by the magnetic sensor, and the reference signal is generated by a second transmitting unit; the reference signal comprises a periodic square wave signal, and a half period of the periodic square wave signal is greater than a sampling interval of the magnetic sensor; Obtaining magnetic field working data of the working magnetic field; wherein the magnetic field working data is provided by a field transmitter; In the signal detection data, two same and adjacent signal data are determined as reference signal data, and one of the reference signal data is determined as target signal data; in the periodic square wave signal, a signal edge closest to the target signal data is determined as target signal edge; a position of the target signal edge is target position; a reference time difference between the signal detection data and the reference signal is determined according to time information of the target position and time information of the target signal data, and the magnetic field detection data and the magnetic field operation data are synchronized according to the reference time difference.

6. The data synchronization method of the electromagnetic navigation system according to claim 5, wherein, The determining the reference time difference according to the time information of the target position and the time information of the target signal data comprises: determining the reference time difference according to a time difference between the time information of the target signal edge and the time information of the target signal data.

7. The data synchronization method of an electromagnetic navigation system according to claim 5, wherein, The determining the reference time difference according to the time information of the target position and the time information of the target signal data comprises: determining the reference time difference according to a time difference between the time information of the target signal edge and the time information of the target signal data and a physical time interval between the target signal edge and a sampling point corresponding to the target signal data; wherein the physical time interval is obtained by pre-simulation.

8. The data synchronization method of the electromagnetic navigation system according to claim 5, wherein, The time information of the target signal edge comprises trigger time information of the target signal edge. The data synchronization method of the electromagnetic navigation system further comprises, before determining the reference time difference between the signal detection data and the reference signal: performing binaryzation processing on the signal detection data by using a preset threshold value. The determining the reference time difference according to the time information of the target position and the time information of the target signal data comprises: determining the reference time difference according to a time difference between the trigger time information of the target signal edge and the time information of the target signal data and a change time required for the target signal edge to change from a trigger value to the preset threshold value; wherein the change time is determined according to an operation characteristic of the second transmitting unit.

9. The data synchronization method of the electromagnetic navigation system according to claim 5, wherein, The reference signal is superimposed on the operation magnetic field, and a frequency of the reference signal is different from a frequency of the operation magnetic field.

10. A data synchronization device for an electromagnetic navigation system, characterized in that The data synchronization device is applied to the electromagnetic navigation system according to any one of claims 1-4. The data synchronization device of the electromagnetic navigation system comprises: a first data acquisition module configured to acquire magnetic field detection data of an operation magnetic field; wherein the magnetic field detection data is obtained by detecting the operation magnetic field by a magnetic sensor, and the operation magnetic field is generated by a first transmitting unit; a second data acquisition module configured to acquire signal detection data of a reference signal; wherein the signal detection data is obtained by detecting the reference signal by the magnetic sensor, and the reference signal is generated by a second transmitting unit; the reference signal comprises a periodic square wave signal, and a half period of the periodic square wave signal is greater than a sampling interval of the magnetic sensor; a third data acquisition module configured to acquire magnetic field operation data of the operation magnetic field; wherein the magnetic field operation data is provided by a field transmitter. The data synchronization module is configured to determine two same and adjacent signal data as reference signal data in the signal detection data, and determine one of the reference signal data as target signal data; determine a signal edge closest to the target signal data as target signal edge in the periodic square wave signal, wherein a position of the target signal edge is a target position; determine a reference time difference between the signal detection data and the reference signal data according to time information of the target position and time information of the target signal data, and synchronize the magnetic field detection data and the magnetic field operation data according to the reference time difference.

11. An electronic device comprising a memory and a processor, characterized in that The memory stores a computer program, and the processor is configured to run the computer program to execute the data synchronization method of the electromagnetic navigation system in any one of claims 5 to 9.

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