A method for evaluating and correcting the consistency of array elements of a three-dimensional ground penetrating radar array antenna

Abstract

The application discloses a kind of three-dimensional ground penetrating radar array antenna array element amplitude consistency evaluation correction methods, comprising the following steps: step 1, full reflection scene simulation in air medium: step 2, data acquisition: step 3, data reorganization and intercept: step 4, array element amplitude consistency evaluation: step 5, each array element amplitude correction coefficient calculation.The method disclosed in the application preliminarily establishes three-dimensional ground penetrating radar array antenna performance evaluation system, and is the supplement to general ground penetrating radar performance evaluation.It makes up for the fact that existing evaluation methods cannot accurately evaluate the matching degree of each array element of three-dimensional ground penetrating radar array antenna, the size of the difference between array elements and whether it will affect the quality and display effect of subsequent various three-dimensional views.Meanwhile, the correction coefficient calculation method not involved before is provided, which can be used for reverse compensation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of ground penetrating radar, and particularly relates to a method for evaluating and correcting the amplitude consistency of array elements of a three-dimensional ground penetrating radar array antenna. BACKGROUND

[0002] Compared with the traditional two-dimensional ground penetrating radar which uses a single antenna to scan and can only obtain single vertical profile data at a time, the three-dimensional ground penetrating radar uses an array antenna to scan and can collect multiple vertical profile data at a time. By arranging the data of each array element according to the corresponding positions, a three-dimensional data volume can be generated to display horizontal profile graphs at different depths, profile graphs at any angle in the longitudinal, transverse and oblique directions, and three-dimensional stereoscopic views. The three-dimensional ground penetrating radar has become the mainstream product in the industry due to its high efficiency and intuitive characteristics. However, due to factors such as the manufacturing process of the three-dimensional ground penetrating radar array antenna, the performance difference of electronic devices, and the crosstalk between array elements, the amplitude of the data of each array element is often not balanced, which leads to the appearance of strip-shaped or patch-shaped interference or artifacts in the displayed image, affecting the detection and recognition results.

[0003] Therefore, it is necessary to establish a performance evaluation system for the three-dimensional ground penetrating radar, and the amplitude consistency of the array elements of the array antenna is an important evaluation index. The better the amplitude consistency of the array elements of the three-dimensional ground penetrating radar array antenna, the higher the quality of the profile graphs in each direction and the three-dimensional stereoscopic view generated. Only when the amplitude consistency of the array elements of the three-dimensional ground penetrating radar array antenna is controlled or corrected within a certain range, can the subsequent target detection and recognition be guaranteed.

[0004] The patent "A general radar antenna amplitude jitter evaluation method (CN113126045B)" discloses collecting ground penetrating radar data of a certain length, finding the amplitude of the direct coupling wave or the reflected wave, and performing operations on the amplitude extreme value and the average value to obtain the ground penetrating radar antenna amplitude jitter. The disadvantage is that it is only suitable for evaluating the two-dimensional ground penetrating radar single antenna or separately evaluating the multiple channels of the three-dimensional ground penetrating radar array antenna from the amplitude stability. It cannot evaluate whether the amplitudes of the array elements of the three-dimensional ground penetrating radar array antenna can be coordinated and unified, and it cannot provide quantitative correction coefficients. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a method for evaluating and correcting the amplitude consistency of array elements of a three-dimensional ground penetrating radar array antenna.

[0006] The present application adopts the following technical solutions:

[0007] A method for evaluating and correcting the amplitude consistency of array elements of a three-dimensional ground penetrating radar array antenna, which is improved and comprises the following steps:

[0008] Step 1: Full reflection scene simulation in air medium

[0009] Lay copper foil flat on the ground, place cubic foam in the center of the copper foil, and place the three-dimensional ground penetrating radar array antenna horizontally on top of the cubic foam with the antenna's radiating surface facing down and the center point of the antenna aligned with the center point of the copper foil.

[0010] Step 2, Data Collection:

[0011] Turn on the 3D ground-penetrating radar and save data for at least 30 seconds for all array elements of the antenna array.

