Systems and methods for navigation

Abstract

The present invention discloses a method for operating a navigation system, the method comprising: generating a signal by a controller; sending the signal to a transmitter system; transmitting the signal through the transmitter system; receiving the transmitted signal at a receiver; sending a receiver signal to the controller based on the received transmitted signal at the receiver; and evaluating the receiver signal to characterize the navigation system.

Description

[0001] Cross-citation of related applications

[0002] This application includes subject matter similar to that disclosed in concurrently filed U.S. Patent Application No. 16 / 855,487 (Attorney's File No. 5074A-000191-US) and U.S. Patent Application No. 16 / 855,521 (Attorney's File No. 5074A-000201-US). The entire disclosure of the above applications is incorporated herein by reference. Technical Field

[0003] This disclosure relates to data communication in navigation systems. Background Technology

[0004] This section provides background information in connection with this disclosure, which is not necessarily prior art.

[0005] Surgical procedures can be performed on objects such as human subjects. Surgical procedures may require incisions within the object to gain access to tissues or organs covered by the object's dermis. Visual access or visual acuity in these areas may be limited due to the presence of opaque tissue. Therefore, the orientation of instruments within the object can be selectively determined. Summary of the Invention

[0006] This section provides a general overview of this disclosure and is not a full disclosure of the complete scope or all features of this disclosure.

[0007] A navigation system can be used to track and determine an attitude, which may include at least some coordinates of the device's position and / or orientation over time. In various embodiments, the device's attitude is understood to include at least some tracked or navigated position coordinates (e.g., x, y, z) and / or orientation coordinates (e.g., roll, pitch, yaw). The navigation system can track position and / or orientation, including six degrees of freedom motion (e.g., three-dimensional position and multiple orientations, such as pitch, roll, and yaw). Therefore, the attitude or position and / or orientation of the tracked device can be determined over time. In various embodiments, a visual representation of the device can be displayed relative to a portion of the object via a display device.

[0008] Therefore, navigation systems can be used to determine position and / or orientation and / or combinations (as posture), including multiple positions and / or orientations and / or postures of the device over time. In various embodiments, the posture of the tracked device can be determined relative to an object. The object can be any suitable object, such as a living or non-living object. In various embodiments, a non-living object may include a hollow or enclosed housing or other suitable inanimate object. The inanimate object may have an opaque outer covering. Therefore, navigation or tracking systems can be used to track the device relative to an inanimate object during use.

[0009] In various implementations, the object may include a living object, such as a human object. The procedure may include a surgical procedure in which instruments are placed within the object to perform the procedure, such as stent placement, depth stimulation probe placement, or placement or implantation of other implantable components, within a selected time period. Furthermore, the selected procedure may include bone resection, foramen formation, etc., relative to the object. In any case, the orientation of the instruments can be determined via a navigation system.

[0010] Navigation systems can operate by transmitting data between various elements or portions of a tracking system. For example, in various embodiments, the navigation system may include a tracking device (e.g., fixed or integrated into the instrument) that wirelessly transmits signals to an array. The array may include an antenna array, as discussed further herein. Similarly or alternatively, the array may wirelessly transmit signals that will be received by the tracking device.

[0011] Spread spectrum, including various techniques discussed herein, can be used to transmit signals, identify distorted signals, and ignore and / or correct distorted signals. Spread spectrum systems (such as frequency hopping) can include modulation and demodulation of selected signals, as well as selected signal transformations for identifying or eliminating distorted or misaligned signals within the system. Therefore, navigation systems can incorporate spread spectrum systems to identify or determine signals for tracking devices.

[0012] Further areas of applicability will become apparent from the description provided herein. The descriptions and specific examples in this overview are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0013] The accompanying drawings described herein are for illustrative purposes only, representing selected embodiments and not all possible specific implementations, and are not intended to limit the scope of this disclosure.

[0014] Figure 1 It is a diagrammatic view showing an overview of navigation systems according to various implementation schemes;

[0015] Figure 2 It is a flowchart of the registration method according to various implementation schemes;

[0016] Figure 3 These are schematic diagrams of locators and trackers according to various implementation schemes;

[0017] Figure 4A It is a flowchart of equalization in a spread spectrum navigation system based on various implementation schemes;

[0018] Figure 4B yes Figure 4A A schematic diagram of the navigation system calibration and equalization method;

[0019] Figure 5A It is a flowchart of equalization in a spread spectrum navigation system based on various implementation schemes;

[0020] Figure 5B yes Figure 5A A schematic diagram of the navigation system calibration and equalization method;

[0021] Figure 6A It is a flowchart of equalization in a spread spectrum navigation system based on various implementation schemes;

[0022] Figure 6B yes Figure 6A A schematic diagram of the navigation system calibration and equalization method;

[0023] Figure 7 It is a graph showing the magnitude response of the received navigation signal to the unbalanced data under various implementation schemes;

[0024] Figure 8 It is a graph showing the magnitude response of the received navigation signal with and without distortion, according to various implementation schemes;

[0025] Figure 9 This is a flowchart of a code multiplexing spread spectrum navigation system with distortion detection and correction according to various implementation schemes; and

[0026] Figure 10 It is a graph showing the quantitative response of the received navigation signal to the balanced state of the object, based on the existence of various implementation schemes and distortions.

[0027] In several views of all the accompanying drawings, the corresponding reference numerals indicate the corresponding parts. Detailed Implementation

[0028] Exemplary embodiments will now be described more fully with reference to the accompanying drawings.

[0029] This document discloses exemplary embodiments, as further discussed herein. Generally, various embodiments may be disclosed relative to human objects. However, it should be understood that various disclosed systems (such as navigation or tracking systems) may be used relative to any object or system that may have a housing or enclosure that can cover internal components or operations. For example, a fuselage or vehicle frame may conceal internal components that may be selected to operate in a chosen procedure. A chosen procedure may include the removal, replacement, etc., of various components of any non-living or inanimate system. Therefore, it should be understood that the discussion herein relative to objects (such as human objects) is merely exemplary.

[0030] Furthermore, as discussed herein, navigation systems may include tracking various components (such as instruments) relative to a coordinate system or a reference frame in space. In various embodiments, the coordinate space may include an object coordinate space or a real space defined by a real space relative to the object. An additional coordinate space may include an image space having an image coordinate space defining an image of the object. As discussed above, the pose of an instrument, which may include the position and orientation of the instrument, may be shown relative to an image (e.g., superimposed on an image) having a graphical representation for user viewing. Such illustrations may require or use registration between the object space or object coordinate space and the image coordinate space or image space.

[0031] Methods for registering an object space defined by an object to an image space may include those disclosed in U.S. Patent Nos. 8,737,708, 9,737,235, 8,503,745, and 8,175,681; all of which are incorporated herein by reference.

[0032] According to various implementation plans Figure 1 This is a schematic view showing an overview of the operating room or surgical environment. In various embodiments, the operating room may include a surgical kit. The surgical kit may include a navigation system 26, which can be used for various procedures, such as procedures relative to object 30.

[0033] Navigation system 26 can be used to track the posture of one or more tracking devices, which may include object tracking devices or dynamic reference frames (DRF) 58, imaging system tracking devices 62, and / or tool tracking devices 66. It should be understood that other tracking devices may also be included, such as user or clinician tracking devices, either alone or in combination with other systems (e.g., augmented reality systems). Tool 68 can be any suitable tool, such as a drill, forceps, or other tool operated by user 72. Tool 68 may also include implants, such as spinal implants or orthopedic implants. It should be further noted that navigation system 26 can be used to navigate any type of instrument, implant, or delivery system, including: guidewires, arthroscopic systems, orthopedic implants, spinal implants, deep brain stimulation (DBS) probes, etc. Furthermore, these instruments can be used to navigate or map any area of ​​the body. Navigation system 26 and various instruments can be used in any appropriate surgical procedure, such as instruments typically used in minimally invasive or open surgery.

[0034] Imaging device 80 can be used to acquire preoperative, intraoperative, or postoperative or real-time image data of an object, such as object 30. However, it should be understood that any suitable object can be imaged, and any suitable surgery can be performed relative to the object. In the example shown, imaging system 80 includes a device sold by Medtronic Navigation, Inc., which has a business location in Louisville, Colorado, USA. Imaging apparatus. Imaging apparatus 80 may have a generally annular frame housing 82 in which an image capture section is movably disposed. The image capture section may include an x-ray source or emitting section, and x-ray receiving sections or image receiving sections are positioned substantially or practically as far as possible 180 degrees apart from each other and mounted on a rotor relative to a track or guide rail. The image capture section may be used to rotate 360 ​​degrees during image acquisition. The image capture section may rotate about a center point or axis, thereby allowing image data of object 30 to be acquired from multiple directions or in multiple planes. Imaging apparatus 80 may include those disclosed in U.S. Patent Nos. 7,188,998; 7,108,421; 7,106,825; 7,001,045; and 6,940,941; all of which are incorporated herein by reference, or in any appropriate portion thereof. In one example, imaging apparatus 80 may utilize flat panel technology with a viewing area of ​​1,720 × 1,024 pixels.

[0035] The position of the imaging device 80 and / or its parts, such as the image capture portion, can be precisely known relative to any other part of the imaging device 80. According to various embodiments, the imaging device 80 can know and recall precise coordinates relative to a fixed or selected coordinate system. This allows the imaging system 80 to know its position relative to the patient 30 or other references. Furthermore, as discussed herein, precise knowledge of the position of the image capture portion can be used in conjunction with a tracking system to determine the position of the image capture portion and image data relative to the tracked object, such as the patient 30.

