Phase calibration method, system and platform suitable for radar antenna channel

Abstract

The invention discloses a phase calibration method, system and platform suitable for a radar antenna channel. The phase calibration method comprises the following steps: generating and acquiring at least two pieces of first data corresponding to the radar antenna channel to be subjected to phase calibration through the method; wherein the first data is frequency point number data in a radar working frequency band; generating corresponding second data according to the first data, and preprocessing the second data to generate third data corresponding to the first data; performing unwrapping processing on the third data, and generating fourth data corresponding to the third data; wherein the fourth data is phase matrix data subjected to unwrapping processing; and on the basis of the fourth data and in combination with a two-point method or a least square method, calibrating and processing the phase of the radar antenna channel to be subjected to phase calibration in real time, and a system and a platform corresponding to the method, so that the accuracy of channel calibration at different signal frequency points is improved under the condition of saving antenna channel calibration time and calibration data storage space; and the target angle measurement precision is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar phase calibration processing, and in particular relates to a phase calibration method, system and platform suitable for a radar antenna channel. Background Art

[0002] Radar is one of the important sensors for target perception and is widely used in various fields. Its basic working principle is that the transmitting antenna transmits electromagnetic waves, which are reflected by the target and received by the receiving antenna. The distance of the target is estimated based on the time delay of the received signal relative to the transmitted signal, and the radial velocity of the target is estimated based on the Doppler frequency of the echo signal. If the angle information of the target needs to be estimated, it is necessary to design at least two receiving antenna channels at different positions to form an antenna array, and estimate the angle of the target based on the phase difference of the received signal of the receiving antenna. If better angle measurement accuracy and angular resolution are to be achieved, more antenna receiving channels and a certain array are required.

[0003] like Figure 1 As shown, the phase differences ΔΦ and Δd of the target signals received by the two receiving antennas satisfy the following relationship:

[0004]

[0005] In the formula, λ is the wavelength of the signal. For broadband signals, it is the wavelength corresponding to the center frequency of the effective signal. It is generally assumed that the target is far away and in the far field of the radar, so the echo is close to a parallel wave, and the following geometric relationship exists:

[0006] Δd=lsinθ (2)

[0007] Where l is the distance between the receiving antennas, and θ is the angle of the target (the angle with the front). Combining the above two formulas, the target angle can be obtained:

[0008]

[0009] For a specific radar design, the signal wavelength λ and antenna spacing l are fixed, so as long as the target signal amplitude phase information (generally expressed as a complex number) of different receiving channels is obtained, the target angle can be calculated. This is a relatively simple principle of angle estimation. Of course, there are other algorithms to estimate angles, such as beam scanning, DML, etc., but no matter which method is used, the most basic requirement is that the phase relationship of the signal between channels is only related to the target angle and the receiving antenna spacing. If there is a phase error introduced by other aspects, the channel phase needs to be calibrated.

[0010] The actual situation is that the target echo received by the receiving antenna must pass through the transmission line to reach the receiver and undergo a series of signal amplification and filtering processes, such as Figure 2As shown in the figure, the rectangular frame is the transmission line. Due to space limitations and other reasons, the transmission line lengths of various antenna channels may be different, which will inevitably cause different phase differences in the signals of each channel.

[0011] At present, the general method to calibrate the above phase difference is to perform point calibration or fitting calibration: point calibration is to place a target at the 0° direction of the radar and calibrate according to the target echo phase at this time. If the difference in transmission lines is not considered, the phases of each channel should be equal in this case, but after adding the influence of the transmission line, there will be a difference in phase. In the future, the phase of this difference can be compensated before each angle measurement.

[0012] Fitting calibration is to control the target to be at multiple angle values ​​of the radar, collect the channel amplitude and phase data at each angle value respectively, and obtain a phase deviation by fitting the phase data at multiple angles, so as to take into account the performance of multiple angles or the overall angle range.

[0013] The above calibration method is effective for a single waveform sequence (at least the waveform with the same center frequency), but for different groups of waveform sequences with different center frequencies, the same deviation of the channel will also change. The phase calibration factor of one group of waveforms cannot calibrate the channel phase of other waveform sequences with different center frequencies. Of course, there is a solution to calibrate each group of waveform sequences, which will inevitably lead to longer calibration time and larger space occupied by the calibration factor. For example, changing the frequency of the waveform sequence is one of the radar anti-interference methods. If there are many changing frequencies, the more waveforms need to be calibrated, the more obvious the disadvantages of the above method.

[0014] Therefore, in view of the technical problems and defects of the poor accuracy of phase calibration of traditional radar antenna channels, it is urgent to design and develop a phase calibration method, system and platform suitable for radar antenna channels. Summary of the invention

[0015] In order to overcome the shortcomings and difficulties of the above-mentioned prior art, the purpose of the present invention is to provide a phase calibration method, system and platform suitable for radar antenna channels, which can improve the accuracy of channel calibration at different signal frequencies while saving antenna channel calibration time and calibration data storage space, thereby improving the target angle measurement accuracy.

[0016] The first object of the present invention is to provide a phase calibration method applicable to a radar antenna channel; the second object of the present invention is to provide a phase calibration system applicable to a radar antenna channel; the third object of the present invention is to provide a phase calibration platform applicable to a radar antenna channel.

