Geomagnetic positioning and navigation method under GPS denial condition

Abstract

The invention provides a geomagnetic positioning and navigation method under a GPS (Global Positioning System) denial condition. The method comprises the following steps: acquiring a geomagnetic value and latitude and longitude coordinate data through an integrated navigation sensor; converting the latitude and longitude coordinates into plane coordinates suitable for establishing a trajectory model, and storing the processed geomagnetic values and corresponding coordinate values into a geomagnetic coordinate database; establishing a plane map track and a geomagnetic plane map model by using the geomagnetic coordinate data of each measurement point; collecting geomagnetic data through a geomagnetic sensor under a GPS denial condition, and storing the geomagnetic data into a geomagnetic database after processing the geomagnetic data; and realizing geomagnetic positioning and navigation under a GPS denial condition by using a matching algorithm based on a minimum Euclidean distance. The geomagnetic positioning and navigation method under the GPS denial condition can effectively solve the positioning problem under the satellite signal limited environment, is suitable for various complex terrain environments, can solve the error accumulation problem existing in GPS navigation, ensures the accuracy of long-term navigation, and has wide application prospects.

Description

Technical Field

[0001] The invention relates to the field of navigation and positioning technology, in particular to a geomagnetic positioning and navigation method under GPS denial conditions. Background Art

[0002] Navigation and positioning technology is one of the key technologies in modern society. It has a long history of development, from the use of natural celestial bodies to the development of artificial satellite navigation systems, and the technology has been continuously improving. Satellite navigation systems (GNSS) provide vital positioning, navigation and timing (PNT) services to users around the world and have become an indispensable infrastructure in modern society. However, these systems have problems with limited signal reception in specific environments such as underground, underwater, or in densely populated areas of high-rise buildings in cities, resulting in reduced navigation accuracy or even failure. In addition, satellite navigation systems also face the problem of error accumulation, especially in long-term navigation, where the accumulation of errors can lead to deviations in positioning results.

[0003] In order to overcome these limitations, multi-source fusion navigation and positioning technology came into being. This technology combines multiple navigation methods such as satellite navigation, inertial navigation, optical / acoustic navigation, gravity / magnetic navigation, etc. to improve the accuracy and reliability of positioning. As an important component of it, geomagnetic navigation and positioning technology is considered to be one of the potential important navigation and positioning means in the future due to its advantages such as wide available area, no cumulative error, passive and strong concealment. Geomagnetic navigation technology includes three important contents: measurement of magnetic field information, establishment of geomagnetic reference map and design of geomagnetic positioning method. Summary of the invention

[0004] In view of the above technical deficiencies, the present invention provides a geomagnetic positioning and navigation method under GPS denial conditions, which effectively solves the positioning problem in an environment with limited satellite signals and the error accumulation problem in GPS navigation, and can be applied to a variety of complex application environments.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0006] A geomagnetic positioning and navigation method under GPS denial conditions, comprising the following steps:

[0007] 1) Collect geomagnetic values ​​and longitude and latitude coordinate data through combined navigation sensors;

[0008] 2) Preprocess the collected data and build a geomagnetic coordinate database;

[0009] 3) Based on the data of the geomagnetic coordinate database, construct the plane map trajectory and the geomagnetic plane map model;

[0010] 4) Under GPS denial conditions, geomagnetic data is collected by a geomagnetic sensor and processed according to step 2) to obtain geomagnetic values ​​of the north component X, the east component Y, and the vertical component Z, and stored in a geomagnetic database;

[0011] 5) Use the minimum Euclidean distance to match the geomagnetic value database with the test points in the geomagnetic coordinate database to achieve geomagnetic positioning and navigation under GPS denial conditions.

[0012] The step 2) comprises the following steps:

[0013] 2.1) Use Mercator projection to convert longitude and latitude coordinates into plane coordinates;

[0014] 2.2) Calculate the north component X, east component Y and vertical component Z of the geomagnetic data according to Taylor polynomials;

[0015] 2.3) Construct a geomagnetic coordinate database, and store the acquired geomagnetic values ​​and plane coordinate values ​​of each position component in the geomagnetic coordinate database one by one according to the timestamp of the data.

[0016] The step 2.1) is specifically as follows:

[0017] Using the Mercator projection, the Earth's surface is projected onto a cylinder surrounding the Earth, and the cylinder is unfolded to obtain the plane coordinates (x, y):

[0018] x=R·λ

[0019]

[0020] Where R is the radius of the Earth, and λ represent the geographic latitude and longitude respectively.