[0036] Imaging device 80 can also be tracked using image tracking device 62. According to various embodiments, image data defining the acquired image space of patient 30 can be inherently or automatically registered relative to a target space. The target space can be the space defined by patient 30 in navigation system 26. Automatic registration can be achieved by including a determinable, precise pose on imaging device 80 including tracking device 62 and / or image capture portion. According to various embodiments, as discussed herein, imageable portions, virtual reference points, and other features can also be used to allow automatic or otherwise registration. However, it will be understood that image data of any object that will define an object space can be acquired. Patient space is an exemplary object space. Registration allows mapping between patient space and image space.

[0037] Patient 30 can also be tracked using a patient tracking device, DRF, or tracker 58 as the patient moves. Alternatively or otherwise, patient 30 can be fixed within a navigation space defined by navigation system 26 to allow registration. As further discussed herein, registration of image space with patient space or object space allows navigation of device 68 using image data. When navigating device 68, the posture of device 68 can be shown on display device 84 relative to acquired image data of patient 30. Various tracking systems, including at least one of optical locator 88 or electromagnetic (EM) locator 94, can be used to track device 68. As discussed herein, in various embodiments, locator 94 can transmit signals received by tracking device 66 or other suitable tracking devices. Additionally, a suitable antenna (e.g., a coil) can also be configured to receive. For example, calibration receiver 95 (e.g., a coil) can be configured to receive signals from locator 94. Calibration receiver 95 can be included in any suitable part of navigation system 26 (such as controller 110), as further discussed herein. Those skilled in the art will understand that the calibration receiver 95 does not need to be incorporated into the navigation system 26 during use, but may be set up or used during the initial (e.g., factory) production or calibration of the navigation system 26. In various embodiments, the calibration receiver 95 may receive signals from the locator 94 in a manner similar to that of the tracking device 66 and be used for various purposes as discussed herein.

[0038] More than one tracking system may be used to track the device 68 in the navigation system 26. According to various embodiments, the tracking system may include an EM system with an electromagnetic tracking (EM) locator 94 and / or an optical tracking system with an optical locator 88. As discussed herein, one or both tracking systems may be used to track the selected tracking device. It should be understood that, unless otherwise discussed, the tracking device may be a trackable portion of the selected tracking system. The tracking device does not necessarily refer to the entire component or structure to which the tracking device is attached or associated.

[0039] It should also be understood that the imaging device 80 can be different from... The imaging apparatus may additionally or alternatively include a C-arm fluoroscope. Other exemplary imaging apparatus may include fluoroscopes such as dual-plane fluoroscope systems, ceiling-mounted fluoroscope systems, catheterization lab fluoroscope systems, fixed C-arm fluoroscope systems, isocentric C-arm fluoroscope systems, 3D fluoroscope systems, etc. Other suitable imaging apparatus may also include MRI, CT, ultrasound, etc.

[0040] In various embodiments, the imaging device controller 96 can control the imaging device 80, receive image data generated in the image capture section, and store the images for later use. The controller 96 can also control the rotation of the image capture section of the imaging device 80. It should be understood that the controller 96 does not need to be integrated with the rack housing 82, but can be detached from it. For example, the controller can be part of a navigation system 26, which may include a processing system and / or a control system 98, including a processing unit or processing section 102. However, the controller 96 can be integrated with the rack 82 and may include, for example, a second processor from a laptop computer and a separate processor.

[0041] Patient 30 can be positioned (including secured) on operating table 104. According to one example, operating table 104 can be an Axis system sold by OSI, a subsidiary of Mizuho Ikakogyo Corporation with a business location in Tokyo, Japan, or Orthopedic Systems, Inc. with a business location in California, USA. Operating table. Patient positioning equipment can be used with the operating table and includes... The clamps are those described in U.S. Patent Application Publication No. 2004 / 0199072 (U.S. Patent Application No. 10 / 405,068), entitled “An Integrated Electromagnetic Navigation and Patient Positioning Device,” published on October 7, 2004, which is incorporated herein by reference.

[0042] Therefore, the position of the patient 30 relative to the imaging system 80 can be determined by the navigation system 26. The tracking device 62 can be used to track at least a portion of the imaging device 80 (e.g., the rack or housing 82) and determine its orientation. As discussed further herein, the patient 30 can be tracked using a dynamic reference frame 58. Therefore, the position of the patient 30 relative to the imaging system 80 can be determined. Furthermore, the orientation of the imaging portion relative to the housing 82 can be determined due to the precise position of the imaging portion on the guide rails within the housing 82, the substantially inflexible rotor, etc. If the imaging device 80 is sold by Medtronic Navigation, Inc., which has a business location in Louisville, Colorado... Imaging apparatus, wherein imaging apparatus 80 may include, for example, an accuracy within 10 micrometers. Precise positioning of the imaging portion is further described in U.S. Patent Nos. 7,188,998; 7,108,421; 7,106,825; 7,001,045; and 6,940,941; all of which are incorporated herein by reference.

[0043] According to various embodiments, imaging device 80 can generate and / or emit x-rays from an x-ray source, which propagate through patient 30 and are received by an x-ray imaging receiving section. An image capture section generates image data representing the intensity of the received x-rays. Typically, the image capture section may include an image intensifier that first converts the x-rays into visible light and a camera (e.g., a charge-coupled device) that converts the visible light into digital image data. The image capture section may also be a digital device that directly converts X-rays into digital image data to form an image, potentially avoiding distortion caused by first converting to visible light.

[0044] Two-dimensional and / or three-dimensional fluorescence microscopy image data that can be captured by imaging device 80 can be captured and stored in imaging device controller 96. Multiple image data acquired by imaging device 80 can also be captured and combined to provide a larger view or image of the entire area of ​​patient 30, rather than focusing on only a portion of patient 30. For example, multiple image data of the spine of patient 30 can be appended together to provide a complete view of the spine or a complete set of image data.

[0045] Image data can then be forwarded from the image device controller 96 to a navigation computer and / or processor system 102, which may be part of a controller or workstation 98 having a display 84 and a user interface 106. It is also understood that the image data does not necessarily need to be stored in the controller 96 first, but may be directly transmitted to the workstation 98. The workstation 98 may provide facilities for displaying the image data as image 108 on the display 84 and for saving, digitally processing, or printing a hard copy of the received image data. The user interface 106, which may be a keyboard, mouse, stylus, touchscreen, or other suitable device, allows the user 72 to provide input to control the imaging device 80 or adjust the image settings of the display 84 via the image device controller 96. The workstation 98 may also instruct the image device controller 96 to adjust the image capture portion of the imaging device 80 to obtain various two-dimensional images along different planes, thereby generating representative two-dimensional and three-dimensional image data.

[0046] Continue to refer to Figure 1 The navigation system 26 may also include a tracking system comprising one or both of an electromagnetic (EM) locator 94 and / or an optical locator 88. The tracking system may include a controller and interface portion 110. The controller 110 may be connected to a processor portion 102, which may include a processor contained within a computer. The EM tracking system may include those sold by Medtronic Navigation, Inc., which has a business location in Louisville, Colorado. AXIEM TMThe navigation system may be, or may be, the EM tracking system described in the following patents: U.S. Patent Application Serial No. 10 / 941,782, filed September 15, 2004, entitled “METHOD AND APPARATUS FORSURGICAL NAVIGATION”; U.S. Patent No. 5,913,820, published June 22, 1999, entitled “Position Location System”; and U.S. Patent No. 5,592,939, published January 14, 1997, entitled “Method and System for Navigating a Catheter Probe”; each of these patents is incorporated herein by reference. It should be understood that the navigation system 26 may also be or include any suitable tracking system, including those with optical locators. or S7 TM The tracking system, which can be used as an optical locator 88, is sold by Medtronic Navigation, Inc., located in Louisville, Colorado. Other tracking systems include acoustic systems, radiation systems, radar systems, etc. The tracking system can be used according to techniques generally known or described in the references combined above. Details are not included herein unless the selected operation of the subject matter is clarified.

[0047] Wired or physical connectors can interconnect the tracking system, imaging device 80, etc. Alternatively, unlike direct coupling to controller 110, various components such as instrument 68 can utilize wireless communication channels, such as those disclosed in U.S. Patent No. 6,474,341, entitled "Surgical Communication Power System," issued November 5, 2002, which is incorporated herein by reference. Furthermore, tracking devices 62, 66 can generate fields and / or signals sensed by locators 88, 94. In various embodiments, instrument tracking device 66 and / or other suitable tracking devices can communicate with controller 110 and / or array 94 via wireless signal 113 as discussed herein. In various embodiments, array 94 can operate via a spread spectrum signal to communicate with tracking device 66.

[0048] Various parts of the navigation system 26, such as the device 68, and other parts described in detail below, may be equipped with at least one and typically multiple tracking devices 66. The device may also include more than one type or form of tracking device 66, such as EM tracking devices and / or optical tracking devices. The device 68 may include a grippable or manipulable portion at its proximal end, and the tracking device may be fixed near the manipulable portion of the device 68. However, it should be understood that the tracking device may also be placed at the distal or interventional end of the device 68.

[0049] Another representative or alternative positioning and tracking system is described in U.S. Patent No. 5,983,126, entitled "Catheter Location System and Method," issued November 9, 1999, which is incorporated herein by reference. Navigation system 26 may be a hybrid system including components from various tracking systems.

[0050] According to various embodiments, navigation system 26 can be used to track device 68 relative to patient 30. Device 68 can be tracked by a tracking system, as discussed herein, such as by tracking and determining the posture of tracking device 66. Image data of patient 30 or a suitable object can be used to assist user 72 in guiding device 68. However, the image data is registered to patient 30. The image data defines an image space that is registered to a patient space defined by patient 30. Registration can be performed automatically, manually, or in combination thereof, as discussed herein.

