Accelerated satellite searching method based on elliptical coverage and satellite communication terminal

Abstract

The invention discloses an accelerated satellite searching method based on elliptical coverage and a satellite communication terminal, and relates to the field of satellite communication. The method comprises the following steps: determining an uncertain area of a satellite position based on satellite almanac data, wherein a first size of the area in an orbit direction is greater than a second size in a vertical orbit direction; determining that a first coverage width of a single search beam in an orbit direction is greater than a second coverage width in a vertical orbit direction based on a relative geometrical relationship between the terminal and a satellite and the beam width, and forming an elliptical coverage shape; according to the first size, the second size, the first coverage width and the second coverage width, the number and layout of wave positions needed for covering the uncertain area are determined; and sequentially searching satellite signals according to the number of the wave positions and the layout. According to the method, the directivity characteristics of almanac errors are utilized, the elliptical beams are adopted to replace traditional circular beams, the beam shape is matched with error distribution, the number of needed beam positions is remarkably reduced, the satellite searching time is effectively shortened, and the response speed of the terminal is improved.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and more specifically, to an accelerated satellite search method based on elliptical coverage and a satellite communication terminal. Background Technology

[0002] In satellite communication systems, after powering on or losing signal lock, a terminal needs to enter the initial satellite acquisition phase to acquire visible satellites. During this phase, the terminal typically relies on locally stored satellite ephemeris data to estimate the approximate position of the satellites. However, due to the timeliness limitations of satellite ephemeris data and the influence of factors such as satellite orbital perturbations, there is a certain error between the satellite position calculated from the ephemeris and the actual position. Research shows that this error has a significant directional characteristic: since satellites primarily move along their orbital direction, the ephemeris error is mainly concentrated along that direction, while the error perpendicular to the satellite's orbit is relatively small. Therefore, the satellite position calculated from ephemeris data is not entirely accurate; furthermore, the satellite terminal's beam is narrow, only covering a certain area; therefore, multiple beam combinations are needed to achieve complete coverage of the possible satellite positions.

[0003] Traditional satellite search methods typically assume that the beam pointing is perpendicular to the coverage area when calculating beam position distribution, meaning that the projection of a circular beam onto the ground is considered circular. However, in actual satellite communication, except in the special case where the satellite is directly above the terminal, there is an angle between the beam pointing and the ground normal, causing the projection of a circular beam onto the ground to actually be elliptical. Traditional methods ignore this projection effect and still calculate beam position spacing based on circular coverage, resulting in an inflated number of calculated beam positions and prolonged search time.

[0004] Therefore, this invention proposes a method to optimize the wavelet coverage calculation method by utilizing the directional characteristics of satellite ephemeris data errors, thereby reducing the number of wavelets and shortening the satellite search time while ensuring coverage integrity. Summary of the Invention

[0005] The purpose of this invention is to provide an accelerated satellite search method and satellite communication terminal based on elliptical coverage, so as to overcome the defects of existing technologies that use circular wave position coverage, resulting in a large number of wave positions and a long satellite search time.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an accelerated satellite search method based on elliptical coverage, comprising: The uncertain region of satellite position is determined based on satellite almanac data. The uncertain region has a first dimension along the direction of satellite orbit and a second dimension perpendicular to the direction of orbit, and the first dimension is larger than the second dimension. Based on the relative geometric relationship between the terminal and the satellite and the beamwidth of the terminal, a first coverage width of a single search beam along the satellite orbit direction and a second coverage width in the vertical orbit direction are determined, wherein the first coverage width is greater than the second coverage width, so as to form an elliptical coverage shape. Based on the first size, the second size, the first coverage width, and the second coverage width, determine the number of wave positions and the wave position layout required to cover the uncertain region; Satellite signal search is performed sequentially according to the number of wavelets and the corresponding wavelet layout.

[0007] Preferably, the first coverage width and the second coverage width are calculated based on the distance from the terminal to the satellite, the elevation angle of the terminal to the satellite, the distance from the satellite to the Earth's center, and the beamwidth of the terminal antenna.

