Method for adaptively measuring energy beam center by microwave energy receiving antenna

Abstract

The invention discloses a method for adaptively measuring an energy beam center by a microwave energy receiving antenna, which comprises the following steps of: S1, obtaining power density distribution of an energy signal on a receiving array plane by using an N * N rectangular power detection array, and performing phase adjustment on the obtained power density distribution of the energy signal, restoring the distribution condition when the energy center is aligned with the normal of the rectangular power detection array; and S2, carrying out B-spline interpolation approximation on the energy signal after phase adjustment, fitting the received signal, and calculating the beam center position of the received energy signal. According to the method provided by the invention, the position of the energy beam center can be accurately measured on the energy receiving array antenna.

Description

Technical Field

[0001] The invention relates to a microwave energy receiving antenna, in particular to a method for adaptively measuring an energy beam center of a microwave energy receiving antenna. Background Art

[0002] With the development of satellite technology, satellite technology has become closely related to human life. At present, the commonly used satellite energy supply method is to install solar panels on each satellite, which absorb solar energy and convert it into electrical energy to ensure energy supply. However, this method has disadvantages: 1. If the satellite runs into the shadow area, the sunlight cannot shine on the satellite's solar panels, then the satellite cannot guarantee normal energy supply at this time. 2. The life of the solar panels determines the life of the satellite itself. If the satellite's solar panels are damaged, even if other components of the satellite are normal, they cannot be used normally. In order to solve the above problems, it is very important to develop a new satellite energy supply method. Microwave wireless energy transmission technology can solve this kind of problem. The role of launching a space charging pile satellite is to convert solar energy into electrical energy, and transmit the electrical energy to the receiving satellite that needs energy supply through microwave wireless energy transmission, so as to ensure that the receiving satellite can still work normally when the solar panels cannot supply energy normally due to some reason.

[0003] The key to ensuring high efficiency of microwave energy transmission is to achieve high-precision alignment of the energy beam with the energy receiving array antenna. The beam pointing accuracy directly affects the efficiency of energy transmission. If the beam pointing is inaccurate, part of the energy may be scattered in unnecessary directions, resulting in reduced energy transmission efficiency and increased energy transmission time and cost. For the energy beam, the key to aligning the center of the energy beam with the energy receiving array antenna is to accurately measure the position of the energy beam on the energy receiving array antenna. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to 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 an energy receiving array antenna.

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

[0006] S1. Use an N×N rectangular power detection array to obtain the power density distribution of the energy signal on the receiving array, 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 detection array;

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

[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. The present invention adopts the B-spline interpolation approximation method to improve the measurement accuracy of the energy beam center. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0012] Figure 3 is a phase compensation flow chart of the present invention;

[0013] Figure 4 The flowchart of finding the energy center by B-spline algorithm interpolation of the present invention. DETAILED DESCRIPTION

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

[0015] Assume that in a microwave energy transmission system, there is a group of energy receiving array antennas for the energy receiver, and the energy beam center is measured by measuring the maximum power on the energy receiving array antennas;

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

[0017] The energy receiving antenna array is a group of N×N rectangular power detection array antennas, where N is an arbitrary positive integer. The spacing d between each antenna in the x-axis direction is x The distance d from the y-axis y are 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 detection array to obtain the power density distribution of the energy signal on the receiving array, 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 detection array;

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

[0021] like Figure 3 As shown, assuming that the angle of the transmitter measured by the angle measuring antenna is the center angle, a group of angles are obtained at fixed steps near the center angle and the direction vector corresponding to each angle on the rectangular power detection array is obtained. The direction vector of this group of angles is used to scan the energy beam within this angle range, the phase adjustment value corresponding to the maximum power is obtained, and the phase weighting of the received energy signal is performed. The process includes:

[0022] S101. Using an N×N rectangular power detection array to obtain the power density distribution of the energy signal on the receiving array, including:

[0023] The rectangular power detection array is a group of N×N antennas. The position of the array element (0,0) is the origin position O, and the coordinates are expressed as (0,0). 0,0 represents the incident beam received by the array element (0,0), S k,l Indicates that the coordinates of the array element are (x k ,y l ) received incident beam, P k,l Indicates that the coordinates of the array element are (x k ,y l ) 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 xk,yl (θ, φ) is expressed as:

[0025]

[0026] Among them, d x and d y They represent the spacing between adjacent antenna elements parallel to the x-axis and y-axis directions 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 energy beam power received at the elevation angle and azimuth angle of θ and φ is expressed as:

[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 angles θ and azimuth angles φ respectively;

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

[0031]

[0032] S102. 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 of the rectangular power detection array:

[0033] Assume that when the transmitter transmits an energy signal with an elevation angle of θ0 and an azimuth angle of φ0 to the receiving array, the received signal power is the largest. The receiver of θ0 and φ0 is known. Due to environmental reasons, the signal actually received by the receiving array is the elevation angle of θ0+Δ θ , the azimuth is φ0+Δ φ , Δ θ With Δ φ is an unknown quantity; it is necessary to find the phase adjustment weight when the received power is maximum, and then solve the pitch angle θ at this time through the phase adjustment weight i =θ0+Δ θ , azimuth φ i =φ0+Δ φ , using θ i ,φ i Solve the power distribution at this time. The specific process is:

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

[0035]

[0036] Through formula (3), the phase adjustment weights w corresponding to different elevation angles and azimuth angles are k Substituting the incident signal, the expression is:

[0037]

[0038] In the formula,

[0039]

[0040] Among them, θ i and φ i are the corresponding elevation and azimuth angles under the phase adjustment weight;

