A method and system for calibrating the pose of an array antenna

Abstract

The application discloses a method and system for calibrating the attitude of an array antenna, which comprises the following steps: accurately measuring the real coordinates of the center point of the array direction-finding antenna; obtaining acceleration values; calculating the pitch angle and roll angle of the array antenna according to the acceleration values; placing a positioning tag around the array antenna, measuring the real coordinates of the positioning tag, and calculating the azimuth angle and pitch angle of the positioning tag relative to the array antenna; calculating the measured coordinates of the positioning tag and the coordinates after rotation of the measured coordinates; and calculating the azimuth angle by combining the pitch angle, roll angle, measured coordinates of the positioning tag and the coordinates after rotation of the measured coordinates of the array antenna. The application improves the efficiency and accuracy of calibration by installing an accelerometer on the array antenna and comprehensively using the accelerometer and the positioning tag for calibration. In this way, the calibration work can be completed by using only one tag position.

Description

Technical Field

[0001] This invention relates to the field of wireless communication positioning technology, and more specifically to a method and system for calibrating the attitude of an array antenna. Background Technology

[0002] With the increasingly widespread application of indoor positioning and its enormous commercial value, various positioning technologies have emerged. Compared with ranging-based positioning methods, array-based direction finding positioning methods can greatly reduce the number of base stations deployed. However, it is quite sensitive to the attitude of the array antenna and has high requirements for attitude accuracy. That is, the attitude error of the array antenna may lead to a relatively large positioning deviation.

[0003] To eliminate positioning errors caused by the antenna array's installation attitude, we need to strictly control its installation attitude. However, this is too difficult in practical use and cannot be widely adopted. Manually measuring the antenna array's attitude is time-consuming, requires specialized equipment, and is costly. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for calibrating the attitude of an array antenna by comprehensively using accelerometers and positioning tags, which can greatly improve the efficiency and accuracy of calibration and solve the problems of high difficulty, high cost and complex calibration methods in the process of calibrating array antennas.

[0005] To achieve the aforementioned objective, this invention provides a method for calibrating the attitude of an array antenna, comprising:

[0006] Accurately measure the true coordinates of the center point A of the array antenna;

[0007] An accelerometer is installed on the array antenna to obtain the pitch angle p and roll angle r of the array antenna;

[0008] Positioning tags are placed around the array antenna, and the true coordinates Pr of the positioning tags, as well as the azimuth angle θ and elevation angle of the positioning tags relative to the array antenna, are measured.

[0009] Using the true coordinates of the center point A of the array direction-finding antenna, the azimuth angle θ and elevation angle And the measured coordinates P of the positioning tag are calculated from the actual coordinates Pr of the positioning tag;

[0010] The coordinates P' of the measured coordinate point P after rotation are obtained;

[0011] The azimuth angle δ is calculated using the coordinates of P and P', in conjunction with the pitch angle p and roll angle r.

[0012] Optionally, the coordinate system of the accelerometer mounted on the array antenna coincides with the coordinate system of the array antenna.

[0013] Optionally, the process of obtaining the elevation angle p and roll angle r of the array antenna includes: the acceleration values ​​obtained by the accelerometer in the x, y, and z directions of the coordinate system are a, p, and r, respectively. x ,a y ,a z The elevation angle p and roll angle r of the array antenna are obtained as follows:

[0014]

[0015] r = arctan(a y / a z ).

[0016] Optionally, the elevation angle of the positioning tag relative to the array antenna The range is from 20 degrees to 50 degrees.

[0017] Optionally, the array antenna collects data and uploads it to a server, whereby the server performs direction finding processing on the positioning tag to obtain the azimuth angle θ and elevation angle.

[0018] The actual coordinates of the center point A of the array direction-finding antenna, the azimuth angle θ and the elevation angle are used. The process of determining the actual coordinates Pr of the positioning tag includes:

[0019] Using the true coordinates (x0, y0, z0) of the center point A of the array direction-finding antenna, the azimuth angle θ and the elevation angle The measured coordinates P of the positioning tag are calculated using the actual coordinates Pr(Xr1,Yr1,Zr1) of the positioning tag.