[0008] Preferably, the number of wave positions is calculated based on the spacing between adjacent wave position centers along the track direction, provided that the second dimension is offset in the vertical track direction.

[0009] Preferably, the first dimension and the second dimension are estimated based on the age of the satellite almanac data using a preset error growth model, or are preset fixed values ​​based on the satellite orbit type; The expression for the error growth model is: ; ; in, For the first size, The age of the satellite almanac data, This is the error growth factor along the satellite orbit direction. The initial error along the satellite orbit direction, For the second size, This represents a fixed error in the direction perpendicular to the track.

[0010] Preferably, the satellite velocity vector along the satellite orbit direction is determined based on the satellite almanac data.

[0011] Preferably, when the terminal uses a phased array antenna, the elliptical coverage shape is an elliptical beam synthesized by the phased array antenna through amplitude and phase weighting.

[0012] Preferably, when the terminal uses an elliptical horn-feed antenna, the elliptical coverage shape is an elliptical beam formed by mechanical scanning of the elliptical horn-feed antenna.

[0013] Second aspect A satellite communication terminal, characterized in that it comprises: The positioning module is used to obtain the terminal's location information; Storage module, used to store satellite almanac data; The beam control module, connected to the positioning module and the storage module, is used to perform the following operations: Based on the terminal location information and the satellite almanac data, the uncertain region of the satellite position is determined in a first dimension along the orbital direction and a second dimension in the perpendicular orbital direction; Based on the relative geometric relationship between the terminal and the satellite and the beamwidth of the terminal, the first coverage width of a single search beam in the orbital direction and the second coverage width in the vertical orbital direction are determined. Based on the first size, the second size, the first coverage width, and the second coverage width, determine the number of beam positions and the beam position layout required to cover the uncertain area, and output beam control commands; The antenna module, connected to the beam control module, is used to sequentially point to each beam position to search for satellite signals according to the beam control command.

[0014] Preferably, the antenna module is a phased array antenna, and the beam control module controls the amplitude and phase weighting of the phased array antenna to synthesize an elliptical beam with a first coverage width greater than a second coverage width. When the antenna module uses a reconfigurable antenna such as a phased array antenna, it can actively synthesize an elliptical beam so that its major axis is aligned with the satellite orbit direction. When this actively synthesized elliptical beam illuminates the ground at an oblique angle, due to the superposition of projection effects, its coverage length along the orbit direction will further increase, thereby obtaining a longer effective coverage than a naturally projected ellipse and further reducing the number of wave positions.

[0015] Preferably, the antenna module is an elliptical horn feed antenna, and the beam control module controls the elliptical horn feed antenna to form an elliptical beam with a first coverage width greater than a second coverage width through mechanical scanning.

[0016] The beneficial effects of this invention are as follows: This invention improves the traditional circular beam coverage calculation method to elliptical beam coverage calculation, so that the beam shape matches the directional characteristics of the ephemeris error. That is, the major axis corresponds to the track direction with larger error, and the minor axis corresponds to the vertical track direction with smaller error, thereby significantly improving the coverage efficiency of a single beam along the track direction.

[0017] Meanwhile, this invention provides an analytical calculation method for the semi-major axis and semi-minor axis of the elliptical beam through theoretical geometric modeling, providing a precise mathematical basis for beam position layout optimization.

[0018] Finally, compared to circular coverage, elliptical coverage requires fewer waveforms under the same error conditions, directly shortening the total satellite search time and improving the terminal's satellite search speed and user experience.

[0019] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing embodiments of the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a comparative schematic diagram of circular and elliptical coverage in an embodiment of the present invention; Figure 2 This is a schematic diagram of the geometric relationship of elliptical coverage in an embodiment of the present invention; Figure 3 A flowchart illustrating an accelerated satellite search method based on elliptical coverage, provided for an embodiment of the present invention; Figure 4 This is a curve comparing the number of elliptical and circular wave positions in an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be defined and explained again in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] Example 1 First, combine Figure 2 This paper elaborates on the geometric modeling process of the coverage area of ​​the elliptical beam.