[0017] The first object of the present invention is achieved in that the method comprises the following steps:

[0018] Generate and obtain at least two first data corresponding to the radar antenna channels to be phase calibrated; wherein the first data is frequency point number data within the radar operating frequency band;

[0019] Generate corresponding second data according to the first data, and pre-process the second data to generate third data corresponding to the first data; wherein the second data is wave signal data; and the third data is phase matrix data;

[0020] De-wrapping the third data and generating fourth data corresponding to the third data; wherein the fourth data is phase matrix data after de-wrapping;

[0021] Based on the fourth data and in combination with a two-point method or a least squares method, a real-time calibration process is performed on the phase of the radar antenna channel to be phase-calibrated.

[0022] Further, the generating and acquiring at least two first data corresponding to the radar antenna channels to be phase calibrated further includes:

[0023] A plurality of first data corresponding to the radar antenna channels to be phase calibrated are generated and acquired in order from small to large.

[0024] Further, the generating corresponding second data according to the first data, and preprocessing the second data to generate third data corresponding to the first data, further includes:

[0025] According to the first data, fifth data with the first data as the transmission center frequency is generated and sent, and sixth data corresponding to the fifth data is obtained; wherein the fifth data is frequency modulated continuous wave signal data; and the sixth data is corresponding echo signal data;

[0026] The sixth data is mixed and filtered in sequence to generate corresponding seventh data, and the seventh data is transformed to generate corresponding eighth data; wherein the seventh data is the corresponding zero intermediate frequency signal data; the eighth data is the amplitude and phase information data of each antenna channel; and the transformation processing includes ADC transformation processing and Fourier transformation processing.

[0027] Further, the generating corresponding second data according to the first data, and preprocessing the second data to generate third data corresponding to the first data, further includes:

[0028] Generate and obtain phase data corresponding to any antenna channel, and normalize the phase data;

[0029] Generate and obtain phase data corresponding to each element in the third data, and generate phase vector data corresponding to the antenna channel.

[0030] Further, the de-wrapping process of the third data and generating fourth data corresponding to the third data further includes:

[0031] The radian phase angle in the processing vector is expanded, and based on the jump numerical relationship between the radian phase angle and the radian, the corresponding phase angle is translated in real time.

[0032] Furthermore, the method further comprises the steps of:

[0033] Generate and obtain ninth data and tenth data corresponding to the radar antenna channel to be phase calibrated respectively; wherein the ninth data is the current working center frequency data of the antenna channel; and the tenth data is the channel amplitude phase data of the target object;

[0034] Calculate and generate eleventh data corresponding to the ninth data; wherein the eleventh data is channel phase error data corresponding to the frequency point; the calculation formula is as follows:

[0035] kf0+ΔΦ e =[k1f0+ΔΦ e1 k2f0+ΔΦ e2 …k M f0+ΔΦ eM ](17)

[0036] Where: k = [k1 k2…k M ] is a vector, where each element is the k value of a different channel, i.e. k i represents the k value of the ith channel, there are M channels in total; f0 is the center frequency of the radar working waveform signal;

[0037] According to the eleventh data, the tenth data is processed by real-time phase error compensation; wherein the compensation expression is:

[0038]

[0039] In the formula, x c is the channel amplitude and phase data vector after calibration; x = [x1 x2…x M ] is the amplitude and phase data vector of each channel of a target, x i is the amplitude and phase data of the i-th channel; is the inner product operation symbol of the vector.

[0040] The second object of the present invention is achieved in this way: the system is applied to the phase calibration method applicable to the radar antenna channel, and the system comprises:

[0041] A data generation and acquisition unit, used to generate and acquire at least two first data corresponding to the radar antenna channels to be phase calibrated; wherein the first data is frequency point number data within the radar operating frequency band;

[0042] A first data generating unit, configured to generate corresponding second data according to the first data, and pre-process the second data to generate third data corresponding to the first data; wherein the second data is wave signal data; and the third data is phase matrix data;

[0043] A second data generating unit, configured to perform de-wrapping processing on the third data and generate fourth data corresponding to the third data; wherein the fourth data is the phase matrix data after the de-wrapping processing;

[0044] The phase calibration processing unit is used to calibrate the phase of the radar antenna channel to be phase-calibrated in real time based on the fourth data and in combination with the two-point method or the least squares method.

[0045] Furthermore, the data generation and acquisition unit further includes:

[0046] A first generating module is used to sequentially generate and acquire a plurality of first data corresponding to the radar antenna channels to be phase calibrated in order from small to large;

[0047] And / or, the first data generating unit further includes:

[0048] A second generating module is used to generate and send fifth data with the first data as a transmission center frequency according to the first data, and obtain sixth data corresponding to the fifth data; wherein the fifth data is frequency modulated continuous wave signal data; and the sixth data is corresponding echo signal data;

[0049] A third generating module is used to sequentially mix and filter the sixth data to generate corresponding seventh data, and transform the seventh data to generate corresponding eighth data; wherein the seventh data is the corresponding zero intermediate frequency signal data; the eighth data is the amplitude and phase information data of each antenna channel; the transformation processing includes ADC transformation processing and Fourier transformation processing;

[0050] A fourth generating module is used to generate and obtain phase data corresponding to any antenna channel, and normalize the phase data;

[0051] A fifth generating module, used to generate and obtain phase data corresponding to each element in the third data, and generate phase vector data corresponding to the antenna channel;

[0052] And / or, the second data generating unit further includes:

[0053] The first processing module is used to expand the radian phase angle in the processing vector, and based on the jump numerical relationship between the radian phase angle and the radian, perform real-time translation processing on the corresponding phase angle.

