Method for north-seeking measurement of magnetic compass based on astronomical orientation technology

Abstract

The application relates to the technical field of navigation, and discloses a magnetic compass north-seeking measurement method based on celestial orientation technology, which comprises the following steps: obtaining UTC time and geographical position information of an observer at the current moment by using a preset Beidou module; capturing a celestial image by using an imaging module; preprocessing the celestial image by using an image processing board to extract celestial coordinates of the celestial body, combining the UTC time and the geographical position information, and using a preset astronomical solution module to solve the azimuth and the pitch angle of an optical axis under a geographical coordinate system to determine current true north reference information; comparing the true north reference information with original magnetic azimuth angle data synchronously output by the magnetic compass of the observer to calculate a magnetic declination angle error of the magnetic compass; performing correction processing of the magnetic azimuth angle information by using the magnetic compass to obtain target magnetic azimuth angle information, and performing north-seeking measurement processing based on the target magnetic azimuth angle information. The application can realize high-precision north-seeking measurement under all-weather conditions in a complex environment.

Description

Technical Field

[0001] This invention relates to a magnetic compass north-finding measurement method based on astronomical orientation technology, belonging to the field of navigation technology. Background Technology

[0002] Astronomical orientation technology using magnetic compass for north-finding measurement refers to a high-precision autonomous orientation method that integrates astronomical observation and geomagnetic sensing. It enables rapid autonomous north-finding under all-weather conditions, observing the sun during the day and stars at night, overcoming the limitations of traditional magnetic compasses that are susceptible to interference and require external calibration. At the same time, it provides a reliable backup orientation method for individual soldier equipment and vehicle-mounted platforms that does not rely on satellite navigation, significantly improving survivability in complex battlefield environments.

[0003] Traditional magnetic compass north-finding measurement methods mainly rely on the principle of geomagnetic field induction, using magnetic sensors to directly sense the direction of the Earth's magnetic field lines to output the magnetic azimuth. This method has an inherent magnetic declination problem, as there is an angle between magnetic north and true north that varies with geographical location. Traditional methods require manual consultation of magnetic declination data or reliance on external benchmarks for correction, and cannot perform real-time autonomous calibration. As a result, it is impossible to achieve high-precision north-finding measurement under all-weather conditions in complex environments. Summary of the Invention

[0004] This invention provides a magnetic compass north-finding measurement method based on astronomical orientation technology, the main purpose of which is to improve the operational stability of the celestial wheel system.

[0005] To achieve the above objectives, the present invention provides a magnetic compass north-finding measurement method based on astronomical orientation technology, comprising: The current UTC time and the observer's geographical location information are obtained using a pre-set BeiDou module; Celestial images are captured using an imaging module; wherein the celestial images include solar images captured with filters applied in daytime mode and stellar images captured in nighttime mode. The celestial image is preprocessed by the image processing board to extract the celestial coordinates. Based on the celestial coordinates, combined with the UTC time and geographical location information, the azimuth and elevation angles of the optical axis in the geographic coordinate system are calculated using the preset astronomical calculation module to determine the current true north reference information. The true north reference information is compared with the original magnetic azimuth data synchronously output by the observer's magnetic compass to calculate the magnetic declination error of the magnetic compass. Based on the magnetic declination error, the magnetic compass is used to perform magnetic azimuth information correction processing to obtain the target magnetic azimuth information, and based on the target magnetic azimuth information, north-finding measurement processing is performed.

[0006] Optionally, the celestial image is preprocessed using an image processing panel to extract the celestial coordinates of the celestial body, including: When the celestial image is a solar image, the solar centroid coordinates of the solar image are calculated using the image processing board; When the celestial image is a stellar image, the coordinates of the stellar barycenter of the stellar image are calculated using the image processing board; The coordinates of the Sun's center of mass and the coordinates of the star's center of mass are used as the celestial coordinates of the celestial body.

[0007] Optionally, when the celestial image is a solar image, the coordinates of the solar barycenter in the solar image are calculated using the image processing panel, including: When the celestial image is a solar image, the image processing board performs high dynamic range processing on the solar image to extract the solar disk outline of the solar image; The geometric center coordinates of the solar disk contour are calculated as the coordinates of the solar mass center.