[0020] If the center point A(x0,y0,z0) of the array antenna is translated to (0,0,z0), then the real coordinates Pr of the positioning tag will also become: (Xr1-x0,Yr1-y0,Zr1), denoted as: (X1,Y1,Z1).

[0021] When the array antenna is located at (0,0,z0), the height of the positioning tag is Z1. Therefore, the height difference between the positioning tag and the array antenna is z0-Z1, calculated using the azimuth angle θ and the elevation angle. Determine the coordinates of the location tag's measurement coordinate P:

[0022]

[0023] The measured coordinates P of the positioning tag are obtained as (x1, y1, z1), where z1 is the actual height of the positioning tag.

[0024] The process of obtaining the coordinates P' of the measured coordinate point P after rotation includes: connecting the center point A of the array direction finding antenna with the real coordinates Pr of the positioning tag to obtain a line segment APr; rotating the horizontal plane through the rotation matrix R to obtain a plane; the intersection of the line segment APr and the plane is P'; then the position of P' relative to the array antenna coordinate system is the same as the position of P relative to the map coordinate system, so P' is the point P after rotation through the rotation matrix R.

[0025] Using the coordinates of point A (0,0,z0) and point P (x1,y1,z1), we obtain:

[0026]

[0027] The coordinates of P' are calculated as (x′1, y′1, z′1) based on the actual coordinates Pr(X1, Y1, Z1) of the positioning tag and the length of AP'.

[0028] Optionally, the process of calculating the azimuth angle by combining the coordinates of pitch angle p, roll angle r, P, and P' includes:

[0029] According to the formula:

[0030] R = R z R y R x

[0031] Where R represents the rotation matrix;

[0032] Rz, Ry, and Rx represent rotation matrices in the z, y, and x directions, respectively;

[0033] δ, p, r represent the azimuth, pitch, and roll angles, respectively.

[0034]

[0035]

[0036]

[0037] Because P′=RP, therefore:

[0038]

[0039]

[0040] Given the pitch angle and roll angle p and r, let:

[0041]

[0042] but:

[0043]

[0044] The above formula simplifies to:

[0045]

[0046] The above equation can be transformed into:

[0047]

[0048] so:

[0049]

[0050] Thus, the azimuth angle δ is obtained.

[0051] Optionally, the process of calculating the azimuth angle by combining the pitch angle p, roll angle r, P, and P' coordinates can also be as follows: select the positions of multiple different positioning tags, and calculate the azimuth angle δ using multiple sets of P and P', thus obtaining:

[0052]

[0053] set up:

[0054]

[0055]

[0056]

[0057] but:

[0058] Am = b

[0059] The above formula uses the least squares method to find m:

[0060] m=(A T A) -1 A T b

[0061] Find cos(δ) and sin(δ) to obtain the azimuth angle δ.

[0062] Optionally, it also includes calibrating the measurement coordinates of the positioning tag using a rotation matrix R.

[0063] Optionally, calibrating the measurement coordinates of the positioning tag using the rotation matrix R includes:

[0064] According to the formula:

[0065]

[0066] When the base station is located at point A(0,0,z0), the azimuth and elevation angles of the positioning tag relative to the base station are obtained through direction finding. Calculate the measured coordinates P of the positioning tag:

[0067]

[0068] Where z is the height of the positioning label;

[0069] Rotate the measured coordinates P(x,y,z) of the positioning tag using a rotation matrix R to obtain point P':

[0070]

[0071] Calculate the intersection point Pr(X1,Y1,z) of the straight line determined by base station A and point P' and the horizontal plane where the positioning label is located;

[0072] Based on the actual location of the base station, the actual location of the positioning tag is calculated as (X1+x0,Y1+y0,z).

[0073] The present invention also provides a system for calibrating the attitude of an array antenna, comprising: an acceleration measurement module, a direction finding module, a calculation module, and an attitude angle acquisition module;

[0074] The acceleration measurement module is used to obtain the pitch angle p and roll angle r of the array antenna;

[0075] The direction-finding module is used to accurately measure the true coordinates of the center point A of the array antenna, the true coordinates of the positioning tag, and the azimuth angle θ and elevation angle of the positioning tag relative to the array antenna.