[0051] Typically, registration allows for the generation of a mapping (also known as a registration mapping) of the physical pose of the device 68 relative to the image space of the image data. This mapping allows the tracked pose of the device 68 to be displayed on the display device 84 relative to the image data 108. It should be understood that the display device 84 can be any suitable display device, or may include more than one display device, such as an augmented reality viewer, a head-mounted display, etc. A graphical representation 68i (also known as an icon) can be used to illustrate the pose of the device 68 relative to the image 108 (e.g., three-dimensional coordinate position and one or more degrees of freedom orientation).

[0052] Continue to refer to Figure 1 And refer to other sources Figure 2 An object registration system or method may use an object tracking device 58. The tracking device 58 may include a trackable portion or component 120, but may also serve as or be operable as a reference point assembly. The reference point assembly 120 may include a clamp or other fixing portion 124 and an imageable reference point body 120. However, it should be understood that the component 120 may be separate from the tracking device 58. The fixing portion 124 may be provided to fix any suitable portion, such as a part of an anatomical structure. Figure 1 As shown, the reference point assembly 120 can be interconnected with a portion of the spine (such as the spinous process of object 30).

[0053] The fixing portion 124 can be interconnected with the spinous process in any suitable manner. For example, a pin or screw can be driven into the spinous process. Alternatively or otherwise, a clamping portion 124 can be provided to interconnect the spinous processes. The reference point portion 120 can be imaged using the imaging device 80. However, it should be understood that individual parts of the object (e.g., the spinous process) can also be used as reference point portions.

[0054] In various embodiments, when the reference point portion 120 is imaged with the imaging device 80, image data including or identifying the reference point portion 120 is generated. The reference point portion 120 can be identified automatically (e.g., by a processor executing a program), manually (e.g., by selecting an identifier of user 72), or a combination thereof (e.g., by selecting an identifier of user 72 as a seed point and a segmentation performed by the processor executing the program) in the image data. Methods for automatic imageable portion identification include those disclosed in U.S. Patent No. 8,150,494, published April 3, 2012, which is incorporated herein by reference. Manual identification may include selecting elements (e.g., pixels) or regions in the image data where the imageable portion has been imaged. In any case, the reference point portion 120 identified in the image data can be used as a reference point or reference point location that can be used to register the image data or the image space of the image data with the patient space.

[0055] In various embodiments, in order to register an image space or coordinate system to another space or coordinate system, such as a navigation space, the reference point portion 120 identified in image 108 can then be identified in an appropriate manner within the object space defined by object 30. For example, if the reference point portion is attached to object 30 at the same location during image data acquisition to generate image 108, user 72 can move instrument 68 relative to object 30 to contact reference point portion 120. It should be understood that, as discussed above in various embodiments, reference point portion 120 may be attached to object 30 and / or may include anatomical portions of object 30. Additionally, tracking devices may be incorporated into reference point portion 120, and they may remain with object 30 after image acquisition. In this case, registration or identification of reference point portion 120 can be performed in object space. However, according to various embodiments, user 72 can move instrument 68 to contact reference point portion 120.

[0056] According to various embodiments, the tracking system can track the posture of the instrument 68 by means of the tracking device 66 attached to the instrument 68. This allows the user 72 to identify the posture (including, for example, six degrees of freedom information, including position and orientation) of the reference point portion 120 identified in image 108 in a navigation space (which may include or may be part of the object space). After identifying the position of the reference point portion 120 in the navigation space, mapping can be performed between the subject space defined by object 30 and the image space defined by image 108 in the navigation space. Thus, as discussed further herein, identical or known locations allow for registration.

[0057] During registration, a mapping is established between the image data coordinate system of image data, such as image 108, and the patient space defined by patient 30. Once registration occurs, device 68 can be tracked using a tracking system registered to the image data, allowing the posture of the tracked device 68 to be identified and illustrated as an icon superimposed on the image data. Registration of image 108 (or any selected image data) to object 30 can occur at any appropriate time.

[0058] In various implementations, image space 108 and object space defined by object 30 can be registered according to method 150. As discussed above, image-to-patient registration may include acquiring and / or accessing image data (e.g., from a memory system on which image data is stored) of an object (such as object 30) having a reference point in box 152. The image data of object 30 may be any suitable image data, such as image data acquired using imaging system 80. Furthermore, as described above, the reference point may include a reference point portion 120 and / or a suitable anatomical portion of object 30. For example, the reference point portion may include a portion of an anatomical structure, such as a spinous process of object 30. However, the acquired image data may include a reference point. Once the image data of the object having the reference point has been acquired, the identification of the reference point in the image space can occur in box 154.

[0059] As discussed above, the identification of reference points in the image space within box 154 can occur. For example, reference points can be automatically identified in image data defining the image space, such as through automatic segmentation of reference point portions within the image. Manual identification and / or a combination of manual and automatic identification can also be used to determine reference points in the image space. This combination may include user 72 identifying one or more pixels as seed pixels and processor performing a segmentation procedure based on the seed pixels.

[0060] The identification of reference points in the object space and / or navigation space occurs in box 156. The object space may extend together with and / or overlap with the navigation space. Typically, the navigation space is a volume that can be tracked by a tracking system such as locator 94 and may contain all or part of the object or patient 30. The identification of reference points in the navigation space can occur in various ways, such as relative to reference point portion 120 (which may also be a tracking device) and / or spinous process movement of a trackable instrument such as instrument 68. The tracking system of navigation system 26 can track instrument 68, and navigation system 26 may include an input for inputting a portion of reference point portion 120 in the navigation space. The determination or identification of the pose of the reference points in the navigation space (e.g., including selected degrees of freedom information including three-dimensional position and orientation) can then be used to form a mapping between two or more coordinate systems in box 160.

[0061] The mapping determined in box 160 can be the correlation or registration of the image space coordinate system with respect to the object and / or the coordinate system of the navigation space. The mapping allows a determined pose of the tracking portion in the navigation space to be mapped to an equivalent or identical pose in the image. Once the mapped pose is determined, the pose can be illustrated or displayed relative to the image 108, such as by overlaying the icon 68i onto the image 108 or by overlaying the icon relative to the image.

[0062] Image-to-patient registration allows the device or article to be illustrated relative to image 108. However, without registration, any element that is not traceable or registered to image 108 may not be properly or accurately illustrated in its real-world pose relative to image 108. Therefore, registration allows, for example, the determined pose of device 68 relative to object 30 to be shown via icon 68i.

[0063] After registering the image space to the patient space, it can be tracked relative to the image 108 by the device 68. For example... Figure 1 As shown, an icon 68i representing the posture of the instrument 68 (which may include a 6-DOF posture (including 3-dimensional position and 3-DOF orientation)) can be displayed on the display 84 relative to the image 108. Due to the image space-to-patient space registration, the posture of the icon 68i relative to the image 108 can substantially identify or simulate the posture of the instrument 68 relative to the patient 30 in the patient space. As described above, this allows the navigation process to occur.

[0064] For further reference Figure 2 and Figure 3 And continue to refer to Figure 1 The positioner 94 (which may also be referred to as an array or antenna array) can be set in any physical configuration for a selected or appropriate procedure. For example, as Figure 1As shown, the positioner 94 is configured or formed to include a selected geometry, such as a petal shape. In various embodiments, such as Figure 3 As shown, the locator 94 may be planar or more elongated. The locator 94 may include multiple coils (such as any suitable number) to generate a navigation field or domain. The navigation field or domain may include volume 180. The navigation volume 180 is typically sized or moved or positioned relative to object 30 to allow navigation of one or more instruments (such as instrument 68) relative to object 30. Instrument 68 may include one or more tracking devices (such as tool tracking device 66). As discussed further herein, array 94 may transmit signals that can be received by tracking device 66 or other suitable tracking devices (such as object tracker 58 and / or imaging device tracker 62).

[0065] In various embodiments, array 94 may be incorporated into bed or support 104. Alternatively or otherwise, array 94 may be configured in a shape or size such that array 94 can be placed below object 30 and object 30 is positioned on top of at least a portion of array 94. In various embodiments, for example, array 94 may be placed (e.g., fixed) near the lumbar vertebrae and / or head of object 30 to allow navigation field 180 to be centered and / or cover selected areas of object 30 for navigation.

[0066] Navigation system 26 can operate in selected environments, such as in an operating room that includes various other components besides instrument 68. For example, navigation system 26 can operate in an operating room that includes imaging system 80, operating table 104, and / or other components. Furthermore, multiple instruments can be configured for selected procedures, such as instrument 68 and additional or alternative instruments (such as drill motor 69, which may be placed in storage or holding area 71). Holding area 71 may include conductive and / or magnetic materials, such as a metal tray or a conductive polymer tray. Tray 71 may be formed of various or selected metals or metal alloys (such as aluminum or stainless steel). In various embodiments, signals emitted by array 94 may be interfered with or distorted due to interactions from various metallic materials (such as tray 71, drill 69, imaging system 80, or other metallic components in the operating room where navigation system 26 is housed). Objects or items that can distort fields or signals may be referred to as distorting objects.

[0067] As further discussed herein, array 94 is operable to emit a signal or field. The field emitted by locator 94 can be sensed by one or more of the tracking devices, such as instrument tracking device 66. Therefore, the field emitted by array 94 may be distorted due to a metallic object in or near navigation volume 180. Thus, the signal received by tracking device 66 or other tracking devices in navigation system 26 may include both the emitted signal and the distortion. Distortion may be generated by eddy currents in conductive articles or magnetization in magnetic articles, which may be referred to herein as “distorting articles.” The signal received by tracking device 66 may be transmitted to a suitable processing system, such as one or more processors in controller 110 and / or processing unit 102. If an object is near navigation volume 180 causing distortion, the received signal may include distortion. Therefore, distortion detection and correction (DDC) module 190 (which may include equalization) may be combined or performed by processing unit 102. As further discussed herein, DDC module 190 may be used to assist in removing distortion from the signal received by tracking device 66. Once distortion is removed in the DDC module 190, the navigation module 198 can also be incorporated into and / or executed by the processing unit 102. The navigation module 198 navigates using calibrated signals to determine the orientation of the tracking device 66 within the navigation volume 180. Therefore, the tracking signal can be emitted by the locator and received by the tracking device 66. The received tracking signal may include distortion. As discussed above, navigation of the instrument 68 included in the tracking device 66 allows a graphical representation 68i of the instrument 68 to be shown relative to the image 108 of the object 30.