[0008] Optionally, when the celestial image is a stellar image, the coordinates of the stellar barycenter of the stellar image are calculated using the image processing panel, including: When the celestial image is a star image, the image processing board performs background dark current subtraction processing on the star image to extract star spots that meet the preset magnitude in the star image; The sub-pixel level centroid coordinates of the stellar spots are calculated using a gray-scale weighted centroid fitting algorithm and used as the stellar centroid coordinates.

[0009] Optionally, the BeiDou module can be used to obtain the current UTC time and the observer's geographical location information, including: The BeiDou module is used to receive BeiDou satellite navigation signals in real time, and the BeiDou satellite navigation signals are processed and demodulated by radio frequency front-end to obtain navigation messages; Extract the raw observation data and UTC synchronization parameters of the navigation message, wherein the raw observation data includes pseudorange observations and satellite ephemeris data; The least squares method is used to solve the pseudorange observations and satellite ephemeris data to obtain the observer's geographical location information and the receiver's local clock error. The receiver outputs the UTC time of the current moment using the local clock difference and the UTC synchronization parameters.

[0010] Optionally, celestial images are captured via an imaging module, including: The imaging module acquires light signals within the field of view and adaptively switches to daytime mode or nighttime mode based on the light signals. In daytime mode, a filter is added to the incident light path of the imaging module to acquire solar images; In night mode, the filter is removed, and the gain and exposure parameters of the imaging module are adjusted to a high sensitivity level to acquire stellar images.

[0011] Optionally, the imaging module includes: a low-light lens, a filter, a low-light CMOS sensor, and a signal processor connected thereto, wherein, The low-light lens is used to focus celestial radiation signals to increase the amount of light entering the lens; The filter is used to switch the incoming light path in daytime mode to attenuate solar radiation energy, and to switch the incoming light path out in nighttime mode to allow full light signal transmission. The low-light CMOS is used to convert light signals into image signals; The signal processor is used to acquire optical signals to generate mode switching signals, and to control the operation of the filter and adjust the gain and exposure parameters of the low-light CMOS according to the mode switching signals.

[0012] Optionally, based on the celestial coordinates and combined with the UTC time and geographical location information, a preset astronomical calculation module is used to calculate the azimuth and elevation angles of the optical axis in the geographic coordinate system, including: When the celestial coordinates are the coordinates of the center of mass of a star, the right ascension and declination of the optical axis in the inertial coordinate system are determined in order to calculate the inertial coordinate expression of the optical axis in the inertial coordinate system. The attitude transfer matrix from the inertial coordinate system to the geographic coordinate system is calculated using the UTC time and geographic location information. Based on the inertial coordinate expression and the attitude transfer matrix, the geographic coordinate expression of the optical axis in the geographic coordinate system is calculated, and the pitch angle and azimuth angle of the optical axis are solved using the astronomical calculation module.

[0013] Optionally, based on the celestial coordinates and combined with the UTC time and geographical location information, a preset astronomical calculation module is used to calculate the azimuth and elevation angles of the optical axis in the geographic coordinate system, including: When the celestial coordinates are the coordinates of the Sun's center of mass, a star-sensor coordinate expression for the Sun in the star-sensor coordinate system is constructed based on the Sun's center of mass coordinates, so as to calculate the yaw and pitch distances between the Sun and the optical axis; The astronomical calculation module uses the heading angle distance and pitch angle distance to calculate the pitch angle and azimuth angle of the optical axis.

[0014] Optionally, based on the magnetic declination error, the magnetic compass is used to perform magnetic azimuth information correction processing to obtain target magnetic azimuth information, including: generating the target magnetic azimuth information after magnetic compass correction by algebraically adding the original magnetic azimuth data and the magnetic declination error.

