A dynamic space simulation method for global satellite navigation constellations

Abstract

The application belongs to the technical field of simulation test, and particularly discloses a dynamic space simulation method for a global satellite navigation constellation, which is based on the idea of optimizing the overall antenna layout and locally compensating power, and proposes a dynamic space simulation method for the global satellite navigation constellation. The key core of the method is a design process based on triangular antenna layout and a local navigation signal power compensation strategy. The method has the advantages of small antenna quantity requirement, uniform layout, simple antenna path calculation, etc. By using the dynamic space simulation method for the global satellite navigation constellation, the construction of a dynamic test environment for all visible satellite navigation signals from different directions at any position in the global range can be realized in the test space, and the simulation of all visible satellite navigation signals at any position in the global range can be realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of simulation test, and particularly discloses a dynamic space simulation method for a global satellite navigation constellation. BACKGROUND

[0002] Global navigation satellites are distributed in space, continuously fly along their respective orbits, and continuously emit navigation signals to the earth. After a satellite navigation receiving device receives the navigation signals, the position of the satellite navigation receiving device is determined. The ability of beam forming is an important ability of a satellite navigation receiving device, which can enhance the beam in the direction of the satellite signal and improve the positioning ability of the device. Therefore, when testing the beam enhancement ability of the satellite navigation receiving device with an array antenna, because the test result is sensitive to the direction of the navigation signal, the test environment should have the condition of simulating different navigation signals, so as to stimulate the beam forming ability of the receiving antenna of the satellite navigation receiving device and realize the overall test of the satellite navigation receiving device. At present, most of the test conditions use a small number of antenna arrays for radiating navigation signals. Although the single satellite or combined navigation signals can be broadcast to construct the test navigation signal environment, only the real signal direction of a fixed position for a short time can be simulated, and the whole cycle of the navigation satellite constellation cannot be covered. Therefore, in order to meet the test of the satellite navigation receiving device with the beam forming ability, it is very necessary to establish a dynamic test environment for a global satellite navigation constellation based on an antenna array, simulate the navigation signal with the direction characteristics, and construct the dynamic test environment for the navigation signal with different directions from all visible satellite navigation signals at any position in the global range. SUMMARY

[0003] In order to solve the problems in the background art, the application discloses a dynamic space simulation method for a global satellite navigation constellation. The core of the method is based on the design process of triangular antenna layout and the local navigation signal power compensation strategy. The dynamic test environment for the navigation signal with different directions from all visible satellite navigation signals at any position in the global range can be constructed by using the dynamic space simulation method for the global satellite navigation constellation.

[0004] In order to achieve the above-mentioned application purposes, the application adopts the following technical scheme:

[0005] A dynamic space simulation method for a global satellite navigation constellation comprises the following steps:

[0006] (1) According to the possible geographical position and height of the satellite navigation receiving device to be tested, the maximum number of simultaneously visible satellites is determined, and the number of satellites deployed in the positive and negative elevation angles is determined.

[0007] (2) According to the maximum number of array antennas of the satellite navigation receiving device to be tested, the beam 3dB bandwidth of the array element antenna is determined.

[0008] (3) According to the design size of the test space and the beam 3dB bandwidth of the array element antenna, the angle range A1 between the navigation signal direction of arrival under the real starry sky and the actual antenna navigation signal in the test space is determined;

[0009] (4) The line segment from any point on the hemisphere to the nearest antenna point around is taken as the chord length, and the central angle of the sphere formed by the chord length with respect to the test space center should be less than or equal to the angle range A1 between the navigation signal direction of arrival under the real starry sky and the actual antenna navigation signal in the test space determined in step (3), which is taken as the test space antenna layout constraint condition, and a triangular layout method is used to form an antenna layout coordinate scheme;

[0010] (5) According to the antenna layout coordinate scheme in step (4), the navigation antennas are installed and arranged, and the navigation antennas and the navigation signal simulation source are connected one by one through radio frequency lines;

[0011] (6) When simulating the satellite constellation, the fixed antenna closest to the actual satellite orbit in the triangular antenna array is controlled to emit the corresponding satellite navigation signal, the navigation antennas are controlled to switch, and the real starry sky satellite position is simulated by relay, during which, if there is a certain uncertainty angle between the antenna direction of arrival and the real position, power compensation correction is performed.

