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

Abstract

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

Description

Technical Field

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

[0002] Electromagnetic transient simulator (EMTS) is one of the mainstream surgical navigation system technology solutions. The most typical EMTS basic principle is to generate a time-varying magnetic field through a field transmitter, detect the time-varying magnetic field through a magnetic sensor, and then solve the position and posture of the magnetic sensor. The phase method is a commonly used positioning calculation method. This method requires obtaining the magnetic field working state (such as phase, intensity) and magnetic field detection data at the same physical moment. Among them, the magnetic field working state is determined according to the magnetic field working data of the field transmitter. 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 with a magnetic sensor.

[0003] Since the device clocks between the field transmitter and the magnetic sensor are not synchronized, and in the magnetic sensor, the acquisition time of the magnetic field detection data and the time stamp generation time 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 moment. In the pose solver, there is a phase difference between the measured value and the model value of the time-varying magnetic field, which will increase the positioning error of the magnetic sensor. Among them, 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] In electromagnetic navigation systems, there is a time difference between the time information of magnetic field working data and magnetic field detection data corresponding to the same physical moment, which leads to an increase in the positioning error of the magnetic sensor. At present, no effective solution has been proposed. Summary of the invention

[0005] The present invention provides an electromagnetic navigation system and a data synchronization method, device and electronic device thereof to solve the problem that in the related electromagnetic navigation system, 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 moment, which leads to an increase in the positioning error of the magnetic sensor.

[0006] In a first aspect, the present invention provides an electromagnetic navigation system, the electromagnetic navigation system comprising: a field transmitter and a magnetic sensor, the field transmitter comprising a first transmitting unit and a second transmitting unit;

[0007] The first transmitting unit is used to generate a working magnetic field, and the working magnetic field is used to locate the magnetic sensor;

[0008] The second transmitting unit is used to generate a reference signal, and the reference signal is used to synchronize the magnetic field detection data and the magnetic field working 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 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 includes a square wave transmitter or a pulse transmitter.

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

[0012] In some of the embodiments, the first transmitting unit and the second transmitting unit are configured to operate synchronously;

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

[0014] In a second aspect, the present invention provides a data synchronization method for an electromagnetic navigation system, wherein the data synchronization method is applied to the electromagnetic navigation system described in the first aspect;

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

[0016] 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;

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

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

[0019] A reference time difference between the signal detection data and the reference signal is determined, and the magnetic field detection data and the magnetic field operation data are synchronized according to the reference time difference.

[0020] In some embodiments, determining a 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] The reference time difference is determined according to the time information of the target position and the time information of the target signal data.

[0023] In some of the 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 step 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 comprises:

[0025] In the signal detection data, two identical and adjacent signal data 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; wherein the position of the target signal edge is the target position.

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

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

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

[0030] The reference time difference is determined 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 between the target signal edge and the corresponding sampling points of the target signal data; wherein the physical time interval is obtained by pre-simulation.

[0031] In some of the embodiments, the time information of the target signal edge includes 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] Using a preset threshold to perform binarization processing on the signal detection data;

[0034] 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:

[0035] The reference time difference is determined based on 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 based on the working characteristics of the second transmitting unit.

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

[0037] The step 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 comprises:

[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 the position of the target pulse is the target position.

[0040] In some embodiments, determining the reference time difference according to the time information of the target position and the time information of the target signal data includes:

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

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

[0043] In a third aspect, the present invention provides a data synchronization device for an electromagnetic navigation system, wherein the data synchronization device is applied to the electromagnetic navigation system described in the first aspect;

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

[0045] A first data acquisition module, used 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, used to acquire signal detection data of a reference signal; wherein the signal detection data is obtained by the magnetic sensor detecting the reference signal, and the reference signal is generated by a second transmitting unit;

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

[0048] The data synchronization module is used 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 working data according to the reference time difference.

[0049] In a fourth aspect, the present invention 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 described in the second aspect when executing the computer program.

[0050] In a fifth aspect, the present invention provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements the data synchronization method of the electromagnetic navigation system described in the second aspect.

[0051] Compared with the related art, the electromagnetic navigation system and its data synchronization method, device and electronic device provided in the present invention can eliminate the time difference between the magnetic field working data and the magnetic field detection data of the working magnetic field by setting a second transmitting unit that can generate a reference signal in the field transmitter, thereby eliminating the misalignment of the positioning result and the positioning error of the magnetic sensor, and finally improving the positioning accuracy of the magnetic sensor. The problem that the time difference between the 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 is solved, which leads to an increase in the positioning error of the magnetic sensor.

