Array phase measurement method based on motion trail fitting

Abstract

The invention discloses an array phase measurement method based on motion trail fitting, which aims at the high-precision measurement requirement of target detection on the phase, utilizes the geometric position relation generated when a signal source moves relative to a phased-array antenna, and utilizes the signal source motion geometry as the prior information of a linear model. And the array phase is measured based on motion trail fitting. The phase offset can be measured through an algorithm, a traditional darkroom calibration method does not need to be used any more, the cost is saved, meanwhile, the test process is simplified, and the method is suitable for large-scale industrial use and popularization.

Description

Technical Field

[0001] The invention belongs to the technical field of array radar target detection, and in particular relates to an array phase measurement method based on motion trajectory fitting. Background Art

[0002] Radar signal reception adopts the form of digital receiving phased array. The phase offset between multiple antennas needs to be measured before use. For radar systems that use multi-antenna multi-channel interferometric angle measurement technology, it is necessary to accurately measure the phase offset between multiple antennas.

[0003] In the prior art, the measurement is generally performed by darkroom calibration, which requires the array antenna to be placed in a darkroom for phase calibration, which has the problem of high test cost and complicated test process. Summary of the invention

[0004] The object of the present invention is to provide an array phase measurement method based on motion trajectory fitting to solve the problems of high cost and complicated experimental process when measuring phase offset between multiple antennas in the prior art.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] An array phase measurement method based on motion trajectory fitting comprises the following steps:

[0007] Step 1: Set up a radar signal source and an N-dimensional uniform linear array signal receiving array antenna in a multi-antenna multi-channel interferometric angle measurement test site; establish a plane rectangular coordinate system with the radar signal source as the origin and the moving direction of the radar signal source as the positive direction of the X-axis;

[0008] Step 2, moving the radar signal source multiple times at equal intervals or at specified intervals on the X-axis, determining each position of the radar signal source on the X-axis, and using a signal receiving array antenna to record the multi-channel radar data corresponding to each position;

[0009] Perform FFT on all multi-channel radar data to obtain the corresponding normalized array manifold vector, and then obtain the measurement data containing only angle information at each position of the signal receiving array antenna;

[0010] Step 3, based on all the measurement data containing only angle information, establish an overdetermined set of equations for the projection position of the signal receiving array antenna on the motion trajectory of the radar signal source and the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source; use the least squares method to solve the set of equations to obtain the projection position data of the signal receiving array antenna on the X-axis and the vertical distance data from the signal receiving array antenna to the motion trajectory of the radar signal source;

[0011] Step 4, using the data obtained in step 3 to determine the true incident angle of the signal receiving array antenna at each position, and determining the theoretical array manifold vector of the true incident angle of the signal receiving array antenna at each position;

[0012] Step 5: Combine all theoretical array manifolds and their corresponding measured array manifolds to obtain the phase offset of each array element of the signal receiving array antenna, and complete the measurement of the array phase.

[0013] The present invention also has the following features:

[0014] Furthermore, in step 1, an open field is selected as a test site for multi-antenna multi-channel interferometric angle measurement.

[0015] Further, step 2 includes the following sub-steps:

[0016] Step 21, the radar signal source is moved M times on the X-axis with equal spacing, each moving distance is Δx, and each position of the radar signal source on the X-axis is sequentially recorded as 1, 2, 3, ..., M;

[0017] Step 22, select any position in 1-M and record the position as m(1 <m<M-1);

[0018] Step 23, perform FFT on the data received by the signal receiving array antenna at the two adjacent positions m and m+1 selected this time, and obtain the normalized array manifold vectors at the two adjacent positions m and m+1, respectively, as shown in the following formula:

[0019]

[0020] in, It represents the angle at which the radar signal source is incident on the signal receiving array antenna at position m;

[0021] It represents the angle at which the radar signal source is incident on the signal receiving array antenna at position m+1;

[0022] represents the normalized array manifold vector at m;

[0023] represents the normalized array manifold vector at m+1;

[0024] (1) represents the first array element in the signal receiving array antenna, (2) represents the second array element in the signal receiving array antenna, and N represents the Nth array element in the signal receiving array antenna.

