An array phase measurement method based on motion trajectory fitting

Abstract

The application discloses an array phase measurement method based on motion trajectory fitting. In view of the high-precision phase measurement requirement of target detection, the geometric position relationship generated when a signal source moves relative to a phased array antenna is utilized, prior information that the motion geometry of the signal source is a straight line model is utilized, and the array phase is measured based on motion trajectory fitting. The measurement of the phase offset can be realized through the algorithm, and the traditional darkroom calibration method is no longer needed, so that the test process is simplified while the cost is saved, and the method is suitable for large-scale use and popularization in industry.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of array radar target detection, and particularly relates to an array phase measurement method based on motion trajectory fitting. BACKGROUND

[0002] The radar signal reception adopts a digital receiving phased array form, and the phased array antenna needs to be measured for phase bias among multiple antennas before use. For a radar system adopting a multi-antenna multi-channel interference angle measurement technology, the phase bias among multiple antennas needs to be accurately measured.

[0003] In the prior art, the measurement is generally performed in a darkroom calibration manner. This method needs to set the array antenna in a darkroom for phase calibration, and this method has the problems of high test cost and complicated test process. SUMMARY

[0004] The present application aims to provide an array phase measurement method based on motion trajectory fitting, so as to solve the problems of high cost and complicated test process in measuring the phase bias among multiple antennas in the prior art.

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

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

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

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

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

[0010] Step 3, establishing an over-determined equation set of 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 according to all measurement data containing only angle information; solving the equation set using the least square method 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 radar signal source motion trajectory;

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

[0012] Step 5, obtaining the phase bias of each element of the signal receiving array antenna by combining all the theoretical array manifolds with the corresponding measured array manifolds, and completing the measurement of the array phase.

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

[0014] Further, in step 1, an open field is selected as the test field of the multi-antenna multi-channel interferometric angle measurement.

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

[0016] Step 21, moving the radar signal source on the X-axis for M times at equal intervals, and the distance of each movement 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, selecting any position in 1-M, and recording the position as m (1<m<M-1);

[0018] Step 23, performing FFT on the data received by the signal receiving array antenna at the two adjacent positions of the selected m and m+1 this time, respectively obtaining the normalized array manifold vectors at the two adjacent positions of m and m+1, as follows:

[0019]

[0020] Wherein, represents the angle of the radar signal source incident to the signal receiving array antenna at m;

[0021] represents the angle of the radar signal source incident to the signal receiving array antenna at 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 element in the signal receiving array antenna, (2) represents the second element in the signal receiving array antenna, and N represents the Nth element in the signal receiving array antenna.

[0025] represents the phase bias amount of the first element, represents the phase bias amount of the second element, and so on. denotes the phase bias of the Nth array element;

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

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

[0028] d denotes the array 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 bias, and obtain the measurement data containing only angle, as follows:

[0030]

[0031] wherein k denotes any one array element in the array of the signal receiving array antenna;

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

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

[0034] Step 31, according to the measurement data containing only angle of the radar signal source at each position obtained in step 2, record

[0035] wherein angle(·) denotes the complex phase;

[0036] Step 32, establish the overdetermined equation group of the projection position of the signal receiving array antenna on the movement track of the radar signal source and the vertical distance from the signal receiving array antenna to the movement track of the radar signal source:

[0037]

[0038] wherein x1 to x M denote 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, respectively;

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

[0040] R0 denotes the vertical distance from the signal receiving array antenna to the movement track of the radar signal source;

[0041] Step 33, since M » 2, the least square method is used to fit to obtain the values of x i and R0.

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

[0043] Step 41, according to the projection of the signal receiving array antenna on the X axis and the perpendicular distance from the signal receiving array antenna to the movement track of the radar signal source obtained in step 3, the real incident angle of the signal receiving array antenna to each of 1 to M is determined;

[0044] Step 42, the theoretical array manifold vector of each of 1 to M is determined using the following formula:

[0045]

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

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

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

[0049]

[0050] Wherein, represents the phase offset amount, (i=1, 2, …, N-1).