[0015] This invention integrates BeiDou positioning, astronomical observation, and magnetic compass technology to construct an all-weather, high-precision north-finding method. Utilizing the high-precision spatiotemporal reference provided by BeiDou and the true north reference information calculated from astronomical observations, it can accurately calculate and correct the magnetic declination error of the magnetic compass in real time. This effectively overcomes the shortcomings of traditional magnetic compasses, such as susceptibility to environmental magnetic field interference and systematic bias, significantly improving the accuracy and reliability of north-finding measurements. Furthermore, the day-night dual-mode imaging design enables all-weather operation, greatly enhancing the system's environmental adaptability and achieving automated, high-precision orientation measurement, thus possessing extremely high engineering application value. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating a magnetic compass north-finding measurement method based on astronomical orientation technology, provided in an embodiment of the present invention. Figure 2 This is a diagram showing the astronomical orientation module's sensitive calculation method based on a magnetic compass north-finding measurement method using astronomical orientation technology, provided in an embodiment of the present invention. Figure 3 This is a diagram showing the completion of the astronomical orientation module's calculation of the magnetic compass north-finding measurement method based on astronomical orientation technology, according to an embodiment of the present invention. Figure 4 This is a star-sensor calculation diagram of an astronomical orientation module based on a magnetic compass north-finding measurement method using astronomical orientation technology, provided in an embodiment of the present invention. Figure 5 This is a diagram showing the completion of star-sensor calculation for the orientation module of the magnetic compass north-finding measurement method based on astronomical orientation technology, provided in an embodiment of the present invention. Figure 6 A schematic diagram of a computer device for a magnetic compass north-finding measurement method based on astronomical orientation technology, provided in an embodiment of the present invention; The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0017] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0018] This application provides a method for finding north using a magnetic compass based on astronomical orientation technology. The execution entity of this method includes, but is not limited to, at least one electronic device that can be configured to execute the method provided in this application, such as a server or a terminal. In other words, the method can be executed by software or hardware installed on a terminal device or a server device. The server includes, but is not limited to, a single server, a server cluster, a cloud server, or a cloud server cluster.

[0019] Reference Figure 1 The diagram shown is a flowchart illustrating a magnetic compass north-finding measurement method based on astronomical orientation technology according to an embodiment of the present invention. In this embodiment, the magnetic compass north-finding measurement method based on astronomical orientation technology includes: S1. Use the BeiDou module to obtain the current UTC time and the geographical location of the observer.

[0020] This invention utilizes the BeiDou module to obtain the current UTC time and the observer's geographical location information. The BeiDou module also provides a high-precision spatiotemporal reference, enabling real-time and accurate calculation of celestial positions without manual input, significantly improving the automation and response speed of north-finding measurement.

[0021] In detail, the process of using the BeiDou module to obtain the current UTC time and the observer's geographical location information includes: The BeiDou module is used to receive BeiDou satellite navigation signals in real time, and the BeiDou satellite navigation signals are processed and demodulated by radio frequency front-end to obtain navigation messages; Extract the raw observation data and UTC synchronization parameters of the navigation message, wherein the raw observation data includes pseudorange observations and satellite ephemeris data; The least squares method is used to solve the pseudorange observations and satellite ephemeris data to obtain the observer's geographical location information and the receiver's local clock error. The receiver outputs the UTC time of the current moment using the local clock difference and the UTC synchronization parameters.

[0022] The BeiDou satellite navigation signal refers to the radio frequency signal at the B1I or B1C frequency points broadcast to the ground by the BeiDou satellite constellation. The BeiDou module refers to a hardware module integrating a radio frequency front-end, baseband processing chip, and microprocessor, capable of receiving, tracking, demodulating BeiDou satellite navigation signals, and calculating position and time information. The navigation message refers to the data bit stream contained in the BeiDou satellite navigation signal. The UTC synchronization parameters refer to the leap second parameters and time synchronization correction parameters contained in the navigation message, used to convert the BeiDou system time to Coordinated Universal Time. The pseudorange observation value refers to the value obtained by the BeiDou module through measurements of satellite signals. The distance observation value is calculated by multiplying the time delay between the satellite signal transmission time and the receiver reception time by the speed of light. The satellite ephemeris data refers to a set of parameters describing the satellite's precise orbital position in space. The observer refers to the carrier carrying the BeiDou module and magnetic compass to perform north-finding measurement operations. The geographical location information refers to the observer's spatial coordinates on the Earth's surface. The receiver's local clock bias refers to the deviation between the local clock time inside the BeiDou module and the BeiDou system standard time. The UTC time refers to the high-precision standard time obtained by correcting the BeiDou system time and combining it with UTC synchronization parameters.

[0023] S2. Capture celestial images through an imaging module; wherein the celestial images include solar images captured with filters applied in daytime mode and star images captured in nighttime mode.

[0024] This invention captures celestial images through an imaging module and suppresses strong light interference through filters, enabling all-weather, multi-target acquisition of celestial signals and significantly improving the system's time availability and environmental adaptability.