[0025] Indicates the phase offset of the first array element, Indicates the phase offset of the second array element... Indicates the phase offset of the N-1th array element;

[0026] d represents the element spacing in the signal receiving array antenna;

[0027] λ represents the wavelength of the transmitted signal of the radar signal source;

[0028] d represents the element spacing in the signal receiving array antenna;

[0029] Step 24, divide the normalized array manifold vectors at m and m+1 to eliminate the phase offset and obtain measurement data containing only the angle, as shown in the following formula:

[0030]

[0031] Wherein, k represents any array element in the array of the signal receiving array antenna;

[0032] Step 25, select a position again, and repeat steps 23-24 until each position is traversed; obtain measurement data containing only angle information at each position and its adjacent positions.

[0033] Further, step 3 includes the following sub-steps:

[0034] Step 31, based on the measurement data of the radar signal source at each position obtained in step 2, which only contains angle information, record

[0035] Where angle(·) means to find the complex-valued phase;

[0036] Step 32, establish an overdetermined set of equations for the projection position of the signal receiving array antenna on the radar signal source motion trajectory and the vertical distance from the signal receiving array antenna to the radar signal source motion trajectory:

[0037]

[0038] Among them, x1 to x M In turn, they represent the coordinate origin, the position of the radar signal source on the X-axis after the first movement, ..., the position of the radar signal source on the X-axis after the M-1th movement;

[0039] x i Indicates the projection position of the signal receiving array antenna on the X-axis;

[0040] R0 represents the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source;

[0041] Step 33, since M>>2, use the least squares method to fit x i and the value of R0.

[0042] Further, step 4 includes the following sub-steps:

[0043] Step 41, determining the true incident angle of the signal receiving array antenna to each of 1 to M according to the projection of the signal receiving array antenna on the X-axis obtained in step 3 and the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source;

[0044] Step 42, using the following formula, determine the theoretical array manifold vector at each location from 1 to M:

[0045]

[0046] Among them, a m (θ m ) represents the theoretical array manifold vector at position m;

[0047] θ m represents the actual incident angle of the signal receiving array antenna at position m.

[0048] Furthermore, in step 5, the corresponding phase offset is calculated using the following formula:

[0049]

[0050] in, Represents the phase offset, (i=1,2,…,N-1).

[0051] Compared with the prior art, the present invention has the following technical effects:

[0052] The array phase measurement method based on motion trajectory fitting of the present invention is aimed at the high-precision measurement requirements of the phase for target detection. It uses the geometric position relationship generated when the signal source moves relative to the phased array antenna, and uses the prior information that the motion geometry of the signal source is a linear model to measure the array phase based on motion trajectory fitting. The phase offset can be measured through the algorithm, and the traditional darkroom calibration method is no longer needed. It saves costs and simplifies the test process, which is suitable for large-scale use and promotion in industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the arrangement of a radar signal source and a signal receiving array antenna in one embodiment of the present invention. DETAILED DESCRIPTION

[0054] It should be noted that, unless otherwise specified, all methods in the present invention adopt methods known in the prior art, such as "FFT" and "least square method", which are both known methods in the prior art.

[0055] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0056] An array phase measurement method based on motion trajectory fitting comprises the following steps:

[0057] Step 1, such as Figure 1 As shown, a radar signal source and an N-dimensional uniform linear array signal receiving array antenna are set up in a multi-antenna multi-channel interferometric angle measurement test site, and a plane rectangular coordinate system is established with the radar signal source as the origin and the moving direction of the radar signal source as the positive direction of the X-axis;

[0058] Step 2: The radar signal source is moved multiple times on the X-axis at equal intervals or at specified intervals. The signal receiving array antenna records the multi-channel radar data received by the signal receiving array antenna after each movement of the radar signal source. FFT is performed on all the multi-channel radar data, and the complex value at the maximum value of the spectrum is taken to obtain measurement data containing only angle information at each position of the radar signal source on the X-axis.

[0059] Step 3, combining all the measurement data containing only angle information, establishing an overdetermined equation group of the projection of the signal receiving array antenna on the motion trajectory of the radar signal source and the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source, and solving the projection of the signal receiving array antenna on the X-axis and the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source in the overdetermined equation group;

[0060] Step 4, using the data obtained in step 3 to solve the actual incident angle of the receiving array at each position, and obtain the theoretical array manifold vector at each transmitting antenna position;

[0061] Step 5: Combine the theoretical array manifold and the measured array manifold to obtain the phase offset of each array element of the signal receiving array antenna, and complete the measurement of the array phase.

