A method for adaptively measuring the energy beam center of a microwave energy receiving antenna

Abstract

The application discloses a method for adaptively measuring an energy beam center of a microwave energy receiving antenna, and comprises the following steps: S1. obtaining a power density distribution of an energy signal on a receiving array surface by using an N*N rectangular power detection array, and performing phase adjustment on the obtained energy signal power density distribution to restore the distribution when the energy center is aligned with the normal line of the rectangular power detection array; and S2. performing B-spline interpolation approximation on the energy signal after the phase adjustment, fitting the receiving signal, and calculating the position of the receiving energy signal beam center. The method provided by the application can accurately measure the position of the energy beam center on the energy receiving array antenna.

Description

Technical Field

[0001] This invention relates to microwave energy receiving antennas, and more particularly to a method for adaptively measuring the energy beam center of a microwave energy receiving antenna. Background Technology

[0002] With the development of satellite technology, it has become closely related to human life. Currently, the common method for satellite power supply is to install solar panels on each satellite, converting solar energy into electricity to ensure energy supply. However, this method has drawbacks: 1. If the satellite operates in a shadow area, sunlight cannot reach the solar panels, and the satellite cannot guarantee a normal energy supply. 2. The lifespan of the solar panels determines the lifespan of the satellite itself. If the satellite's solar panels are damaged, even if other components are functioning normally, the satellite cannot be used properly. To solve these problems, developing new satellite energy supply methods is crucial. Microwave wireless power transmission technology can solve these problems. Launching a space charging station satellite would convert solar energy into electricity and transmit it to a receiving satellite that needs energy through microwave wireless power transmission, thus ensuring that the receiving satellite can continue to function normally even if its solar panels fail to supply energy for some reason.

[0003] The key to ensuring high-efficiency microwave energy transmission is achieving high-precision alignment of the energy beam with the energy receiving array antenna. Beam pointing accuracy directly affects energy transmission efficiency. Inaccurate beam pointing can cause some energy to scatter in unwanted directions, leading to reduced transmission efficiency and increased transmission time and cost. For the energy beam, the crucial step in aligning its center with the energy receiving array antenna is to accurately measure its position on the antenna. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for high-precision adaptive measurement of the energy beam center of a microwave energy receiving antenna, which can accurately measure the position of the energy beam center on the energy receiving array antenna.

[0005] The objective of this invention is achieved through the following technical solution: a method for high-precision adaptive measurement of the energy beam center using a microwave energy receiving antenna, comprising the following steps:

[0006] S1. Use an N×N rectangular power detector array to obtain the power density distribution of the energy signal on the receiving array surface, perform phase adjustment on the obtained power density distribution of the energy signal, and restore the power distribution when the energy center is aligned with the normal of the rectangular power detector array;

[0007] S2. The phase-adjusted energy signal is approximated by B-spline interpolation, and the received signal is fitted to calculate the beam center position of the received energy signal.

[0008] The beneficial effects of the present invention are: 1. The present invention adopts phase adjustment technology to obtain phase compensation for the maximum value of received energy power.

[0009] 2. This invention employs a B-spline interpolation approximation method, which improves the measurement accuracy of the energy beam center. Attached Figure Description

[0010] Figure 1 This is a diagram of the energy receiving antenna array of the present invention;

[0011] Figure 2 This is a flowchart of the energy beam center measurement process of the present invention;

[0012] Figure 3 This is a flowchart of the phase compensation process of the present invention;

[0013] Figure 4 The flowchart for finding energy centers using the B-spline algorithm interpolation of this invention is shown. Detailed Implementation

[0014] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0015] In a microwave energy transmission system, there is a set of energy receiving array antennas for the energy receiver. The center of the energy beam is measured by measuring the maximum power on the energy receiving array antennas.

[0016] Energy receiving antenna array, such as Figure 1 As shown, it includes:

[0017] The energy receiving antenna array is a group of N×N rectangular power detection array antennas, where N is any positive integer. The spacing d between the antennas along the x-axis is... x The distance d between the y-axis and the y-axis y They are all equal, and d x =d y .

[0018] like Figure 2 As shown, the energy beam center measurement process of the present invention includes the following steps;

[0019] S1. Use an N×N rectangular power detector array to obtain the power density distribution of the energy signal on the receiving array surface, perform phase adjustment on the obtained power density distribution of the energy signal, and restore the power distribution when the energy center is aligned with the normal of the rectangular power detector array;

[0020] S2. The phase-adjusted energy signal is approximated by B-spline interpolation, and the received signal is fitted to calculate the beam center position of the received energy signal.