[0012] Further, in the global satellite navigation constellation dynamic space simulation method, the specific scheme process of forming the test space antenna layout coordinate scheme by using the triangular layout method in step (4) is as follows:

[0013] 4.1) According to the principle that the maximum error is less than A1 and the number of antennas is the least, a calculation method of equally dividing the triangular side length by four is selected;

[0014] 4.2) The starry sky spherical surface is divided into twenty triangular spherical surfaces, the connecting lines between the vertices of the twenty triangular spherical surfaces form equilateral triangles, the three sides of the equilateral triangle are equally divided by four, and the connecting lines between the corresponding division points divide the equilateral triangle into 1+3+5+7 small triangles;

[0015] 4.3) The small triangles are mapped to the spherical surface by engineering software to divide the spherical surface;

[0016] 4.4) Since the area of the triangle is Wherein, m, n, and l represent the lengths of the three sides of the small triangle, p=(m+n+l) / 2, r is the radius of the circumscribed circle of the small triangle, that is, the length from the center point of the small triangle to the vertex of the small triangle, and then, The maximum and minimum values of the circumscribed circle radius of the small triangle are calculated according to the lengths of the three sides of the small triangle;

[0017] 4.5) With the constraint condition that the maximum value of the excircle radius of all small triangles should not be greater than A1 at the corresponding central angle of the spherical surface projection chord of its tangent plane, the side length and area of the small triangle are determined, and the three vertices of the small triangle are the test space antenna layout point coordinates, forming an antenna layout coordinate scheme.

[0018] Further, the specific method for power compensation correction in step (6) of the global satellite navigation constellation dynamic space simulation method is as follows:

[0019] 6.1) A relationship diagram F1 about different array element beams is established by pre-simulation;

[0020] 6.2) The minimum half-beam angle A2 corresponding to the maximum array element is determined through the beam pattern gain curve diagram;

[0021] 6.3) With the power resolution of the signal source as an interval, the ordinate in the relationship diagram F1 is equally divided within the range of ±A2, the corresponding elevation angle is obtained by looking up the diagram, and a power compensation value and angle relationship table T1 is formed for different array element numbers;

[0022] 6.4) In the beam forming process, the power in the direction corresponding to the elevation angle is enhanced by looking up T1, and then radiated to the satellite navigation receiving equipment.

[0023] Compared with the prior art, the beneficial effects of the present application are:

[0024] The present application is based on the idea of optimizing the overall antenna layout and locally compensating the power, and proposes a global satellite navigation constellation dynamic space simulation method. The key core of the method is a design process based on triangular antenna layout and a local (triangular interior) navigation signal power compensation strategy. The method has the advantages of small number of antenna requirements, uniform layout, simple antenna path calculation, etc. Using the global satellite navigation constellation dynamic space simulation method proposed in the present application, a dynamic test environment of all visible satellite navigation signals from different directions at any position in the global range can be constructed in the test space, and the simulation of all visible satellite navigation signals at any position in the global range can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the work flow diagram of the present application;

[0026] Figure 2 is the icosahedral triangular partition structure diagram in the present application;

[0027] Figure 3 is the navigation signal real trajectory and antenna switching relationship diagram in the present application;

[0028] Figure 4 isFigure 2 The schematic diagram of the unfolded figure structure of the middle triangle face;

[0029] Figure 5 Is Figure 4 The calculation of the circumradius of the middle triangle E;

[0030] Figure 6 Is Figure 4 The calculation of the circumradius of the middle triangle A;

[0031] Figure 7 It is the schematic diagram of the middle triangle antenna array distribution and the actual satellite orbit. DETAILED DESCRIPTION

[0032] The principle of the global satellite navigation constellation dynamic space simulation method of the application is introduced as follows:

[0033] The application proposes a global satellite navigation constellation dynamic space simulation method, and the basic principle is to map the movement orbit of the navigation satellite in space to the antenna closest to the orbit point on the antenna array, simulate the global navigation satellite movement discretely by switching the navigation signal on the antenna array, and ensure that the discrete points meet the test accuracy requirements through design. The navigation signal is generated by a navigation signal simulator, which is consistent with the number of antennas on the antenna array, and is connected to each antenna through a radio frequency cable. Under the overall control and scheduling, the global satellite navigation signal characteristics, especially the space direction characteristics, are simulated by switching control of the navigation signal source, as shown in Figure 1 .