[0062] Furthermore, in step 1, an open field is selected as a test site for multi-antenna multi-channel interferometric angle measurement.

[0063] Further, step 2 includes the following sub-steps:

[0064] Step 21, the radar signal source is moved M times on the X-axis with equal spacing, and the distance of each movement is Δx. Each position of the radar signal source after moving on the X-axis is recorded as 1, 2, 3, ..., M in sequence;

[0065] Step 22, select a position on the X-axis after the radar signal source moves, and record the position as m(1 <m<M-1);

[0066] Step 23, perform FFT on the data received by the signal receiving array antenna at the two adjacent positions m and m+1 selected this time, and obtain the normalized array manifold vectors at the two adjacent positions m and m+1, respectively, as shown in the following formula:

[0067]

[0068] in, It represents the angle at which the radar signal source is incident on the signal receiving array antenna at position m;

[0069] It represents the angle at which the radar signal source is incident on the signal receiving array antenna at position m+1;

[0070] represents the normalized array manifold vector at m;

[0071] represents the normalized array manifold vector at m+1;

[0072] T means transposing the matrix;

[0073] (1) represents the first array element in the signal receiving array antenna, (2) represents the second array element in the signal receiving array antenna, and N represents the Nth array element in the signal receiving array antenna;

[0074] Indicates the phase offset;

[0075] d represents the element spacing in the signal receiving array antenna;

[0076] λ represents the wavelength of the transmitted signal of the radar signal source;

[0077] Step 24, divide the normalized array manifold vectors at m and m+1 to eliminate the phase offset, and obtain the following measurement data containing only the angle:

[0078]

[0079] Wherein, k represents any array element in the array of the signal receiving array antenna;

[0080] Step 25, randomly select a position for which measurement data containing only angles has not been calculated, and repeat steps 23-24 until all positions of the radar signal sources after movement have been traversed; and obtain measurement data containing only angle information at each position of the radar signal source on the X-axis.

[0081] Further, step 3 includes the following sub-steps:

[0082] Step 31, based on the measurement data of the radar signal source obtained in step 2, which only contains angle information at each position on the X-axis, record

[0083] Where angle(·) means to find the complex-valued phase;

[0084] The following further describes step 31:

[0085] remember

[0086] Also because

[0087]

[0088] according to Figure 1 The geometric relationship shown in Can be expressed as:

[0089]

[0090] Δθ m(m+1) Can be expressed as:

[0091]

[0092] Step 32, establish an overdetermined set of equations for the projection of the signal receiving array antenna on the radar signal source motion trajectory and the vertical distance from the signal receiving array antenna to the radar signal source motion trajectory:

[0093]

[0094] Among them, x1 to x M In turn, they represent the position of the radar signal source on the X-axis after the first movement, the position of the radar signal source on the X-axis after the second movement, ..., the position of the radar signal source on the X-axis after the M-1th movement;

[0095] x i Represents the projection of the signal receiving array antenna on the X-axis;

[0096] R0 represents the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source;

[0097] Step 33, since M>>2, use the least squares method to fit x i and the value of R0.

[0098] Further, step 4 includes the following sub-steps:

[0099] Step 41: Substitute the projection of the signal receiving array antenna on the X-axis obtained in step 3 and the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source into determining the true angle of incidence on the array plane at each position;

[0100] Step 42, determine the theoretical array manifold vector a at position m according to the actual incident angle m (θ m ):

[0101]

[0102] Further, step 5 includes the following sub-steps:

[0103] Step 5: Combine the theoretical array manifold vector a m (θ m ) and the measurement array manifold vector The phase offset is calculated using the following formula:

[0104]

[0105] in, Represents the phase offset, (i=1,2,…,N-1).