[0052] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

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

[0055] Figure 2 It is a schematic diagram of the composition of the electromagnetic navigation system provided by the present invention;

[0056] Figure 3 is a flow chart of a data synchronization method for an electromagnetic navigation system provided by the present invention;

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

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

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

[0060] Figure 7 It is a structural block diagram of the data synchronization device of the electromagnetic navigation system provided by the present invention. DETAILED DESCRIPTION

[0061] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0062] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the", "these" and the like in this application do not represent quantitative restrictions, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. Usually, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0063] The method embodiment provided in this embodiment can be executed in a terminal, a computer or a similar computing device. For example, running on a terminal, Figure 1 1 is a hardware structure diagram of a terminal for executing the data synchronization method of the electromagnetic navigation system provided by the present invention. Figure 1 As shown, the terminal may include one or more ( Figure 1Only one is shown in the figure) processor 102 and memory 104 for storing data, wherein processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA. The above terminal may also include a transmission device 106 and an input and output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.

[0064] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the data synchronization method of the electromagnetic navigation system provided in the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0065] The transmission device 106 is used to receive or send data via a network. The above network includes a wireless network provided by the communication provider of the terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as 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 (Radio Frequency, referred to as RF) module, which is used to communicate with the Internet wirelessly.

[0066] The present invention provides an electromagnetic navigation system. Figure 2 Schematic diagram of the electromagnetic navigation system provided by the present invention. Figure 2The electromagnetic navigation system includes: a field transmitter 100 and a magnetic sensor 200, the field transmitter 100 includes a first transmitting unit 110 and a second transmitting unit 120; the first transmitting unit 110 is used to generate a working magnetic field, and the working magnetic field is used to locate the magnetic sensor 200; the second transmitting unit 120 is used to generate a reference signal, and the reference signal is used to synchronize the magnetic field detection data and the magnetic field working data of the working magnetic field; 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 and the second transmitting unit are configured to share the 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 locate the magnetic sensor 200. The magnetic field detection data obtained by detecting the working magnetic field by the magnetic sensor 200, and the magnetic field working data of the working magnetic field output by the field transmitter 100, can determine the position of the magnetic sensor 200 in the working magnetic field. Among them, the first transmitting unit 110 mainly includes components such as a motor, an absolute position encoder and a permanent magnet. When the permanent magnet is driven to rotate by the motor, a time-varying magnetic field is generated, and the absolute position encoder records the rotation state of the permanent magnet, that is, the angular position at each moment. The magnetic field working data includes the angular position information of each permanent magnet at each moment.

[0068] As described above, it is the main component of the current electromagnetic navigation system. Compared with the existing electromagnetic navigation system, the electromagnetic navigation system provided by the present invention is mainly improved by adding a second transmitting unit 120.

[0069] In one 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 working simultaneously means that both are turned on and off at the same time. In this embodiment, the second transmitting unit 120 can generate a reference signal that 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, and the signal detection data corresponding to the reference signal and the magnetic field detection data corresponding to the working magnetic field are obtained respectively. The magnetic field detection data is used for the positioning of the magnetic sensor 200, while the signal detection data is not used for the positioning of the magnetic sensor 200, but is used for the time measurement between the synchronous 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 may work before the first transmitting unit 110, and the magnetic sensor 200 first detects the reference signal to obtain signal detection data. At this time, electromagnetic navigation has not started, and the magnetic sensor 200 may be in a relatively static state. After the second transmitting unit 120 finishes working, the electromagnetic navigation work 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 time measurement between the magnetic sensor 200 and the field transmitter 100 can be synchronized by the signal detection data before 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, a reference signal with 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 so that it is unique at some positions, that is, the signal strength at some positions is unique, and then the corresponding signal detection data is identifiable. That is to say, when the magnetic sensor 200 outputs identifiable signal detection data, the position of these data in the reference signal can be reversely inferred. Furthermore, the identifiable signal detection data and its corresponding position in the reference signal constitute a reference physical quantity. At this time, the time difference between the time measurements of the field transmitter 100 and the magnetic sensor 200 on the same reference physical quantity can be determined. Exemplarily, it is assumed that there is signal detection data A, and its corresponding position B in the reference signal. Since the signal detection data A and the position B correspond to the same physical moment, 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 there is a deviation in the time measurement of the signal detection data A and the position B, the deviation is the time difference between the time measurement of the magnetic sensor 200 and the field transmitter 100. Furthermore, the time difference can be used to synchronize the magnetic field detection data and the magnetic field working data.

[0072] It can be known from the above description that the electromagnetic navigation system provided in the present invention can eliminate the time difference between the magnetic field working data and the magnetic field detection data of the working magnetic field by setting the second transmitting unit 120 that can generate a reference signal in the field transmitter 100, and can eliminate the positioning error of the magnetic sensor 200 by synchronizing the time measurement between the field transmitter 100 and the magnetic sensor 200 through the reference signal, thereby eliminating the positioning error of the magnetic sensor 200, and finally improving the positioning accuracy of the magnetic sensor 200. The problem that the positioning error of the magnetic sensor 200 increases due to the time difference between the 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 is solved.

