Satellite antenna capturing method based on track matching

Abstract

The invention discloses a satellite antenna capturing method based on track matching, and relates to the technical field of communication. The gain loss matrix is generated according to the radiation pattern of the antenna and is stored in the antenna controller. And then noise and drifting of the received signal strength are considered in the whole working process, noise reduction processing is performed through Kalman filtering, and the influence of errors on the capturing speed and precision is reduced. After a satellite capture process is started, an antenna beam executes single conical scanning around a current position, and a rough direction and angle search space of a satellite is determined according to a recorded received signal strength value. And segmenting the search space, and performing track matching on a track formed by the search path and the received signal strength value and the gain loss matrix so as to determine a directional deviation angle needing to be compensated for by the antenna beam directional angle. According to the method, the capture efficiency of the satellite antenna is effectively improved, and the contradictory relation between the capture speed and the capture precision can be flexibly balanced by dividing the angle search space and setting the precision threshold.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and particularly to a satellite antenna acquisition method based on trajectory matching. Background Art

[0002] Satellite communication technology has demonstrated its unique advantages in achieving a wide coverage area, especially in regions where laying terrestrial wired networks is impractical, such as remote villages and areas with extremely low population density. Given that satellite communication links often need to span long distances, the signal inevitably suffers significant attenuation during transmission. To ensure the stability and reliability of communication, communication satellite antennas must use high-gain directional antennas, and the high directivity of such antennas requires the antenna to be precisely aligned with the satellite. Quickly and accurately capturing the satellite signal is a crucial performance indicator in a satellite communication system. In traditional satellite acquisition methods, techniques such as step scanning or conical scanning are usually adopted. These methods need to perform multiple scans repeatedly until a satellite signal with sufficient strength is received, and such acquisition efficiency is low. Summary of the Invention

[0003] In view of this, the present invention proposes a satellite antenna acquisition method based on trajectory matching. When the satellite is within the main lobe of the antenna beam, this method can quickly and accurately determine the deviation angle through a single conical scan, thereby achieving rapid acquisition of the satellite and improving the acquisition efficiency.

[0004] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A satellite antenna acquisition method based on trajectory matching, comprising the following steps:

[0006] Step 1, generating a gain loss matrix according to the radiation pattern of the antenna;

[0007] Step 2, using a Kalman filter to reduce the noise of the satellite signal reception intensity;

[0008] Step 3, using a single conical scan trajectory to determine the rough direction and angular search space of the satellite;

[0009] Step 4, dividing the angular search space, and matching the noise-reduced satellite signal reception intensity corresponding to the scan trajectory with the gain loss matrix to obtain the pointing angle deviation;

[0010] Step 5, compensating the pointing angle deviation to the command angle to drive the antenna beam to point to the satellite.

[0011] Further, the specific manner of Step 1 is:

[0012] Set a normalization gain threshold, project the normalized three-dimensional radiation pattern of the antenna onto the azimuth and elevation planes. The value at each point on the projection map is the normalized gain corresponding to the azimuth angle and elevation angle at that location. In the first null-depth region, according to the division condition that the normalized gain is greater than the normalization gain threshold, divide the projection map into corresponding normalized gain threshold regions. Construct the circumscribed rectangle of the normalized gain threshold region in the projection map, and divide the circumscribed rectangle into multiple small regions along the azimuth and elevation directions. Construct a gain loss matrix based on the values corresponding to the center points of all small regions.

[0013] Further, the state variable x of the Kalman filter in step 2 includes the satellite signal reception strength p and its first-order time derivative.

[0014]

[0015] The value of the satellite signal reception strength p is modeled as the value of the satellite signal reception strength at the previous moment plus a drift change and is disturbed by Gaussian white noise. The observed quantity z is the measured value of the satellite signal reception strength.

[0016] Further, the specific method of step 3 is as follows:

[0017] Step 301, control the antenna beam to rotate around its current position for one week. During the rotation process, the pointing angle of the antenna beam is:

[0018]

[0019] where are the azimuth angle and elevation angle of the current position, k represents the count value within a single scan period, k = 1, 2, 3 ……, N, N is the total number of scans within a single scan period, are the azimuth angle and elevation angle of the kth rotation position within a single scan period, δ θ and correspond to the scan amplitudes of the azimuth and elevation axes respectively, taking 1 / 15 - 1 / 10 of the beam width; for the kth rotation position, record the corresponding denoised satellite signal reception strength p k ;

[0020] Step 302, record the azimuth angle and elevation angle positions corresponding to the maximum value of p k as p k and record the azimuth angle and elevation angle positions corresponding to the minimum value of p as

[0021] Step 303: Starting from the center point of the normalized gain threshold region and using the positive direction of the azimuth axis as the starting line for rotation, rotate counterclockwise. The calculation method for the rotation angle of the line corresponding to the rough direction of the antenna beam pointing to the satellite is as follows:

[0022]

[0023] Step 304: Calculate the rotation angles γ1 and γ2:

[0024]

[0025] Starting from the center point of the normalized gain threshold region and using the positive direction of the azimuth axis as the starting line for rotation, the regions formed by the lines rotating counterclockwise by γ1 and γ2 respectively and the boundary line of the normalized gain threshold region have an included angle of 30°. Denote this region as the angular search space.