[0054] Furthermore, the system further comprises:

[0055] The sixth generation module is used to respectively generate and obtain ninth data and tenth data corresponding to the radar antenna channel to be phase calibrated; wherein the ninth data is the current working center frequency data of the antenna channel; and the tenth data is the channel amplitude phase data of the target object;

[0056] The seventh generating module is used to calculate and generate eleventh data corresponding to the ninth data; wherein the eleventh data is channel phase error data corresponding to the frequency point; the calculation formula is as follows:

[0057] kf0+ΔΦ e =[k1f0+ΔΦ e1 k2f0+ΔΦ e2 …k M f0+ΔΦ eM ](17)

[0058] Where: k = [k1 k2…k M ] is a vector, where each element is the k value of a different channel, i.e. k i represents the k value of the ith channel, there are M channels in total; f0 is the center frequency of the radar working waveform signal;

[0059] The second processing module is used to process the tenth data by real-time phase error compensation according to the eleventh data; wherein the compensation expression is:

[0060]

[0061] In the formula, x c is the channel amplitude and phase data vector after calibration; x = [x1 x2…x M ] is the amplitude and phase data vector of each channel of a target, x i is the amplitude and phase data of the i-th channel; is the inner product operation symbol of the vector.

[0062] The third object of the present invention is achieved as follows: it includes a processor, a memory, and a phase calibration platform control program applicable to a radar antenna channel; wherein the phase calibration platform control program applicable to the radar antenna channel is executed in the processor, the phase calibration platform control program applicable to the radar antenna channel is stored in the memory, and the phase calibration platform control program applicable to the radar antenna channel implements the phase calibration method applicable to the radar antenna channel.

[0063] The present invention generates and obtains at least two first data corresponding to the radar antenna channels to be phase-calibrated through a method; wherein the first data is frequency point number data within the radar working frequency band; according to the first data, corresponding second data is generated, and the second data is pre-processed to generate third data corresponding to the first data; wherein the second data is wave signal data; the third data is phase matrix data; the third data is unwrapped and processed, and fourth data corresponding to the third data is generated; wherein the fourth data is phase matrix data after unwrapping; based on the fourth data, and in combination with a two-point method or a least squares method, the phase of the radar antenna channel to be phase-calibrated is calibrated in real time, and a system and a platform corresponding to the method are used to improve the accuracy of channel calibration at different signal frequencies while saving antenna channel calibration time and calibration data storage space, thereby improving the target angle measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0065] Figure 1 Schematic diagram of the principle of estimating target angle for two receiving antennas;

[0066] Figure 2 This is a schematic diagram of an antenna and transmission line connection example;

[0067] Figure 3 A schematic flow chart of the steps of a phase calibration method applicable to a radar antenna channel of the present invention;

[0068] Figure 4 A schematic diagram of the phase relationship of each channel at different frequencies in an embodiment of a phase calibration method applicable to a radar antenna channel of the present invention;

[0069] Figure 5 Schematic diagram of the phase relationship of each channel at different frequencies in an embodiment of a phase calibration method applicable to a radar antenna channel of the present invention, wherein rad is radians;

[0070] Figure 6 A schematic diagram of analysis of calibration results of an embodiment of a phase calibration method applicable to a radar antenna channel of the present invention;

[0071] Figure 7 A schematic diagram of a phase calibration system architecture applicable to a radar antenna channel according to the present invention;

[0072] Figure 8 The present invention is a schematic diagram of a phase calibration platform architecture suitable for a radar antenna channel. DETAILED DESCRIPTION

[0073] In order to better understand the purpose, technical solutions and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0074] The present invention may also be implemented or applied through other different specific examples, and the details in this specification may also be modified and changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0075] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0076] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. Secondly, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0077] Preferably, the phase calibration method for radar antenna channels of the present invention is applied in one or more terminals or servers. The terminal is a device that can automatically perform numerical calculations and / or information processing according to pre-set or stored instructions, and its hardware includes but is not limited to microprocessors, application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), digital signal processors (DSP), embedded devices, etc.

[0078] The terminal can be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The terminal can interact with the client through a keyboard, a mouse, a remote control, a touch pad, or a voice control device.

[0079] The present invention is to realize a phase calibration method, system and platform applicable to a radar antenna channel.

[0080] like Figure 3 , which is a flow chart of a phase calibration method applicable to a radar antenna channel provided by an embodiment of the present invention.

[0081] In this embodiment, the phase calibration method applicable to the radar antenna channel can be applied to a terminal with a display function or a fixed terminal. The terminal is not limited to a personal computer, a smart phone, a tablet computer, a desktop computer or an all-in-one computer equipped with a camera, etc.