[0021] The step 2.2) is specifically as follows:

[0022]

[0023] in, and λ represent the geographic latitude and longitude respectively, and λ0 are the latitude and longitude of the origin of the Taylor polynomial model expansion, A nm are the coefficients of the polynomial model, N is the highest order of Taylor polynomial expansion, n is and m is the coefficient, 0≤n≤N, 0≤m≤n.

[0024] The step 3) comprises the following steps:

[0025] 3.1) Extract the north component X, east component Y and vertical component Z of the geomagnetic value of each measuring point from the geomagnetic coordinate database, as well as the plane coordinate value corresponding to each geomagnetic value;

[0026] 3.2) Draw the discrete measurement points on the map and connect them into lines according to their spatial relationship to form a planar map trajectory;

[0027] 3.3) Superimpose the geomagnetic value information of each measurement point on the map to obtain a geomagnetic plane map model.

[0028] The step 5) comprises the following steps:

[0029] 5.1) Calculate the Euclidean distance between a test point A in the geomagnetic value database and the geomagnetic values ​​of all test points in the geomagnetic coordinate database;

[0030] 5.2) Find the test point B with the shortest distance as the closest geomagnetic value to the test point A, assign the plane coordinate value of the test point B to the test point A, and complete the matching of the coordinates of the new measurement point.

[0031] The step 5.1) is specifically as follows:

[0032] For the newly collected geomagnetic value M new =(X ′ ,Y ′ ,Z ′ ) and the geomagnetic value M of the i-th test point in the database i =(X i ,Y i ,Z i ), calculate the Euclidean distance d between the two i :

[0033]

[0034] The step 5.2) is specifically as follows:

[0035] Find the minimum distance between measured points and their corresponding indices:

[0036] i min =armgin i d i

[0037] d min =min i d i

[0038] Among them, i min Indicates the index of the point with the smallest distance, d min Indicates the minimum distance value, argmin i d i It means that the function d i Get the value of index i of the minimum value.

[0039] The present invention has the following beneficial effects and advantages:

[0040] The geomagnetic positioning and navigation method under GPS denial conditions designed by the present invention can effectively solve the positioning problem in an environment with limited satellite signals, is applicable to a variety of complex terrain environments, and can also solve the error accumulation problem existing in GPS navigation, thus ensuring the accuracy of long-term navigation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic flow chart of a geomagnetic positioning and navigation method under GPS denial conditions of the present invention;

[0042] Figure 2 The effect diagram of the geomagnetic plane map model constructed in the present invention;

[0043] Figure 3 The effect diagram of geomagnetic matching positioning and navigation in the present invention. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0045] The present invention proposes a geomagnetic positioning and navigation method under GPS denial conditions. The method can effectively solve the positioning problem in an environment with limited satellite signals, is applicable to a variety of complex terrain environments, and can solve the error accumulation problem existing in GPS navigation, ensure the accuracy of long-term navigation, and has broad application prospects. Through this method, high-precision positioning and navigation can be achieved without relying on satellite signals.

[0046] like Figure 1 As shown, the present invention relates to a geomagnetic positioning and navigation method under GPS denial conditions, the method mainly comprising:

[0047] S1, obtaining geomagnetic values ​​and longitude and latitude coordinate data, including the following steps:

[0048] S11, connect the integrated navigation sensor to the receiving port of the data acquisition system, and ensure that the sending data port of the data acquisition system is connected to the industrial computer. Check the interface compatibility, use appropriate connection cables and adapters to ensure stable and reliable data transmission, and check after connection to ensure that there is no looseness or poor contact;

[0049] S12, start the collection function of geomagnetic data and longitude and latitude coordinate data, and check the received data stream through the monitoring software interface to ensure that the sensor is working properly and verify the accuracy and integrity of the data. At the same time, a preliminary check of the data is required to identify any possible abnormal values ​​or errors, which helps to promptly discover and solve possible problems in the sensor or connection;

[0050] S2, data processing and construction of geomagnetic coordinate database, including the following steps:

[0051] S21, convert the longitude and latitude coordinates into plane coordinates suitable for establishing trajectory models. First, the earth is approximated as an ellipsoid, and the longitude and latitude system provides a global reference frame, where longitude λ represents the angle relative to the prime meridian, and latitude Represents the angle relative to the equator. The present invention uses the Mercator projection, which is a cylindrical projection that projects the earth's surface onto a cylinder surrounding the earth, and then unfolds the cylinder to obtain plane coordinates. The formula is as follows:

[0052] x=R·λ

[0053]

[0054] Here, R is the radius of the Earth, longitude λ and latitude The unit should be radians.