[0026] Further, the specific manner of Step 4 is as follows:

[0027] Step 401: Draw parallel lines according to the boundary line of the normalized gain threshold region in the angular search space, divide the angular search space into two parts, and denote the elements in the corresponding gain loss matrix that are closest to the center points of each part as G s1 、G s2 , and execute Step 403;

[0028] Step 402: If the angular search space includes two arc segments, connect the midpoints of the two arc segments. If the angular search space includes only one arc segment, connect the midpoint of the arc segment and the center point of the normalized gain threshold region. Divide the angular search space into two parts according to the connection line, and denote the elements in the corresponding gain loss matrix that are closest to the center points of each part as G s1 、G s2 , and execute Step 403;

[0029] Step 403: Calculate the objective function values f1 and f2 according to G s1 、G s2 :

[0030]

[0031] If min(f1, f2) < σ, then the azimuth angle and elevation angle of the element in the corresponding gain loss matrix of min(f1, f2) are the pointing angle deviation, and execute Step 5; otherwise, after designating the part where the element of min(f1, f2) is located as the new angular search space, if the previous step is Step 401, then execute Step 402; if the previous step is Step 402, then execute Step 401;

[0032] Among them, p1 represents the received intensity of the noise-reduced satellite signal corresponding to the first rotation position in a single conical scan; the single conical scan trajectory is translated respectively to make the positions of G s1 and G s2 on the translated trajectory correspond to the position of the first rotation position in the single conical scan. On the translated trajectory, select the position corresponding to the k-th rotation position in the single conical scan, and record the element in the gain loss matrix closest to it as σ is the precision threshold of the trajectory matching algorithm.

[0033] Due to the above technical solutions, the beneficial effects of the present invention compared with the prior art are as follows:

[0034] 1. The present invention takes into account the noise and drift of the received intensity of satellite signals (RSSI), and performs noise reduction processing on it through Kalman filtering, reducing the influence of RSSI errors on the capture speed and accuracy.

[0035] 2. The present invention generates an RSSI signal trajectory by performing a single conical scan, and realizes the rapid determination of the pointing deviation angle through the trajectory matching with the gain loss matrix, effectively improving the capture speed of the satellite.

[0036] 3. In the trajectory matching algorithm of the present invention, by dividing the angular search space and setting the precision threshold, the contradictory relationship between the capture speed and the capture accuracy can be flexibly balanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic diagram of the formation of the gain loss matrix of a satellite antenna capture method based on trajectory matching in an embodiment of the present invention.

[0038] Figure 2 is a schematic diagram of generating an angular search space by a single conical scan in an embodiment of the present invention.

[0039] Figure 3 is a schematic diagram of the angular search space division of the trajectory matching algorithm in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The following further describes the content of the present invention in conjunction with the drawings and specific embodiments.

[0041] A satellite antenna capture method based on trajectory matching includes the following steps:

[0042] Step 1, generate a gain loss matrix (GLM) according to the radiation pattern of the antenna;

[0043] Step 2, use a Kalman filter to reduce the noise of the received intensity of satellite signals (RSSI);

[0044] Step 3: Determine the approximate direction and angular search space of the satellite using a single conical scanning trajectory;

[0045] Step 4: Divide the angular search space, match the noise-reduced satellite signal reception intensity corresponding to the scanning trajectory with the gain loss matrix, and obtain the pointing angle deviation;

[0046] Step 5: Compensate the pointing angle deviation to the command angle and drive the antenna beam to point to the satellite.

[0047] Furthermore, the specific method of Step 1 is as follows:

[0048] Set the normalized gain threshold, project the normalized three-dimensional radiation pattern of the antenna onto the azimuth and elevation planes. The value at each point on the projection is the normalized gain corresponding to the azimuth angle and elevation angle at that point. In the first null-depth region, according to the division condition that the normalized gain is greater than the normalized gain threshold, divide the projection to obtain the corresponding normalized gain threshold region. Construct the circumscribed rectangle of the normalized gain threshold region in the projection, and divide it into multiple small regions along the azimuth and elevation directions. Construct the gain loss matrix based on the values corresponding to the center points of all small regions.