[0034] Due to the discreteness of the antenna, there will inevitably be an angle deviation between the actual movement orbit point of the satellite and the position of the antenna. When simulating the movement orbit of the global navigation satellite through the antenna array arranged at different positions, the position of the navigation signal antenna should be consistent with the position of the real satellite as much as possible. Generally speaking, the denser the antenna arrangement, the better the simulation consistency, but due to the limitation of the number of antennas, the cost and the control complexity, only a limited number of antennas can be switched to approximate the continuous orbit of the satellite movement, but as long as the angle formed by the satellite and the signal transmitting antenna relative to the measured product is less than the beam width of the antenna of the measured product, the test requirements can be met. For this purpose, the application designs a triangular navigation antenna arrangement method to solve the problem of overall optimization of antenna layout. In actual antenna arrangement, every three adjacent points on the spherical surface can form a triangle, and the navigation antenna is arranged at the three vertices of each small triangle. This method divides the spherical space into twenty triangular spherical surfaces, and further divides the triangular spherical surface into a plurality of small triangles, as shown in Figure 2As shown, when the antenna is arranged, the three vertices of the small triangle are arranged with the antenna, the maximum distance of the center point of the small triangle from the three vertices can be considered as the difference between the real antenna position and the simulated navigation satellite position, and the angle formed between the distance between the two points and the center of the sphere can be considered as the maximum uncertainty of the navigation simulation and the real position. When the navigation signal is switched between the antennas, path diversification is formed, which can be equivalent to the signal passing through different triangular areas, and the angle error analysis is as follows Figure 3 As shown, Figure 3 The middle blue line is the satellite simulation trajectory, and the red point is the antenna path of the switch. When the satellite moves to point A (the center of the circumcircle outside the triangle), the transmitting antenna is switched from Figure 3 Position 1 to position 2, which is the maximum error between the antenna and the simulated satellite position in the motion trajectory, which is within the allowable range.

[0035] On the basis of the above antenna layout design, considering the multi-beam antenna beam width as a constraint, the more the number of array elements, the narrower the beam width. As long as the angle cone formed by the satellite position and the satellite relative to the center of the sphere is less than half the beam width, the influence of the spatial angle error on the signal receiving power is about 3dB. If the power loss caused by the angle error can be corrected by software, the influence on the test results can be eliminated. For this purpose, on the basis of the above triangular layout, a local navigation signal power correction strategy is adopted for the case of the trajectory point inside the triangle. When performing beam forming anti-jamming test, the corresponding relationship between the actual satellite antenna position and the satellite ephemeris position affects the beam enhancement test precision, that is, the closer the navigation signal direction to the satellite position in the ephemeris, the higher the beam enhancement performance test precision. In view of the case that the simulated satellite position is between two actual antennas, the antenna direction and the real position will have a certain angle of uncertainty, a relationship diagram about the beam direction elevation angle and the gain of different array elements is established in advance, the minimum half-beam angle corresponding to the maximum array element is determined, within this range, the relationship diagram is discretely sampled, and then for different array element numbers, a power compensation value and angle relationship table can be formed. When the test environment space is constructed, the power of the corresponding elevation angle direction is adjusted, and then the satellite navigation receiving device is radiated.

[0036] The working process of the global satellite navigation constellation dynamic space simulation method of the application is as follows:

[0037] (1) According to the possible geographical position and height of the satellite navigation receiving device to be tested, the maximum number of simultaneously visible stars is determined, and the number of satellites deployed in the positive and negative elevation angles is also determined.

[0038] (2) According to the maximum possible number of array antennas of the satellite navigation receiving device to be tested, the 3dB bandwidth of the array element antenna is determined.