[0082] The phase calibration method applicable to the radar antenna channel can also be applied to a hardware environment composed of a terminal and a server connected to the terminal through a network. The network includes but is not limited to: a wide area network, a metropolitan area network or a local area network. The phase calibration method applicable to the radar antenna channel of the embodiment of the present invention can be executed by a server, can be executed by a terminal, or can be executed by both a server and a terminal.

[0083] For example, for a terminal that needs to perform phase calibration for a radar antenna channel, the phase calibration function for a radar antenna channel provided by the method of the present invention can be directly integrated on the terminal, or a client for implementing the method of the present invention can be installed. For another example, the method provided by the present invention can also be run on a server or other device in the form of a software development kit (SDK), and an interface for a phase calibration function for a radar antenna channel is provided in the form of SDK. The terminal or other device can implement the phase calibration function for a radar antenna channel through the provided interface. The present invention is further described below in conjunction with the accompanying drawings.

[0084] like Figure 3 to Figure 6 As shown, the present invention provides a phase calibration method applicable to a radar antenna channel, wherein the method comprises the following steps:

[0085] S01, generating and acquiring at least two first data corresponding to the radar antenna channels to be phase calibrated; wherein the first data is frequency point number data within the radar operating frequency band;

[0086] S02. Generate corresponding second data according to the first data, and pre-process the second data to generate third data corresponding to the first data; wherein the second data is wave signal data; and the third data is phase matrix data;

[0087] S03, de-wrapping the third data and generating fourth data corresponding to the third data; wherein the fourth data is phase matrix data after de-wrapping;

[0088] S04. Based on the fourth data and in combination with a two-point method or a least squares method, calibrate the phase of the radar antenna channel to be calibrated in real time.

[0089] The generating and acquiring at least two first data corresponding to the radar antenna channels to be phase calibrated further includes:

[0090] S011. Generate and acquire, in order from small to large, a plurality of first data corresponding to the radar antenna channels to be phase calibrated.

[0091] The method of generating corresponding second data according to the first data, and preprocessing the second data to generate third data corresponding to the first data further includes:

[0092] S021. Generate and send fifth data with the first data as the transmission center frequency according to the first data, and obtain sixth data corresponding to the fifth data; wherein the fifth data is frequency modulated continuous wave signal data; and the sixth data is corresponding echo signal data;

[0093] S022. Mix and filter the sixth data in sequence to generate corresponding seventh data, and transform the seventh data to generate corresponding eighth data; wherein the seventh data is the corresponding zero intermediate frequency signal data; the eighth data is the amplitude and phase information data of each antenna channel; the transformation processing includes ADC transformation processing and Fourier transformation processing.

[0094] The method of generating corresponding second data according to the first data, and preprocessing the second data to generate third data corresponding to the first data further includes:

[0095] S023, generating and acquiring phase data corresponding to any antenna channel, and normalizing the phase data;

[0096] S024. Generate and obtain phase data corresponding to each element in the third data, and generate phase vector data corresponding to the antenna channel.

[0097] The de-wrapping process of the third data and generating fourth data corresponding to the third data further includes:

[0098] S031. Expand the radian phase angle in the processing vector, and based on the jump numerical relationship between the radian phase angle and the radian, perform real-time translation processing on the corresponding phase angle.

[0099] To achieve the purpose of the present invention, the method further comprises the steps of:

[0100] S05, respectively generate and obtain ninth data and tenth data corresponding to the radar antenna channel to be phase calibrated; wherein the ninth data is the current working center frequency data of the antenna channel; and the tenth data is the channel amplitude phase data of the target object;

[0101] S06. Calculate and generate eleventh data corresponding to the ninth data; wherein the eleventh data is channel phase error data corresponding to the frequency point; the calculation formula is as follows:

[0102] kf0+ΔΦ e =[k1f0+ΔΦ e1 k2f0+ΔΦ e2 …k M f0+ΔΦ eM ] (17)

[0103] Among them, the bold letters in the letter variables represent vectors (same vectors) or matrices, and the non-bold letters represent an element in a vector or matrix, which is a scalar.

[0104] Definition Where, Δd t is the difference in transmission line length, v t It is the propagation speed of the signal on the transmission line. Its actual meaning is the change in phase difference caused by changing the unit center frequency.

[0105] k=[k1 k2…k M ] is a vector, where each element is the k value of a different channel, i.e. k i represents the k value of the ith channel, and there are M channels in total. f0 is the center frequency of the radar operating waveform signal.

[0106] The channel phase deviation corresponding to the frequency point is: kf0+ΔΦ e ; Among them, kf0 is generated by the center frequency, ΔΦ e It is the other inherent phase deviation, which is independent of the center frequency.

[0107] ΔΦ e =[ΔΦ e1 ΔΦ e2 …ΔΦ eM], which represents the inherent phase deviation vector of each channel.

[0108] S07. According to the eleventh data, the tenth data is processed by real-time phase error compensation; wherein the compensation expression is:

[0109] x c =exp(-1j*(kf0+ΔΦ e ))x

[0110] =[exp(-1j(k1f0+ΔΦ e1 ))*x1 exp(-1j(k2f0+ΔΦ e2 ))*x2…exp(-1j(k M f0+ΔΦ eM ))*x M ](18)

[0111] In the formula, x c is the channel amplitude and phase data vector after calibration; x = [x1 x2…x M ] is the amplitude and phase data vector of each channel of a target, x i is the amplitude and phase data of the i-th channel; is the inner product operation symbol of the vector.