[0055] S22, processing the collected geomagnetic data, and calculating the north component (X), east component (Y) and vertical component (Z) of the geomagnetic field according to Taylor polynomials, which can be expressed as:

[0056]

[0057] in, and λ represent the geographic latitude and longitude respectively, and λ0 are the latitude and longitude of the origin of the Taylor polynomial model expansion, A nm are the coefficients of the polynomial model, which can be determined by the least squares method.

[0058] S23, construct a geomagnetic coordinate database, design a reasonable data structure to store timestamps, geomagnetic values ​​of north component X, east component Y, vertical component Z, and plane coordinate values, and store the acquired geomagnetic values ​​and plane coordinate values ​​of each position in the geomagnetic coordinate database one by one according to the timestamp to ensure the timeliness and accuracy of the data. In order to ensure data security, the database will be backed up regularly to prevent data loss or system failure.

[0059] S3, establishing a plane map trajectory and a geomagnetic plane map model, including the following steps:

[0060] S31, extracting the north component X, east component Y and vertical component Z of each measurement point from the geomagnetic coordinate database, which describe the distribution of the geomagnetic field in three-dimensional space. At the same time, it is also necessary to obtain the plane coordinate values ​​corresponding to these geomagnetic values;

[0061] S32, depicting these discrete points on the map and connecting them into lines according to their spatial relationships to form a plane map trajectory model, so as to intuitively display the distribution of the measurement path in the geographic space;

[0062] S33, based on the plane map trajectory model, the geomagnetic value information of each point is superimposed on the map to establish a complete geomagnetic plane map model. Figure 2 As shown, the green line is the plane map trajectory model, and the red dots show some measurement points and their corresponding geomagnetic values ​​(north component X, east component Y, vertical component Z).

[0063] S4, under GPS denial conditions, geomagnetic data is collected through a geomagnetic sensor and processed to obtain geomagnetic values ​​of the north component X, east component Y, and vertical component Z, and stored in a geomagnetic database, wherein the geomagnetic data collection method, geomagnetic data processing method, and geomagnetic data storage database structure are the same as steps S1 and S2.

[0064] S5, using the matching algorithm based on the minimum Euclidean distance to achieve geomagnetic positioning and navigation under GPS denial conditions. The geomagnetic value database collected under GPS denial conditions is matched with the existing data in the geomagnetic coordinate database. The core idea of ​​this algorithm is to calculate the difference between the newly collected geomagnetic value and the geomagnetic value of each test point in the database, and use the Euclidean distance to measure this difference. Specifically, for the newly collected geomagnetic value M new =(X ′ ,Y ′ ,Z ′ ) and the geomagnetic value M of the i-th test point in the database i =(X i ,Y i ,Z i ), the Euclidean distance between them is calculated using the following formula:

[0065]

[0066] This represents the linear distance in three-dimensional space between the geomagnetic value collected under GPS denial conditions and the geomagnetic value of the i-th test point in the database. This algorithm performs such calculations for all test points in the database, and then finds the point with the smallest distance, that is, the newly collected geomagnetic value is considered to be closest to the geomagnetic value of this point. Use the following formula to find the minimum distance and its corresponding index:

[0067] i min =argmin i d i

[0068] d min =min i di

[0069] Here, I min Indicates the index of the point with the smallest distance, d min Represents the minimum distance value. Once the best matching point is determined, the plane coordinate value of the point is assigned to the new measurement point to complete the matching of the coordinates of the new measurement point, thereby achieving geomagnetic positioning and navigation under GPS denial conditions. This process not only takes into account the three components of the geomagnetic field, but also ensures the accuracy of the matching by minimizing the distance, so that the newly collected data can be accurately mapped to the corresponding position in the geomagnetic coordinate database. Figure 3 As shown in the figure, positioning in the geomagnetic plane model map can be achieved under GPS denial conditions. The blue dot shows the matching positioning of the test point in the plane map trajectory model, and its coordinate value can be displayed at the same time.