[0068] Therefore, due to navigation registration, user 72 can view the posture of instrument 68 relative to object 30 via monitor 84. Those skilled in the art will understand that tracking device 66 can also transmit signals received by locator 94. The transmitted signals can be received by locator 94, and similar equalizers and navigation modules can be used to determine the posture of tracking device 66 relative to object 30 in a similar manner, but where the signals are received by locator 94 rather than transmitted by locator 94. Furthermore, those skilled in the art will understand that when multiple instruments are tracked substantially simultaneously relative to object 30 in navigation volume 180, multiple instruments can be navigated substantially simultaneously to allow multiple instruments to be displayed simultaneously relative to image 108.

[0069] Regardless of its configuration or external geometry, the locator 94 may include one or more coils 200. The locator may include an appropriate number of coils 200, such as sufficient to transmit signals to be resolved at the tracking device 66 for navigation of the tracking device 66. Therefore, the locator 94 may include one or more coils 200, including nine or more coils, 12 or more coils 200, or up to 36 coils, or an appropriate number of coils 200. The coils 200 may be arranged in any appropriate number, and the numbers discussed herein are merely exemplary. For example, the locator 94 may include three coils that are substantially orthogonally oriented and placed relative to each other around a single center or origin. Alternatively or otherwise, one or more coils may be placed and oriented relative to each other at a selected angle within the locator 94. Regardless of the configuration, the one or more coils generate a navigation field via electromagnetic (EM) signals, which can be sensed by the corresponding tracking device (including the tracking device 66) to allow determination of the orientation of the tracking device 66 in space.

[0070] Continue to refer to Figure 1 And attached references Figure 3 Positioner 94 can be configured in any suitable manner, including those discussed herein. Figure 3 The example shown is a rectangular locator assembly. The locator assembly 94 may include one or more coils 200 (such as a first coil 200a). Coil 200a may be included in the locator 94 along with one or more other coils (such as a second coil 200b). It should be understood that any suitable number of coils may be provided, and the two coils 200a, 200b are merely exemplary. Additionally, the locator 94 may be controlled by a controller 110 and / or have an onboard controller (such as a controller or control module 110'). Furthermore, in various embodiments, a local power source or power converter may be located at the locator 94. For example, a power converter or battery may be configured to provide power to the controller 110' and / or coil 200 to transmit a tracking signal. In various embodiments, as an alternative to and / or supplement to the local power source, an external power source may supply power to the controllers 110, 110' and / or coil 200 from a location remote from the locator 94.

[0071] Regardless of the number or configuration, the respective coils (including coil 200) can be driven to transmit signals that can be received by the tracking device 66. In various embodiments, for example, the respective coils 200a, 200b can be placed or incorporated into an "H" bridge configuration or switching system. Referring to coil 200a, and understanding that the second coil 200b can be incorporated into a similar configuration, coil 200a can be interconnected between the drive source and ground via multiple switches. In various embodiments, for example, coil 200a can be integrated into an "H" bridge assembly 220. The "H" bridge assembly 220 may include multiple switches, including a first switch 222, a second switch 224, a third switch 226, and a fourth switch 228. Switches 222-228 may selectively allow current from a source or voltage source 230 to be driven through coil 200a to ground or outlet 234.

[0072] For example, the first switch 222 and the second switch 224 can be closed to allow voltage to be formed across coil 220a and to allow current to flow through coil 200a in a first direction. Similarly, the third switch 226 and the fourth switch 228 can be closed (where the corresponding first switch 222 and the second switch 224 are open) to allow current to be driven through coil 200a in a second direction. As discussed above, the controller 110 can be used to control selected switches to allow current to flow through coil 200a. The current flowing through coil 200a causes a signal to be emitted by coil 200a and received by tracking device 66.

[0073] Similarly, “H” bridge 220b can be connected to coil 200b and operate in a similar manner. Controller 110 and / or controller 110' can operate either of the “H” bridge assemblies 220a, 220b to supply power or transmit signals through the respective coils 200a, 200b. It should be understood that the “H” bridge assemblies can be positioned relative to the respective coils in any suitable manner, such as by manual or physical switches, transistor switches, or any suitable switches. Furthermore, as discussed above, any suitable number of coils can be supplied to positioner 94 to generate a navigation field, which is selected to generate or provide navigation volume 180. Figure 3 The diagrams or illustrations are for illustrative purposes only and are used in the current discussion.

[0074] A coil (such as coil 200a) may be powered via an "H" bridge assembly 220a to provide signals for navigation of the instrument 68. The "H" bridge assembly 220a may be disposed in the positioner 94 to allow coil 200a to be driven while maintaining selected energy or field emission and heat generation of both coil 200a and the positioner 94. Therefore, the positioner 94 may include an appropriate number of coils, such as between 1 and 36 coils, including three to 15 coils, while still maintaining selected field emission and heat generation. As discussed herein, multiple coils may be driven in an appropriate manner via controllers 110, 110' to generate navigation domain 180.

[0075] The tracking system may include a positioner 94, as discussed above. Positioner 94 may be controlled by controller 110. Positioner 94 may transmit a field or emit a field 113 that can be sensed by the tracking device 66 of instrument 68. It should be understood that other suitable tracking devices or receiving devices (e.g., calibration receiver 95) may also sense the field 113 of positioner 94. Field 113 may be generated in a suitable manner, such as including or having a spread spectrum. Additionally or alternatively, field 113 may also have modulation that can be sensed by tracking device 66. As further discussed herein, field 113 may help reduce or eliminate distortion or interference in the field sensed by tracking device 66, which is due to interference (also referred to as distorting or distortion) of the object.

[0076] As discussed above, depending on the appropriate launch system, the locator 94 may be controlled by controllers 110, 110' (the discussion of controller 110 herein is intended to cover all appropriate controllers, including those discussed above, and reference to controller 110 only is for the convenience of the present discussion). As discussed above, coils such as coil 200a (the discussion of a single coil 200a herein is also exemplary and for the convenience of the present discussion) may be powered or connected via “H” bridge configuration 220a. “H” bridge configuration 220 may be configured in any suitable manner, including by switches (e.g., physical or manual) and / or transistors operable by controller 110. In any case, the coil or coils of the locator 94 may be operated to launch via a binary launch system or scheme (including a binary proximity orthogonal (BNO) launch system or scheme). The coil or coils of the locator 94 may be operated to launch signals as a set of binary proximity orthogonal (BNO) sequences for efficient recovery of the launch signals in the navigation field, as well as the impulse response of the system and the impulse response of the distortion device (also known as the distortion item).

[0077] In the BNO scheme, a pseudo-random binary (PRB) sequence (also known as a pseudo-noise binary (PRB) sequence, one type of which is a maximum length (ML) sequence) can be generated by controller 110 for transmission by positioner 94 as tracking signal 113. The transmission of tracking signal 113 can also be a spread spectrum transmission, such that it spreads across a large or wide spectrum, or over a large or wide spectrum, which can also be segmented by time.

[0078] The PN sequences can be arranged in a substantially or nearly orthogonal manner to provide appropriate transmissions for reception by tracking device 66 or other suitable tracking devices. Tracking signal 113 can be used for navigation of tracking device 66. Furthermore, the discussion of a single tracking device 66 or any suitable or individual portion of the navigation system 26 herein is merely exemplary and intended to simplify the present discussion unless otherwise specifically indicated.

[0079] Therefore, in various implementations, the same repeating PN sequence is emitted via cyclic shifts or offsets, one on each emitter coil. Statistically, the autocorrelation function of the PN sequence is equal to 1 at offset zero and equal to 1 at all other offsets. The sequence length is equal to 2. n -1 and the number of sequence generator bits is equal to n, where n = 14 is available in various implementations. From any different offsets of the sequence, the cyclic shifts or offsets of the PN sequence can be understood as nearly orthogonal to each other in the sense that any sufficiently large value of "n" is poorly correlated. A system that demodulates all the cyclic shift amplitudes in a repeating PN frame can recover the associated coil signal amplitude by multiplying by the inverse of the PN leakage matrix, which has 1 on the diagonal and 1 elsewhere. Furthermore, when the PN offset of the transmitting coil has an interval greater than the duration of the distortion response (i.e., the time for receiving distortion from the distortion object), the method can recover the distortion impulse response for each generator coil. In various embodiments, the offset can be 10 sequence generator bits. The method of selection can be used to perform the calculations discussed above, including the Walsh-Hadamard transform via the Fast Walsh Transform described in Jens Hee's "Impulse response measurements using MLS" http: / / www.jenshee.dk / signalprocessing / mls.pdf (2003). The method can be used to directly perform demodulation (multiplication of the PN sequences under all offsets) and leakage reversal.

[0080] As discussed above, controller 110 may power coil 200a to transmit signals that can be received by tracking device 66. It should be understood that, as discussed above, tracking device 66 may also transmit signals in a similar manner as discussed herein, which are received by one or more coils of locator 94. Tracking device 66 may also include multiple coils, such as coils oriented substantially orthogonally to each other and / or separated from each other around a center point. In various examples, tracking device 66 may include multiple coils, such as three coils 66a, 66b, and 66c. However, tracking device 66 or any suitable receiving coil device (e.g., calibration receiver 95) may include a selected number of coils, such as one coil, more than one coil, at least three coils, or more than three coils, such as six coils. The number of receiving coils may be adapted to the navigation tracking device 66. Each of the coils may be formed of a selected conductive material to induce a current therein through a signal from the locator. In various embodiments, the coil may include wire wound around a center and / or trace formed on a printed circuit board (PCB). However, as discussed herein, the tracking device 66 may receive signals from the locator 94, but those skilled in the art will understand that the locator may receive signals from the tracking device and vice versa.