[0076] The calculation module is used to accurately calculate the measured coordinates P of the positioning tag and the coordinates P' of the measured coordinates P after rotation using the data measured by the direction finding module;

[0077] The attitude angle acquisition module is used to calculate the azimuth angle δ by combining the pitch angle p, roll angle r, P calculated by the calculation module, and P' coordinates.

[0078] Optionally, a calibration module may also be included, which is used to calibrate the coordinates of the positioning tag using the rotation matrix R.

[0079] The present invention also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the method described above.

[0080] Compared to existing technologies, this invention utilizes the true coordinates of a set of array antenna center points A. It obtains the elevation angle p and roll angle r of the array antenna by installing an accelerometer on the antenna. The measured coordinates P of the positioning tag are obtained using its true coordinates Pr and its azimuth and elevation angles relative to the array antenna. Then, the coordinates P' of the rotated point P are obtained. Finally, the azimuth angle δ is calculated by combining the coordinates of the elevation angle p, roll angle r, P, and P'. This invention's technical solution directly obtains the elevation angle p and roll angle r of the array antenna by installing an accelerometer on the antenna, which is simple and fast. By combining accelerometers and positioning tags to calibrate the array antenna attitude, only one positioning tag is needed to complete the calibration, greatly improving the efficiency and accuracy of calibration. The method is simple to operate, does not require third-party professional equipment, and solves the problems of high difficulty, high cost, and complex methods in array antenna attitude calibration. Attached Figure Description

[0081] Figure 1 This is a schematic diagram of the array antenna coordinate system in an embodiment of the present invention;

[0082] Figure 2 This is the procedure for calibrating the attitude of the array antenna in an embodiment of the present invention. Figure 1 ;

[0083] Figure 3 This is the procedure for calibrating the attitude of the array antenna in an embodiment of the present invention. Figure 2 ;

[0084] Figure 4 This is a schematic diagram showing the position of P in the coordinate system in an embodiment of the present invention;

[0085] Figure 5 This is a schematic diagram showing the position of each point in the coordinate system after rotation in an embodiment of the present invention. Detailed Implementation

[0086] The method for calibrating the attitude of an array antenna according to the present invention will now be described in more detail with reference to the schematic diagrams, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0087] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0088] With the increasingly widespread application of indoor positioning and its enormous commercial value, various positioning technologies have emerged. Compared with ranging-based positioning methods, array-based direction finding positioning methods can greatly reduce the number of base stations deployed. However, it is quite sensitive to the attitude of the array antenna and has high requirements for attitude accuracy. That is, the attitude error of the array antenna may lead to a relatively large positioning deviation.

[0089] In related technologies, to eliminate the positioning errors caused by the array antenna's installation attitude, the installation attitude of the array antenna needs to be strictly controlled. However, this is too difficult to implement in practice and cannot be used on a large scale. Manually measuring the array antenna's attitude is time-consuming and requires specialized equipment, resulting in high costs.

[0090] The inventors discovered that the method of using positioning tags to calibrate the attitude of array antennas is relatively simpler to operate than manual measurement. However, each calibration requires precise measurement of at least two tag positions to obtain a good calibration effect. In scenarios with a large number of positioning base stations, this requires a very large workload for calibration.

[0091] Therefore, this invention proposes a method for calibrating the attitude of an array antenna using an accelerometer and a positioning tag.

[0092] The method for calibrating the attitude of an array antenna provided by this invention requires measuring the attitude relationship of the array antenna relative to a map reference coordinate system, such as... Figure 1 As shown, in this embodiment, to facilitate the description of the installation attitude of the array direction-finding antenna, a Cartesian three-dimensional coordinate system with the array antenna as the reference is defined, taking a uniform circular array as an example:

[0093] The origin of the coordinate system is the center point of the uniform circular array;

[0094] The line connecting the first array element to the center of the uniform circular array is the x-axis of the coordinate system, and the direction from the center of the uniform circular array to the first array element is the positive direction.

[0095] The straight line perpendicular to the uniform circular array and passing through the origin of the coordinate system is the z-axis, and the direction of the array antenna toward the ground is the negative direction of the z-axis;

[0096] The y-axis is perpendicular to the xz plane and passes through the origin of the coordinate system.

