Transmitting beam forming method of digital phased array

Abstract

The invention discloses a transmitting beam forming method of a digital phased array. The transmitting beam forming method comprises the following steps: S1, detecting amplitude information and phase information of output signals of each transmitting array element; s2, calculating an amplitude difference and a phase difference of the (2-N) th transmitting array element relative to the reference transmitting array element; s3, fitting a relation function of the amplitude difference and the phase difference between the (2-N) th transmitting array element and the reference transmitting array element along with the temperature change in a plurality of temperature segment intervals; s4, acquiring a baseband transmitting signal of each transmitting array element; s5, determining a phase difference and an amplitude difference according to the actual temperature; s6, acquiring a base band transmitting signal of each transmitting array element after compensation; and S7, forming a transmitting beam. According to the method, the relation function of the amplitude difference and the phase difference between each transmitting array element and the reference transmitting array element along with the temperature change in each temperature segment interval can be fitted, and the baseband transmitting signal of each transmitting array element is compensated when the transmitting beam forming is carried out, so that the influence of channel inconsistency on the transmitting beam forming is overcome.

Description

Technical Field

[0001] The invention relates to a digital phased array, and in particular to a transmit beamforming method of a digital phased array. Background Art

[0002] Digital phased arrays precisely control the antenna's beam pointing and forming in a digital way. Compared with traditional phased array antennas, they have the advantages of small size and low cost. However, due to the differences in device performance between array channels, differences in clock and synchronization signal transmission paths, actual position errors of array antenna units, and mutual coupling effects between array antenna units, the initial phase and amplitude between array channels are inconsistent, which will cause distortion of the array beam pattern.

[0003] Therefore, it is necessary to calibrate the amplitude and phase consistency of the transmitting elements of the digital phased array. However, most traditional calibration methods do not consider the influence of temperature. Although temperature compensation has been considered in recent years, it is generally done through table lookup. The temperature information involved in the table lookup is discrete. If it is between two discrete temperatures, compensation can only be performed by taking the closest temperature, which will have an adverse effect on the accuracy of beamforming. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a transmit beamforming method for a digital phased array, which can fit the relationship function of the amplitude difference and phase difference between each transmit array element and a reference transmit array element as the temperature changes in each temperature segment interval, and compensate the baseband transmit signal of each transmit array element when performing transmit beamforming, thereby overcoming the influence of channel inconsistency on transmit beamforming and achieving accurate beamforming.

[0005] The objective of the present invention is achieved through the following technical solution: A transmit beamforming method for a digital phased array, characterized in that it includes:

[0006] S1. Generate a transmit calibration signal, pass it through N transmit array elements of the digital phased array, and detect the amplitude and phase information of the output signal of each transmit array element;

[0007] S2. Select the first transmitting element of the digital phased array as the reference transmitting element, and calculate the amplitude difference and phase difference of the 2nd to Nth transmitting elements relative to the reference transmitting element;

[0008] S3. In a given temperature range, gradually increase the temperature according to a fixed temperature step, and repeat steps S1 to S2 at each temperature, then segment the temperature range to obtain multiple temperature segment ranges, and fit the relationship function of the amplitude difference and phase difference between the 2nd to Nth transmitting array elements and the reference transmitting array element with the temperature in each temperature segment range;

[0009] S4. When performing transmit beamforming, a digital baseband signal is first generated, and the baseband digital signal is multiplied by the weighting coefficient of each transmit array element to obtain the baseband transmit signal of each transmit array element;

[0010] S5. According to the temperature segmentation interval where the actual temperature is when the signal is transmitted, obtain the relationship function of the amplitude difference and phase difference between the 2nd to Nth transmitting array elements and the reference transmitting array element with the temperature change, and calculate the phase difference and amplitude difference of the 2nd to Nth transmitting array elements relative to the reference transmitting array element;

[0011] S6. Before transmitting the baseband signal of each transmitting array element, the baseband transmission signal of each transmitting array element is compensated by using the phase difference and amplitude difference of the second to Nth transmitting array elements relative to the reference transmitting array element and the amplitude difference and phase difference of the reference transmitting array element to obtain the baseband transmission signal of each transmitting array element after compensation;

[0012] S7. Send the compensated baseband transmission signal of each transmitting array element to the corresponding transmitting array element for transmission, thereby completing the transmission beamforming.