[0041] Because θ i =θ0+Δ θ ,φ i =φ0+Δ φ , taking θ0 and φ0 as initial values, and changing θ in steps of β within the range of [φ0-α, φ0+α] and [θ0-α, θ0+α] respectively. i and φ i The value of θ i and φ i Under this condition, the array receiving power z(θ i ,φ i ), compare different z(θ i ,φ i ), find z(θ i ,φ i ) is the largest, record the value of θ at this time i ,φ i Substitute into (2) and solve for the power P of all array elements: 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, that is, the power distribution when the energy center is aligned with the normal of the rectangular power detection array is obtained, which is recorded as:

[0042]

[0043] The energy signal after phase adjustment is approximated by B-spline interpolation, the received signal is fitted, and the center position of the received energy signal beam is calculated;

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

[0045] B-spline interpolation is performed on the power distribution after phase adjustment, and the B-spline surface is expressed as:

[0046]

[0047] Where S(u,v) is the approximation surface after B-spline interpolation, u and v are the domain parameters on the surface, m and n represent discrete points in the domain of the approximation surface, and P k,l is a point on the surface, that is, the power P of the array element k,l (θ i ,φ i ), k and l represent the indexes on u and v respectively; N k,p (u) is the basis function of the B-spline interpolation acting in the u direction, N l,q (v) is the basis function of B-spline interpolation in the v direction, p and q are the orders of the basis function, p = q = 3, and 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 is the center of the ellipse, which is also the center of the energy beam.

[0051] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, it is still possible for a person skilled in the art to modify the methods described in the above embodiments, such as changing the names of the methods, etc. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for adaptively measuring the center of an energy beam of a microwave energy receiving antenna, characterized in that: The following steps are involved: S1. Use an N×N rectangular power detection array to obtain the power density distribution of the energy signal on the receiving array, 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 detection array; S2. The energy signal after phase adjustment is approximated by B-spline interpolation, the received signal is fitted, and the center position of the received energy signal beam is calculated.

2. The method for adaptively measuring the energy beam center of a microwave energy receiving antenna according to claim 1, characterized in that: The step S1 comprises: S101. Using an N×N rectangular power detection array to obtain the power density distribution of the energy signal on the receiving array, including: The rectangular power detection array is a group of N×N antennas. The position of the array element (0,0) is the origin position O, and the coordinates are expressed as (0,0). 0,0 represents the incident beam received by the array element (0,0), S k,l Indicates that the coordinates of the array element are (x k ,y l ) received incident beam, P k,l Indicates that the coordinates of the array element are (x k ,y l ) received incident beam power, 0≤k≤N-1,0≤l≤N-1 and k and l are integers; S k,l With S 0,0 The delay between It is expressed as: Among them, d x and d y They represent the spacing between adjacent antenna elements parallel to the x-axis and y-axis directions 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 energy beam power received at the elevation angle and azimuth angle of θ and φ is expressed as: 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 angles θ and azimuth angles φ respectively; When 0≤k≤N-1,0≤l≤N-1, for each combination of k and l, the calculated coordinates of the array element are (x k ,y l ) receives the energy beam power P with elevation and azimuth angles θ and φ respectively k,l (θ, φ), the power density distribution of the energy signal on the receiving array is the signal power received by each array element, expressed as a set: S102. 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 of the rectangular power detection array: Assume that when the transmitter transmits an energy signal with an elevation angle of θ0 and an azimuth angle of φ0 to the receiving array, the received signal power is the largest. The receiver of θ0 and φ0 is known. Due to environmental reasons, the signal actually received by the receiving array is the elevation angle of θ0+Δ θ , the azimuth is φ0+Δ φ , Δ θ With Δ φ is an unknown quantity; it is necessary to find the phase adjustment weight when the received power is maximum, and then solve the pitch angle θ at this time through the phase adjustment weight i =θ0+Δ θ , azimuth φ i =φ0+Δ φ , using θ i ,φ i Solve the power distribution at this time. The specific process is: The total power of the energy beam received by the energy receiving antenna array with elevation angles θ and azimuth angles φ respectively is expressed as: Through formula (3), the phase adjustment weights w corresponding to different elevation angles and azimuth angles are k Substituting the incident signal, the expression is: In the formula, Among them, θ i and φ i are the corresponding elevation and azimuth angles under the phase adjustment weight; Because θ i =θ0+Δ θ ,φ i =φ0+Δ φ , taking θ0 and φ0 as initial values, and changing θ in steps of β within the range of [φ0-α, φ0+α] and [θ0-α, θ0+α] respectively. i and φ i The value of θ i and φ i Under this condition, the array receiving power z(θ i ,φ i ), compare different z(θ i ,φ i ), find z(θ i ,φ i ) is the largest, record the value of θ at this time i ,φ i Substitute into (2) and solve for the power P of all array elements: 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, that is, the power distribution when the energy center is aligned with the normal of the rectangular power detection array is obtained, which is recorded as:

3. The method for adaptively measuring the energy beam center of a microwave energy receiving antenna according to claim 1, characterized in that: In step S2, B-spline interpolation is performed on the power distribution after phase adjustment, and the B-spline surface is represented as: Where S(u,v) is the approximation surface after B-spline interpolation, u and v are the domain parameters on the surface, m and n represent discrete points in the domain of the approximation surface, and P k,l is a point on the surface, that is, the power P of the array element k,l (θ i ,φ i ), k and l represent the indexes on u and v respectively; N k,p (u) is the basis function of the B-spline interpolation acting in the u direction, N l,q (v) is the basis function of B-spline interpolation in the v direction, p and q are the orders of the basis function, p = q = 3, and are defined as follows: 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 is the center of the ellipse, which is also the center of the energy beam.

Images