[0097] Define the map reference coordinate system as (which can be combined with...) Figure 4 ):

[0098] X, Y, and the origin are based on the X, Y, and origin on the map;

[0099] The Z-axis is defined as the direction perpendicular to the horizontal plane.

[0100] The installation attitude of the array side antenna is described by Euler angles with a rotation sequence of ZYX. That is, the coordinate system of the array antenna initially coincides with the map reference coordinate system and rotates around ZYX in sequence to generate azimuth, pitch and roll angles.

[0101] Azimuth (yaw): The angle by which the array antenna rotates around the Z-axis;

[0102] Pitch: The angle by which the array antenna rotates around the X-axis;

[0103] Roll angle: The angle at which the array antenna rotates around the Y-axis.

[0104] The method for calibrating the attitude of an array antenna provided by this invention is for obtaining accurate azimuth, pitch, and roll data of the array antenna.

[0105] Please refer to Figure 2-3 The method for calibrating the attitude of the array antenna of the present invention will be described in detail below.

[0106] S1. Accurately measure the true coordinates of the center point A of the array antenna;

[0107] S2. An accelerometer is installed on the array antenna to obtain the pitch angle p and roll angle r of the array antenna;

[0108] S3. Place positioning tags around the array antenna, and measure the true coordinates Pr of the positioning tags, as well as the azimuth angle θ and elevation angle of the positioning tags relative to the array antenna.

[0109] S4. Using the true coordinates of the center point A of the array direction-finding antenna, the azimuth angle θ and elevation angle... And the measured coordinates P of the positioning tag are calculated from the actual coordinates Pr of the positioning tag;

[0110] S5. Obtain the coordinates P' of the measured coordinate point P after rotation;

[0111] S6. Calculate the azimuth angle δ by combining the coordinates of the pitch angle p, roll angle r, P, and P'.

[0112] Specifically, in step S1, the actual coordinates of the precisely measured array antenna center point A on the map are (X0, Y0, Z0).

[0113] In step S2, an accelerometer is installed on the array antenna. In this embodiment, preferably, the coordinate system of the accelerometer coincides with the coordinate system of the array antenna, so the attitude of the accelerometer represents the attitude of the array antenna.

[0114] In other embodiments, coordinate system rotation processing can be used to rotate data from two coordinate systems to the same coordinate system.

[0115] The acceleration values ​​obtained by the velocities in the x, y, and z directions are a, respectively. x ,a y ,a z This allows us to obtain the pitch angle p and roll angle r of the accelerometer, which in turn gives us the pitch angle p and roll angle r of the array antenna.

[0116] Specifically, in step S3, a positioning tag is placed at a certain position below the array antenna, and the actual coordinates Pr(Xr1,Yr1,Zr1) of the positioning tag on the map are accurately measured.

[0117] In this embodiment, preferably, the pitch angle of the tag relative to the array antenna can be between 20 and 50 degrees. In actual measurement, other angles may also be used.

[0118] The array antenna collects data and uploads it to the server. The server performs direction finding processing on the tag to obtain the azimuth angle θ and elevation angle of the tag relative to the array antenna.

[0119] In step S4, the coordinates (x0, y0, z0), azimuth angle, and elevation angle of the center point of the array antenna are used. And the coordinates of the measured coordinates P of the positioning tag are calculated using the actual coordinates Pr(Xr1,Yr1,Zr1) of the positioning tag:

[0120] For ease of calculation, the coordinates of the array antenna center point (x0, y0, z0) are shifted to (0, 0, z0), and the actual coordinates of the positioning tag also become:

[0121] (Xr1-x0,Yr1-y0,Zr1) is denoted as (X1,Y1,Z1).

[0122] Please refer to Figure 4 When the array antenna is located at (0,0,z0), the height of the positioning tag is Z1. Therefore, the height difference between the positioning tag and the array antenna is z0-Z1. This difference is determined by the azimuth angle θ and the elevation angle. Determine the coordinates of the location tag's measurement coordinate P:

[0123]

[0124] Therefore, the coordinates of the measured coordinates P of the N sets of positioning tags are obtained as follows:

[0125] (x1,y1,z1)

[0126] Where z1 is the actual height of the positioning label.