[0013] The beneficial effect of the present invention is as follows: the present invention takes into account the complexity of the amplitude difference and phase difference between each transmitting array element and the reference transmitting array element as the temperature changes. If it is difficult to describe it with a functional relationship within a wide range of temperatures, the temperature interval is segmented. In each segment, the functional relationship can be determined by fitting. Therefore, the present invention fits the relationship function of the amplitude difference and phase difference between each transmitting array element and the reference transmitting array element as the temperature changes in each temperature segment interval. Therefore, when applied, the amplitude difference and phase difference between each transmitting array element and the reference transmitting array element can be obtained according to the actual ambient temperature. Therefore, when transmitting beamforming is performed, the baseband transmission signal is compensated to achieve accurate transmitting beamforming. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0015] 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.

[0016] like Figure 1 As shown, a transmit beamforming method of a digital phased array includes:

[0017] S1. Generate a transmit calibration signal, pass it through N transmit array elements of the digital phased array, and detect the amplitude and phase information of the output signal of each transmit array element;

[0018] S2. Select the first transmitting element of the digital phased array as the reference transmitting element, and calculate the amplitude difference and phase difference of the 2nd to Nth transmitting elements relative to the reference transmitting element;

[0019] S3. In a given temperature range, gradually increase the temperature according to a fixed temperature step, and repeat steps S1 to S2 at each temperature, then segment the temperature range to obtain multiple temperature segment ranges, and fit the relationship function of the amplitude difference and phase difference between the 2nd to Nth transmitting array elements and the reference transmitting array element with the temperature in each temperature segment range;

[0020] S4. When performing transmit beamforming, a digital baseband signal is first generated, and the baseband digital signal is multiplied by the weighting coefficient of each transmit array element to obtain the baseband transmit signal of each transmit array element;

[0021] S5. According to the temperature segmentation interval where the actual temperature is when the signal is transmitted, obtain the relationship function of the amplitude difference and phase difference between the 2nd to Nth transmitting array elements and the reference transmitting array element with the temperature change, and calculate the phase difference and amplitude difference of the 2nd to Nth transmitting array elements relative to the reference transmitting array element;

[0022] S6. Before transmitting the baseband signal of each transmitting array element, the baseband transmission signal of each transmitting array element is compensated by using the phase difference and amplitude difference of the second to Nth transmitting array elements relative to the reference transmitting array element and the amplitude difference and phase difference of the reference transmitting array element to obtain the baseband transmission signal of each transmitting array element after compensation;

[0023] S7. Send the compensated baseband transmission signal of each transmitting array element to the corresponding transmitting array element for transmission, thereby completing the transmission beamforming.

[0024] In an embodiment of the present application, step S1 includes:

[0025] S101. Generate a transmit calibration signal and transmit it to each transmit array element of a digital phased array; the digital phased array comprises a total of N transmit array elements;

[0026] S102. After the transmission calibration signal passes through the transmission array element, the output signal of each transmission array element is detected to obtain the amplitude and phase information of the output signal of each transmission array element.

[0027] In an embodiment of the present application, step S2 includes:

[0028] Assume that the amplitude information of the output signal of the reference transmitting array element is A1, and the phase information is θ1; the amplitude information of the output signals of the 2nd to Nth transmitting array elements are A2, A3, ..., A N , the phase information of the output signals of the 2nd to Nth transmitting array elements is θ2,θ3,...,θ N ;

[0029] The amplitude differences of the 2nd to Nth transmitting array elements relative to the reference transmitting array element are ΔA2, ΔA3, ..., ΔA respectively. N :

[0030] ΔA2=A2-A1;

[0031] ΔA3=A3-A1, ...

[0033] ΔA N =A N -A1

[0034] The phase differences of the 2nd to Nth transmitting array elements relative to the reference transmitting array element are Δθ2, Δθ3, ..., Δθ N

[0035]

[0036] In an embodiment of the present application, step S3 includes:

[0037] S301. Assume that the given temperature range is [T MIN ,T MAX ], the fixed temperature step is ΔT, where T MAX -T MIN is an integer multiple of ΔT;

[0038] At an ambient temperature of T MIN ,T MIN +ΔT,T MIN +2ΔT,....,T MAX When , repeat steps S1 to S2 to obtain the amplitude difference and phase difference of the output signal of the 2nd to Nth transmitting array elements relative to the output signal of the reference transmitting array element at each temperature;

[0039] S302. Evenly segment the temperature interval to obtain multiple temperature segment intervals, each temperature segment interval contains at least M ambient temperatures, M is not less than 5;

[0040] S302. For any temperature segment interval, fit the relationship function between the amplitude difference and phase difference between each transmitting array element and the reference transmitting array element as the temperature changes:

[0041] (1) For the first transmitting array element, since the first transmitting array element is the reference transmitting array element, the amplitude and phase difference between it and the reference transmitting array element are both 0 and do not change with the ambient temperature;

[0042] (2) For any transmitting array element from the 2nd to the Nth transmitting array element:

[0043] There are M ambient temperatures T1, T2, ..., TM in the current temperature segment. The amplitude difference corresponding to the M ambient temperatures is recorded as ΔA. T1 ,ΔA T2 ,...ΔA TM , where ΔA Tj The amplitude difference corresponding to the jth ambient temperature is represented by Δθ, and the phase difference corresponding to the Mth ambient temperature is represented by Δθ T1 ,Δθ T2 ,...Δθ TM , where Δθ Tj represents the phase difference corresponding to the jth ambient temperature, j = 1, 2, ..., M

[0044] Construct a quadratic polynomial regression model:

[0045] y=ax 2 +bx+c

[0046] Among them, a, b, c are the model parameters to be solved, and x and y represent the independent and dependent variables of the model;

[0047] The set of M ambient temperatures {T1, T2, ..., TM} is used as the independent variable value set of the model, and the corresponding amplitude difference set {ΔA T1 ,ΔA T2 ,...ΔA TM} As the dependent variable value set of the model, the quadratic polynomial regression model is fitted to solve the model parameters a, b, c, and obtain the relationship between the amplitude difference between the current transmitting array element and the reference transmitting array element and the temperature change;

[0048] The set {T1, T2, ..., TM} consisting of M ambient temperatures is used as the set of independent variable values ​​of the model, and the corresponding phase differences constitute the set {Δθ T1 ,Δθ T2 ,...Δθ TM} is used as the dependent variable value set of the model, and the quadratic polynomial regression model is fitted to solve the parameters a, b, and c, and the relationship between the phase difference between the current transmitting array element and the reference transmitting array element and the temperature change is obtained;

[0049] (3) For each of the second to Nth transmitting array elements, repeat step (2) to obtain a function of the relationship between the amplitude difference and the phase difference between the second to Nth transmitting array elements and the reference transmitting array element as a function of temperature in the current temperature segmentation interval;

[0050] S303. For each temperature segmentation interval, step S302 is repeatedly executed to obtain a relationship function of the amplitude difference and phase difference between the 2nd to Nth transmitting array elements and the reference transmitting array element with temperature in each temperature segmentation interval.

[0051] In an embodiment of the present application, step S4 includes:

[0052] Assume that N transmitting array elements are distributed along the x-axis and y-axis in the form of an array, and the distance between any two array elements is The wavelength is λ, then represents the normalized distance between array elements; θ and ψ represent the azimuth and elevation angle of the target direction of the transmitted beam respectively; define the intermediate parameter γ x and γ y :

[0053] γ x = sinθcosψ

[0054] γ y = sinθsinψ

[0055] Let the weighted parameter of the kth transmitting array element be denoted as a k , k = 0, 1, 2, ..., N; and the kth transmitting array element is numbered m in the x-axis direction and m in the y-axis direction * ,m=0,1,2,…,M x -1;m * =0,1,2,…,M y -1;M x and M y Respectively represent the number of transmitting array elements along the x-axis and y-axis; then a k It is expressed as:

[0056]

[0057] The baseband transmission signal x of the kth transmitting element of the digital phased array k (n) is expressed as:

[0058] x k (n) = a k s(n);

[0059] Wherein, s(n) represents the baseband digital signal.

[0060] In an embodiment of the present application, step S5 includes:

[0061] S501. When transmitting through a digital phased array, measure the actual ambient temperature, determine the temperature segment interval in which the actual ambient temperature is located, and then obtain the relationship function between the amplitude difference and phase difference between each transmitting element in the second to N transmitting elements and the reference transmitting element as the temperature changes in the temperature segment interval;

[0062] S502. For each of the 2nd to Nth transmitting array elements, the actual ambient temperature is introduced into the relationship function between the amplitude difference between the transmitting array element and the reference transmitting array element and the temperature change, and the amplitude difference between the transmitting array element and the reference transmitting array element is obtained;

[0063] S503. For each of the 2nd to Nth transmitting array elements, the actual ambient temperature is introduced into the relationship function of the phase difference between the transmitting array element and the reference transmitting array element and the temperature change to obtain the phase difference between the transmitting array element and the reference transmitting array element.