Claims

1. An array phase measurement method based on motion trajectory fitting, characterized in that: The following steps are involved: Step 1: Setting a radar signal source and an N-dimensional uniform linear array signal receiving array antenna in a multi-antenna multi-channel interferometric angle measurement test site; A plane rectangular coordinate system is established with the radar signal source as the origin and the moving direction of the radar signal source as the positive direction of the X-axis; Step 2, moving the radar signal source multiple times at equal intervals or at specified intervals on the X-axis, determining each position of the radar signal source on the X-axis, and using a signal receiving array antenna to record the multi-channel radar data corresponding to each position; Perform FFT on all multi-channel radar data to obtain the corresponding normalized array manifold vector, and then obtain the measurement data containing only angle information at each position of the signal receiving array antenna; Step 3, based on all the measurement data containing only angle information, establish an overdetermined set of equations for the projection position of the signal receiving array antenna on the motion trajectory of the radar signal source and the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source; use the least squares method to solve the set of equations to obtain the projection position data of the signal receiving array antenna on the X-axis and the vertical distance data from the signal receiving array antenna to the motion trajectory of the radar signal source; Step 4, using the data obtained in step 3 to determine the true incident angle of the signal receiving array antenna at each position, and determining the theoretical array manifold vector of the true incident angle of the signal receiving array antenna at each position; Step 5: Combine all theoretical array manifolds and their corresponding measured array manifolds to obtain the phase offset of each array element of the signal receiving array antenna, and complete the measurement of the array phase.

2. The array phase measurement method based on motion trajectory fitting according to claim 1, characterized in that: In step 1, an open field is selected as a test site for multi-antenna multi-channel interferometric angle measurement.

3. The array phase measurement method based on motion trajectory fitting according to claim 1, characterized in that: Step 2 includes the following sub-steps: Step 21, the radar signal source is moved M times on the X-axis with equal spacing, each moving distance is Δx, and each position of the radar signal source on the X-axis is sequentially recorded as 1, 2, 3, ..., M; Step 22, select any position in 1-M and record the position as m(1 <m<M-1); Step 23, perform FFT on the data received by the signal receiving array antenna at the two adjacent positions m and m+1 selected this time, and obtain the normalized array manifold vectors at the two adjacent positions m and m+1, respectively, as shown in the following formula: in, It represents the angle at which the radar signal source is incident on the signal receiving array antenna at position m; It represents the angle at which the radar signal source is incident on the signal receiving array antenna at position m+1; represents the normalized array manifold vector at m; represents the normalized array manifold vector at m+1; (1) represents the first array element in the signal receiving array antenna, (2) represents the second array element in the signal receiving array antenna, and N represents the Nth array element in the signal receiving array antenna. Indicates the phase offset of the first array element, Indicates the phase offset of the second array element... Indicates the phase offset of the N-1th array element; d represents the element spacing in the signal receiving array antenna; λ represents the wavelength of the transmitted signal of the radar signal source; d represents the element spacing in the signal receiving array antenna; Step 24, divide the normalized array manifold vectors at m and m+1 to eliminate the phase offset and obtain measurement data containing only the angle, as shown in the following formula: Wherein, k represents any array element in the array of the signal receiving array antenna; Step 25, select a position again, and repeat steps 23-24 until each position is traversed; obtain measurement data containing only angle information at each position and its adjacent positions.

4. The array phase measurement method based on motion trajectory fitting according to claim 1, characterized in that: Step 3 includes the following sub-steps: Step 31, based on the measurement data of the radar signal source at each position obtained in step 2, which only contains angle information, record Where angle(·) means to find the complex-valued phase; Step 32, establish an overdetermined set of equations for the projection position of the signal receiving array antenna on the radar signal source motion trajectory and the vertical distance from the signal receiving array antenna to the radar signal source motion trajectory: Among them, x1 to x M In turn, they represent the coordinate origin, the position of the radar signal source on the X-axis after the first movement, ..., the position of the radar signal source on the X-axis after the M-1th movement; x i Indicates the projection position of the signal receiving array antenna on the X-axis; R0 represents the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source; Step 33, since M>>2, use the least squares method to fit x i and the value of R0.

5. The array phase measurement method based on motion trajectory fitting according to claim 1, characterized in that: Step 4 includes the following sub-steps: Step 41, determining the true incident angle of the signal receiving array antenna to each of 1 to M according to the projection of the signal receiving array antenna on the X-axis obtained in step 3 and the vertical distance from the signal receiving array antenna to the motion trajectory of the radar signal source; Step 42, using the following formula, determine the theoretical array manifold vector at each location from 1 to M: Among them, a m (θ m ) represents the theoretical array manifold vector at position m; θ m represents the actual incident angle of the signal receiving array antenna at position m.

6. The array phase measurement method based on motion trajectory fitting according to claim 1, characterized in that: In step 5, the corresponding phase offset is calculated using the following formula: in, Represents the phase offset, (i=1,2,…,N-1).

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