[0039] (3) According to the design size of the simulation test space and the 3dB bandwidth of the array element antenna beam, the angle range A1 between the navigation signal direction of the real starry sky and the actual antenna navigation signal of the simulation test space is determined;

[0040] (4) The line from any point on the hemisphere to the nearest antenna point around it is taken as the chord length, and the central angle of the sphere formed by the chord length should be less than or equal to the angle range A1 between the navigation signal direction of the real starry sky and the actual antenna navigation signal of the simulation test space determined in step (3) as the antenna layout constraint condition, and a triangular layout method is used to form an antenna layout coordinate scheme, and the specific scheme flow is as follows:

[0041] 4.1) According to the principle of maximum error less than A1 and minimum antenna layout, select the calculation method of four equal divisions of the triangular face side length;

[0042] 4.2) The starry sky sphere is divided into twenty triangular spheres, and the lines between the vertices of the twenty triangular spheres form equilateral triangles, and the three sides of the equilateral triangle are four divided, and the lines between the corresponding division points divide the equilateral triangle into 1+3+5+7 small triangles, and the small triangles are divided into A / B / C / D / E five types according to their side length, as shown in Figure 4 ;

[0043] 4.3) The small triangles are mapped to the sphere by engineering software (such as SolidWorks, PROE) to divide the sphere;

[0044] 4.4) Since the area of the triangle is Where m, n, and l represent the lengths of the three sides of the small triangle, p=(m+n+l) / 2, and r is the radius of the circumscribed circle of the small triangle, i.e. the length from the center point of the small triangle to the vertex of the small triangle, then According to the lengths of the sides of the small triangle, the maximum and minimum values of the circumscribed circle radius of the small triangle are obtained, and all the small triangles in Figure 4 are traversed, and it is known that the circumscribed circle radius of the E-type small triangle is the largest, and the circumscribed circle radius of the A-type triangle is the smallest, as shown in Figure 5 and Figure 6 ;

[0045] 4.5) The maximum value of the circumscribed circle radius of all small triangles is taken as the constraint condition that the central angle of the sphere corresponding to the projection chord length of the tangent surface should not be greater than A1, and the side length and area of the small triangle are determined, the three vertices of the small triangle are the antenna layout point coordinates, and the antenna layout coordinate scheme is formed.

[0046] (5) according to the antenna layout coordinate scheme in step (4), the navigation antenna is installed and arranged, and the navigation antenna is connected with the navigation signal source through the radio frequency line one by one;

[0047] (6) when the satellite constellation simulation is carried out, the fixed antenna closest to the actual satellite motion track in the triangular antenna array is controlled to emit the corresponding satellite navigation signal, the navigation antenna is controlled to switch, and the real sky position is simulated, as shown in Figure 7 Figure 7 The triangular antenna array distribution and the actual satellite track schematic diagram, the brown pentagram represents the fixed antenna simulating the satellite track, the dotted arrow represents the actual track of the satellite, and the solid arrow represents the antenna simulating the satellite track) During this period, if there is a certain uncertain angle between the antenna direction and the real position, power compensation correction is carried out, and the method is as follows:

[0048] 6.1) the relationship diagram F1 about the elevation angle and the gain of different array element beam direction is established through pre-simulation;

[0049] 6.2) the minimum half-beam angle A2 corresponding to the maximum array element is determined through the gain curve diagram of the beam direction diagram;

[0050] 6.3) taking the power resolution of the signal source as an interval, the ordinate in the relationship diagram F1 is equally divided within the range of ±A2, the corresponding elevation angle is obtained by looking up the diagram, and the power compensation value and the angle relationship table T1 are formed for different array elements;

[0051] 6.4) in the process of beam forming, the power in the corresponding elevation angle direction is enhanced through the method of looking up T1, and then the satellite navigation receiving equipment is radiated.