[0064] In the embodiment of the present application, in step S6, for the first transmitting array element, since the first transmitting array element is a reference transmitting array element, the amplitude and phase difference between the first transmitting array element and the reference transmitting array element are both 0, so the compensated baseband digital signal remains unchanged;

[0065] For any transmitting array element among the 2nd to Nth transmitting array elements, it is necessary to compensate the baseband transmitting signal of the transmitting array element according to the amplitude difference and phase difference of the transmitting array element relative to the reference transmitting array element calculated in step S5, so as to obtain the baseband transmitting signal of the transmitting array element after compensation.

[0066] The above is a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A digital phased array transmit beamforming method, characterized in that: include: S1. Generate a transmit calibration signal, pass it through N transmit array elements of the digital phased array, and detect the amplitude and phase information of the output signal of each transmit array element; S2. Select the first transmitting element of the digital phased array as the reference transmitting element, and calculate the amplitude difference and phase difference of the 2nd to Nth transmitting elements relative to the reference transmitting element; S3. In a given temperature range, gradually increase the temperature according to a fixed temperature step, and repeat steps S1 to S2 at each temperature, then segment the temperature range to obtain multiple temperature segment ranges, and fit the relationship function of the amplitude difference and phase difference between the 2nd to Nth transmitting array elements and the reference transmitting array element with the temperature in each temperature segment range; S4. When performing transmit beamforming, a digital baseband signal is first generated, and the baseband digital signal is multiplied by the weighting coefficient of each transmit array element to obtain the baseband transmit signal of each transmit array element; S5. According to the temperature segmentation interval where the actual temperature is when the signal is transmitted, obtain the relationship function of the amplitude difference and phase difference between the 2nd to Nth transmitting array elements and the reference transmitting array element with the temperature change, and calculate the phase difference and amplitude difference of the 2nd to Nth transmitting array elements relative to the reference transmitting array element; S6. Before transmitting the baseband signal of each transmitting array element, the baseband transmission signal of each transmitting array element is compensated by using the phase difference and amplitude difference of the second to Nth transmitting array elements relative to the reference transmitting array element and the amplitude difference and phase difference of the reference transmitting array element to obtain the baseband transmission signal of each transmitting array element after compensation; S7. Send the compensated baseband transmission signal of each transmitting array element to the corresponding transmitting array element for transmission, thereby completing the transmission beamforming.

2. The digital phased array transmit beamforming method according to claim 1, characterized in that: The step S1 comprises: S101. Generate a transmit calibration signal and transmit it to each transmit array element of a digital phased array; the digital phased array comprises a total of N transmit array elements; S102. After the transmission calibration signal passes through the transmission array element, the output signal of each transmission array element is detected to obtain the amplitude and phase information of the output signal of each transmission array element.