[0025] like Figure 2 As shown, O represents the Earth's center, point P is the location of the satellite terminal, and the small circle containing point P represents the Earth's surface. Point B is the satellite's current position, and the great circle containing point B represents the satellite's orbit. The line connecting PB represents the direction of the beam center from the terminal antenna to the satellite. Arc ABC represents the coverage area of ​​the beam along the satellite's orbit. Since the beamwidth is typically narrow (generally ≤5°), arc ABC can be approximated as a straight line segment, which is acceptable in engineering.

[0026] The following parameters are used in the calculation: d: Distance from the terminal to the satellite, i.e. Figure 2 The PB length in the equation. This distance can be obtained from the terminal's GPS coordinates and satellite coordinates calculated from the almanac.

[0027] The distance from the satellite to the Earth's center, i.e. Figure 2 The OB length is calculated based on the satellite orbital elements in the almanac data.

[0028] The elevation angle of the terminal relative to the satellite, i.e. Figure 2 ∠BPD in the equation can be calculated by converting the terminal-satellite vector to the Northeastern Sky (ENU) coordinate system.

[0029] The beamwidth of the terminal antenna, i.e. Figure 2 In this context, ∠APC is the angle. θ is usually determined by the antenna design and is generally ≤5°.

[0030] First, determine the semi-minor axis b of the elliptical beam. In the direction perpendicular to the satellite orbit, the beam coverage does not broaden; therefore, the semi-minor axis is determined by the beamwidth and distance.

[0031] when When it is very small (in radians), it can be simplified to:

[0032] Next, push to the semi-major axis 'a' of the elliptical beam. Figure 2 In triangle OPB, by applying the Law of Sines, we can solve for ∠POB:

[0033] From geometric relationships, we can know that , According to the relationship of the sum of the interior angles of a quadrilateral We can obtain:

[0034] In triangle CPB, applying the law of sines, we can obtain... Length:

[0035] Similarly, within triangle APB, applying the law of sines, we can obtain... Length:

[0036]

[0037]

[0038] semi-major axis a

[0039] At this point, we have obtained the semi-major axis of the elliptical beam. and semi-short axis The parsing expression. See also Figure 3 This embodiment details the specific implementation process of an accelerated satellite search method based on elliptical coverage.

[0040] Step S1: Determine the uncertain region of the satellite position based on satellite almanac data. The uncertain region has a first dimension T along the direction of the satellite orbit and a second dimension N in the direction perpendicular to the orbit, and the first dimension T is greater than the second dimension N. As mentioned earlier, almanac errors are directional, with errors along the orbital direction being much larger than those perpendicular to the orbit. This invention proposes using a linear growth model to estimate the error range. Let the time difference between the current moment and the almanac reference moment be the almanac age Δt (in days), then: The first dimension T and the second dimension N are estimated based on the age of the satellite almanac data using a preset error growth model, or are preset as fixed values ​​based on the satellite orbit type. The expression for the error growth model is: ; ; in, For the first size, The age of the satellite almanac data, This is the error growth factor along the satellite orbit direction. The initial error along the satellite orbit direction, For the second size, This represents a fixed error in the direction perpendicular to the track.

[0041] Where k is the error growth coefficient along the orbital direction, in kilometers per day. Its typical value can be obtained by statistically analyzing the almanac error data of satellites of specific orbital types (such as low Earth orbit and medium Earth orbit). For example, for low Earth orbit satellites, k can be taken as 10 to 20 km / day. T0 is the initial error along the orbital direction, which is usually taken as a fixed constant. N0 is the fixed error in the vertical orbital direction, which is usually much smaller than T, for example, it can be taken as 10 km.