[0021] like Figure 3 As shown, assuming the angle of transmission measured by the angle-measuring antenna is the center angle, a set of angles is obtained in a fixed step around this center angle, and the direction vector corresponding to each angle on the rectangular power detection array is calculated. Using the direction vectors of these angles, the energy beam is scanned within this angular range to obtain the phase adjustment value corresponding to the maximum power, and the received energy signal is phase-weighted. The process includes:

[0022] S101. Obtain the power density distribution of the energy signal on the receiving array surface using an N×N rectangular power detection array, including:

[0023] A rectangular power detection array is an N×N antenna array. The position of the array element (0,0) is the origin position O, and its coordinates are represented as (0,0). 0,0 S represents the incident beam received by array element (0,0). k,l The coordinates of the array element are (x k ,y l The received incident beam, P k,l The coordinates of the array element are (x k ,y l The received incident beam power, 0≤k≤N-1, 0≤l≤N-1, and k and l are integers;

[0024] S k,l With S 0,0 The time delay τ between xk,yl (θ,φ) is represented as:

[0025]

[0026] Where, d x and d y These represent the spacing between adjacent antenna elements in the x and y axes, respectively. The spacing between adjacent antenna elements is equal, and d... x =d y =d; then the coordinates of the array element are (x k ,y l The power of the received beam with elevation and azimuth angles of θ and φ is expressed as follows:

[0027] P k,l (θ,φ)=g k (θ,φ)·exp{jωτ(θ,φ)}

[0028] =g k (θ,φ)exp{-j2πd(xk ·cosφ+y l ·sinφ)·sinθ / λ} (2)

[0029] Where λ is the wavelength of the incident beam, g k (θ,φ) represents the complex amplitude of the energy beam received by the energy receiving antenna array with elevation and azimuth angles of θ and φ, respectively;

[0030] When 0≤k≤N-1, 0≤l≤N-1, for each combination of k and l, the coordinates of the array element are calculated as (x k ,y l The received energy beam power P has elevation and azimuth angles of θ and φ respectively. k,l (θ,φ), the power density distribution of the energy signal on the receiving array surface is the signal power received by each array element, represented as a set:

[0031]

[0032] S102. Perform phase adjustment on the obtained energy signal power density distribution to restore the power distribution when the energy center is aligned with the normal of the rectangular power detection array:

[0033] Assuming the transmitter sends an energy signal with an elevation angle of θ0 and an azimuth angle of φ0 to the receiving array, the received signal power is at its maximum. The receiver knows θ0 and φ0. However, due to environmental factors, the actual signal received by the receiving array has an elevation angle of θ0 + Δ. θ The azimuth angle is φ0+Δ φ Δ θ With Δ φ The unknown quantity is the phase adjustment weight at which the received power is maximum. Then, the elevation angle θ at that point can be solved using the phase adjustment weight. i =θ0+Δ θ azimuth φ i =φ0+Δ φ , using θ i φ i The power distribution at this point is determined as follows:

[0034] The total power of the energy beam received by the energy receiving antenna array at elevation and azimuth angles θ and φ is expressed as:

[0035]

[0036] Using equation (3), the phase adjustment weight w corresponding to different pitch and azimuth angles is adjusted. k Substituting the incident signal, the expression is:

[0037]

[0038] In the formula,

[0039]

[0040] Where, θ i and φ i These are the pitch and azimuth angles corresponding to the phase adjustment weights;

[0041] Because θ i =θ0+Δ θ φ i =φ0+Δ φ Using θ0 and φ0 as initial values ​​respectively, and within the ranges of [φ0-α, φ0+α] and [θ0-α, θ0+α], θ is continuously changed in steps of β. i and φ i The value, and in each θ i and φ i Below, the array received power z(θ) at this time is measured. i ,φ i Compare different z(θ) i ,φ i Find z(θ) i ,φ i Record the maximum value of θ at this point. i φ i Substituting into equation (2), the power P of all array elements can be solved. k,l (θ i ,φ i ), abbreviated as P k,l 0≤k≤N-1, 0≤l≤N-1 and k and l are integers, which gives the power distribution when the energy center is aligned with the normal of the rectangular power detection array, denoted as:

[0042]

[0043] The phase-adjusted energy signal is approximated by B-spline interpolation, and the received signal is fitted to calculate the beam center position of the received energy signal.

[0044] like Figure 4 As shown, the process of finding the energy center using the B-spline interpolation algorithm includes:

[0045] For the phase-adjusted power distribution, B-spline interpolation is performed, and the B-spline surface is represented as follows:

[0046]

[0047] In the formula, S(u,v) is the approximating surface after B-spline interpolation, u and v are the domain parameters on the surface, m and n represent discrete points within the domain of the approximating surface, and P k,l It is a point on the curved surface, that is, the power P of the array element. k,l (θ i ,φ i ), k and l represent the indices on u and v respectively; N k,p (u) is the basis function of the B-spline difference acting in the u direction, N l,q (v) is the basis function of B-spline interpolation applied in the direction of v, where p and q are the orders of the basis functions. Taking p = q = 3, the basis functions are defined as follows:

[0048]

[0049]

[0050] The power distribution after B-spline interpolation is a standard ellipse. The major and minor axes of the ellipse are measured, and the intersection of the two axes is the center of the ellipse, which is also the center of the energy beam.