[0073] In some embodiments, the second transmitting unit 120 includes 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 method of synchronizing the time measurement between the field transmitter 100 and the magnetic sensor 200 by the square wave signal or the pulse signal can refer to the relevant embodiment of the data synchronization method of the electromagnetic navigation system provided by the present invention.

[0074] In some embodiments, the second transmitting unit 120 includes an electromagnetic coil. The electromagnetic coil can generate a magnetic field signal when powered on, 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 invention, a data synchronization method for the electromagnetic navigation system is also provided in the present invention. The data synchronization method is applied to the electromagnetic navigation system provided by the present invention to synchronize the magnetic field detection data and the magnetic field working data of the working magnetic field in the electromagnetic navigation system.

[0076] Figure 3 1 is a flow chart of the data synchronization method of the electromagnetic navigation system provided by the present invention. Figure 3 The data synchronization method of the electromagnetic navigation system includes steps S310 to S340. Among them:

[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 a magnetic sensor, and the working magnetic field is generated by a first transmitting unit.

[0078] Step S320, acquiring 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 the second transmitting unit.

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

[0080] Step S340, 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.

[0081] Specifically, the first transmitting unit is a transmitting unit of the working magnetic field of the field transmitter, and the working magnetic field is a time-varying magnetic field used to locate the magnetic sensor. The magnetic field detection data obtained by the magnetic sensor detecting the working magnetic field and the magnetic field working data of the working magnetic field output by the field transmitter can determine the position 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 be unique at some positions, that is, the signal strength at some positions is unique, and the corresponding signal detection data is identifiable. In other words, when the magnetic sensor outputs identifiable signal detection data, the position of these data in the reference signal can be reversely inferred. Furthermore, the identifiable signal detection data 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 signal detection data by the magnetic sensor, 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 each position of the reference signal by the field transmitter. 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, the time measurement deviation between the field transmitter and the magnetic sensor can be determined according to the time measurement of the same reference physical quantity (the same physical moment) by the field transmitter and the magnetic sensor. 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 by the reference time difference between the signal detection data and the reference signal.

[0084] Specifically, in step S340, the reference time difference between the signal detection data and the reference signal is determined, including: step S341, determining the target signal data in the signal detection data, and determining the target position corresponding to the target signal data in the reference signal; step S342, determining the reference time difference based on the time information of the target position and the time information of the target signal data.

[0085] The target signal data is the signal detection data with identification. Accordingly, 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 mainly determined based on 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 moment. If the target signal data and the target position correspond to the same physical moment, the time information deviation between the two is the time measurement deviation between the field transmitter 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 moment, but can also correspond to two different physical moments, but the time interval between the two physical moments 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 transmitter and the magnetic sensor, and the other is the physical time interval between the target signal data and the target position. Therefore, it is only necessary to deduct the physical time interval from the time signal deviation to obtain the time measurement deviation.

[0087] The data synchronization method of the electromagnetic navigation system provided by the present invention mainly obtains the magnetic field detection data and signal detection data of the working magnetic field from the magnetic sensor, and obtains the magnetic field working data of the working magnetic field from the field transmitter through data calculation and processing equipment, and finally synchronizes 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 transmitter and the magnetic sensor can be determined. The time measurement deviation can eliminate the time difference between the magnetic field working data and the magnetic field detection data of the working magnetic field, thereby eliminating the misalignment of the positioning result and the positioning error of the magnetic sensor, and finally improving the positioning accuracy of the magnetic sensor. The problem that 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 moment in the existing electromagnetic navigation method, resulting in an increase in 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 in the attached figure, the step numbers only serve to distinguish the steps, not the execution order of the steps. The execution order of the steps can be determined according to the actual use requirements and the technical relevance between the steps. Specifically, step S320 can be executed before step S310, and step S320 can also be executed at the same time as step S310.

[0090] In an embodiment where step S310 is performed before step S320, a reference signal may be first generated by the second transmitting unit, and the reference signal may be detected by the magnetic sensor to obtain signal detection data of the reference signal, and then a working magnetic field may be generated by the first transmitting unit, and the working magnetic field may be 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 may first obtain the signal detection data of the reference signal, and then obtain the magnetic field detection data and magnetic field working data of the working magnetic field. Finally, a reference time difference between the signal detection data and the reference signal is determined, and the magnetic field detection data and the magnetic field working data are synchronized based on the determined reference time difference.