[0081] In various implementations, as discussed above, controller 100 may cause or signal one or more coils (such as coil 200a) of positioner 94 to transmit a signal, also referred to as a tracking signal, as discussed herein. Coil 200 may be formed of a coil of selected conductive material, such as a metal or metal alloy wire. The impulse response is calculated based on a set of continuously transmitted BNO signals received from the transmitting coil. The tracking signal is a set of BNO signals comprising the same binary PN signal delayed by a different amount for each coil of the positioner. The inter-coil offset may include a selected time delay interval, which is longer than the length of the metal distortion impulse response. The signal delay or interval may include a selected duration (such as about 1 to 20 milliseconds, including 5 to 10 milliseconds) having an equivalent or greater interval between signals from each coil.

[0082] The transmitted tracking signal can be in any suitable frequency range, such as from about 5 Hz to about 30 MHz, including about 10 Hz to about 3 MHz, and also including about 10 Hz to about 400 kHz. The signal can be transmitted across a frequency range in a spread spectrum manner, either at a selected frequency or within a selected range. For example, a spread spectrum signal can be transmitted across a spectrum from about 1 Hz to 30 MHz, including from about 10 Hz to about 400 kHz at a sample rate equal to or about 375 kHz. In various embodiments, control of the signal is the sample rate and waveform, which may include a binary drive waveform. From direct current (DC) to the sample rate, the spectrum can be flat. Therefore, in various embodiments, the spectrum is flat in the navigation device, as discussed above. A controller configured via an H-bridge can drive coils (such as coil 200a) at a selected frequency or across a spread spectrum of frequencies near the selected frequency.

[0083] As discussed above, the locator 94 can transmit signals from the controller 110 via one or more of the coils (such as coil 200a). As further discussed above, the H-bridge configuration 220a can be configured in any suitable way, such as including transistors at switches 222-228. Therefore, the controller 100 can cause coil 200a to transmit signals (e.g., electromagnetic signals) that will be received by the tracking device 66. However, the navigation system 26 can use any suitable method (including, but not limited to, H-bridge circuitry and closed-loop analog circuitry) to transmit magnetic signals.

[0084] refer to Figure 4A and Figure 4B This illustrates the transmit-to-receive calibration and / or equalization (C / E) procedure 300 and its associated schematic diagram. As discussed herein, refer to... Figure 5A and Figure 5B as well as Figure 6A and Figure 6B Various additional and / or alternative C / E methods and systems can be used. In various implementations, C / E may include or be performed as a system-wide C / E and / or as various sub-channels or components.

[0085] First refer to Figure 4A and Figure 4BThe C / E procedure 300 can be a system-wide C / E (also known as an end-to-end C / E), including various procedural steps, such as starting in the start block 310. After starting in the start block 310, in block 311 (schematically shown as 311'), a calibration or equalization signal can be generated from the controller 110 and sent to the positioner 94 (which may also be referred to as a transmitter). Then, in block 314 (schematically shown as 314'), a calibration signal can be transmitted from the positioner 94, which will be received, for example, at a calibration receiving coil 95 and / or other suitable receiver (such as tracking device 66). The transmission of the calibration signal in block 314 may include transmitting the calibration signal according to a spread spectrum scheme, as discussed above. Additionally, the transmission may include PN signals from coil 200a and other coils 200 of the positioner 94.

[0086] As discussed above, the signal transmitted by the coil can be generated as a PN sequence. The PN sequence may include a selected length, such as 1023 to 16383 in the sequence. Various coils may be offset relative to each other by an appropriate amount (such as approximately 1023 units of length) to achieve differentiation between the several coils 200 of the positioner 94. The PN sequence can be generated and transmitted via the controller 110. As discussed above, the transmitted signal at a selected frequency or spread spectrum will be received by the tracking device 66 and / or other suitable receivers (such as calibration receiver 95) (even if only one receiver coil is referred to herein). Thus, the coils 200 can generate or transmit signals at appropriate times (such as sequentially or substantially simultaneously) for reception by the tracking device 66. The PN sequence can be generated according to any suitable technique. In various embodiments, for example, the PN sequence can be generated by an irreducible polynomial.

[0087] In block 318 (schematically shown as 318'), the tracking device 66 can receive the transmitted calibration signal and transmit the received signal to the controller 110. The received calibration signal in block 318 can then be sampled, and various calculations can be performed by the controller 120 (or any suitable processor system) to perform calibration in block 322. The calibration in block 322 may include calibration based on various parameters such as transmission distance, field strength at a known attitude, or other suitable calibration parameters.

[0088] The calibration in block 322 can be performed according to suitable techniques, as discussed below. In various embodiments, the calibration in block 322 may include impulse response normalization, which involves positioning the tracking device 66 (e.g., including coils) in a fixed posture relative to one or more of the coils 200 via a positioner 94. Transmission calibration may include measurements of the transmitted magnetic field via an external or separate magnetometer and / or as previously characterized at the tracking device 66 (e.g., sensing coil). Receiver coil calibration may include measurements of the received voltage via an external multimeter at or near the tracking device and / or as previously characterized by the tracking device 66 (e.g., sensing coil).

[0089] The calibration in block 322 may include ensuring the known or clean room field strength in a selected posture. Calibration may include placing the locator 94 at a selected location (which may also be referred to as the origin) and moving the tracking device 66 or a suitable receiving tracking device relative to the origin in several known postures (i.e., position and orientation). The signal received by the tracking device 66 may then be used in calibration 322. For example, calibration may include or account for possible distortion or noise in the signal as it begins to travel in parallel through transmitter (e.g., locator 94) circuitry and filters, transmitter coils, air, tracking device 66 coils, circuitry and filters associated with or included with tracking device 66, and then when the signal is received back at the controller.

[0090] The equalization calibration can then be performed in the equalization step in block 324, and is determined in any way (including those discussed above). In the equalization in block 324, the equalization is determined between each of the coils 200 of the positioner 94 and the tracking device 66. Each transmitting coil 200 and the tracking device 66 can be equalized for impulse response recovery and signal normalization. It should be understood that the discussion of the tracking device 66 may include the discussion of multiple coils in the tracking device 66 (such as three coils, as discussed above). Therefore, the equalization can be between each of the coils 200 of the positioner 94 and each of the coils of the tracking device 66. For example, between coil 200a and each of coils 66a, 66b, and 66c.

[0091] Equalization involves removing distortion and / or taking into account system noise (including various circuitry from controller 110, positioner 94, and receiver 66) to allow recovery of discrete-time binary signals from an interference-free system. Typically, equalization is performed by removing distortion from the driver and receiver hardware, leaving only signals and noise from any external distortion responses. Specifically, a binary single-valued pseudo-noise signal (measured as a voltage at the receiving coil of tracking device 66) can be measured and its inverse calculated. The equalization process then convolves the determined inverse with the signal received at tracking device 66 (i.e., the coil in tracking device 66) to remove the effects of positioner 94 and tracking device 66 and their associated hardware, leaving only the drive signal from controller 110 and noise or external distortion in the field.

[0092] Equalization is performed by determining coefficients. Specifically, the algorithm can be used to determine the coefficients in the equalization determination for testing or calibration. Equalization can be performed in any suitable manner, including those generally understood by those skilled in the art. For example, optimizing and combining finite impulse response (FIR) filters and bidirectional infinite impulse response (IIR) filters can be used to equalize the channel. The determined coefficients can be used to remove hardware distortion in the equalization between any coils of the locator coil 200 and the tracking device 66.

[0093] Therefore, the equalization box 324 can be used to generate or determine a distortion-free signal because the hardware of the positioner 94 transmits via coil 200 and is received at the tracking device 66 and the coils included therein. Thus, the equalized signal can be used to determine the orientation of the tracking device in the field generated by the positioner 94. As discussed above, the positioner 94 can transmit signals according to a BNO scheme, where each coil 200 is offset by approximately 1023 bits from the other coil in the PN sequence.

[0094] In various implementations, as briefly described above, selected sub-channels or sub-sections of navigation system 26 can be calibrated and equalized. For example, refer to... Figure 5A and Figure 5B Each of the transmitter or locator 94 and / or receiver or tracking device 66, and its corresponding sub-channel, can be individually calibrated and equalized. This can be used as a supplement to and / or alternative to calibrating and equalizing the entire system, and concludes as discussed above. Figure 4A and Figure 4B As shown in the image.

[0095] First refer to Figure 5AThe diagram illustrates a method 300a for calibration and equalization. Method 300a may include sections similar to those discussed above in method 300, and similar reference numerals will be highlighted with a lowercase "a". Thus, method 300a may begin at block 310a. The process 300a may then move to block 311a to generate a signal via a controller (such as controller 110). The generated signal may include a PN sequence, as discussed above. Thus, signal generation at the controller in block 311a is similar to signal generation in block 311 as discussed above. Signal generation and controller 311a may then be transmitted via and / or sent to various components of the navigation system 26, including those discussed above.

[0096] A calibration signal can be sent to the locator in block 326 (schematically shown as line 326'). The signal can be sent to various components from controller 110 to locator 94, including various circuits and filters, transmitter coils (e.g., coil 200), and other components between controller 110 and locator 94 and / or including locator 94. The signal sent to locator 94 can then be transmitted back to controller 110 after passing through all components of the locator section of navigation system 26. Therefore, controller 110 can receive signals returned from locator components, such as those transmitted from coils and / or returned to controller 110 via return lines (after passing through all components of the locator 94 section).