[0127] In step S5, the coordinates of point P' after rotating the measured coordinates P of the positioning tag are calculated:

[0128] Please refer to Figure 5 In this embodiment, all coordinates in the figure are values ​​in the map coordinate system; the coordinates of the center point A of the array antenna in the figure are (0,0,z0), and Pr(X1,Y1,Z1) are the position coordinates of the actual position of the positioning tag after the same translation; the ideal attitude of the array antenna is the attitude parallel to the map reference coordinate system, and the actual attitude of the array antenna has a rotation angle compared with the ideal attitude; it is assumed that the actual attitude of the array antenna is obtained by rotating the ideal attitude around point A according to the rotation matrix R, point O is the origin of the map coordinate system, O' is the point after rotating point O by the rotation matrix R, and the plane L' parallel to the array antenna and passing through point O is also the plane obtained by rotating the horizontal plane L by the rotation matrix R.

[0129] The azimuth angle θ and elevation angle are measured by the array direction-finding antenna. Calculate the measured coordinates P(x1, y1, z1) of the positioning tag. Since P and Pr are located on the same horizontal plane, z1 = Z1. P' is the intersection of the line APr and the plane L'. Also, the azimuth angle θ and pitch angle of Pr relative to point A are calculated. The azimuth θ and elevation angle of point P relative to point A They are the same. P' is a point on the straight line APr and on the plane L'. Therefore, the position of P' relative to the array antenna coordinate system is the same as the position of P relative to the map coordinate system. So P' is also the point after P is rotated by the rotation matrix R, that is, (x′1,y′1,z′1)=R(x1,y1,z1).

[0130] Therefore:

[0131]

[0132] Using the coordinates of point A (0,0,z0), the actual coordinates of the positioning tag Pr (X1,Y1,Z1), and the length of AP', calculate the coordinates of P' (x′1,y′1,z′1).

[0133] In step S6, according to the formula:

[0134] R = R z R y R x

[0135] Where R represents the rotation matrix;

[0136] Rz, Ry, and Rx represent rotation matrices in the z, y, and x directions, respectively;

[0137] δ, p, r represent the azimuth, pitch, and roll angles, respectively.

[0138]

[0139]

[0140]

[0141] Because P′=RP, therefore:

[0142]

[0143] Given the pitch angle and roll angle p and r, let:

[0144]

[0145] but:

[0146]

[0147] Since the azimuth angle is independent of the Z value, the above formula simplifies to:

[0148]

[0149] The above equation can be transformed into:

[0150]

[0151] so:

[0152]

[0153] Thus, the azimuth angle δ is obtained.

[0154] In other embodiments, the process of calculating the azimuth angle δ by combining the pitch angle p, roll angle r, P, and P' coordinates in step S6 can also be: selecting multiple sets of different positioning tag positions, and using multiple sets of P and P' to calculate the azimuth angle δ, thus having:

[0155]

[0156] set up:

[0157]

[0158]

[0159]

[0160] but:

[0161] Am = b

[0162] The above formula uses the least squares method to find m:

[0163] m=(A T A) -1 A T b

[0164] Find cos(δ) and sin(δ) to obtain the azimuth angle δ.

[0165] Furthermore, in this embodiment of the invention, the method further includes calibrating the measurement coordinates of the positioning tag using a rotation matrix R, as follows:

[0166] According to the formula:

[0167]

[0168] Assuming the base station is located at point A(0,0,z0), the azimuth and elevation angles of the positioning tag relative to the base station are obtained through direction finding. Then the measured coordinates P of the positioning tag can be calculated:

[0169]

[0170] Where z is the height of the positioning label;

[0171] Rotate the measured coordinates P(x,y,z) of the positioning tag using a rotation matrix R to obtain point P':

[0172]

[0173] Calculate the intersection point Pr(X1,Y1,z) of the straight line determined by base station A and point P' and the horizontal plane where the positioning tag is located;

[0174] Based on the actual location of the base station, calculate the actual location of the positioning tag: (X1+x0,Y1+y0,z).