[0049] As Figure 1 shown, the matrix element value is the normalized gain, and each element corresponds to a unique set of deviation angles. After determining the element in the GLM corresponding to the current antenna beam pointing, the deviation angle can be determined. Specifically, if it is a circular antenna, the boundary line of the normalized gain threshold region is circular; if it is an elliptical antenna, the boundary line of the normalized gain threshold region is elliptical.

[0050] Furthermore, the state variable x of the Kalman filter in Step 2 includes the satellite signal reception intensity p and its first-order time derivative

[0051]

[0052] The value of the satellite signal reception intensity p is modeled as the value of the satellite signal reception intensity at the previous moment plus the drift change and is disturbed by Gaussian white noise. The observed quantity z is the measured value of the satellite signal reception intensity.

[0053] Furthermore, the specific method of Step 3 is as follows:

[0054] Step 301: Control the antenna beam to rotate one week around its current position During the rotation, the pointing angle of the antenna beam is:

[0055]

[0056] In the formula, is the azimuth angle and elevation angle of the current position, k represents the count value within a single scan period, k = 1, 2, 3 ……, N, and N is the total number of scans within a single scan period. is the azimuth angle and elevation angle of the k-th rotation position within a single scan period, δ θ and respectively correspond to the scan amplitudes of the azimuth and elevation axes, taking 1 / 15 to 1 / 10 of the beam width; for the k-th rotation position, record the received satellite signal strength p after noise reduction corresponding thereto k ;

[0057] In this example, N = 100, δ θ and take 1 / 10 of the beam width;

[0058] Step 302, record the azimuth angle and elevation angle positions corresponding to the maximum value of p k as point p k record the azimuth angle and elevation angle positions corresponding to the minimum value of p

[0059] Step 303, as Figure 2 shown, divide the GLM evenly into 24 sector regions, starting from the center point S of the normalized gain threshold region, with the positive direction of the azimuth axis as the starting line of the rotation angle, and rotate counterclockwise. The calculation method of the rotation angle corresponding to the rough direction of the antenna beam pointing to the satellite is as follows:

[0060]

[0061] Step 304, calculate the rotation angles γ1 and γ2:

[0062]

[0063] Starting from the center point of the normalized gain threshold region, with the positive direction of the azimuth axis as the starting line of the rotation angle, rotate the lines L1 and L2 of γ1 and γ2 counterclockwise respectively. The regions formed by the lines L1 and L2 and the boundary line of the normalized gain threshold region with an included angle of 30° are denoted as the angle search space.

[0064] Furthermore, as Figure 3 shown, the specific method of Step 4 is as follows:

[0065] Step 401, make parallel lines according to the boundary line of the normalized gain threshold region in the angle search space, divide the angle search space into two parts evenly, and denote the elements in the corresponding gain loss matrix that are closest to the center points of each part as G s1 、G s2 , and execute Step 403;

[0066] Step 402: If the angular search space includes two arc segments, connect the midpoints of the two arc segments; if the angular search space includes only one arc segment, connect the midpoint of the arc segment with the center point of the normalized gain threshold region. Divide the angular search space into two parts according to the connection line, and denote the elements in the corresponding gain loss matrix that are closest to the center points of each part as G s1 and G s2 , and execute Step 403;

[0067] Step 403: Calculate the objective function values f1 and f2 according to G s1 and G s2 :

[0068]

[0069] If min(f1, f2) < σ, then take the azimuth angle and elevation angle of the element in the corresponding gain loss matrix of min(f1, f2) as the pointing angle deviation, and execute Step 5; otherwise, after determining the part where the element in the corresponding gain loss matrix of min(f1, f2) is located as the new angular search space, if the previous step is Step 401, execute Step 402; if the previous step is Step 402, execute Step 401;

[0070] where p1 represents the received intensity of the noise-reduced satellite signal corresponding to the first rotation position in a single conical scan; translate the single conical scan trajectory respectively so that the positions of G s1 and G s2 on the translated trajectory correspond to the position of the first rotation position in the single conical scan. Select the position on the translated trajectory corresponding to the kth rotation position in the single conical scan, and denote the element in the gain loss matrix that is closest to it as σ is the accuracy threshold of the trajectory matching algorithm.

[0071] Specifically, Figure 3 the 1, 2, 3, 4, 5 in it are the results of executing Step 401 and Step 402 multiple times respectively; point C is the center point when the loop ends.

[0072] In summary, when the satellite is within the main lobe of the antenna beam, this method can quickly and accurately determine the deviation angle through a single conical scan, thereby achieving rapid capture of the satellite and improving the capture efficiency.