[0097] The controller 110 may also transmit signals to receiving coils, such as the tracking device 66 and / or calibration receiver 95 (also referred to herein as a receiver). The signals transmitted to receiver 66 may be substantially the same as those transmitted to positioner 94. Furthermore, signals may be transmitted substantially simultaneously and / or sequentially. Thus, signals generated from the controller 110 may also be transmitted to receiver 66, such as through all its components, including receiver circuitry and / or filters, and (e.g., the) sensor receiving coils of the tracking device 66 (including all of its selected or appropriate components). The signal may then return to the controller 110 after passing through all components, such as the controller 110 receiving a return signal from receiver 66.

[0098] Therefore, both blocks 326 and 328 may include two components, including transmit and return signals from corresponding components including a locator and a receiver. In other words, signals can be sent from and returned to controller 110 for calibration and equalization. Thus, instead of only requiring signals to be transmitted to locator 94, then transmitted and received by receiver 66, and then transmitted back to controller 110, signals can be sent and returned from each of the individual components as separate sub-channel calibration and equalization.

[0099] The returned signal can then be further processed by controller 110 or a suitable processor system, as discussed above. Calibration can be performed in block 322a in a manner similar to that discussed above. Calibration can include various calibration techniques or measurements, similar to those discussed above. For example, calibration can include measurements such as those by a selected magnetometer and / or fields as previously characterized by the corresponding coils in locator 94 and / or receiver 66. The calibration signal and / or information can then be used for equalization in block 324a. Similarly, equalization in block 324a can include equalization as discussed above for the equalization of signals in navigation system 26.

[0100] Therefore, the calibration and equalization of navigation system 26 may include, as discussed above, and as... Figure 5A and Figure 5B The individual or sub-channel calibration and equalization portions and / or steps are illustrated in the example.

[0101] Additional and / or alternative subchannel calibration and equalization may include, for example: Figure 6A and Figure 6B The method is illustrated. Initially, method 300b may include steps or portions similar to those of methods 300 and 300a, as discussed above. Similar portions will be referred to by similar numerals enhanced with "b". Thus, method 300b may begin in start block 310b and include the generation of signals at the controller in block 311b. The generation of signals at the controller may be similar to or the same as the generation of signals at controller 100 as discussed above.

[0102] The signal can be a PN sequence and can then be transmitted or sent to various components of the navigation system 26. For example, the signal can be sent to the locator 94 via various components of the locator system (including circuitry, filters, transmitter coils, etc.). The transmission of the signal to the locator 94 and the return of the signal to the controller in block 326b can be similar to that discussed above in block 326. The signal sent to the locator 94 can be sent from the controller 110 to the locator 94 via various circuitry of the locator. As discussed above and further herein, the return signal to the controller 110 for various calibrations and equalizations can be returned in various selected manners. As discussed above, the signal can be transmitted or returned to the controller via various return paths from the locator 94 to the controller 110. In addition or alternatively, various external components, such as magnetometers, can receive the transmitted signal from the locator 94, and the signal from the external component can be returned to the controller. However, the signal does not need to be wirelessly transmitted. The signal that has passed through various components (such as the circuitry, filters, and coils of the locator 94) can then have a signal that returns to the controller 110.

[0103] In addition, the generated signal can be transmitted to various circuits and components that receive the 66 channels, such as Figure 6BAs shown. For example, the receiving coil circuit 66' / 95' may include various circuits, cables, filters, etc., associated with the tracking device 66 and / or calibration coil 95. The receiving coil circuit 66' / 95' may include various hardware or components generally understood to be fixed to the navigation system 26. For example, as discussed above, the controller 110 may be connected to various tracking devices and / or receive tracking device information from various selected tracking devices (such as tracking device 66). In addition and / or alternatively, various other tracking devices (such as tracking device 62) may also be connected to the controller 110.

[0104] During a selected procedure, for example, tracking device coils or components 66, 95 may be interchanged with receiver electronics 66' / 95' and thus connected to controller 110. Furthermore, as those skilled in the art will understand, more than one device may be tracked individually and independently during one or more selected procedures. Therefore, multiple tracking devices 66 may be tracked individually and independently. Thus, at a selected time, the identity of the selected and attached tracking device 66 may be entered. Therefore, a system (such as controller 110) may recall the characterization of the selected and entered tracking device 66 from a storage system. Therefore, sub-component calibration and equalization of the receiver circuitry 66' / 95' may allow calibration of the navigation system 26, such as via the tracking device 66, independent of the individual components tracked therein.

[0105] In view of the above, in block 330, the generated signal from block 311b can be transmitted to the receiving circuit. The signal received from the receiving circuit 66' / 95' can be received in any suitable manner, such as in a return signal and / or from external components, including voltage measurements from external multimeters or other suitable sensors.

[0106] Therefore, the calibration and equalization of navigation system 26 may also include invoking the characterization of a selected receiver (also referred to as a receiver coil or component). For example, as discussed above, various components may be interconnected with navigation system 26 for navigation of selected components. Thus, navigation system 26 can be calibrated and equalized without a specific and selected tracking device 66. During a selected time period (such as during a procedure), when a specific tracking device is selected, the identity of the selected tracking device can be entered (e.g., manually by user 72, automatically by sensing or receiving signals from the tracking device, or other appropriate mechanisms). Navigation system 26 may invoke previously made and predetermined characterizations (including equalization) of the selected tracking device. Thus, the characterization of the tracking device may be completed at any prior time. Characterization may include calibration and equalization information, which may be previously determined and stored in a selected memory, such as in a database and / or in the memory of navigation system 26, including workstation 98 or processor system 98.

[0107] Previously determined characterizations (such as manual and / or automatic and / or combinations thereof) can be invoked to complete the calibration and equalization of the entire navigation system 26 (including the selected specific receiver coil 66 / 95). Therefore, when a selected receiver is selected, the invoked characterizations can be combined and / or used with the received signals from the receiver circuitry in block 330 and from the locator in block 326b for calibration and equalization. Thus, calibration can be performed in block 322b using the characterizations invoked from block 322. After calibration in block 322b, equalization can be performed in block 324b. Calibration and equalization may include procedures such as those discussed above.

[0108] Therefore, the calibration and equalization of navigation system 26 can be performed in appropriate ways, including those discussed above, such as... Figures 4A to 6B As described and illustrated. It should be understood that the calibration and equalization of navigation system 26 can be performed in any suitable manner and may include any of the systems or methods described above and / or combinations thereof. For example, end-to-end completion of calibration and equalization may be performed according to method 300. Additionally, during a selected procedure, calibration method 300b may be used to enhance and / or update the calibration and equalization of navigation system 26 when adding and / or changing tracking devices during and / or between selected procedures. Therefore, it should be understood that calibration and equalization can be performed in any suitable manner and are not necessarily limited to a single method as discussed above, but may include multiple methods and / or combinations thereof, such as end-to-end calibration and equalization according to method 300, which may be supplemented and / or re-completed according to sub-channel procedures (according to any and / or both of methods 300a and 300b).

[0109] According to various implementation schemes (including those discussed above), in step 324, the signal received at tracking device 66 can be equalized by equalizer 190 according to the equalization process discussed above. Reference Figure 7 The unbalanced impulse response may include a causal component 340 and an anti-causal component 344. The anti-causal component can be used to compensate for various components of the navigation system 26 and can vary accordingly. Therefore, various different components can be used in the navigation system 26 and allow or cause variations in the causal component 340. The causal component 340 can be used to compensate for variations and phases in various components of the system's passband and also in the circuitry of the positioner 94. Therefore, the equalization signal in block 324 can use, for example... Figure 7 The pre-equalized impulse response shown is used to calibrate and equalize the signal.

[0110] Positioner 94 can transmit a signal to generate an electromagnetic field. The signal can be a spread-spectrum signal transmitted via a BNO scheme. The signal (including the BNO scheme) can be referred to as a tracking signal comprising a binary signal. The binary signal can be measured at the tracking device 66 involved in transmitting the signal. As further discussed herein, the received signal can include various components due to various distortions as described above and discussed herein. Equalization can help ensure the recovery of the impulse response transmitted by positioner 94.

[0111] Steering Reference Figure 8 and Figure 9 The pre-equalized signal is in Figure 8 The signal is shown as being received by tracking device 66. Figure 8 The pre-equalization signal in the graph illustrates different received signals caused by system distortion, including distortion of materials in the field or near the path of tracking device 66. For example, graph 350 relates to the value of the pre-equalization signal received by tracking device 66 over time in the absence of distorted items. A second graph 354 shows the received signal over time when a portion of aluminum is placed or positioned near the received signal or causes distortion in the received signal. A third graph 358 shows the received signal when a selected steel material is positioned near tracking device 66. Figure 8 As shown in graphs 350-358, the signal received by tracking device 66 may vary depending on materials located near tracking device 66 and / or that would distort the signal emitted by locator 94. As further discussed herein, distortion caused by the selected material can be removed by analyzing the received signal to determine if distortion exists and, if so, removing it. As discussed herein, distortion can be determined regardless of its presence. If distortion is determined to exist, it can be removed to allow recovery of an undistorted tracking signal, including an impulse response.

[0112] refer to Figure 9 The diagram illustrates a method or process for navigation 370. The navigation process may begin at start box 374 and includes transmitting one or more signals in box 378. As discussed above, the transmitted signals may include a spread spectrum signal according to the BNO scheme discussed above. The signal transmitted by locator 94 may be transmitted into navigation volume 180. As discussed above, the transmitted signal may generate a near-field magnetic field with a wavelength greater than or equal to 10 meters. Navigation volume 180 may depend on various factors, such as the size of coil 200, the overall size of locator 94, power transmission, and other factors. However, navigation volume 180 may be approximately 0.001 m. 3 Approximately 1m 3 Including approximately 0.01m 3 To approximately 0.5m 3 The volume.