[0091] In an 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 emitted by the second transmitting unit needs to be different from the frequency of the working magnetic field emitted 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 magnetic field detection data and signal detection data. Exemplarily, the frequency of the working magnetic field is low, usually lower than 100Hz, and the reference signal can be set to a higher frequency, such as 400Hz. 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 magnetic field working data of the working magnetic field. And in the process of continuous data acquisition, as the data is continuously accumulated or updated, the reference time difference between the signal detection data and the reference signal can be updated and adjusted in real time, and the current magnetic field detection data and magnetic field working data can be synchronized in real time based on the latest reference time difference.

[0092] In some of the 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, which is usually a certain margin added to the sampling interval of the magnetic sensor.

[0093] Step S341, determining the target signal data in the signal detection data, and determining the target position corresponding to the target signal data in the reference signal, specifically includes: Step S3411, in the signal detection data, determining two identical and adjacent signal data as reference signal data, and determining one of the reference signal data as the target signal data; Step S3412, in the periodic square wave signal, determining the signal edge closest to the target signal data as the target signal edge; wherein the position of the target signal edge is the target position.

[0094] Specifically, the reference signal can be a periodic square wave signal directly, or a periodic square wave signal can be used intermittently, that is, other signals can be set between two periodic square wave signals or no signal can be set. The sampling interval of the magnetic sensor can be set to a value between 1ms and 10ms. The half period T of the periodic square wave signal p =T s +δT s , where 0<δT s <T s , that is, a certain value longer than the sampling interval of the magnetic sensor. 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 may 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 appear alternately, but as the difference between the half-period of the periodic square wave signal and the sampling interval of the magnetic sensor continues to accumulate, two consecutive identical signal data will appear, both high signal data or both low signal data. At this time, the two consecutive identical 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; 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 Schematic diagram of sampling of periodic square wave signals in some embodiments of the present invention. Figure 4 In the figure: the black dots represent the sampling points of the periodic square wave signal, that is, the corresponding positions of the various signal detection data in the periodic square wave signal; the x-axis represents the time axis of the working clock of the field transmitter, and the r-axis represents the time axis of the working clock of the magnetic sensor. For example, Figure 4 As shown in the figure, there are two high signal sampling points in the area shown by the dotted box, corresponding to two reference signal data. Figure 4 The situation shown is used to explain this embodiment in more detail.

[0096] After determining two consecutive high signal data as reference signal data, it is necessary to first 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, the high signal data and the low signal data appear alternately, corresponding to different high level signal segments and low level signal segments, respectively, so the high level signal segment where the two reference signal data are located can be determined based on the number of high signal data before the two reference signal data. For example, before the two reference signal data, 10 high signal data (alternating with low signal data) have appeared, which means that the two reference signal data are 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 it is located is determined as the target signal edge.

[0097] Further, see Figure 4 , the time measurement of the target signal edge by the field transmitter is t 1 , but the sampling point corresponding to the target signal data is not exactly at the edge of the target signal, and there is a physical time interval △t between the two 1 The time measurement of the target signal data by the magnetic sensor is t 3 .t 1 and t 3 All are indicated by data timestamp. 2 Indicates the actual acquisition time of the corresponding high signal data in the working clock of the magnetic sensor. Since there is a time interval between the acquisition time and the timestamp time of the same data in the magnetic sensor, t 2 and t 3 They are not at the same time, there is a physical time interval △t between them 2 △t 2 It is the time interval between the acquisition time and the timestamp 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 △t 1 It is relatively small, smaller than the difference between the half period of the periodic square wave signal and the sampling interval of the magnetic sensor, and usually much smaller than the time measurement deviation between the magnetic sensor and the field transmitter. Therefore, the physical time interval △t can be ignored when calculating the above time measurement deviation. 1 At the same time, from the above description, it can be seen that the closer the half period of the periodic square wave signal is to the sampling interval of the magnetic sensor, the greater the physical time interval △t 1 The smaller it is, the smaller the synchronization error between the magnetic field working data and the magnetic field detection data of the working magnetic field is.

[0099] Therefore, in one embodiment, step S342, determining a reference time difference based on the time information of the target position and the time information of the target signal data, specifically includes: step S3421, determining a reference time difference based on 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), and the other is the physical time interval (△t 1 ), and the third is the physical time interval between the acquisition time and the timestamp time of the same data in the magnetic sensor (△t 2 ). The first error and the second error together constitute the time measurement deviation between the field transmitter and the magnetic sensor. In this embodiment, the physical time interval (△t 1 ) 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 in the end.

[0101] Correspondingly, in another 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 includes: 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 (△t 1 ), determine the reference time difference; where the physical time interval (△t 1 ) is obtained through pre-simulation.

[0102] Different from the previous embodiment, in this embodiment, in order to more accurately determine the time measurement deviation between the field transmitter and the magnetic sensor, the physical time interval (△t 1 Specifically, the physical time interval (△t 1 ), and finally obtain a more accurate time measurement deviation (time synchronization parameter) between the field transmitter and the magnetic sensor.