[0175] This invention also provides an attitude calibration system for an array direction-finding antenna, comprising: an acceleration measurement module, a direction-finding module, a calculation module, and an attitude angle acquisition module;

[0176] The acceleration measurement module is used to obtain the pitch angle p and roll angle r of the array antenna;

[0177] The direction-finding module is used to accurately measure the true coordinates of the center point A of the array antenna, the true coordinates of the positioning tag, and the azimuth angle θ and elevation angle of the positioning tag relative to the array antenna.

[0178] The calculation module is used to accurately calculate the measured coordinates P of the positioning tag and the coordinates P' of the measured coordinates P after rotation using the data measured by the direction finding module;

[0179] The attitude angle acquisition module is used to calculate the azimuth angle δ by combining the pitch angle p, roll angle r, and the coordinates of P and P' calculated by the calculation module.

[0180] The acceleration measurement module specifically obtains the elevation angle p and roll angle r of the array antenna in the following manner:

[0181] The acceleration values ​​obtained by the accelerometer in the x, y, and z directions of the coordinate system are a, a, and a, respectively. x ,a y ,a z The elevation angle p and roll angle r of the array antenna are obtained as follows:

[0182]

[0183] r = arctan(a y / a z ).

[0184] The calculation module is specifically used to obtain the measured coordinates P of the positioning tag in the following form:

[0185] The true coordinates (x0, y0, z0), azimuth angle θ, and elevation angle of the center point A of the array direction-finding antenna are obtained by measuring using the direction-finding module. The measured coordinates P of the positioning tag are calculated using the actual coordinates Pr(Xr1,Yr1,Zr1) of the positioning tag.

[0186] If the center point A(x0,y0,z0) of the array antenna is translated to (0,0,z0), then the real coordinates Pr of the positioning tag will also become: (Xr1-x0,Yr1-y0,Zr1), denoted as: (X1,Y1,Z1).

[0187] Please refer to Figure 4 When the array antenna is located at (0,0,z0), the height of the positioning tag is Z1. Therefore, the height difference between the positioning tag and the array antenna is z0-Z1. This difference is determined by the azimuth angle θ and the elevation angle. Determine the coordinates of the location tag's measurement coordinate P:

[0188]

[0189] The measured coordinates P of the positioning tag are obtained as (x1, y1, z1), where z1 is the actual height of the positioning tag.

[0190] The calculation module is specifically used to obtain the rotated coordinates P' in the following manner:

[0191] The coordinates of the center point A of the array antenna are (0,0,z0). Pr(X1,Y1,Z1) are the position coordinates of the actual position of the positioning tag after the same translation. The actual attitude of the array antenna is rotated by an angle compared with the ideal attitude. It is assumed that the actual attitude of the array antenna is obtained by rotating the ideal attitude around point A with rotation matrix R. Point O is the origin of the map coordinate system. O' is the point after rotating point O with rotation matrix R. The plane L', which is parallel to the array antenna and passes through point O, is also the plane obtained by rotating the horizontal plane L with rotation matrix R.

[0192] The azimuth angle θ and elevation angle are measured by the array direction-finding antenna. Calculate the measured coordinates P(x1, y1, z1) of the positioning tag. Since P and Pr are located on the same horizontal plane, z1 = Z1. P' is the intersection of the line APr and the plane L'. Also, the azimuth angle θ and pitch angle of Pr relative to point A are calculated. The azimuth θ and elevation angle of point P relative to point A They are the same. P' is a point on the line APr and on the plane L'. Therefore, the position of P' relative to the array antenna coordinate system is the same as the position of P relative to the map coordinate system. So P' is also the point after P is rotated by the rotation matrix R, that is, (x1′,y1′,z1′)=R(x1,y1,z1).

[0193] Therefore:

[0194]

[0195] Using the coordinates of point A (0,0,z0), the actual coordinates of the positioning tag Pr (X1,Y1,Z1), and the length of AP', calculate the coordinates of P' (x′1,y′1,z′1).

[0196] The attitude angle acquisition module is specifically used to obtain the rotation matrix R according to the following method: Based on the formula:

[0197] R = R z R y R x

[0198] Where R represents the rotation matrix;

[0199] Rz, Ry, and Rx represent rotation matrices in the z, y, and x directions, respectively;

[0200] δ, p, r represent the azimuth, pitch, and roll angles, respectively.