[0112] Specifically, in an embodiment of the present invention, this solution proposes a radar antenna channel phase calibration method. Considering the transmission line difference, the phase difference of the channel at different center frequencies can be expressed as:

[0113]

[0114] Among them, Δd is the path difference of the echo, Δd t is the difference in the length of the transmission line, λ is the wavelength of the electromagnetic wave transmitted in the air, t is the wavelength of the electromagnetic wave transmitted in the transmission line, λ and λ t All are related to the center frequency f0, ΔΦ e Fixed phase deviation introduced by other aspects.

[0115] For wave transmission, the following formula is satisfied: v=λf, where v is the speed of wave propagation, λ is the wavelength (for the sake of generality, λ is still used here, but it is different from the λ used in other places), and f is the frequency of the wave. For the commonly used broadband linear frequency signals, f is the center frequency.

[0116]

[0117] Here, C represents the speed of light, f0 is the center frequency of the signal, and v t is the propagation speed of the signal on the transmission line, due to Δd t and v tunchanged, we can order:

[0118]

[0119] but

[0120]

[0121] The right side of the equal sign in the above formula is divided into two parts. Information used for angle measurement, kf0+ΔΦ e is the error part of the channel, which is linearly related to the signal center frequency f0. Therefore, as long as k and ΔΦ are pre-set e By measuring and performing channel calibration based on these parameters, the antenna channel at any frequency point within the working frequency band can be calibrated more accurately.

[0122] Based on the above principles, the method and steps for antenna channel calibration for multi-frequency waveform sequence applications are as follows: First, the calibration environment is described: Generally, the radar and the set target (corner reflector or target simulator) are placed in a dark box to avoid other interferences. The line connecting the target and the center of the radar antenna is perpendicular to the plane of the radar antenna. The distance between the target and the radar is R. To ensure the calibration effect, R needs to meet the far-field condition:

[0123]

[0124] Where D is the radar antenna aperture.

[0125] Step 1: Select several frequency points f from small to large within the radar working frequency band i (i=1,2,…N, N is the number of frequency points, N>1, f1 f N Try to cover the radar's operating frequency band as much as possible;

[0126] Step 2: Make the radar work at frequency f in sequence i , that is, the transmission center frequency is f i Frequency modulated continuous wave signal, the received target echo signal is mixed and filtered to form a zero intermediate frequency signal, the digital signal of the zero intermediate frequency signal after ADC conversion is sent to the digital signal processor chip for signal processing, usually after Fourier transform for signal accumulation, the signal of each channel will have a strong accumulation energy at the distance R position, each channel takes the Fourier transform result at the corresponding distance R, that is, the amplitude phase information of each antenna channel of the set target, recorded as x i =[x i1 x i2 …x iM ], x ij is the center frequency f i Amplitude and phase data of channel j, complex numbers.

[0127] Randomly select the data of a certain channel to normalize the phase. Let’s select the Tth channel. The result after phase normalization is:

[0128] x i / x iT =[x i1 / x iT x i2 / x iT …x iM / x iT ] (9)

[0129] Then take the phase of each element of the above matrix: in is 0;

[0130] Since each frequency point will get a set of channel phase vectors, the vectors of all frequencies together are a phase matrix

[0131]

[0132] Step 3: Since the phase information represented by each element in Φ is entangled, that is, it is classified into the interval [-π:π), it is necessary to untangle it by column. Generally, the waveform signal we use is a narrowband signal, that is, the bandwidth is B f0, and in general, the difference in transmission line length will not be particularly large, so Right now Therefore, the phase difference between any two antenna channels changes due to the change in center frequency.

[0133]

[0134] That is, two adjacent phases will only be entangled by a 2π cycle at most.

[0135] Unwrapping corresponds to the function Q=unwrap(P) in MATLAB, which expands the radian phase angle in the vector P. Whenever the jump between consecutive phase angles is greater than or equal to π radians, unwrap will shift the phase angle by increasing the integer multiple of ±2π until the jump is less than π.

[0136] The result after Φ unwinding is:

[0137]

[0138] Each column of Φ' corresponds to each antenna channel about the center frequency f i As mentioned before, the phase relationship is linear, that is, Φ'=kf0+ΔΦ e , so the slope can be estimated by the two-point method or the least squares method:

[0139] k=[k1 k2 …k M] and ΔΦ e =[ΔΦ e1 ΔΦ e2 …ΔΦ eM ] (13)

[0140] At this point, the antenna channel calibration process for one radar has been completed.

[0141] For multiple radars, the calibration results of k are the same and can be reused, while ΔΦ e There may be differences. This can be calibrated using the point calibration or fitting calibration method mentioned above. Since this calibration radar works at a specific frequency f c , so the phase error ΔΦ ec is the phase error at a certain frequency point, so formula (7) can be transformed into the following expression:

[0142]

[0143] Therefore, the specific frequency f c Calibration phase error ΔΦ under ec With ΔΦ e The relationship is:

[0144] ΔΦ e =-kf0+ΔΦ ec (15)

[0145] Therefore, when calibrating different radars during production, it is only necessary to make a conversion according to the above formula, so the calibration time during mass production will not be increased.