[0073] Those skilled in the art will realize that the described embodiments are provided to assist the reader in understanding the principles of the present invention, and it should be understood that the protection scope of the present invention is not limited to the described embodiments. For those skilled in the art, various changes and modifications can be made to the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A satellite antenna capture method based on trajectory matching, characterized in that: The following steps are involved: Step 1, generating a gain loss matrix according to the radiation pattern of the antenna; Step 2: Use Kalman filter to reduce the noise of satellite signal reception strength; Step 3, using a single conical scan trajectory to determine the satellite's rough direction and angular search space; Step 4, divide the angle search space, match the noise-reduced satellite signal reception strength corresponding to the scanning trajectory with the gain loss matrix, and obtain the pointing angle deviation; Step 5: Compensate the pointing angle deviation to the command angle and drive the antenna beam to point to the satellite.

2. A satellite antenna capture method based on trajectory matching according to claim 1, characterized in that: The specific method of step 1 is: A normalized gain threshold is set, and the normalized three-dimensional radiation pattern of the antenna is projected on the azimuth and elevation planes. The value of each point on the projection diagram is the normalized gain corresponding to the azimuth and elevation angles. In the first zero-depth region, the projection diagram is divided into corresponding normalized gain threshold regions according to the division condition that the normalized gain is greater than the normalized gain threshold. A circumscribed rectangle of the normalized gain threshold region is constructed in the projection diagram, and multiple small regions are divided in the circumscribed rectangle along the azimuth and elevation directions. A gain loss matrix is ​​constructed according to the values ​​corresponding to the center points of all small regions.

3. The satellite antenna capture method based on trajectory matching according to claim 2, characterized in that: The state variable x of the Kalman filter in step 2 includes the satellite signal reception strength p and its first-order time derivative The value of the satellite signal reception strength p is modeled as the value of the satellite signal reception strength at the previous moment with an increase in drift change and is interfered by Gaussian white noise. The observation z is the measured value of the satellite signal reception strength.

4. The satellite antenna capture method based on trajectory matching according to claim 3, characterized in that: The specific method of step 3 is: Step 301, control the antenna beam around its current position After one rotation, the pointing angle of the antenna beam during the rotation is: In the formula, are the azimuth and elevation angles of the current position, k represents the count value in a single scanning cycle, k = 1, 2, 3..., N, N is the total number of scans in a single scanning cycle, is the azimuth and elevation angle of the kth rotation position in a single scanning cycle, δ θ and The scanning amplitudes corresponding to the azimuth and elevation axes are 1 / 15 to 1 / 10 of the beam width respectively; for the kth rotation position, the corresponding satellite signal reception strength p after noise reduction is recorded k ; Step 302, record p k The azimuth and elevation angle positions corresponding to the maximum values ​​are: p k The azimuth and elevation angle positions corresponding to the minimum value are Step 303, starting from the center point of the normalized gain threshold area and rotating counterclockwise with the positive direction of the azimuth axis as the starting line of the rotation angle, the rotation angle of the straight line corresponding to the rough direction of the antenna beam pointing to the satellite is calculated as follows: Step 304, calculate the rotation angles γ1 and γ2: Taking the center point of the normalized gain threshold area as the starting point and the positive direction of the azimuth axis as the starting line of the rotation angle, the lines of γ1 and γ2 rotated counterclockwise respectively and the boundary line of the normalized gain threshold area form an area with an angle of 30°, which is recorded as the angle search space.

5. The satellite antenna capture method based on trajectory matching according to claim 4, characterized in that: The specific method of step 4 is: Step 401: Draw parallel lines according to the boundary line of the normalized gain threshold region in the angular search space to divide the angular search space into two parts, and record the elements in the corresponding gain loss matrix closest to the center point of each part as G s1 , G s2 , execute step 403; Step 402: If the angle search space includes two arc segments, the midpoints of the two arc segments are connected; if the angle search space includes only one arc segment, the midpoint of the arc segment is connected to the center point of the normalized gain threshold region, and the angle search space is divided into two parts according to the connection line. The elements in the corresponding gain loss matrix closest to the center point of each part are respectively recorded as G s1 , G s2 , execute step 403; Step 403, according to G s1 , G s2 Calculate the objective function values ​​f1 and f2: If min(f1,f2)<σ, then min(f1,f2) corresponds to the azimuth and elevation angles of the elements in the gain loss matrix. is the pointing angle deviation, execute step 5; otherwise, after the part where the element in the gain loss matrix corresponding to min(f1,f2) is located is defined as the new angle search space, if the previous step is step 401, execute step 402; if the previous step is step 402, execute step 401; Where p1 represents the satellite signal reception strength after noise reduction corresponding to the first rotation position in a single conical scan; the single conical scan trajectory is translated so that G s1 , G s2 The position on the translated trajectory corresponds to the position of the first rotation position in a single conical scan. The position corresponding to the kth rotation position in a single conical scan is selected on the translated trajectory, and the element in the gain loss matrix closest to it is recorded as σ is the accuracy threshold of the trajectory matching algorithm.

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