[0201]

[0202]

[0203]

[0204] Because P′=RP, therefore:

[0205]

[0206] Given the pitch angle and roll angle p and r, let:

[0207]

[0208] but:

[0209]

[0210] Since the azimuth angle is independent of the Z value, the above formula simplifies to:

[0211]

[0212] The above equation can be transformed into:

[0213]

[0214] so:

[0215]

[0216] Thus, the azimuth angle δ is obtained.

[0217] The attitude angle acquisition module can also be used to obtain the rotation matrix R in the following manner:

[0218] By selecting multiple sets of different location tags and calculating the azimuth angle δ using multiple sets of P and P', we can obtain:

[0219]

[0220] set up:

[0221]

[0222]

[0223]

[0224] but:

[0225] Am = b

[0226] The above formula uses the least squares method to find m:

[0227] m=(A T A) -1 A T b

[0228] Find cos(δ) and sin(δ) to obtain the azimuth angle δ.

[0229] Furthermore, it also includes a calibration module, which is used to calibrate the measurement coordinates of the positioning tag using a rotation matrix R.

[0230] Specifically, the calibration module is calibrated in the following manner:

[0231] According to the formula:

[0232]

[0233] Assuming the base station is located at point A(0,0,z0), the azimuth and elevation angles of the positioning tag relative to the base station are obtained through direction finding. Then the measured coordinates P of the positioning tag can be calculated:

[0234]

[0235] Where z is the height of the positioning label;

[0236] Rotate the measured coordinates P(x,y,z) of the positioning tag using a rotation matrix R to obtain point P':

[0237]

[0238] Calculate the intersection point Pr(X1,Y1,z) of the straight line determined by base station A and point P' and the horizontal plane where the positioning tag is located;

[0239] Based on the actual location of the base station, calculate the actual location of the positioning tag: (X1+x0,Y1+y0,z).

[0240] Accordingly, other embodiments of this application may also provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the various method embodiments of this application. Computer-readable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0241] In summary, the technical solution of this invention directly obtains the pitch angle p and roll angle r of the array antenna by installing an accelerometer on the array antenna, which is simple and quick. By combining the use of accelerometers and positioning tags to calibrate the attitude of the array antenna, only one positioning tag is needed to complete the calibration work, which greatly improves the efficiency and accuracy of calibration. The operation is simple and does not require third-party professional equipment. It solves the problems of high difficulty, high cost and complex methods in the process of array antenna attitude calibration, which is both efficient and accurate. Multiple positioning tags can also be used in combination to further increase the accuracy of calibration.

[0242] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for calibrating the attitude of an array antenna, characterized in that, include: Accurately measure the true coordinates of the center point A of the array antenna; An accelerometer is installed on the array antenna to obtain the pitch angle p and roll angle r of the array antenna; Positioning tags are placed around the array antenna, and the true coordinates Pr of the positioning tags and the azimuth angle of the positioning tags relative to the array antenna are measured. and pitch angle ; Using the true coordinates of the center point A of the array antenna, the azimuth angle and pitch angle And the measured coordinates P of the positioning tag are calculated from the actual coordinates Pr of the positioning tag; A line segment APr is obtained by connecting the center point A of the array antenna with the real coordinate Pr of the positioning tag. The horizontal plane is rotated by the rotation matrix R to obtain a plane. The intersection point of the line segment APr and the plane is P'. The azimuth angle δ of the array antenna is calculated by combining the coordinates of the elevation angle p, roll angle r, P, and P'.

2. The method for calibrating the attitude of an array antenna as described in claim 1, characterized in that, The coordinate system of the accelerometer mounted on the array antenna coincides with the coordinate system of the array antenna.

3. The method for calibrating the attitude of an array antenna as described in claim 1, characterized in that, The process of obtaining the elevation angle p and roll angle r of the array antenna includes: the acceleration values ​​obtained by the accelerometer in the x, y, and z directions of the coordinate system are respectively The elevation angle p and roll angle r of the array antenna are obtained as follows: ； 。 4. The method for calibrating the attitude of an array antenna as described in claim 1, characterized in that, The elevation angle of the positioning tag relative to the array antenna The range is from 20 degrees to 50 degrees.