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

[0052] The array phase measurement method based on movement track fitting of the present application aims at the high-precision measurement requirement of phase for target detection, utilizes the geometric position relationship generated when the signal source moves relative to the phased array antenna, utilizes the prior information that the movement geometry of the signal source is a straight line model, and measures the array phase based on movement track fitting. The measurement of the phase offset can be realized through the algorithm, and the traditional darkroom calibration method is no longer needed, thereby saving the cost and simplifying the test process, and the present application is suitable for large-scale use and popularization in industry. BRIEF DESCRIPTION OF DRAWINGS

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

[0054] It should be noted that all the methods in the present application, such as no special description, all adopt the methods known in the prior art. For example, “FFT” and “least square method” are all known methods in the prior art.

[0055] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

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

[0057] Step 1, as follows Figure 1 As shown, a radar signal source and an N-dimensional uniform linear array signal receiving antenna are set up in the 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 direction of movement of the radar signal source as the positive X-axis.

[0058] Step 2: Move the radar signal source multiple times at equal intervals or specified intervals along the X-axis. 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. Perform FFT on all multi-channel radar data, take the complex value at the maximum value of the spectrum, and obtain the measurement data containing only angle information at each position of the radar signal source on the X-axis.

[0059] Step 3: Combine all the measurement data containing only angle information to establish an overdetermined set of equations for the projection of the signal receiving array antenna on the trajectory of the radar signal source and the vertical distance from the signal receiving array antenna to the trajectory of the radar signal source. Solve the overdetermined set of equations for the projection of the signal receiving array antenna on the X-axis and the vertical distance from the signal receiving array antenna to the trajectory of the radar signal source.

[0060] Step 4: Use the data obtained in Step 3 to solve for the true 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 element of the signal receiving array antenna, thus completing the measurement of the array phase.

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

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

[0064] Step 21: Move the radar signal source M times at equal intervals along the X-axis. The distance moved each time is Δx. Each position of the radar signal source after moving along the X-axis is recorded as 1, 2, 3...M.

[0065] Step 22, select any radar signal source on the X-axis after it has moved, and denote this position as m(1). <m<M-1);

[0066] Step 23, FFT is performed on the data received by the signal receiving array antenna at the two adjacent positions of m and m+1 selected this time, to obtain the normalized array manifold vectors at the two adjacent positions of m and m+1 respectively, as follows:

[0067]

[0068] wherein, represents the angle of incidence of the radar signal source to the signal receiving array antenna at m;

[0069] represents the angle of incidence of the radar signal source to the signal receiving array antenna at m+1;

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

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

[0072] T represents transposition of a matrix;

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

[0074] represents the phase bias;

[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, the normalized array manifold vectors at m and m+1 are divided to eliminate the phase bias, to obtain the measurement data containing only angles as follows:

[0078]

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

[0080] Step 25, an optional position not calculated to contain only angle measurement data is selected, and steps 23-24 are repeated until all positions of the radar signal source after movement are traversed; the measurement data containing only angle information of the radar signal source at each position on the X axis is obtained.

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

[0082] Step 31, according to the measurement data containing only angle information of the radar signal source at each position on the X axis obtained in step 2, the measurement data is recorded as

[0083] where angle(·) denotes the phase of a complex value;

[0084] The following further explains step 31:

[0085] Note that

[0086] Also because

[0087]

[0088] According to Figure 1 the geometric relationship shown in FIG. 3, can be expressed as:

[0089]

[0090] Δθ m(m+1) can be expressed as:

[0091]

[0092] Step 32, establish an over-determined equation set of the projection of the signal receiving array antenna on the movement trajectory of the radar signal source and the perpendicular distance of the signal receiving array antenna to the movement trajectory of the radar signal source:

[0093]

[0094] where x1 to x M denote 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, respectively;

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

[0096] R0denotes the perpendicular distance of the signal receiving array antenna to the movement trajectory of the radar signal source;

[0097] Step 33, since M » 2, the least square method is used to fit to obtain the value of x i and R0.

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

[0099] Step 41, according to the projection of the signal receiving array antenna on the X axis and the perpendicular distance of the signal receiving array antenna to the movement trajectory of the radar signal source obtained in step 3, substitute into to determine the real incident angle of the array plane at each position;

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

[0101]

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

[0103] Step 5, combine the theoretical array manifold vector a m (θ m ) with the measured array manifold vector The phase bias is calculated using the following formula:

[0104]

[0105] wherein, denotes the phase bias, (i = 1, 2, …, N-1).