3. The digital phased array transmit beamforming method according to claim 1, characterized in that: The step S2 comprises: Assume that the amplitude information of the output signal of the reference transmitting array element is A1, and the phase information is θ1; the amplitude information of the output signals of the 2nd to Nth transmitting array elements are A2, A3, ..., A N , the phase information of the output signals of the 2nd to Nth transmitting array elements is θ2,θ3,...,θ N ; The amplitude differences of the 2nd to Nth transmitting array elements relative to the reference transmitting array element are ΔA2, ΔA3, ..., ΔA respectively. N : ΔA2=A2-A1; ΔA3=A3-A1, ... ΔA N =A N -A1 The phase differences of the 2nd to Nth transmitting array elements relative to the reference transmitting array element are Δθ2, Δθ3, ..., Δθ N 4. The digital phased array transmit beamforming method according to claim 1, characterized in that: The step S3 comprises: S301. Assume that the given temperature range is [T MIN ,T MAX ], the fixed temperature step is ΔT, where T MAX -T MIN is an integer multiple of ΔT; At an ambient temperature of T MIN ,T MIN +ΔT,T MIN +2ΔT,....,T MAX When , repeat steps S1 to S2 to obtain the amplitude difference and phase difference of the output signal of the 2nd to Nth transmitting array elements relative to the output signal of the reference transmitting array element at each temperature; S302. Evenly segment the temperature interval to obtain multiple temperature segment intervals, each temperature segment interval contains at least M ambient temperatures, M is not less than 5; S302. For any temperature segment interval, fit the relationship function between the amplitude difference and phase difference between each transmitting array element and the reference transmitting array element as the temperature changes: (1) For the first transmitting array element, since the first transmitting array element is the reference transmitting array element, the amplitude and phase difference between it and the reference transmitting array element are both 0 and do not change with the ambient temperature; (2) For any transmitting array element from the 2nd to the Nth transmitting array element: There are M ambient temperatures T1, T2, ..., TM in the current temperature segment. The amplitude difference corresponding to the M ambient temperatures is recorded as ΔA. T1 ,ΔA T2 ,...ΔA TM , where ΔA Tj The amplitude difference corresponding to the jth ambient temperature is represented by , and the phase difference corresponding to the M ambient temperatures is recorded as Δθ T1 ,Δθ T2 ,...Δθ TM , where Δθ Tj represents the phase difference corresponding to the jth ambient temperature, j = 1, 2, ..., M Construct a quadratic polynomial regression model: y=ax 2 +bx+c Among them, a, b, c are the model parameters to be solved, and x and y represent the independent and dependent variables of the model; The set of M ambient temperatures {T1, T2, ..., TM} is used as the independent variable value set of the model, and the corresponding amplitude difference set {ΔA T1 ,ΔA T2 ,...ΔA TM } As the dependent variable value set of the model, the quadratic polynomial regression model is fitted to solve the model parameters a, b, c, and obtain the relationship between the amplitude difference between the current transmitting array element and the reference transmitting array element and the temperature change; The set {T1, T2, ..., TM} consisting of M ambient temperatures is used as the set of independent variable values ​​of the model, and the corresponding phase differences constitute the set {Δθ T1 ,Δθ T2 ,...Δθ TM } is used as the dependent variable value set of the model, and the quadratic polynomial regression model is fitted to solve the parameters a, b, and c, and the relationship between the phase difference between the current transmitting array element and the reference transmitting array element and the temperature change is obtained; (3) For each of the second to Nth transmitting array elements, repeat step (2) to obtain a function of the relationship between the amplitude difference and the phase difference between the second to Nth transmitting array elements and the reference transmitting array element as a function of temperature in the current temperature segmentation interval; S303. For each temperature segmentation interval, step S302 is repeatedly executed to obtain a relationship function of the amplitude difference and phase difference between the 2nd to Nth transmitting array elements and the reference transmitting array element with temperature in each temperature segmentation interval.

5. The digital phased array transmit beamforming method according to claim 1, characterized in that: The step S4 comprises: Assume that N transmitting array elements are distributed along the x-axis and y-axis in the form of an array, and the distance between any two array elements is The wavelength is λ, then represents the normalized distance between array elements; θ and ψ represent the azimuth and elevation angle of the target direction of the transmitted beam respectively; define the intermediate parameter γ x and γ y : c x =sinθcosψ c y =sinθsinψ Let the weighted parameter of the kth transmitting array element be denoted as a k , k = 0, 1, 2, ..., N; and the kth transmitting array element is numbered m in the x-axis direction and m in the y-axis direction * ,m=0,1,2,…,M x -1;m * =0,1,2,…,M y -1;M x and M y Respectively represent the number of transmitting array elements along the x-axis and y-axis; then a k It is expressed as: The baseband transmission signal x of the kth transmitting element of the digital phased array k (n) is expressed as: x k (n)=a k s(n); Wherein, s(n) represents the baseband digital signal.

6. The digital phased array transmit beamforming method according to claim 1, characterized in that: The step S5 comprises: S501. When transmitting through a digital phased array, measure the actual ambient temperature, determine the temperature segment interval in which the actual ambient temperature is located, and then obtain the relationship function between the amplitude difference and phase difference between each transmitting element in the second to N transmitting elements and the reference transmitting element as the temperature changes in the temperature segment interval; S502. For each of the 2nd to Nth transmitting array elements, the actual ambient temperature is introduced into the relationship function between the amplitude difference between the transmitting array element and the reference transmitting array element and the temperature change, and the amplitude difference between the transmitting array element and the reference transmitting array element is obtained; S503. For each of the 2nd to Nth transmitting array elements, the actual ambient temperature is introduced into the relationship function of the phase difference between the transmitting array element and the reference transmitting array element and the temperature change to obtain the phase difference between the transmitting array element and the reference transmitting array element.

7. The digital phased array transmit beamforming method according to claim 6, characterized in that: In step S6, for the first transmitting array element, since the first transmitting array element is a reference transmitting array element, the amplitude and phase difference between the first transmitting array element and the reference transmitting array element are both 0, so the compensated baseband digital signal remains unchanged; For any transmitting array element among the 2nd to Nth transmitting array elements, it is necessary to compensate the baseband transmitting signal of the transmitting array element according to the amplitude difference and phase difference of the transmitting array element relative to the reference transmitting array element calculated in step S5, so as to obtain the baseband transmitting signal of the transmitting array element after compensation.

Images