5. The method for calibrating the attitude of an array antenna as described in claim 1, characterized in that, The array antenna collects data and uploads it to the server. The server performs direction finding processing on the positioning tag to obtain the azimuth angle. and pitch angle .

6. The method for calibrating the attitude of an array antenna as described in claim 1, characterized in that, The azimuth angle is obtained by using the true coordinates of the center point A of the array antenna. and pitch angle The process of determining the actual coordinates Pr of the positioning tag includes: The center point A of the array antenna Translation Then the actual coordinates Pr of the positioning tag also become: Recorded as: ; When the array antenna is located At that time, the height of the positioning tag is The height difference between the positioning tag and the array antenna is z0- Through the azimuth angle and pitch angle Determine the coordinates of the location tag measurement coordinate P: The measured coordinates P of the positioning tag are obtained: ,in This is the actual height of the positioning tag.

7. The method for calibrating the attitude of an array antenna as described in claim 6, characterized in that, Through the coordinates of point A Coordinates of point P get: The actual coordinates of the positioning tag as well as The length of P' is calculated, and the coordinates of P' are given by [reference to a specific coordinate system]. .

8. The method for calibrating the attitude of an array antenna as described in claim 7, characterized in that, The process of calculating the azimuth angle δ of the array antenna by combining the elevation angle p, roll angle r, P, and P' coordinates includes: According to the formula: Where R represents the rotation matrix; Rz, Ry, and Rx represent rotation matrices in the z, y, and x directions, respectively; δ, p, r represent the azimuth, pitch, and roll angles, respectively. Because there is ,so: Given the pitch angle and roll angle p and r, let: but: The above formula simplifies to: The above equation can be transformed into: so: 。 9. The method for calibrating the attitude of an array antenna as described in claim 8, characterized in that, The process of calculating the azimuth angle δ of the array antenna by combining the elevation angle p, roll angle r, and coordinates P and P' includes: selecting multiple sets of different positioning tag positions, and using multiple sets of P and P' to calculate the azimuth angle δ of the array antenna, thus: set up: but: The above formula uses the least squares method to find m: By obtaining cos(δ) and sin(δ), the azimuth angle δ of the array antenna can be obtained.

10. The method for calibrating the attitude of an array antenna as described in claim 9, characterized in that, Also includes: The measurement coordinates of the positioning tag are calibrated using a rotation matrix R.

11. The method for calibrating the attitude of an array antenna as described in claim 10, characterized in that, The calibration of the measurement coordinates of the positioning tag using the rotation matrix R includes: According to the formula: When the center point A of the array antenna is located The azimuth and elevation angles of the positioning tag relative to the array antenna are obtained through direction finding. Calculate the measured coordinates P of the positioning tag: Where z is the height of the positioning label; Use rotation matrix R to locate the measured coordinates P of the tag. Rotate to obtain point P': Calculate the intersection point P of the straight line determined by point A and point P' with the horizontal plane where the positioning label is located. ; Based on the actual position of the array antenna, the actual position of the positioning tag is calculated: .

12. A system for calibrating the attitude of an array antenna, characterized in that, include: Acceleration measurement module, direction finding module, calculation module, and attitude angle acquisition module; The acceleration measurement module is used to obtain the pitch angle p and roll angle r of the array antenna; The direction-finding module is used to accurately measure the true coordinates of the center point A of the array antenna, the true coordinates Pr of the positioning tags placed around the array antenna, and the azimuth angle of the positioning tags relative to the array antenna. and pitch angle ; The calculation module is used to accurately calculate the measured coordinates P and P' of the positioning tag using the data measured by the direction finding module. The line segment APr is obtained by connecting the center point A of the array antenna with the actual coordinates Pr of the positioning tag. The horizontal plane is rotated by the rotation matrix R to obtain a plane. The intersection point of the line segment APr and the plane is P'. The attitude angle acquisition module is used to calculate the azimuth angle δ of the array antenna by combining the pitch angle p, the roll angle r, and the coordinates of P and P' calculated by the calculation module.

13. The system for calibrating the attitude of an array antenna as described in claim 12, characterized in that, It also includes a calibration module, which is used to calibrate the coordinates of the positioning tag using the rotation matrix R.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions that, when executed by a processor, implement the steps of the method as described in any one of claims 1 to 9.

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