[0103] Among them, due to the physical time interval (△t 1 ) has nothing to do with the time measurement deviation between the field transmitter and the magnetic sensor, but is only related to the half-period of the periodic square wave signal and the acquisition period of the magnetic sensor. Therefore, its expected value can be obtained through prior simulation. In the simulation environment, the actual periodic square wave signal and the actual acquisition action of the magnetic sensor can be simulated to obtain the physical time interval (△t) between the sampling point corresponding to the target signal data and the target signal edge. 1 Then, the physical time interval (△t 1 ) average, and finally obtain a more accurate time measurement deviation between the field transmitter and the magnetic sensor.

[0104] It should be noted that the time measurement deviation between the field transmitter and the magnetic sensor obtained through the above steps includes two parts: one is the time difference between the working clock of the field transmitter and the working clock of the magnetic sensor, that is, there is a time difference between the initial moments of the two working clocks; the other is the physical time interval (△t 2 ). Since the above two parts will cause the magnetic field detection data and the magnetic field working data to be misaligned, the time measurement deviation between the field transmitter and the magnetic sensor can be directly used to synchronize the magnetic field detection data and the magnetic field working data without specifically solving the above two parts. At the same time, the data synchronization method in the present invention is explained, which not only eliminates the time difference between the working clock of the field transmitter and the working clock of the magnetic sensor, but also eliminates the physical time interval (△t 2 ), which can more accurately synchronize the magnetic field detection data and the magnetic field working data.

[0105] It should also be noted that Figure 4The figure shows only a specific way to determine the target signal data and the target signal edge. Accordingly, in addition to determining two consecutive high signal data as reference signal data, two consecutive low signal data can also be determined as reference signal data. At the same time, for a set of reference signal data, in addition to determining the previous reference signal data as the target signal data, the next reference signal data can also be determined as the target signal data. Accordingly, the target signal edge is preferably the signal edge closest to the target signal data, and then when the target signal data changes, the target signal edge also changes accordingly. The signal edge closest to the target signal data is selected as the target signal edge, mainly considering that the physical time interval between the two is the smallest, thereby reducing the impact of the interval on the data synchronization accuracy. Correspondingly, other signal edges that have a clear correspondence with the target signal data can also be selected as the target signal edge, but the impact on the data synchronization accuracy is greater.

[0106] Figure 5 Schematic diagram of binarization processing of periodic square wave signals in some embodiments of the present invention. Figure 5 In some embodiments, the time information of the target signal edge includes the 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 a reference time difference based on the time information of the target position and the time information of the target signal data, including: Step S3423, determining a reference time difference based on 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 value; wherein the change time is determined based on the working characteristics of the second transmitting unit.

[0108] In this embodiment, it is considered that when the second transmitting unit adopts an electromagnetic coil, it is difficult to transmit a standard periodic square wave signal in the actual working process, mainly because the conversion between the high signal and the low signal in the reference signal takes a certain amount of time. The actual waveform is as follows: Figure 5 In order to detect the standard periodic square wave signal, after obtaining the signal detection data through the magnetic sensor, the preset threshold (corresponding to Figure 5 The signal detection data is binarized (at the position of the dotted line c in the middle). The signal detection data after binarization can be equivalent to the data obtained by detecting the standard periodic square wave signal, that is, the binarized periodic square wave signal, such as Figure 5As shown in waveform b. 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 is delayed compared to the signal edge trigger time of the actual periodic square wave signal.

[0109] Therefore, in the 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: the first is the time difference between the working clock of the field transmitter and the working clock of the magnetic sensor (the initial time difference between 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 acquisition time and the timestamp marking time of the same data in the magnetic sensor. Among them, the first part of the error and the second part of the error together constitute the time measurement deviation between the field transmitter 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 binarized 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 transmitter and the magnetic sensor can be obtained more accurately.

[0110] Reference Figure 4 Correspondingly, in the above embodiment, the physical time interval (△t 1 In the actual simulation process, in order to obtain the above physical time interval (△t 1 ), usually simulated with a standard periodic square wave signal. Thus, the physical time interval (△t 1), is the physical time interval between the target signal edge and the corresponding sampling point of the target signal data in the binarized periodic square wave signal, that is, the physical time interval between the point corresponding to 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 point corresponding to 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 from the time difference between the time information of the target signal edge and the time information of the target signal data, so as to more accurately obtain the time measurement deviation between the field transmitter and the magnetic sensor.