[0113] In block 382, ​​tracking device 66 may receive one or more transmitted signals. The received signals in block 382 may be received by tracking device 66 and / or transmitted to navigation processor 102. It should be understood that method or process 370 may be executed by processor 102, wherein transmitted signal 378 may be a signal transmitted to locator 94, and received signal in block 382 may be a signal received from tracking device 66 and transmitted to navigation processor 102. Method 370 may include transmitting signals by locator 94 and receiving signals by tracking device 66, or vice versa, and navigation processor 102 may execute instructions to determine navigation in method 370.

[0114] After one or more signals are received in block 382, ​​signal processing, such as demultiplexing and equalization, can be performed in block 386. As discussed above, the received signal is received via a BNO scheme, and therefore the code for each cyclic shift or offset (corresponding to each transmit coil) can be demultiplexed from the received signal for further analysis. The equalization in block 386 can be similar to that in equalization block 324, as discussed above. Typically, as discussed above, positioner 94 may include coil 200a and tracking device 66 may include coil 66a. It should be understood that the discussion of coil 66a herein may include or be similar to the discussion of multiple coils at tracking device 66, and the discussion of a single coil 66a herein is merely exemplary. The equalization between coil 66a and coil 200a allows for the recovery of the impulse response of the transmitted signal.

[0115] After equalizing the signal in box 386 (such as via equalizer 190 as discussed above), the equalized signal can be evaluated to allow determination of the presence of distortion in box 390. The determination of the presence of distortion can be based on the received signal, for example, as... Figure 10 As shown. Figure 10 As shown, the received signal may include the determination or evaluation of the initial pulse, such as by... Figure 10 The black dot 394 in the graph is shown. The impulse response can be an equalized impulse response from the received signal, as equalized in block 386. The impulse response may also include a residue or tail, which is a non-pulse or distorted portion that may include one or more tail signals or points 398. Tail points 398 may include multiple tail points in tail portion 402. The presence of tail portion 402 or tail portion can be used to determine whether distortion is present. Therefore, if it includes, as shown in block 386, the impulse response may be considered as a non-pulse or distorted portion of the signal. Figure 10 The signal of the impulse response shown substantially excludes the tail (as plotted over time), thus determining that it is distortion-free and follows a distortion-free path 410. As discussed above according to one or more of the various methods, calibration and equalization may include characterization of the system, including its noise floor and distortion limits. The absence of the tail (i.e., distortion) can be defined as within these previously determined limits.

[0116] If no distortion is detected in the received signal after equalization, such as determining that there is no tail 402 in the signal and that a distortion-free path 410 is followed, navigation of the tracking device 66 can be performed without correcting for distortion. As discussed above, distortion may be present or detected in the received signal due to various distorting elements in the signal path (such as those affecting the signal emitted by the locator 94). Distortion may be caused by various items (such as items in or near the navigation system 26), as discussed above, including the imaging device 80, the instrument 68, the operating table or patient support table 104, or other items. In addition, distortion may occur due to other items actively emitting fields (such as electric fields from a drill bit, other coils in the locator 94 besides the pair being analyzed or evaluated at one time), or other items. Equalization can be performed on a pair basis (e.g., a single coil 200a of the locator 94 and a single coil 66a of the tracking device 66). Therefore, determining the orientation of the tracking device 66 can be performed by determining the orientation of each of the coils 66a-66c of the tracking device 66 for each of the coils 200a-200n of the locator 94. However, it should be understood that tracking of the instrument 68 via the tracking device 66 can include navigation between the locator and a selected number of coils of the tracking device 66. Thus, for example, navigation can be performed using a tracking device and using nine or twelve transmitting coils in the locator 94. Other examples may include combinations ranging from one receiving coil using five transmitting coils to three receiving coils using three transmitting coils to twelve receiving coils using one transmitting coil.

[0117] After determining that there is no distortion, an evaluation of whether certain metrics are acceptable can be performed in box 414. Metrics may include signal metrics or any other suitable metrics. Additional predetermined acceptable ranges or thresholds for the metrics may be generated and stored for access by the navigation processor 102. In various examples, predetermined signal strength values ​​above or below the threshold may be determined. Thus, if the received signal is above the threshold, it can be determined that the tracking device is too close to the locator, and if the received signal is below the threshold, the tracking device may be too far from the locator. However, the threshold may relate to locator size and / or power, tracking device configuration, etc. Therefore, metrics can be analyzed and determined in box 414.

[0118] If the metric is determined to be unacceptable in box 414, a return or loop path 418 can be followed to transmit a signal in box 378 and / or receive a signal again in box 382. In various embodiments, the transmission may be automatically repeated, so looping back to transmission may not be necessary or desirable, and looping back to reception in box 382 may be appropriate. The signal can be reanalyzed by receiving it again at tracking device 66. The transmitted signal may be transmitted over a selected time span, such as milliseconds, including sequences of 1 to 100 milliseconds, including approximately 30 milliseconds of interruption or pause in the transmission, which may or may not occur later. Thus, if the metric is determined to be unacceptable in box 414, and if it is not found to be unacceptable, the signal can be received again in box 382 without interfering with navigation of navigation system 26 for a period acceptable to user 72. However, if no acceptable metric is found within a reasonable time period (such as approximately 30 to 500 milliseconds), navigation system 26 can provide output (such as via display device 84) that identifies to user 72 that an error has occurred and must be resolved.

[0119] If the measurement is acceptable in box 414, then "Yes" or solution path 422 can be followed. Solution path 422 can lead to navigation solution or pose determination in box 428. Navigation solution in box 428 can allow representation 68i to be displayed on the display device relative to image data 108 on display device 84. Navigation solution allows the pose of tracking device 66 relative to object 30 to be shown and / or determined. Therefore, navigation of instrument 68 relative to object 30 can be performed.

[0120] Continue to refer to Figure 9 If distortion is detected in box 390, navigation method 370 may also follow distortion determination or distortion discovery path 440. Distortion path 440 may lead to or enter distortion correction (also known as removal) subroutine 460. As discussed herein, subroutine 460 may include various procedures or processes for identifying and correcting selected distortions. Within the subroutine, those skilled in the art will understand that the processes described herein may be performed sequentially and / or simultaneously, as discussed herein. Therefore, although Figure 9 Subroutines are shown in a selected order, but the processes in subroutine 460 can be performed substantially simultaneously.

[0121] The cause of distortion can be any, including those discussed above. For example, a conductive metallic object may be in the path of the field generated by locator 94. For example, as... Figure 1 As shown, an aluminum object (such as a tray 71 that can be formed from it) can be in the path of the signal from the locator 94 to the tracking device 66. The aluminum tray 71 can result in a tail 402, as... Figure 10 As shown. The tail portion 402 may include, for example, along... Figure 10The x-axis in the graph shows multiple response data points separated by time. For example... Figure 10 As exemplified, time can be separated in microsecond increments, but it can also be any suitable time division. However, the determination and identification of the tail 402 can be used to ensure or determine the appropriate magnitude of the initial pulse 394.

[0122] Typically, when a signal is received in block 382, ​​the initial pulse 394 occurs at time “zero.” Specifically, a signal is transmitted in block 378 and received in block 382, ​​and the reception of the signal in block 382 will be at time zero, which is also understood as the start of a PN code or a PN code signal or shift. Any tail or residual received signal after this may be due to distortion objects (such as tray 71) in the field along the signal path. Therefore, the initial pulse 394 may be distorted (e.g., in terms of magnitude) and this distortion is indicated by the distortion tail 402.

[0123] Continue to refer to Figure 10 The initial pulse 394 can be plotted on a graph for discussion and calculation, as discussed herein. The initial pulse 394 is shown as a zero-time response to exemplarily show the initial pulse at time zero on the X-axis. Additionally, the initial pulse is shown as a zero magnitude value to better illustrate the value of the residual or tail response received in block 382 (if distortion is present). The corrected or undistorted size of the initial pulse 394 can be determined by calculating the tail 402 entering the initial pulse 394. The initial pulse and tail can typically be causal responses, where the tail 402 can be used to determine the expected or undistorted pulse magnitude value.

[0124] Distortion path 440 may first proceed to the residual or tail separation in block 444. Residual separation may include the determination of all tail portions. As discussed above, the initial pulse at time zero may be determined, for example, based on a determined or selected amount of time between the transmitted and received signals in blocks 378 and 382, ​​respectively. For example, it may be determined that the time between transmitting a signal from locator 94 and receiving a signal at tracking device 66 may be much less than microseconds. Thus, navigation system 26 may determine that the received signal at a selected amount of time after the transmission of the signal in block 378 may be zero time and the initial pulse. After this, any recovered pulse response may be determined as tail 402. However, tail 402 may be determined in any suitable manner, such as any recovered signal after the identified initial pulse. In any case, tail 402, which may be determined or detected in block 390 when determining the presence of distortion, may be separated from the initial pulse or first pulse 394. Residual separation provides separation of tail size or magnitude for further reconstruction.

[0125] After the tail is separated in box 444, reconstruction can be performed in box 448. Reconstruction box 448 may include reconstruction of the distorted impulse response. As discussed above, the initial or zero-time pulse 394 may be distorted, and this distortion may be determined by the tail 402 (if present). Therefore, once the tail is separated in box 444, the separated tail can be reconstructed into the distorted initial pulse to determine the actual or corrected pulse. Reconstruction can be of any suitable type.

[0126] For example, direct reconstruction can include an addition (or additive) reconstruction by adding the value of the tail 402 of a selected time amount (such as about 1 to 10 milliseconds, including 5 milliseconds) to the value of the initial or zero-time pulse of the distortion. Direct reconstruction allows for rapid reconstruction of the distortion pulse and is applicable to selected materials, such as conductive materials (such as certain plastics or polymers, metal alloys, etc.).