[0146] Based on the calibration data, the calibration process before angle measurement is as follows:

[0147] S1: Get the current working center frequency f0 and the channel amplitude and phase data of the target:

[0148] x=[x1 x2 …x M ] (16)

[0149] S2: Calculate the channel phase error of this frequency point:

[0150] kf0+ΔΦ e =[k1f0+ΔΦ e1 k2f0+ΔΦ e2 …k M f0+ΔΦ eM ] (17)

[0151] S3: Perform phase error compensation on channel amplitude and phase data:

[0152]

[0153] xc is the channel amplitude and phase data vector after calibration.

[0154] S4: The above has completed the channel data calibration before angle measurement, and normal angle measurement can be performed afterwards.

[0155] Embodiment 1:

[0156] (1) The phase information Φ of the amplitude and phase data of the multi-channel collected at each frequency point (76-77 GHz, step 0.1 GHz), such as Figure 4 As shown, it can be seen that channel2 has phase entanglement from 76.2 GHz to 76.3 GHz.

[0157] (2) Φ' after Φ is unwound, such as Figure 5 shown.

[0158] (3) Angular measurement error results under different calibration methods. Here, the data of 76.2 GHz and 76.8 GHz are selected as verification. The calibration data collected at each frequency point is -60° to 60°, with an interval of 1°, a total of 121 angle directions of channel amplitude and phase data. The calibration table is generated by fitting the data, and the calibration results are verified by this group of data. A total of 4 groups of results are calculated and analyzed, such as Figure 6 As shown in the figure, the horizontal axis is different angles, and the vertical axis is the angle measurement error, that is, the difference between the measured angle and the actual angle. It can be seen that the angle measurement error of the individual frequency points is small (the blue and red curves in the figure below), while the 76.8GHz data is calibrated with the 76.2GHz calibration result, and there is an obvious deviation (the green curve in the figure below). After using the optimization method of this patent, the angle measurement result is basically normal (the black curve in the figure below).

[0159] To achieve the above object, the present invention further provides a phase calibration system applicable to a radar antenna channel, wherein the system is applied to the phase calibration method applicable to a radar antenna channel, such as Figure 7 As shown, the system specifically includes:

[0160] A data generation and acquisition unit, used to generate and acquire at least two first data corresponding to the radar antenna channels to be phase calibrated; wherein the first data is frequency point number data within the radar operating frequency band;

[0161] A first data generating unit, configured to generate corresponding second data according to the first data, and pre-process the second data to generate third data corresponding to the first data; wherein the second data is wave signal data; and the third data is phase matrix data;

[0162] A second data generating unit, configured to perform de-wrapping processing on the third data and generate fourth data corresponding to the third data; wherein the fourth data is the phase matrix data after the de-wrapping processing;

[0163] The phase calibration processing unit is used to calibrate the phase of the radar antenna channel to be phase-calibrated in real time based on the fourth data and in combination with the two-point method or the least squares method.

[0164] The data generation and acquisition unit further includes:

[0165] A first generating module is used to sequentially generate and acquire a plurality of first data corresponding to the radar antenna channels to be phase calibrated in order from small to large;

[0166] And / or, the first data generating unit further includes:

[0167] A second generating module is used to generate and send fifth data with the first data as a transmission center frequency according to the first data, and obtain sixth data corresponding to the fifth data; wherein the fifth data is frequency modulated continuous wave signal data; and the sixth data is corresponding echo signal data;

[0168] A third generating module is used to sequentially mix and filter the sixth data to generate corresponding seventh data, and transform the seventh data to generate corresponding eighth data; wherein the seventh data is the corresponding zero intermediate frequency signal data; the eighth data is the amplitude and phase information data of each antenna channel; the transformation processing includes ADC transformation processing and Fourier transformation processing;

[0169] A fourth generating module is used to generate and obtain phase data corresponding to any antenna channel, and normalize the phase data;

[0170] A fifth generating module, used to generate and obtain phase data corresponding to each element in the third data, and generate phase vector data corresponding to the antenna channel;

[0171] And / or, the second data generating unit further includes:

[0172] The first processing module is used to expand the radian phase angle in the processing vector, and based on the jump numerical relationship between the radian phase angle and the radian, perform real-time translation processing on the corresponding phase angle.

[0173] The system further includes: a sixth generating module, used to respectively generate and obtain ninth data and tenth data corresponding to the radar antenna channel to be phase calibrated; wherein the ninth data is the current working center frequency data of the antenna channel; and the tenth data is the channel amplitude phase data of the target object;

[0174] The seventh generating module is used to calculate and generate eleventh data corresponding to the ninth data; wherein the eleventh data is channel phase error data corresponding to the frequency point; the calculation formula is as follows:

[0175] kf0+ΔΦ e =[k1f0+ΔΦ e1 k2f0+ΔΦ e2 …k M f0+ΔΦ eM ](17)

[0176] The second processing module is used to process the tenth data by real-time phase error compensation according to the eleventh data; wherein the compensation expression is:

[0177]

[0178] In the formula, x c is the channel amplitude and phase data vector after calibration.