[0111] Usually, the preset threshold can be set to the middle value between the high signal and the low signal, then the change time Δt lag =τIn(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 determined as the time information of the signal edge. In order to obtain a more accurate time measurement deviation result between the field transmitter and the magnetic sensor, the change time required for the target signal edge to change from the trigger value to the preset threshold value can be further removed from the time measurement deviation obtained in the aforementioned embodiment, thereby more accurately obtaining the time measurement deviation between the field transmitter and the magnetic sensor.

[0113] The above mainly introduces the technical solution of data synchronization through periodic square wave signals. In addition, data synchronization can also be performed through periodic pulse signals.

[0114] In some of the embodiments, the reference signal includes a periodic pulse signal; step S341, determining the target signal data in the signal detection data, and determining the target position corresponding to the target signal data in the reference signal, including: step S3413, determining the high signal data as the target signal data in the signal detection data; step S3414, determining the pulse corresponding to the target signal data in the periodic pulse signal as the 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 top position of the pulse by the magnetic sensor. Therefore, when 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 it can be determined in the periodic pulse signal.

[0116] Furthermore, in order to more accurately determine the target pulse, the period of the periodic pulse signal can be set to be twice higher than the maximum deviation of the time measurement between the field transmitter and the magnetic sensor. Exemplarily, assuming that the estimated maximum deviation of the time measurement between the field transmitter 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 magnetic transmitter is between the 9th and 11th seconds, and this time interval is less than the period of the periodic pulse signal, and thus there is one and only one pulse in this time interval, that is, the pulse generated at the 9th second under the time measurement of the field transmitter, and this pulse is the target pulse.

[0117] Correspondingly, step S342, determining a reference time difference according to the time information of the target position and the time information of the target signal data, includes: step S345, determining a 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] When determining the target signal data and the target pulse, the time difference between the time information of the target pulse and the time information of the target signal data can be calculated. This time difference reflects 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.

[0119] As described above, two technical solutions for data synchronization are introduced respectively through periodic pulse signals and periodic square wave signals. It should be noted that the specific waveform of the reference signal is not limited to the above two signal waveforms. The waveform design requirement for the reference signal is that there are some identifiable signal positions in the waveform, and accordingly, the signal detection data corresponding to these signal positions are also identifiable. Therefore, when identifiable signal detection data appears, the corresponding position of the signal detection data in the reference signal can be reversely determined. It should be understood that any reference signal that meets the above waveform design requirements can implement the data synchronization method of the electromagnetic navigation system provided by the present invention.

[0120] The technical solution in this application is described in detail through some specific embodiments as follows.

[0121] In the data synchronization method of the electromagnetic navigation system provided by the present invention, an electromagnetic coil for synchronization is added to 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 used for positioning.

[0122] In this technical solution, the time-varying working magnetic field used for positioning can be generated by a coil or a rotating magnet with a low frequency, such as less than 100Hz. The reference signal used for time synchronization is a periodic square wave signal with a higher frequency, such as 400Hz, which is about 50% of the sampling rate of the magnetic sensor and is generated by an electromagnetic coil. The frequency difference between the two signals is large (a difference of several hundred Hz), and the two can be separated by a digital filter, and positioning and time synchronization processing can be performed at the same time. The magnetic sensor end only needs to collect magnetic field data in real time, stamp it with a local timestamp, and then send it to the processing unit at a certain frequency (sending frequency ≤ sampling rate). The magnetic sensor end does not distinguish between "positioning mode" or "synchronization mode", that is, there is no need to distinguish between magnetic field detection data and signal detection data, thereby reducing the complexity of the magnetic sensor end and making the entire system workflow logic simpler. Since time synchronization can be carried out continuously, the synchronization performance will not degrade significantly over time.

[0123] Reference Figure 4 , assuming the sampling interval of the magnetic sensor is T s , where the mean is between 1ms and 10ms. At the magnetic sensor end, there is a certain interval △t between the time when the magnetic sensor actually samples the data and the time when the MCU (microcontroller unit) obtains the data and timestamps it. 1 , 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] Where 0 < δT s <T s , that is, it can be guaranteed 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 guarantee that the rising edge of the signal will be captured. Since the period of the square wave signal is not equal to an integer multiple of the sampling interval, and as time accumulates, the relative position of the sampling point on the square wave signal will shift. And because T p >T s , so as the above displacement continues to accumulate, there will be two consecutive high magnetic field signals (at other times, one high and one low appear alternately). At this time, the interval between the sampling moment of the first of the two consecutive high magnetic field signals and the rising edge of the magnetic field is:

[0127] Δt 1 =(t 2 -T r0 )-(t 1 -T x0 )

[0128] Among them, T x0 is the initial time of the field transmitter's working clock, T r0 is the time in the working clock of the magnetic sensor corresponding to the initial time of the field transmitter. That is, T x0 and T r0 It is the time measurement of the working clocks of two devices at the same physical moment (the initial moment of the transmitter). Determining the time difference between the two is one of the purposes of the data synchronization method in the present invention. 1 is the logic time of the actual data sampling moment of the magnetic sensor on the magnetic sensor end, t 2 It is the logical time of the rising edge of the square wave signal on the field transmitter.