[0042] It should be noted that this error growth model is only one preferred implementation of the present invention. In specific applications, fixed values ​​for T and N can also be preset directly according to the satellite orbit type. For example, for a certain type of low-Earth orbit satellite, T=700 km and N=10 km can be preset.

[0043] Step S2: Based on the relative geometric relationship between the terminal and the satellite and the beamwidth of the terminal, determine the first coverage width of a single search beam in the direction along the satellite orbit and the second coverage width in the direction perpendicular to the orbit, wherein the first coverage width is greater than the second coverage width to form an elliptical coverage shape; Step S3: Determine the number of wave positions and wave position layout required to cover the uncertain area based on the first size, the second size, the first coverage width, and the second coverage width; like Figure 1 As shown, assuming the error range in the vertical orbit direction is the second dimension N, the first coverage width of the elliptical beam is twice the semi-major axis a, and the second coverage width is twice the semi-minor axis b.

[0044] To fully cover the error range of the second dimension N in the vertical direction, the offset of the wave position center in the vertical direction is the second dimension N. Given the offset of the second dimension N in the vertical direction, the effective coverage length of a single elliptical wave position along the orbital direction can be obtained from the ellipse equation.

[0045] Let the equation of the ellipse be... Where x is the coordinate along the track direction and y is the coordinate perpendicular to the track direction. When y = N, the corresponding x-coordinate is:

[0046] This requires N≤b, meaning the vertical error cannot exceed the semi-minor axis of the ellipse; otherwise, single-layer coverage is not possible, and the number of wavelet layers needs to be increased.

[0047] The distance between adjacent wavefront centers along the orbital direction is... ,Right now:

[0048] Let the total uncertain distance along the orbital direction be the first dimension T, then the number of elliptical wavefronts required to cover the entire uncertain region is... for:

[0049] Step S4: Search for satellite signals sequentially according to the number of wave positions and the corresponding wave position layout.

[0050] See Figure 4 In contrast, when using traditional circular beam coverage (radius b), the center-to-center spacing between adjacent circular beam positions is also determined by the second dimension N of the vertical error, and the total number of circular beam positions required is... for:

[0051] Since the semi-major axis a of the elliptical beam is greater than the semi-minor axis b (and much greater than b), it is obvious that:

[0052] In other words, elliptical coverage requires fewer wave positions than circular coverage, thus enabling faster satellite search.

[0053] Example 2 This embodiment assumes the following parameters for a low-Earth orbit satellite communication system: Satellite altitude: 1000 km, then the distance from the satellite to the Earth's center. km; Terminal location: Set the elevation angle between the terminal and the satellite. Distance from terminal to satellite km (approximate by geometric relationships); Terminal antenna beamwidth: (Converted to approximately 0.05236 radians); Almanac Data: Almanac Age 26 days, take the error growth factor km / day km, km.

[0054] Step 1: Determine the uncertain region of the satellite's position based on satellite almanac data. The uncertain region has a first size along the satellite's orbital direction. It has a second dimension in the direction of the vertical track. And the first size Larger than the second size ;

[0055] Step 2: Based on the relative geometric relationship between the terminal and the satellite and the beamwidth of the terminal, determine the first coverage width of a single search beam in the direction along the satellite orbit and the second coverage width in the direction perpendicular to the orbit, wherein the first coverage width is greater than the second coverage width to form an elliptical coverage shape; The second coverage width, which is twice the semi-minor axis b of the ellipse, is calculated based on the distance from the terminal to the satellite and the antenna beamwidth of the terminal.

[0056] Therefore, the second coverage width is .

[0057] Based on the distance from the terminal to the satellite, the elevation angle of the terminal to the satellite, the distance from the satellite to the Earth's center, and the beamwidth of the terminal antenna, the first coverage width is calculated to be twice the semi-major axis 'a' of the ellipse. Note that... Convert to radians Calculate the two sine terms separately:

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064] The first coverage width is ,satisfy .