[0051] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the methods described in the foregoing embodiments, such as changing the names of the methods. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of adaptively measuring the center of a microwave energy receiving antenna energy beam, characterized by: Comprising the following steps: S1. Obtain the power density distribution of the energy signal on the receiving array surface using an N x N rectangular power detection array; Phase adjustment is performed on the obtained energy signal power density distribution to restore the power distribution when the energy center is aligned with the normal line of the rectangular power detection array, comprising: Assume that the transmitting party transmits an energy signal with an elevation angle θ0 and an azimuth angle φ0 to the receiving array, the received signal power is maximum, θ0 and φ0 are known by the receiving party, due to environmental reasons, the actual signal received by the receiving array is an energy signal with an elevation angle θ0+Δ θ and an azimuth angle φ0+Δ φ , Δ θ and Δ φ are unknown quantities; it is necessary to find the phase adjustment weight when the received power is maximum, and then solve the elevation angle θ i = θ0+Δ θ and the azimuth angle φ i = φ0+Δ φ at this time by using the phase adjustment weight, and then use θ i and φ i to solve the power distribution at this time, the specific process is as follows: The total power of the energy beam received by the energy receiving antenna array surface at the elevation angle and azimuth angle θ, φ is expressed as: where P k,l (θ,φ) is the power of the energy beam received by the array element with coordinates (x k ,y l ) at the elevation and azimuth angles θ and φ, respectively. The phase adjustment weight w corresponding to different elevation angles and azimuth angles k Substituting the incident signal, the expression is: In the formula, where θ i and φ i are the phase-adjusted weights corresponding to the elevation and azimuth angles, respectively. Because θ i = θ0+ Δ θ , φ i = φ0+ Δ φ , the values of θ i and φ i are changed constantly with β as a step in the range of [φ0- α, φ0+ α] and [θ0- α, θ0+ α] respectively with θ0and φ0as initial values, and at each θ i and φ i , the array receiving power z(θ i , φ i ) at this time is measured, different z(θ i , φ i ) are compared, the maximum case of z(θ i , φ i ) is found, θ i and φ i at this time are recorded, and the power P k,l (θ i , φ i ) of all array elements is solved, which is simply recorded as P k,l , 0≤k≤N-1, 0≤l≤N-1 and k, l are integers, i.e. the power distribution situation when the energy center is aligned with the normal line of the rectangular power detection array is obtained, which is recorded as: S2. The B-spline interpolation approximation is used on the phase-adjusted energy signal to fit the received signal and calculate the received energy signal beam center position.

2. The method of claim 1, wherein: the microwave energy receiving antenna is a phased array antenna; and the microwave energy receiving antenna is configured to receive microwave energy from a plurality of microwave energy sources. In the step S1, the power density distribution of the energy signal on the receiving array surface is obtained using an N x N rectangular power detection array, comprising: A rectangular power detection array is a set of N x N antennas, the position of the array element (0, 0) is the origin position O, the coordinate is represented as (0, 0), S 0,0 represents an incident beam received by the array element (0, 0), S k,l represents an incident beam received by the array element with coordinates (x k , y l ), P k,l represents the power of the incident beam received by the array element with coordinates (x k , y l ), 0≤k≤N-1, 0≤l≤N-1 and k, l are integers; S k,l the latency between S 0,0 and S is represented as: where d x and d y respectively represent the adjacent antenna element spacing in the x and y axis directions, the adjacent spacing between each antenna element is equal, and d x = d y = d; the element coordinates are (x k , y l ), and the energy beam power received with the elevation angle and azimuth angle being θ and φ respectively is represented as: P k,l (θ,φ) = g k (θ,φ) · exp{jωτ(θ,φ)} = g k (θ,φ)exp{-j2πd(x k ·cosφ+y l ·sinφ)·sinθ / λ} (2) where λ is the wavelength of the incident beam, g k (θ,φ) denotes the complex amplitude of the energy beam received by the energy receiving antenna array at an elevation angle and azimuth angle of θ,φ, respectively. The array element coordinates are calculated as (x k ,y l ) for each combination of k, l when 0≤k≤N-1, 0≤l≤N-1. k,l The power density distribution of the energy signal on the receiving array surface is the signal power received by each array element, expressed as a set:

3. The method of claim 1, wherein: the microwave energy receiving antenna is a phased array antenna; and the microwave energy receiving antenna is configured to receive microwave energy from a plurality of microwave energy sources. In the step S2, the B-spline interpolation is performed on the phase-adjusted power distribution, and the B-spline surface is expressed as: where S(u, v) is the approximated surface after B-spline interpolation, u and v are the domain parameters on the surface, m and n represent the discrete points in the domain of the approximated surface, P k,l is the point on the surface, i.e. the power P k,l (θ i , φ i ) of the element, k and l represent the index in u and v respectively; N k,p (u) is the basis function of B-spline interpolation in u direction, N l,q (v) is the basis function of B-spline interpolation in v direction, p and q are the order of the basis function, p = q = 3 is taken, and the definition is as follows: The power distribution after B-spline interpolation is a standard ellipse, the long and short semi-axes of the ellipse are measured, and the intersection of the two is the center of the ellipse, that is, the center of the energy beam.

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