[0129] The appearance of two consecutive high magnetic field signals has a certain randomness, △t 1 is a random variable with mean E(Δt)=kδT s , if k<1, the specific parameters can be simulated and counted in advance. So far, the synchronization reference point (a 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. The time synchronization is performed through the time measurement deviation between the two. The synchronization error can be controlled within δT s With the improvement of statistics, the error can be further reduced and controlled, such as <10μs. The specific calculation process is as follows:

[0130] t 3 -t 1

[0131] =(T r0 -T x0 +Δ t2 )+Δ t1

[0132] So as to obtain the time synchronization parameters:

[0133] T r0 -T x0 +Δt 2

[0134] =t 3 -t 1 -Δt 1

[0135] ≈t 3 -t 1 -E(Δt)

[0136] It can be seen from the above formula that the data synchronization method in this embodiment is used to convert △t 2 This is also taken into account, so the above interval is automatically corrected when the local logic moment of the magnetic sensor is calibrated:

[0137] t syn

[0138] =t 3 -(T r0 -T x0 +Δt 2 )

[0139] =(t 3 -Δt 2 )-(T r0 -T x0 )

[0140] =t 2 -(T r0 -T x0 )

[0141] Correction result syn That is, the actual sampling moment in the working clock of the magnetic sensor corresponds to the moment in the working clock of the field transmitter, which facilitates the accurate search and interpolation of the corresponding magnetic field working data of the time-varying working magnetic field.

[0142] Reference Figure 5 Another thing to consider is 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 the relaxation time constant of the electromagnetic coil is τ, it takes Δt from the start of the trigger signal to the time when the signal (current) rises to half its height. lag =τIn(2). At the same time, the program sets the 50% peak value as the binarization threshold. If the square wave signal strength is lower than the 50% peak value, the signal data is set to 0, and if it is higher, it is set to 1. Then the rising edge of the obtained binary square wave signal will be delayed by Δt relative to the rising edge of the actual square wave signal. lag , so the time synchronization parameters need to be modified:

[0143] T r0 -T x0 +Δt 2

[0144] =t 3 -t 1 -(Δt 1 +Δt lag )

[0145] ≈t 3 -t 1 -(E(Δt)+Δt lag )

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

[0147] Finally, it should be noted that the reference signal can also be generated intermittently. Figure 6 Schematic diagram of the waveform of the reference signal in some embodiments of the present invention. Figure 6 As shown, the reference signal lasts for T 1 Time, interval T 2 Time, the specific length can be adjusted.

[0148] In each T 1 The double high magnetic field signal may appear more than once within a certain period of time. In this case, the average of multiple time synchronization parameters can be calculated.

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

[0150] 1. The data synchronization method is suitable for the 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 less than 100 Hz.

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

[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 low-pass and band-pass filters to achieve synchronization and positioning at the same time.

[0153] 4. When processing the synchronization signal, first perform binarization processing on it; then find the location where two consecutive high magnetic field intensity sampling points appear, record the timestamp of the first sampling point and the number of captured high magnetic field waves N; then find the trigger timestamp of the rising edge generated by the field transmitter based on N; finally calculate the difference t 3 -t 1 , then deduct E(Δt) and the delay Δt caused by the electromagnetic coil lag , we can get the time synchronization parameter T r0 -T x0 +Δt 2 .

[0154] The present invention also provides a data synchronization device for an electromagnetic navigation system, which is used to implement the above-mentioned embodiments and preferred implementation modes, and will not be repeated hereafter. The terms "module", "unit", "subunit", etc. used below may be a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0155] Figure 7 is a structural block diagram of the data synchronization device of the electromagnetic navigation system provided by the present invention, such as Figure 7 As shown, the device comprises:

[0156] A first data acquisition module 710 is used 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;

[0157] A second data acquisition module 720 is used 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 the second transmitting unit;

[0158] A third data acquisition module 730 is used to acquire magnetic field working data of the working magnetic field; wherein the magnetic field working data is provided by the field transmitter;

[0159] The data synchronization module 740 is used 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 working data according to the reference time difference.

[0160] Through the above device, the time measurement deviation between the field transmitter 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, thereby eliminating the misalignment of the positioning result and the positioning error of the magnetic sensor, and finally improving the positioning accuracy of the magnetic sensor. The problem that 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 moment in the existing electromagnetic navigation method, which leads to an increase in the positioning error of the magnetic sensor, is solved.