[0070] It should be clear that the above-displayed process form can be flexibly adjusted according to needs, including reordering, adding or removing steps, etc. For example, the steps recorded in the present invention can be executed in parallel, sequentially, or in a different order, as long as the expected results of the technical solution proposed by the present invention can be achieved, and this document does not limit it here.

[0071] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A geomagnetic positioning and navigation method under GPS denial conditions, characterized in that: The following steps are involved: 1) Collect geomagnetic values ​​and longitude and latitude coordinate data through combined navigation sensors; 2) Preprocess the collected data and build a geomagnetic coordinate database; 3) Based on the data of the geomagnetic coordinate database, construct the plane map trajectory and the geomagnetic plane map model; 4) Under GPS denial conditions, geomagnetic data is collected by a geomagnetic sensor and processed according to step 2) to obtain geomagnetic values ​​of the north component X, the east component Y, and the vertical component Z, and stored in a geomagnetic database; 5) Use the minimum Euclidean distance to match the geomagnetic value database with the test points in the geomagnetic coordinate database to achieve geomagnetic positioning and navigation under GPS denial conditions.

2. The method for geomagnetic positioning and navigation under GPS denial conditions according to claim 1, characterized in that: Step 2) The following steps are involved: 2.1) Use Mercator projection to convert longitude and latitude coordinates into plane coordinates; 2.2) Calculate the north component X, east component Y and vertical component Z of the geomagnetic data according to Taylor polynomials; 2.3) Construct a geomagnetic coordinate database, and store the acquired geomagnetic values ​​and plane coordinate values ​​of each position component in the geomagnetic coordinate database one by one according to the timestamp of the data.

3. The method for geomagnetic positioning and navigation under GPS denial conditions according to claim 2, characterized in that: The step 2.1) is specifically as follows: Using the Mercator projection, the Earth's surface is projected onto a cylinder surrounding the Earth, and the cylinder is unfolded to obtain the plane coordinates (x, y): x=R·λ Where R is the radius of the Earth, and λ represent the geographic latitude and longitude respectively.

4. The method for geomagnetic positioning and navigation under GPS denial conditions according to claim 2, characterized in that: The step 2.2) is specifically as follows: in, and λ represent the geographic latitude and longitude respectively, and λ0 are the latitude and longitude of the origin of the Taylor polynomial model expansion, A nm are the coefficients of the polynomial model, N is the highest order of Taylor polynomial expansion, n is and m is the coefficient, 0≤n≤N, 0≤m≤n.

5. The method for geomagnetic positioning and navigation under GPS denial conditions according to claim 1, characterized in that: The step 3) comprises the following steps: 3.1) Extract the north component X, east component Y and vertical component Z of the geomagnetic value of each measuring point from the geomagnetic coordinate database, as well as the plane coordinate value corresponding to each geomagnetic value; 3.2) Draw the discrete measurement points on the map and connect them into lines according to their spatial relationship to form a planar map trajectory; 3.3) Superimpose the geomagnetic value information of each measurement point on the map to obtain a geomagnetic plane map model.

6. The method for geomagnetic positioning and navigation under GPS denial conditions according to claim 1, characterized in that: The step 5) comprises the following steps: 5.1) Calculate the Euclidean distance between a test point A in the geomagnetic value database and the geomagnetic values ​​of all test points in the geomagnetic coordinate database; 5.2) Find the test point B with the shortest distance as the closest geomagnetic value to the test point A, assign the plane coordinate value of the test point B to the test point A, and complete the matching of the coordinates of the new measurement point.

7. The method for geomagnetic positioning and navigation under GPS denial conditions according to claim 6, characterized in that: The step 5.1) is specifically as follows: For the newly collected geomagnetic value M new =(X ′ ,Y ′ ,Z ′ ) and the geomagnetic value M of the i-th test point in the database i =(X i ,Y i ,Z i ), calculate the Euclidean distance d between the two i :

8. The method for geomagnetic positioning and navigation under GPS denial conditions according to claim 6, characterized in that: The step 5.2) is specifically as follows: Find the minimum distance between measured points and their corresponding indices: i min =argmin i d i the min =min i the i Among them, i min Indicates the index of the point with the smallest distance, d min Indicates the minimum distance value, argmin i d i It means that the function d i Get the value of index i of the minimum value.

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