[0065] Step 3: Determine the number of wave positions and the wave position layout required to cover the uncertain area based on the first size, the second size, the first coverage width, and the second coverage width; First, the wave position spacing is calculated based on the first size T, the second size N, the first coverage width a, and the second coverage width b. :

[0066]

[0067] Based on wavelet spacing Get the number of wave positions :

[0068] The number of wave positions obtained by moving upwards is Each wave position.

[0069] In traditional circular beamforming, the total number of circular beams is calculated, with the radius of the circular waveform taken as b= km;

[0070]

[0071] Rounding up, we get 8 circular wave positions.

[0072] Step 4: Search for satellite signals sequentially according to the number of wave positions and the corresponding wave position layout.

[0073] In this embodiment, elliptical coverage requires only 5 positions, while circular coverage requires 8 positions, reducing the number of positions by 37.5%. Assuming the search time for each position is t, the total search time is reduced from 8t to 5t, significantly improving the search speed.

[0074] Example 3 This embodiment details how to implement elliptical beams in a real terminal.

[0075] Method 1: Synthesizing elliptical beams using phased array antennas For terminals employing phased array antennas, the desired beamform can be synthesized by controlling the amplitude and phase weighting of each array element. Specifically: Determine the desired elliptical beam pattern, i.e., the main lobe width along the orbit direction (corresponding to the first coverage width) is greater than the main lobe width perpendicular to the orbit direction (corresponding to the second coverage width).

[0076] Based on the desired radiation pattern, the excitation amplitude and phase of each element in the phased array are calculated. For arrays with rectangular grid arrangements, elliptical beams can be achieved through weighted calculation using a two-dimensional window function. For example, the element spacing along the track direction can be larger, while the element spacing perpendicular to the track direction can be smaller, or the beamwidth in the two directions can be controlled separately using Taylor weighting, Chebyshev weighting, or other methods.

[0077] The beam control module drives each array element channel according to the calculated amplitude and phase weights to synthesize an elliptical beam and controls the beam direction to scan each wave position sequentially.

[0078] Method 2: Mechanical scanning combined with elliptical horn feed For terminals employing mechanically scanned antennas, an elliptical horn can be used as a feed source, combined with a parabolic reflector to form an elliptical beam. The aperture size of the elliptical horn differs in two directions, resulting in different beamwidths. For example, a smaller horn dimension along the track direction produces a wider beam, while a larger dimension perpendicular to the track direction produces a narrower beam. The antenna pointing is controlled by a servo mechanism, sequentially scanning each beam position.

[0079] This invention provides two methods for realizing elliptical beams: phased array synthesis and mechanical scanning. These methods are applicable to terminal devices with different cost and performance requirements and have wide applicability.

[0080] Example 4 This embodiment provides a satellite communication terminal, including: Positioning module: usually a GPS / BeiDou receiver, used to obtain the terminal's current geographical location (latitude, longitude, altitude) in real time and output it to the beam control module.

[0081] Storage module: Used to store satellite almanac data. The almanac data contains approximate information about the satellite's orbital elements and can be updated periodically via the internet or satellite broadcast.

[0082] Beam control module: This is the core computing unit of the invention, typically implemented using a microprocessor or FPGA. This module connects the positioning module and the storage module and performs the following operations: Read terminal location information and satellite almanac data; Calculate the approximate position and velocity of the satellite based on almanac data, and determine the direction along the orbit (velocity vector direction). The first dimension T and the second dimension N are obtained based on the age in the almanac; Based on the terminal location and the approximate location of the satellite, calculate the distance d from the terminal to the satellite and the elevation angle α, and combine this with the known beamwidth θ to calculate the semi-minor axis b and semi-major axis a of the elliptical beam. Calculate the wavelet spacing and the number of wavelets based on the first dimension T, the second dimension N, the semi-major axis a, and the semi-minor axis b. Generate a beam position scanning sequence and output the corresponding beam control commands to the antenna module; Antenna module: Connected to the beam control module, used to search for signals by pointing to a specific beam position according to instructions. The antenna module can be a phased array antenna or a mechanically scanned antenna.