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

[0162] The present invention also provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

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

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

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

[0166] It should be understood that the specific embodiments described herein are only used to explain the application, rather than to limit it. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of this application.

[0167] Obviously, the drawings are only some examples or embodiments of the present application. For ordinary technicians in the field, the present application can also be applied to other similar situations based on these drawings without creative work. In addition, it is understandable that although the work done in this development process may be complicated and lengthy, for ordinary technicians in the field, certain changes in design, manufacturing or production based on the technical content disclosed in this application are only conventional technical means and should not be regarded as insufficient content disclosed in this application.

[0168] The term "embodiment" in this application refers to a specific feature, structure or characteristic described in conjunction with the embodiment that can be included in at least one embodiment of the present application. The appearance of this phrase in various locations in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. It is clearly or implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict.

[0169] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of patent protection. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. An electromagnetic navigation system, characterized in that: The electromagnetic navigation system comprises: a field transmitter (100) and a magnetic sensor (200), wherein 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, and the working magnetic field is used to locate the magnetic sensor (200); The second transmitting unit (120) is used to generate a reference signal, and the reference signal is used to synchronize magnetic field detection data and magnetic field working data of the working magnetic field; 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 the working clock of the field transmitter (100).

2. The electromagnetic navigation system according to claim 1, characterized in that: The second transmitting unit (120) comprises a square wave transmitter or a pulse transmitter.

3. The electromagnetic navigation system according to claim 1, characterized in that: The second transmitting unit (120) includes an electromagnetic coil.

4. The electromagnetic navigation system according to claim 1, characterized in that: The first transmitting unit (110) and the second transmitting unit (120) are configured to work synchronously; The first transmitting unit (110) and the second transmitting unit (120) have different operating frequencies.

5. A data synchronization method for an electromagnetic navigation system, characterized in that: The data synchronization method is applied to the electromagnetic navigation system as described in any one of claims 1-4; The data synchronization method of the electromagnetic navigation system comprises: 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; Acquire signal detection data of a 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; Acquiring magnetic field working data of the working magnetic field; wherein the magnetic field working data is provided by a field transmitter; A reference time difference between the signal detection data and the reference signal is determined, 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, characterized in that: The determining a reference time difference between the signal detection data and the reference signal comprises: Determining target signal data in the signal detection data, and determining a target position corresponding to the target signal data in the reference signal; The reference time difference is determined according to the time information of the target position and the time information of the target signal data.

7. The data synchronization method of the electromagnetic navigation system according to claim 6, characterized in that: 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; The step 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 comprises: In the signal detection data, two identical and adjacent signal data are determined as reference signal data, and one of the reference signal data is determined as the 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 the position of the target signal edge is the target position.

8. The data synchronization method of the electromagnetic navigation system according to claim 7, characterized in that: 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: The reference time difference is determined according to the time difference between the time information of the target signal edge and the time information of the target signal data.

9. The data synchronization method of the electromagnetic navigation system according to claim 7, characterized in that: 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: The reference time difference is determined 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 between the target signal edge and the corresponding sampling points of the target signal data; wherein the physical time interval is obtained by pre-simulation.

10. The data synchronization method of the electromagnetic navigation system according to claim 7, characterized in that: 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 comprises, before determining the reference time difference between the signal detection data and the reference signal: Using a preset threshold to perform binarization processing on the signal detection data; 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: The reference time difference is determined based on 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 based on the working characteristics of the second transmitting unit.

11. The data synchronization method of the electromagnetic navigation system according to claim 6, characterized in that: The reference signal includes a periodic pulse signal; The step 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 comprises: In the signal detection data, high signal data is determined as the target signal data; In the periodic pulse signal, a pulse corresponding to the target signal data is determined as a target pulse; wherein the position of the target pulse is the target position.

12. The data synchronization method of the electromagnetic navigation system according to claim 11, characterized in that: 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: The reference time difference is determined according to the time difference between the time information of the target pulse and the time information of the target signal data.

13. The data synchronization method of the electromagnetic navigation system according to claim 5, characterized in that: 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.

14. A data synchronization device for an electromagnetic navigation system, characterized in that: The data synchronization device is applied to the electromagnetic navigation system as described in any one of claims 1 to 4; The data synchronization device of the electromagnetic navigation system comprises: A first data acquisition module, used 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; A second data acquisition module, used to acquire signal detection data of a reference signal; wherein the signal detection data is obtained by the magnetic sensor detecting the reference signal, and the reference signal is generated by a second transmitting unit; A third data acquisition module, used to acquire magnetic field working data of the working magnetic field; wherein the magnetic field working data is provided by a field transmitter; The data synchronization module is used 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 working data according to the reference time difference.

15. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to run the computer program to execute the data synchronization method for an electromagnetic navigation system according to any one of claims 5 to 13.

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