[0025] Specifically, the acquisition of celestial images via the imaging module includes: The imaging module acquires light signals within the field of view and adaptively switches to daytime mode or nighttime mode based on the light signals. In daytime mode, a filter is added to the incident light path of the imaging module to acquire solar images; In night mode, the filter is removed, and the gain and exposure parameters of the imaging module are adjusted to a high sensitivity level to acquire stellar images.

[0026] The light signal refers to the optical radiation energy emitted by the target celestial body (the sun or a star), which is transmitted through the atmosphere and then incident on the lens of the imaging module. Its intensity reflects the current ambient light intensity. The daytime mode refers to the working state when the imaging module determines that the current ambient light intensity is higher than a preset threshold. The nighttime mode refers to the working state when the imaging module determines that the current ambient light intensity is lower than a preset threshold. The incident light path refers to the physical path through which external light enters the photosensitive surface of the imaging module sensor. The filter refers to the optical attenuation element set in the optical path of the imaging module, which is used to attenuate the incident light energy in a strong light environment to prevent the sensor from oversaturating or being damaged. The solar image refers to the digital image data of the solar disk or solar spot acquired after attenuation by the filter in the daytime mode. The stellar image refers to the digital image data containing stellar spot information acquired after high gain and long exposure processing in the nighttime mode.

[0027] Furthermore, the imaging module includes: a low-light lens, a filter, a low-light CMOS sensor, and a signal processor connected thereto, wherein, The low-light lens is used to focus celestial radiation signals to increase the amount of light entering the lens; The filter is used to switch the incoming light path in daytime mode to attenuate solar radiation energy, and to switch the incoming light path out in nighttime mode to allow full light signal transmission. The low-light CMOS is used to convert light signals into image signals; The signal processor is used to acquire optical signals to generate mode switching signals, and to control the operation of the filter and adjust the gain and exposure parameters of the low-light CMOS according to the mode switching signals.

[0028] Wherein, the low-light lens refers to an optical lens with a large aperture and high coating transmittance; the low-light CMOS refers to an optical lens with a large aperture and high coating transmittance; the mode switching signal refers to a control command generated by the signal processor after comparing the intensity of the collected ambient light signal with a preset threshold, used to indicate whether the current working state is daytime mode or nighttime mode; the gain and exposure parameters refer to electronically controlled configuration items that determine the photosensitive characteristics of the imaging module; the gain parameter is used to adjust the amplification factor of the sensor output signal, and the exposure parameter is used to set the integration time of the sensor's photosensitive unit.

[0029] S3. The celestial image is preprocessed by the image processing board to extract the celestial coordinates. Based on the celestial coordinates, combined with the UTC time and geographical location information, the azimuth and elevation angles of the optical axis in the geographic coordinate system are calculated using the preset astronomical calculation module, and the current true north reference information is determined.

[0030] This invention preprocesses the celestial images using an image processing board to extract the celestial coordinates, effectively filtering out image noise and environmental interference, significantly improving the accuracy of celestial feature extraction, and providing a high-precision data foundation for subsequent astronomical positioning calculations.

[0031] Specifically, the preprocessing of the celestial image using an image processing panel to extract the celestial coordinates includes: When the celestial image is a solar image, the solar centroid coordinates of the solar image are calculated using the image processing board; When the celestial image is a stellar image, the coordinates of the stellar barycenter of the stellar image are calculated using the image processing board; The coordinates of the Sun's center of mass and the coordinates of the star's center of mass are used as the celestial coordinates of the celestial body.

[0032] The image processing board refers to a hardware circuit board that integrates a digital signal processing chip; the solar centroid coordinates refer to the geometric center position of the solar imaging area on the target surface of the image sensor; the stellar centroid coordinates refer to the gray-weighted center position of the stellar imaging spot on the target surface of the image sensor; and the celestial coordinates refer to coordinate data that uniformly characterize the position of the sun or a star in the image.

[0033] Furthermore, when the celestial image is a solar image, calculating the coordinates of the solar centroid in the solar image using the image processing board includes: When the celestial image is a solar image, the image processing board performs high dynamic range processing on the solar image to extract the solar disk outline of the solar image; The geometric center coordinates of the solar disk contour are calculated as the coordinates of the solar mass center.