[0083] It should be noted that the specific manner in which each module performs its operation in the apparatus described in the above embodiments has been described in detail in the embodiments of the method, and will not be elaborated here.

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0085] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for accelerating satellite search based on elliptical coverage, characterized in that, include: The uncertain region of satellite position is determined based on satellite almanac data. The uncertain region has a first dimension along the direction of satellite orbit and a second dimension perpendicular to the direction of orbit, and the first dimension is larger than the second dimension. Based on the relative geometric relationship between the terminal and the satellite and the beamwidth of the terminal, a first coverage width of a single search beam along the satellite orbit direction and a second coverage width in the vertical orbit direction are determined, wherein the first coverage width is greater than the second coverage width, so as to form an elliptical coverage shape. Based on the first size, the second size, the first coverage width, and the second coverage width, determine the number of wave positions and the wave position layout required to cover the uncertain region; Satellite signal search is performed sequentially according to the number of wavelets and the corresponding wavelet layout.

2. The accelerated satellite search method based on elliptical coverage according to claim 1, characterized in that, The first coverage width and the second coverage width are calculated based on the distance from the terminal to the satellite, the elevation angle of the terminal to the satellite, the distance from the satellite to the Earth's center, and the beamwidth of the terminal antenna.

3. The accelerated satellite search method based on elliptical coverage according to claim 1, characterized in that, The number of wave positions is calculated based on the spacing between adjacent wave position centers along the track direction, given that the second dimension is offset in the vertical track direction.

4. The accelerated satellite search method based on elliptical coverage according to claim 1, characterized in that, The first dimension and the second dimension are estimated based on the age of the satellite almanac data using a preset error growth model, or are preset fixed values ​​based on the satellite orbit type; The expression for the error growth model is: ； ； in, For the first size, The age of the satellite almanac data, This is the error growth factor along the satellite orbit direction. The initial error along the satellite orbit direction, For the second size, This represents a fixed error in the direction perpendicular to the track.

5. The accelerated satellite search method based on elliptical coverage according to claim 1, characterized in that, The satellite velocity vector, calculated based on the satellite almanac data, is determined along the satellite orbit direction.

6. The accelerated satellite search method based on elliptical coverage according to claim 1, characterized in that, When the terminal uses a phased array antenna, the elliptical coverage shape is an elliptical beam synthesized by the phased array antenna through amplitude and phase weighting.

7. The accelerated satellite search method based on elliptical coverage according to claim 1, characterized in that, When the terminal uses an elliptical horn-feed antenna, the elliptical coverage shape is an elliptical beam formed by mechanical scanning of the elliptical horn-feed antenna.

8. A satellite communication terminal, characterized in that, include: The positioning module is used to obtain the terminal's location information; Storage module, used to store satellite almanac data; The beam control module, connected to the positioning module and the storage module, is used to perform the following operations: Based on the terminal location information and the satellite almanac data, the uncertain region of the satellite position is determined in a first dimension along the orbital direction and a second dimension in the perpendicular orbital direction; Based on the relative geometric relationship between the terminal and the satellite and the beamwidth of the terminal, the first coverage width of a single search beam in the orbital direction and the second coverage width in the vertical orbital direction are determined. Based on the first size, the second size, the first coverage width, and the second coverage width, determine the number of beam positions and the beam position layout required to cover the uncertain area, and output beam control commands; The antenna module, connected to the beam control module, is used to sequentially point to each beam position to search for satellite signals according to the beam control command.

9. A satellite communication terminal according to claim 1, characterized in that, The antenna module is a phased array antenna. The beam control module controls the amplitude and phase of the phased array antenna to synthesize an elliptical beam with a first coverage width greater than the second coverage width.

10. A satellite communication terminal according to claim 8, characterized in that, The antenna module is an elliptical horn feed antenna, and the beam control module controls the elliptical horn feed antenna to form an elliptical beam with a first coverage width greater than a second coverage width through mechanical scanning.

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