[0052] The application mainly solves how to carry out the overall optimal layout of the number and the geometric installation position of the antenna array, and how to simulate the navigation signal at a point outside the antenna, two key problems. Based on the idea of optimizing the overall antenna layout and locally compensating the power, the application proposes a global satellite navigation constellation dynamic space simulation method. The key core of the method is a design process based on triangular antenna layout and a local (triangular interior) navigation signal power compensation strategy. The method has the advantages of small antenna quantity requirement, uniform layout, simple antenna path calculation and the like. By using the global satellite navigation constellation dynamic space simulation method proposed in the application, a dynamic test environment of all visible satellite navigation signals from different directions at any position in the global range can be constructed, and all visible satellite navigation signals at any position in the global range can be simulated.​

Claims

1. A dynamic space simulation method for global satellite navigation constellations, characterized in that, Includes the following steps: (1) Determine the maximum number of simultaneously visible satellites based on the possible geographical location and altitude of the satellite navigation receiving equipment being tested, and at the same time clarify the number of satellites deployed at positive and negative elevation angles; (2) Determine the 3dB beamwidth of the array element antenna based on the maximum possible number of array antennas of the satellite navigation receiving equipment under test; (3) Based on the design dimensions of the test space and the 3dB beam bandwidth of the array element antenna, determine the angle range A1 between the direction of the navigation signal under the real starry sky and the actual antenna navigation signal in the test space; (4) The chord length is the line connecting any point on the hemisphere to the nearest surrounding antenna point. The angle between the center of the sphere formed by the chord length and the center of the test space should be less than or equal to the angle range A1 between the actual navigation signal under the real starry sky determined in step (3) and the actual antenna navigation signal in the test space. The antenna layout constraint condition is used as the antenna layout coordinate scheme. The specific process of forming the antenna layout coordinate scheme of the test space using the triangle layout method is as follows: 4.1) Based on the principle that the maximum error is less than A1 and the number of antennas deployed is minimized, the calculation method of dividing the triangle side length into four equal parts is selected; 4.2) Divide the starry sky sphere into twenty triangular spheres. The lines connecting the vertices of the twenty triangular spheres form equilateral triangles. Divide the three sides of the equilateral triangles into four equal parts. The lines connecting the corresponding division points divide the equilateral triangles into 1+3+5+7 smaller triangles. 4.3) The small triangles are mapped onto the sphere using engineering software to divide the sphere. 4.4) Due to the area of ​​the triangle Where m, n, and l represent the side lengths of the three sides of the smaller triangle, p = (m + n + l) / 2, and r is the radius of the circumcircle of the smaller triangle, i.e., the length from the center point of the smaller triangle to its vertex. Based on the side length of the small triangle, calculate the maximum and minimum values ​​of the circumcircle radius of the small triangle; 4.5) Using the constraint that the angle of the sphere center corresponding to the projection chord length of the maximum circumcircle radius of all small triangles on its tangent plane should not be greater than A1, determine the side length and area of ​​the small triangles. The three vertices of the small triangles are the coordinates of the antenna deployment points in the test space, forming the antenna deployment coordinate scheme. (5) Install and arrange the navigation antenna according to the antenna layout coordinate scheme in step (4). The navigation antenna and the navigation signal analog source are connected one by one through radio frequency lines. (6) When performing satellite constellation simulation, control the fixed antenna in the triangular antenna array that is closest to the actual satellite trajectory to transmit the corresponding satellite navigation signal, control the switching of navigation antennas, and relay the simulation of the real starry sky satellite position. During this period, if there is a certain uncertain angle between the antenna direction and the real position, power compensation correction is performed.

2. The global satellite navigation constellation dynamic space simulation method according to claim 1, characterized in that, The specific method for power compensation correction in step (6) is as follows: 6.1) Establish a graph F1 showing the relationship between elevation angle and gain for different array element beams through pre-simulation; 6.2) Determine the minimum half-beam angle A2 corresponding to the largest array element by using the beam pattern gain curve; 6.3) Using the power resolution of the signal source as the interval, within the range of ±A2, divide the vertical axis of the relationship diagram F1 equally, find the corresponding elevation angle from the diagram, and form a power compensation value and angle relationship table T1 for different array elements; 6.4) During beamforming, the power in the corresponding pitch angle direction is enhanced by checking T1, and then radiated to the satellite navigation receiving equipment.

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