[0179] In the system solution embodiment of the present invention, the method steps involved in the phase calibration applicable to the radar antenna channel have been described above in detail, that is, the functional modules in the system are used to implement the steps or sub-steps in the above method embodiment, which will not be repeated here.

[0180] To achieve the above object, the present invention also provides a phase calibration platform suitable for radar antenna channels, such as Figure 8 As shown, it includes a processor, a memory, and a phase calibration platform control program applicable to a radar antenna channel; wherein the processor executes the phase calibration platform control program applicable to the radar antenna channel, the phase calibration platform control program applicable to the radar antenna channel is stored in the memory, and the phase calibration platform control program applicable to the radar antenna channel implements the phase calibration method steps applicable to the radar antenna channel. For example:

[0181] S01, generating and acquiring at least two first data corresponding to the radar antenna channels to be phase calibrated; wherein the first data is frequency point number data within the radar operating frequency band;

[0182] S02. Generate corresponding second data according to the first data, and pre-process the second data to generate third data corresponding to the first data; wherein the second data is wave signal data; and the third data is phase matrix data;

[0183] S03, de-wrapping the third data and generating fourth data corresponding to the third data; wherein the fourth data is phase matrix data after de-wrapping;

[0184] S04. Based on the fourth data and in combination with a two-point method or a least squares method, calibrate the phase of the radar antenna channel to be calibrated in real time.

[0185] The specific details of the steps have been explained above and will not be repeated here.

[0186] In the embodiment of the present invention, the built-in processor of the phase calibration platform applicable to the radar antenna channel may be composed of an integrated circuit, for example, a single packaged integrated circuit, or a plurality of integrated circuits packaged with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and combinations of various control chips. The processor uses various interfaces and lines to connect various components, and executes or executes programs or units stored in the memory, and calls data stored in the memory to perform various functions and process data for the phase calibration of the radar antenna channel;

[0187] The memory is used to store program codes and various data. It is installed in a phase calibration platform suitable for the radar antenna channel and can realize high-speed and automatic access to programs or data during operation.

[0188] The memory includes read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electronically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, magnetic disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0189] The present invention generates and obtains at least two first data corresponding to the radar antenna channels to be phase-calibrated through a method; wherein the first data is frequency point number data within the radar working frequency band; according to the first data, corresponding second data is generated, and the second data is pre-processed to generate third data corresponding to the first data; wherein the second data is wave signal data; the third data is phase matrix data; the third data is unwrapped and processed, and fourth data corresponding to the third data is generated; wherein the fourth data is phase matrix data after unwrapping; based on the fourth data, and in combination with a two-point method or a least squares method, the phase of the radar antenna channel to be phase-calibrated is calibrated in real time, and a system and a platform corresponding to the method are used to improve the accuracy of channel calibration at different signal frequencies while saving antenna channel calibration time and calibration data storage space, thereby improving the target angle measurement accuracy.

[0190] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A phase calibration method suitable for a radar antenna channel, characterized in that: The method comprises the steps of: Generate and obtain at least two first data corresponding to the radar antenna channels to be phase calibrated; wherein the first data is frequency point number data within the radar operating frequency band; Generate corresponding second data according to the first data, and pre-process the second data to generate third data corresponding to the first data; wherein the second data is wave signal data; and the third data is phase matrix data; De-wrapping the third data and generating fourth data corresponding to the third data; wherein the fourth data is phase matrix data after de-wrapping; Based on the fourth data and in combination with a two-point method or a least squares method, a real-time calibration process is performed on the phase of the radar antenna channel to be phase-calibrated.

2. A phase calibration method applicable to a radar antenna channel according to claim 1, characterized in that: The generating and acquiring at least two first data corresponding to the radar antenna channels to be phase calibrated further includes: A plurality of first data corresponding to the radar antenna channels to be phase calibrated are generated and acquired in order from small to large.

3. A phase calibration method applicable to a radar antenna channel according to claim 1, characterized in that: The method of generating corresponding second data according to the first data, and preprocessing the second data to generate third data corresponding to the first data further includes: According to the first data, fifth data with the first data as the transmission center frequency is generated and sent, and sixth data corresponding to the fifth data is obtained; wherein the fifth data is frequency modulated continuous wave signal data; and the sixth data is corresponding echo signal data; The sixth data is mixed and filtered in sequence to generate corresponding seventh data, and the seventh data is transformed to generate corresponding eighth data; wherein the seventh data is the corresponding zero intermediate frequency signal data; the eighth data is the amplitude and phase information data of each antenna channel; and the transformation processing includes ADC transformation processing and Fourier transformation processing.

4. A phase calibration method applicable to a radar antenna channel according to claim 1 or 3, characterized in that: The method of generating corresponding second data according to the first data, and preprocessing the second data to generate third data corresponding to the first data further includes: Generate and obtain phase data corresponding to any antenna channel, and normalize the phase data; Generate and obtain phase data corresponding to each element in the third data, and generate phase vector data corresponding to the antenna channel.