[0034] The high dynamic range processing refers to the process of eliminating image ghosting and halos and clearly restoring the edge contour of the sun by adjusting exposure parameters or synthesizing algorithms to address the overexposure problem caused by high brightness imaging of the sun. The solar disk contour refers to the closed curve of the edge of the solar disk in the image, and the geometric center coordinates refer to the position of the geometric center point of the circular area calculated based on the pixel distribution of the solar disk contour.

[0035] Furthermore, when the celestial image is a stellar image, calculating the stellar barycenter coordinates of the stellar image using the image processing panel includes: When the celestial image is a star image, the image processing board performs background dark current subtraction processing on the star image to extract star spots that meet the preset magnitude in the star image; The sub-pixel level centroid coordinates of the stellar spots are calculated using a gray-scale weighted centroid fitting algorithm and used as the stellar centroid coordinates.

[0036] The background dark current subtraction process refers to the process of filtering out background dark current noise in the star image to eliminate the interference of sensor dark current on the extraction of star speckles. The preset magnitude refers to the set star brightness threshold standard, which is used to select bright star targets that meet the requirements of navigation and positioning accuracy. This invention can be set to level 6. The star speckle refers to the tiny spot area of ​​light that is imaged on the image sensor after the star is focused by the lens. The gray-scale weighted centroid fitting algorithm is a sub-pixel-level positioning algorithm that uses the gray value of each pixel in the star speckle as weight to calculate the position of its energy center. The sub-pixel-level centroid coordinates refer to the exact position of the star center inside the pixel.

[0037] Based on the celestial coordinates, combined with the UTC time and geographical location information, this invention uses a preset astronomical calculation module to calculate the azimuth and elevation angles of the optical axis in the geographic coordinate system, and then determines the current true north reference information. This effectively eliminates the influence of magnetic compass errors and environmental interference, and achieves high-precision true north orientation and attitude determination without relying on external references.

[0038] In detail, the step of calculating the azimuth and elevation angles of the optical axis in the geographic coordinate system based on the celestial coordinates, combined with the UTC time and geographic location information, using a preset astronomical calculation module includes: When the celestial coordinates are the coordinates of the center of mass of a star, the right ascension and declination of the optical axis in the inertial coordinate system are determined in order to calculate the inertial coordinate expression of the optical axis in the inertial coordinate system. The attitude transfer matrix from the inertial coordinate system to the geographic coordinate system is calculated using the UTC time and geographic location information. Based on the inertial coordinate expression and the attitude transfer matrix, the geographic coordinate expression of the optical axis in the geographic coordinate system is calculated, and the pitch angle and azimuth angle of the optical axis are solved using the astronomical calculation module. Wherein, the optical axis refers to the central axis of the optical system; the inertial coordinate system refers to a coordinate system with the center of the celestial sphere as the origin and the coordinate axes pointing towards fixed stars; the right ascension refers to the longitude coordinates of a celestial body in the inertial coordinate system; the declination refers to the latitude coordinates of a celestial body in the inertial coordinate system; the inertial coordinate expression refers to the three-dimensional vector form of the optical axis direction in the inertial coordinate system, expressed in terms of right ascension and declination; the attitude transfer matrix refers to a rotation matrix calculated based on the longitude, latitude, and UTC time of the observation point, used to transform the vector in the inertial coordinate system to the geographic coordinate system; the geographic coordinate expression refers to the three-dimensional vector form of the optical axis direction in the geographic coordinate system; the astronomical calculation module refers to the algorithm program integrated in the astronomical orientation module, used to perform vector transformation and attitude angle calculation; the pitch angle refers to the angle between the optical axis and the ground plane; and the azimuth angle refers to the angle between the projection of the optical axis on the horizontal plane and the due north direction.

[0039] Optionally, when the celestial coordinates are the coordinates of the star's center of mass: The inertial coordinate expression is as follows:

[0040] in, Indicates the optical axis in the inertial coordinate system Components of the axis, Indicates the optical axis in the inertial coordinate system Components of the axis, Indicates the optical axis in the inertial coordinate system Components of the axis, This represents the latitudinal coordinates of the optical axis in an inertial coordinate system. This represents the longitude coordinates of the optical axis in the inertial coordinate system. Represents the cosine function. This represents the sine function.