Claims

1. A method for measuring array phase based on motion trajectory fitting, characterized in that, Includes the following steps: Step 1: Set up a radar signal source and... within the multi-antenna, multi-channel interferometric angle measurement test site. A 3D uniform linear array signal receiving array antenna; A Cartesian coordinate system is established with the radar signal source as the origin and the direction of movement of the radar signal source as the positive X-axis. Step 2: Move the radar signal source multiple times at equal intervals or specified intervals along the X-axis to determine each position of the radar signal source on the X-axis, and use the 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 projected position of the signal receiving array antenna on the trajectory of the radar signal source and the vertical distance from the signal receiving array antenna to the trajectory of the radar signal source; solve the set of equations using the least squares method 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 trajectory of the radar signal source. Step 4: Use the data obtained in Step 3 to determine the true incident angle of the signal receiving array antenna at each position, and determine 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 with their corresponding measurement array manifolds to obtain the phase offset of each element of the signal receiving array antenna, thus completing the measurement of the array phase.

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

3. The array phase measurement method based on motion trajectory fitting as described in claim 1, characterized in that, Step 2 includes the following sub-steps: Step 21: Move the radar signal source multiple times at equal intervals along the X-axis. Each time, the distance moved is... The positions of the radar signal source on the X-axis are sequentially labeled 1, 2, 3... ; Step 22, in 1- Choose any position and denote that position as , ; Step 23, select the ones this time and Perform an FFT on the data received by the signal receiving array antennas at two adjacent locations to obtain... and The normalized array manifold vectors at two adjacent positions are as follows: in, express The angle at which the signal is incident on the antenna of the signal receiving array; express The angle at which the signal is incident on the antenna of the signal receiving array; express Normalized array manifold vector at the location; express Normalized array manifold vector at the location; (1) represents the first element in the signal receiving array antenna, (2) represents the second element in the signal receiving array antenna... The first in the signal receiving array antenna N Each array element; The phase offset of the first array element, The phase offset of the second element... No. N-1 Phase offset of each array element; d Indicates the spacing between array elements in the signal receiving array antenna; express Transmitted signal wavelength; Step 24, and Divide the normalized array manifold vector at the given point to eliminate the phase bias, and obtain measurement data containing only angles, as shown in the following equation: in, This refers to any element in the array of signal receiving array antennas; Step 25: Select another location and repeat steps 23-24 until every location has been traversed; obtain measurement data containing only angle information for each location and its adjacent locations.

4. The array phase measurement method based on motion trajectory fitting as described in claim 3, characterized in that, Step 3 includes the following sub-steps: Step 31: Based on the measurement data containing only angle information of the radar signal source at each location obtained in Step 2, record... in, This indicates the calculation of the complex phase. Step 32, establish an overdetermined set of equations for the projected position of the signal receiving array antenna on the trajectory of the radar signal source and the vertical distance from the signal receiving array antenna to the trajectory of the radar signal source: in, to The coordinate origin, the position of the radar signal source on the X-axis after its first movement, ..., the position of the radar signal source on the X-axis after its first movement are represented sequentially. Position on the X-axis after -1 movement; This indicates the projected position of the signal receiving array antenna on the X-axis; This represents the vertical distance from the signal receiving array antenna to the trajectory of the radar signal source. Step 33, because The least squares method was used to fit the result. and The value of .

5. The array phase measurement method based on motion trajectory fitting as described in claim 4, characterized in that, Step 4 includes the following sub-steps: Step 41: Based on 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 trajectory of the radar signal source, determine the distance from the signal receiving array antenna to the radar signal source. The true angle of incidence at every point; Step 42, use the following formula to determine 1 to... Theoretical array manifold vector at each point: in, Indicates in Theoretical array manifold vector at the location Indicates the signal receiving array antenna in The true angle of incidence at that point.

6. The array phase measurement method based on motion trajectory fitting as described in claim 5, characterized in that, In step 5, the corresponding phase offset is calculated using the following formula: in, This indicates the phase offset. .

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