[0127] The reconstruction may also include modeling reconstruction of the impulse response, which may be based on weighting certain portions of the tail, adding or removing certain portions of tail 402, or other suitable modeling techniques. In various embodiments, the reconstruction may not include first removing the tail in block 444, but may include simultaneous separation and modeling. In various embodiments, the tail may be summed and added to the impulse, particularly for conductive distortion materials. In other words, in direct calculations, the residue is summed as a function of the residue to determine the initial distortion impulse. In modeling or indirect calculations, the tail may be decomposed into individual functions and then fitted to determine the distortion effect. For example, the decomposed function may be fitted to a predetermined or measured distortion material or article. In other words, the residue can be modeled by a combination of parameterized impulse responses (with conductive and conductive and magnetic contributions) and / or by a combination of measured impulse responses (including expected conductive and conductive and magnetic contributions).

[0128] Reconstruction can be performed in box 448 to determine the corrected or undistorted impulse response in box 454. After the reconstruction of the distorted impulse response in box 448, removal or deconvolution of the impulse response is performed in box 454. Removal or deconvolution of the impulse response in box 454 may include separating the distorted impulse response from the full impulse response via removal or deconvolution to determine the corrected or undistorted impulse response and impulse.

[0129] Following the removal or deconvolution in box 454, navigation method 370 can then proceed to determine whether the selected metric is acceptable in box 414. Similar to what has been discussed above, the determination of whether the metric is acceptable in box 414 allows for receiving additional signals in loop path 418 and / or navigation resolution in box 428.

[0130] Therefore, method 370 may follow a distortion-free path 410 and / or a distortion path 440 to resolve navigation and determine the orientation of the tracking device 66 relative to the object 30 in space. Method 370 may include a distortion-free path 410 and a distortion path 440, the distortion path of which may include a distortion correction subroutine 460. The distortion correction subroutine 460 may be executed by controller 110 or navigation processor 102 to allow the removal or correction of distortion from the distorted object in order to determine the true or correct orientation of the tracking device 66. Distortion may be detected in block 390 and removed in distortion correction subroutine 460, as discussed above.

[0131] As briefly discussed above, subroutine 460 can be substantially sequential, as discussed above. Therefore, it is possible to... and... Figure 9 The sequence of various computations (such as instructions executed by a processor) is directly shown in the diagram. However, in various embodiments, all processes in subroutine 460 may be performed simultaneously, or a selected number of processes may be performed simultaneously. In other words, subroutine 460 may be performed via simultaneous separation 444, reconstruction 448, and removal or deconvolution 454. However, subroutine 460 may still follow the determination in block 390 whether the recovered impulse response includes a distorted tail. Subroutine 460 may then include simultaneous separation and deconvolution of the reconstructed distorted impulse response from the recovered impulse response to discover the corrected impulse response and pulse. The corrected impulse response and pulse can be determined by fitting the residual to a combination of measured or modeled impulse responses, including the expected conductivity and the contributions of conductivity and magnetism.

[0132] Therefore, as discussed above, navigation system 26 can be used to determine the orientation of tracking device 66 associated with (e.g., connected to) device 68. Thus, navigation system 26 can track tracking device 66 and navigate device 68, such as by displaying device 68 as representation 68i on display device 84. The use of diffuse spectrum transmission allows for low-power and high-fidelity signal transmission via selected electronics (such as the “H” bridge configuration discussed above). Additionally, selected schemes (such as the BNO scheme) allow for transmission of signals substantially free of distortion or obfuscation caused by external signals relative to tracking device 66. Furthermore, the received signal can be analyzed or reconstructed to determine if distortion exists or has been caused by a distorting object, and if present, the distortion can be removed. Therefore, the orientation of tracking device 66 can be determined with selected accuracy and correctness based on the received signal at tracking device 66.

[0133] The foregoing description of embodiments has been provided for illustrative and descriptive purposes. The foregoing description is not intended to be exhaustive or limiting of the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable and may also be used in selected embodiments where applicable, even if not specifically shown or described. The same element or feature may be varied in many ways. Such variations are not considered to depart from the invention, and all such modifications are intended to be included within the scope of the invention.

[0134] It should be understood that the various aspects disclosed herein can be combined in different combinations than those specifically presented in the specification and figures. It should also be understood that, depending on the example, certain actions or events of any process or method described herein may be performed in a different order, and may be added, combined, or omitted entirely (e.g., performing the described technique may not require all the described actions or events). Furthermore, although for clarity some aspects of this disclosure are described as being performed by a single module or unit, it should be understood that the techniques of this disclosure can be performed by a combination of units or modules associated with, for example, a medical device.

[0135] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functionality may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include non-transitory computer-readable media, which correspond to tangible media such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and is accessible by a computer).

[0136] The instructions can be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, graphics processing units (GPUs), application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Therefore, as used herein, the term "processor" can refer to any of the aforementioned structures or any other physical structures suitable for implementing the described technology. Furthermore, this technology can be fully implemented in one or more circuit or logic elements.

Claims

1. A method of operating a navigation system, the method comprising: generating a signal by a controller; sending the signal to a transmitter system; transmitting the signal by the transmitter system; receiving the transmitted signal at a receiver; sending a receiver signal to the controller based on the received transmitted signal at the receiver; and evaluating the receiver signal to characterize the navigation system, wherein evaluating the receiver signal to characterize the navigation system includes utilizing the signal from the controller to calibrate and equalize the receiver signal to generate an equalized signal, and wherein the equalized signal can be utilized with a tracking device signal and noise from external distortions to determine a pose of a tracking device.

2. The method of claim 1, wherein generating the signal includes generating a spread spectrum signal.

3. The method of claim 2, wherein generating the signal further includes generating a pseudo noise signal.

4. The method of any one of claims 1 to 3, wherein sending the signal to a transmitter system includes sending the signal from the controller to the transmitter system via a wired connection.

5. The method of any one of claims 1 to 4, further comprising: sending the signal through at least one coil and one electronic component of the transmitter system prior to transmitting the signal.

6. The method of claim 5, further comprising: sensing the signal by a coil of the receiver; and sending the sensed signal through at least one receiver electronic component prior to sending the receiver signal to the controller.

7. The method of claim 1, further comprising: generating a tracking signal in a spread spectrum by the controller; transmitting the tracking signal; sensing the tracking signal by the tracking device; and evaluating the sensed tracking signal by the controller to determine the pose of the tracking device based on the characterization of the navigation system.

8. A method of operating a navigation system, the method comprising: generating a first signal by a controller; sending the first signal to a transmitter system; receiving a transmitter signal at the controller based on the first signal sent to the transmitter system; generating a second signal by the controller; sending the second signal to a receiver system; receiving a receiver signal at the controller based on the second signal sent to the receiver system; and evaluating the transmitter signal and the receiver signal to characterize the navigation system, wherein evaluating the transmitter signal and the receiver signal to characterize the navigation system includes calibrating and equalizing the transmitter signal and the receiver signal to the respective first signal and second signal to generate an equalized signal, and wherein the equalized signal can be utilized with a tracking device signal and noise from external distortions to determine a pose of a tracking device.

9. The method of claim 8, wherein generating the signal includes generating a spread spectrum signal.

10. The method of claim 9, wherein generating the signal further includes generating a pseudo noise signal.

11. The method of any of claims 8-10, further comprising: transmitting, by at least one coil and one electronic component of the transmitter system, the first signal prior to receiving the transmitter signal at the controller.

12. The method of claim 11, further comprising: transmitting, by at least one coil and one electronic component of the receiver system, the second signal prior to receiving the receiver signal at the controller.

13. The method of claim 8, further comprising: generating, by the controller, a tracking signal in a spread spectrum; transmitting the tracking signal; sensing, by the tracking device, the tracking signal; and evaluating, by the controller, the sensed tracking signal to determine the pose of the tracking device based on the characterization of the navigation system.

14. The method of claim 13, wherein the first signal and the second signal are the same signal.

15. A method of operating a navigation system, the method comprising: generating, by a controller, a first signal; transmitting the first signal to a transmitter system; receiving, at the controller, a transmitter signal based on the first signal transmitted to the transmitter system; generating, by the controller, a second signal; transmitting the second signal to a first portion of a receiver system; receiving, at the controller, a receiver signal based on the second signal transmitted to the first portion of receiver system; calling a receiver characterization of a second portion of the receiver system; and evaluating the transmitter signal, the receiver signal, and the called receiver characterization to characterize the navigation system, wherein the transmitter signal, the receiver signal, and the called receiver characterization comprise calibrating and equalizing the transmitter signal and the receiver signal to the respective first signal and second signal, and wherein the equalized signals enable determination of a pose of a tracking device with a tracking device signal and noise from external distortions.

16. The method of claim 15, wherein generating the signals comprises generating spread spectrum signals.

17. The method of any of claims 15 or 16, wherein the first signal and the second signal are the same signal.

18. The method of any of claims 15-17, further comprising: transmitting, by at least one coil and one electronic component of the transmitter system, the first signal prior to receiving the transmitter signal at the controller.

19. The method of claim 15, wherein the second portion of the receiver system comprises the tracking device, the method further comprising: receiving an identification of the tracking device; wherein calling the receiver characterization of the second portion of the receiver system comprises accessing a database of predetermined characterizations of the tracking device.

20. The method of claim 19, further comprising: generating, by the controller, a tracking signal in a spread spectrum; transmitting the tracking signal; sensing, by the tracking device, the tracking signal; and evaluating, by the controller, the sensed tracking signal to determine the pose of the tracking device based on the characterization of the navigation system. ​ ​ evaluating, by the controller, the sensed tracking signals to determine the pose of the tracking device based on the characterization of the navigation system.

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