[0041] Wherein, the attitude transition matrix is:

[0042] in, Represents the attitude transition matrix. This indicates the observer's geographical longitude in the geographic location information. This indicates the geographic latitude of the observer in the geographic location information. It represents Greenwich Mean Sidereal Time.

[0043] The geographic coordinate expression is as follows:

[0044] in, Indicates the optical axis in the geographic coordinate system Components of the axis, Indicates the optical axis in the geographic coordinate system Components of the axis, Indicates the optical axis in the geographic coordinate system Components of the axis, Indicates pitch angle, Indicates the azimuth angle.

[0045] In detail, the step of calculating the azimuth and elevation angles of the optical axis in the geographic coordinate system based on the celestial coordinates, combined with the UTC time and geographic location information, using a preset astronomical calculation module includes: When the celestial coordinates are the coordinates of the Sun's center of mass, a star-sensor coordinate expression for the Sun in the star-sensor coordinate system is constructed based on the Sun's center of mass coordinates, so as to calculate the yaw and pitch distances between the Sun and the optical axis; The astronomical calculation module uses the heading angle distance and pitch angle distance to calculate the pitch angle and azimuth angle of the optical axis.

[0046] Wherein, the star sensor coordinate system refers to a right-handed coordinate system with the optical center of the star sensor as the origin, its X and Y axes parallel to the image sensor plane, and the Z axis in the direction of the optical axis. The star sensor coordinate expression refers to the three-dimensional vector form of the sun in the star sensor coordinate system. The heading angle distance refers to the angle between the projection of the optical axis on the horizontal plane and the projection of the sun on the horizontal plane. The pitch angle distance refers to the angle between the optical axis and the sun in the vertical direction.

[0047] Optionally, when the celestial coordinates are the coordinates of the Sun's center of mass: The star-sensor coordinates of the sun in the star-sensor coordinate system are expressed as follows:

[0048] in, Indicates the optical axis in the star sensor coordinate system Components of the axis, Indicates the optical axis in the star sensor coordinate system Components of the axis, Indicates the optical axis in the star sensor coordinate system Components of the axis, Represents the coordinates of the Sun's center of mass. pixel coordinates of the axis This represents the projection point of the optical axis of the star sensor onto the image sensor. coordinate, This represents the projection point of the optical axis of the star sensor onto the image sensor. coordinate, Indicates the focal length of the star sensor. This represents the projection of the solar barycenter coordinates onto the image sensor. coordinate.

[0049] It should be explained that the true north reference information refers to the precise azimuth reference value representing the true north direction of the Earth's rotation axis.

[0050] Combination Figure 2 and Figure 3 Explanation of the solar sensor calculation process: In daytime mode, the imaging module captures images of the sun through filters. For example... Figure 2 As shown, the system interface displays "Starting astronomical orientation, please wait...", indicating that the system has captured an image of the sun and is performing image preprocessing and astronomical calculations. During the calculation process, the sun's image spot is displayed in the center of the interface, surrounded by an image recognition bounding box used to locate the sun's barycenter coordinates. After the calculation is completed, as shown... Figure 3 As shown, the interface status changes to "Astronomical Orientation Completed," and the final calculated precise azimuth result (e.g., 168.78°) is highlighted in a box above.

[0051] Combination Figure 4 and Figure 5 Explanation of the star sensor calculation process: In night mode, the imaging module removes the filter and adjusts parameters to capture an image containing multiple stars. For example... Figure 4 As shown, the interface at this time also displays "Starting astronomical orientation, please wait...", with a starry sky as the background and a central box used to identify and locate stellar spots. After preprocessing the captured stellar images, such as background dark current subtraction and centroid fitting, the system enters the astronomical calculation stage. After the calculation is completed, as shown... Figure 5 As shown, the interface status also changes to "Astronomical Orientation Completed," and displays the same information as before. Figure 3 Consistent, high-precision azimuth results (e.g., 168.78°).

[0052] S4. Compare the true north reference information with the original magnetic azimuth data synchronously output by the observer's magnetic compass to calculate the magnetic declination error of the magnetic compass.