5. The phase calibration method applicable to a radar antenna channel according to claim 1, characterized in that: The de-wrapping process of the third data and generating fourth data corresponding to the third data further includes: The radian phase angle in the processing vector is expanded, and based on the jump numerical relationship between the radian phase angle and the radian, the corresponding phase angle is translated in real time.

6. The phase calibration method applicable to a radar antenna channel according to claim 1, characterized in that: The method further comprises the steps of: Generate and obtain ninth data and tenth data corresponding to the radar antenna channel to be phase calibrated respectively; wherein the ninth data is the current working center frequency data of the antenna channel; and the tenth data is the channel amplitude phase data of the target object; Calculate and generate eleventh data corresponding to the ninth data; wherein the eleventh data is channel phase error data corresponding to the frequency point; the calculation formula is as follows: kf0+DF e =[k1f0+ΔΦ e1 k2f0+DF e2 …k M f0+DF eM ](17) Where: k = [k1 k2…k M ] is a vector, where each element is the k value of a different channel, i.e. k i represents the k value of the ith channel, there are M channels in total; f0 is the center frequency of the radar working waveform signal; According to the eleventh data, the tenth data is processed by real-time phase error compensation; wherein the compensation expression is: In the formula, x c is the channel amplitude and phase data vector after calibration; x = [x1 x2…x M ] is the amplitude and phase data vector of each channel of a target, x i is the amplitude and phase data of the i-th channel; is the inner product operation symbol of the vector.

7. A phase calibration system suitable for a radar antenna channel, characterized in that: The system is applied to the phase calibration method applicable to a radar antenna channel as claimed in any one of claims 1 to 6, and the system comprises: A data generation and acquisition unit, used to generate and acquire at least two first data corresponding to the radar antenna channels to be phase calibrated; wherein the first data is frequency point number data within the radar operating frequency band; A first data generating unit, configured to generate corresponding second data according to the first data, and pre-process the second data to generate third data corresponding to the first data; wherein the second data is wave signal data; and the third data is phase matrix data; A second data generating unit, configured to perform de-wrapping processing on the third data and generate fourth data corresponding to the third data; wherein the fourth data is the phase matrix data after the de-wrapping processing; The phase calibration processing unit is used to calibrate the phase of the radar antenna channel to be phase-calibrated in real time based on the fourth data and in combination with the two-point method or the least squares method.

8. A phase calibration system suitable for a radar antenna channel according to claim 7, characterized in that: The data generation and acquisition unit further includes: A first generating module is used to sequentially generate and acquire a plurality of first data corresponding to the radar antenna channels to be phase calibrated in order from small to large; And / or, the first data generating unit further includes: A second generating module is used to generate and send fifth data with the first data as a transmission center frequency according to the first data, and obtain sixth data corresponding to the fifth data; wherein the fifth data is frequency modulated continuous wave signal data; and the sixth data is corresponding echo signal data; A third generating module is used to sequentially mix and filter the sixth data to generate corresponding seventh data, and transform the seventh data to generate corresponding eighth data; wherein the seventh data is the corresponding zero intermediate frequency signal data; the eighth data is the amplitude and phase information data of each antenna channel; the transformation processing includes ADC transformation processing and Fourier transformation processing; A fourth generating module is used to generate and obtain phase data corresponding to any antenna channel, and normalize the phase data; A fifth generating module, used to generate and obtain phase data corresponding to each element in the third data, and generate phase vector data corresponding to the antenna channel; And / or, the second data generating unit further includes: The first processing module is used to expand the radian phase angle in the processing vector, and based on the jump numerical relationship between the radian phase angle and the radian, perform real-time translation processing on the corresponding phase angle.

9. A phase calibration system suitable for a radar antenna channel according to claims 7-8, characterized in that: The system further comprises: The sixth generation module is used to respectively generate and obtain ninth data and tenth data corresponding to the radar antenna channel to be phase calibrated; wherein the ninth data is the current working center frequency data of the antenna channel; and the tenth data is the channel amplitude phase data of the target object; The seventh generating module is used to calculate and generate eleventh data corresponding to the ninth data; wherein the eleventh data is channel phase error data corresponding to the frequency point; the calculation formula is as follows: kf0+DF e =[k1f0+ΔΦ e1 k2f0+DF e2 …k M f0+DF eM ](17) Where: k = [k1 k2…k M ] is a vector, where each element is the k value of a different channel, i.e. k i represents the k value of the ith channel, there are M channels in total; f0 is the center frequency of the radar working waveform signal; The second processing module is used to process the tenth data by real-time phase error compensation according to the eleventh data; wherein the compensation expression is: In the formula, x c is the channel amplitude and phase data vector after calibration; x = [x1 x2…x M ] is the amplitude and phase data vector of each channel of a target, x i is the amplitude and phase data of the i-th channel; is the inner product operation symbol of the vector.

10. A phase calibration platform suitable for a radar antenna channel, characterized in that: The invention comprises a processor, a memory and a phase calibration platform control program applicable to a radar antenna channel; wherein the phase calibration platform control program applicable to the radar antenna channel is executed by the processor, the phase calibration platform control program applicable to the radar antenna channel is stored in the memory, and the phase calibration platform control program applicable to the radar antenna channel implements the phase calibration method applicable to the radar antenna channel as described in any one of claims 1 to 6.

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