[0053] This invention compares the true north reference information with the raw magnetic azimuth data synchronously output by the observer's magnetic compass, enabling precise calculation of the magnetic declination error of the magnetic compass, thereby achieving calibration and correction. The raw magnetic azimuth data refers to the azimuth value representing the magnetic north pole, directly measured and output by the magnetic compass's internal magnetic field sensor without any software calibration or compensation. The magnetic declination error is the difference between the raw magnetic azimuth data output by the magnetic compass and the true north reference information obtained through high-precision astronomical calculation. This error value quantifies the deviation of the magnetic north pole from the geographic north pole and is a key parameter for measuring the accuracy of the magnetic compass and for its calibration. It is obtained by subtracting the azimuth of the raw magnetic azimuth data from the azimuth of the true north reference information.

[0054] S5. Based on the magnetic declination error, the magnetic compass is used to perform magnetic azimuth information correction processing to obtain target magnetic azimuth information, and based on the target magnetic azimuth information, north-finding measurement processing is performed.

[0055] Based on the magnetic declination error, the magnetic compass is used to perform magnetic azimuth information correction processing to obtain target magnetic azimuth information. This eliminates environmental magnetic field interference and geomagnetic model errors, thereby outputting high-precision target magnetic azimuth information.

[0056] In detail, the step of performing magnetic azimuth information correction processing using the magnetic compass based on the magnetic declination error to obtain target magnetic azimuth information includes: generating the target magnetic azimuth information after magnetic compass correction by algebraically adding the original magnetic azimuth data and the magnetic declination error.

[0057] The algebraic addition refers to the addition operation between the original magnetic azimuth data and the magnetic declination error. The target magnetic azimuth information refers to the magnetic azimuth value that the magnetic compass should display after magnetic declination error correction, which should accurately point to true north.

[0058] In one embodiment, a computer device is provided, which may be a server or a client, and its internal structure diagram may be as follows: Figure 6 As shown. The computer device includes a processor, memory, network interface, and database connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile and / or volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used for communication with external clients via a network connection. When the computer program is executed by the processor, it implements the functions or steps of the server or client side of the magnetic compass north-finding measurement method based on astronomical orientation technology.

[0059] It should be noted that the functions or steps that can be implemented by the computer-readable storage medium or computer device described above can be referred to the relevant descriptions on the server side and client side in the foregoing method embodiments. To avoid repetition, they will not be described one by one here.

[0060] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0061] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0062] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0063] Finally, it should be noted that in the above embodiments, each embodiment can be combined with each other or independent. Deleting any one of them will not affect the technical implementation of other embodiments. The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for measuring north by a magnetic compass based on astronomical orientation technology, characterized in that, The method includes: The current UTC time and the observer's geographical location information are obtained using a pre-set BeiDou module; Celestial images are captured using an imaging module; wherein the celestial images include solar images captured with filters applied in daytime mode and stellar images captured in nighttime mode. The celestial image is preprocessed by the image processing board to extract the celestial coordinates. Based on the celestial coordinates, combined with the UTC time and geographical location information, the azimuth and elevation angles of the optical axis in the geographic coordinate system are calculated using the preset astronomical calculation module to determine the current true north reference information. The true north reference information is compared with the original magnetic azimuth data synchronously output by the observer's magnetic compass to calculate the magnetic declination error of the magnetic compass. Based on the magnetic declination error, the magnetic compass is used to perform magnetic azimuth information correction processing to obtain the target magnetic azimuth information, and based on the target magnetic azimuth information, north-finding measurement processing is performed.

2. The method for north-seeking measurement of a magnetic compass based on celestial orientation technology according to claim 1, characterized in that, The celestial image is preprocessed using an image processing panel to extract the celestial coordinates of the celestial body, including: When the celestial image is a solar image, the solar centroid coordinates of the solar image are calculated using the image processing board; When the celestial image is a stellar image, the coordinates of the stellar barycenter of the stellar image are calculated using the image processing board; The coordinates of the Sun's center of mass and the coordinates of the star's center of mass are used as the celestial coordinates of the celestial body.

3. The method for magnetic compass north-seeking measurement based on celestial orientation technology according to claim 2, characterized in that, When the celestial image is a solar image, the coordinates of the solar barycenter in the solar image are calculated using the image processing board, including: When the celestial image is a solar image, the image processing board performs high dynamic range processing on the solar image to extract the solar disk outline of the solar image; The geometric center coordinates of the solar disk contour are calculated as the coordinates of the solar mass center.

4. The method for finding north by using the magnetic compass based on the celestial orientation technology according to claim 2, characterized in that, When the celestial image is a stellar image, the coordinates of the stellar barycenter are calculated using the image processing panel, including: When the celestial image is a star image, the image processing board performs background dark current subtraction processing on the star image to extract star spots that meet the preset magnitude in the star image; The sub-pixel level centroid coordinates of the stellar spots are calculated using a gray-scale weighted centroid fitting algorithm and used as the stellar centroid coordinates.

5. The method for north seeking measurement of a magnetic compass based on celestial orientation technology according to claim 1, characterized in that, The BeiDou module is used to obtain the current UTC time and the observer's geographical location information, including: The BeiDou module is used to receive BeiDou satellite navigation signals in real time, and the BeiDou satellite navigation signals are processed and demodulated by radio frequency front-end to obtain navigation messages; Extract the raw observation data and UTC synchronization parameters of the navigation message, wherein the raw observation data includes pseudorange observations and satellite ephemeris data; The least squares method is used to solve the pseudorange observations and satellite ephemeris data to obtain the observer's geographical location information and the receiver's local clock error. The receiver outputs the UTC time of the current moment using the local clock difference and the UTC synchronization parameters.

6. The method for north seeking measurement of a magnetic compass based on celestial orientation technology according to claim 1, characterized in that, Capturing celestial images using an imaging module, including: The imaging module acquires light signals within the field of view and adaptively switches to daytime mode or nighttime mode based on the light signals. In daytime mode, a filter is added to the incident light path of the imaging module to acquire solar images; In night mode, the filter is removed, and the gain and exposure parameters of the imaging module are adjusted to a high sensitivity level to acquire stellar images.

7. The method for north seeking measurement of a magnetic compass based on celestial orientation technology according to claim 6, characterized in that, The imaging module includes: a low-light lens, a filter, a low-light CMOS sensor, and a signal processor connected to it. The low-light lens is used to focus celestial radiation signals to increase the amount of light entering the lens; The filter is used to switch the incoming light path in daytime mode to attenuate solar radiation energy, and to switch the incoming light path out in nighttime mode to allow full light signal transmission. The low-light CMOS is used to convert light signals into image signals; The signal processor is used to acquire optical signals to generate mode switching signals, and to control the operation of the filter and adjust the gain and exposure parameters of the low-light CMOS according to the mode switching signals.

8. The method for north seeking measurement of a magnetic compass based on celestial orientation technology according to claim 1, characterized in that, Based on the celestial coordinates, combined with the UTC time and geographical location information, the azimuth and elevation angles of the optical axis in the geographic coordinate system are calculated using a preset astronomical calculation module, including: When the celestial coordinates are the coordinates of the center of mass of a star, the right ascension and declination of the optical axis in the inertial coordinate system are determined in order to calculate the inertial coordinate expression of the optical axis in the inertial coordinate system. The attitude transfer matrix from the inertial coordinate system to the geographic coordinate system is calculated using the UTC time and geographic location information. Based on the inertial coordinate expression and the attitude transfer matrix, the geographic coordinate expression of the optical axis in the geographic coordinate system is calculated, and the pitch angle and azimuth angle of the optical axis are solved using the astronomical calculation module.

9. The method for north seeking measurement of a magnetic compass based on celestial orientation technology according to claim 1, characterized in that, Based on the celestial coordinates, combined with the UTC time and geographical location information, the azimuth and elevation angles of the optical axis in the geographic coordinate system are calculated using a preset astronomical calculation module, including: When the celestial coordinates are the coordinates of the Sun's center of mass, a star-sensor coordinate expression for the Sun in the star-sensor coordinate system is constructed based on the Sun's center of mass coordinates, so as to calculate the yaw and pitch distances between the Sun and the optical axis; The astronomical calculation module uses the heading angle distance and pitch angle distance to calculate the pitch angle and azimuth angle of the optical axis.

10. The method for north seeking measurement of a magnetic compass based on celestial orientation technology according to claim 1, characterized in that, Based on the magnetic declination error, the magnetic compass is used to perform magnetic azimuth information correction processing to obtain target magnetic azimuth information, including: generating the target magnetic azimuth information after magnetic compass correction by algebraically adding the original magnetic azimuth data to the magnetic declination error.

Images