[0012] Step 3, Data Reassembly and Extraction:

[0013] The data is arranged in the order of the array antenna elements, and the data for the first 10 seconds and the last 10 seconds of each element are removed, retaining only the intermediate data, thus obtaining the effective dataset for each element: {S1, S2, ..., S...} i S N}, where S i S represents the effective dataset of the i-th array element, where N is the total number of array antenna elements. The effective dataset of a single array element contains the received echo signals at several times: S i ={s i1 s i2 , ..., s ij , ..., s im}, where s ij This represents the received echo signal of the i-th array element at time j;

[0014] Step 4, Array element amplitude consistency evaluation:

[0015] The effective dataset S of the i-th element is processed sequentially. i The received echo signal s at a single moment ij Analysis revealed the peak-to-peak amplitude of the ground copper foil reflection wavelet at each moment for this array element: {mm i1 mm i2 ... mm ij ... mm im}, where mm ij MeanMM represents the peak-to-peak amplitude of the ground copper foil reflection signal received by the i-th array element at time j. The mean value of the peak-to-peak amplitude of the ground copper foil reflection wavelet of that array element is obtained by averaging. i =mean(mm) i1 mm i2 ... mm ij ... mm im );

[0016] Then, the peak-to-peak mean amplitudes of the ground copper foil reflected wavelets for all array elements are obtained: [MeanMM1, MeanMM2, ..., MeanMM] i MeanMMN The maximum value of the peak-to-peak mean value of the amplitude of the ground copper foil reflection sub-wave of each array element is MeanMM max The minimum value is MeanMM min The average value is MeanMM mean ;

[0017] The amplitude consistency of each array element of the three-dimensional ground penetrating radar array antenna is:

[0018]

[0019] Step 5, amplitude correction coefficient calculation of each array element:

[0020] The correction coefficient corresponding to the i-th array element of the three-dimensional ground penetrating radar array antenna is: After reverse compensation, the amplitude correction is performed.

[0021] Further, in step 1, the top cross section of the cubic foam is larger than the bottom surface of the array antenna.

[0022] Further, in step 1, the height of the cubic foam is 2λ, and λ is the wavelength corresponding to the center frequency of the array antenna in the air medium.

[0023] Further, in step 1, the copper foil is pasted beyond the edge of the bottom surface of the cubic foam by 4λ in the length and width directions.

[0024] Further, in step 2, the corresponding array antenna default parameters are selected, and the preheating is performed for ten minutes, and it is checked and confirmed that all array elements are in working condition, the time trigger mode, and the normal signal transmission and reception.

[0025] The beneficial effects of the present application are:

[0026] The method disclosed in the present application preliminarily establishes a three-dimensional ground penetrating radar array antenna performance evaluation system, which is a supplement to the general ground penetrating radar performance evaluation. The existing evaluation method cannot accurately evaluate the matching degree of each array element of the three-dimensional ground penetrating radar array antenna, the difference in amplitude between the array elements, and whether it will affect the quality and display effect of various three-dimensional views. At the same time, the correction coefficient calculation method which has not been involved before is provided, which can be used for reverse compensation.

[0027] The method disclosed in the present application provides a basis for three-dimensional ground penetrating radar manufacturers to measure performance indicators, provides guidance for three-dimensional ground penetrating radar users to purchase equipment, and provides a reference for three-dimensional ground penetrating radar application parties to develop secondarily. DETAILED DESCRIPTION

[0028] Figure 1 is a horizontal cross-sectional view when the amplitude consistency of the array element of the three-dimensional ground penetrating radar array antenna is poor;

[0029] Figure 2 is a horizontal profile graph when the amplitude consistency of the array element of the three-dimensional ground penetrating radar array antenna is poor;

[0030] Figure 3 is a flowchart of the method of the present application;

[0031] Figure 4 is a schematic diagram of a total reflection simulation scene in air medium;

[0032] Figure 5 is a ten-element data set of the three-dimensional ground penetrating radar array antenna;

[0033] Figure 6 is a received echo signal graph of a certain element at a single time. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0035] Figure 1 is a horizontal profile graph when the amplitude consistency of the array element of the three-dimensional ground penetrating radar array antenna is poor; Figure 2 is a horizontal profile graph when the amplitude consistency of the array element of the three-dimensional ground penetrating radar array antenna is poor;

[0036] Example 1, the present embodiment discloses an evaluation and correction method for the amplitude consistency of the array element of the three-dimensional ground penetrating radar array antenna. Under static conditions, the reflection waves of the same target are collected by each array element of the three-dimensional ground penetrating radar array antenna at the same time, the reflection wave amplitudes of each array element are counted respectively, the consistency is calculated, and the amplitude correction coefficient of each array element of the array antenna is obtained. As shown in Figure 3 , the specific steps are as follows:

[0037] Step 1, total reflection scene simulation in air medium:

[0038] As shown in Figure 4 , the three-dimensional ground penetrating radar 1500M array antenna is horizontally placed on a cubic foam with a cross section larger than the bottom surface of the array antenna, the foam height is 40cm, and the array antenna with a center frequency of 1500M corresponds to a wavelength of 20cm in air medium. The array antenna radiates downward, and the ground is flat and pasted with copper foil. In the length and width directions, the pasting range of the copper foil exceeds the edge of the antenna bottom surface by 80cm. The center point of the array antenna is aligned with the center point of the pasted copper foil;

[0039] Step 2, data collection:

[0040] Turn on the 3D ground-penetrating radar, select the default parameters for the corresponding array antenna, warm up for ten minutes, and check that all 10 array elements are in working condition, in time-triggered mode, and can transmit and receive signals normally. Simultaneously, save at least 30 seconds of data from each of the 10 array elements.

[0041] Step 3, Data Reassembly and Extraction:

[0042] The data is arranged in the order of the array antenna elements, and the first 10 seconds and last 10 seconds of data for each element are removed, retaining only the middle 10 seconds of data, thus obtaining the following... Figure 5 The 10-element valid dataset is shown. Figure 6 As shown, the effective dataset of a single array element contains the received echo signals at several times;

[0043] Step 4, Array element amplitude consistency evaluation:

[0044] The effective datasets for each array element were statistically analyzed sequentially. For each array element's effective dataset, the received echo signal at a single moment was analyzed sequentially. The peak-to-peak amplitude of the ground copper foil reflection wavelet for each array element at each moment was obtained, and the average was calculated to obtain the peak-to-peak mean amplitude of the ground copper foil reflection wavelet for that array element. Thus, the peak-to-peak mean amplitudes of the ground copper foil reflection wavelets for the 10 array elements were obtained [13161, 11528, 8212, 8718, 8256, 8339, 7440, 6718, 9209, 10147]. The maximum peak-to-peak mean amplitude of the ground copper foil reflection wavelet for the 10 array elements was 13161, the minimum was 6718, and the average was 9172.7. The amplitude uniformity of the three-dimensional ground-penetrating radar array antenna elements was approximately 5.84 dB.

[0045] Step 5, Calculation of amplitude correction coefficients for each array element:

[0046] The amplitude correction coefficients corresponding to the 10 elements of the three-dimensional ground-penetrating radar array antenna are [-7.2203dB, -4.5716dB, 2.2128dB, 1.0179dB, 2.1051dB, 1.9068dB, 4.1873dB, 6.2301dB, -0.0789dB, -2.0186dB]. Amplitude correction can be performed by performing reverse compensation.

Claims

1. A method for evaluating and correcting the amplitude uniformity of an array element of a three-dimensional ground penetrating radar array antenna, characterized by, Comprising the following steps: Step 1, total reflection field simulation in air medium: Lay copper foil on the ground, place cubic foam in the center of the copper foil, and place the three-dimensional ground penetrating radar array antenna horizontally on the top of the cubic foam, with the array antenna radiation surface facing down and the array antenna center point aligned with the copper foil center point; Step 2, data acquisition: Turn on the three-dimensional ground penetrating radar and save the data of all array elements for more than 30 seconds; Step 3, data reorganization and interception: The data is arranged in the order of the array antenna elements, and the data of the first 10 seconds and the last 10 seconds of each element is removed respectively, only the middle data is reserved, so as to obtain the effective data set of each element: {S1, S2, …, S i , …, S N}, wherein S i represents the effective data set of the i-th element, N is the total number of array antenna elements, and the effective data set of a single element contains a plurality of time receiving echo signals: S i ={s i1 , s i2 , …, s ij , …, s im}, wherein s ij represents the receiving echo signal of the i-th element at the j-th time. Step 4, array element amplitude consistency evaluation: S = {s1, s2, …, si, …, sn} is the effective data set of the i th array element i s is the received echo signal at a single time ij Analysis is carried out to obtain the amplitude peak-to-peak value of the ground copper foil reflection wavelet of each array element at each time: {mm i1 , mm i2 , …, mm ij , …, mm im} where mm ij represents the amplitude peak-to-peak value of the ground copper foil reflection in the received echo signal of the i th array element at the j th time, and the average amplitude peak-to-peak value of the ground copper foil reflection wavelet of the array element is obtained after averaging: MeanMM i = mean(mm i1 , mm i2 , …, mm ij , …, mm im ) The peak-to-peak mean value of the ground copper foil reflection sub-wave of each array element is obtained, respectively: [MeanMM1, MeanMM2, …, MeanMMN], the maximum value of the peak-to-peak mean value of the ground copper foil reflection sub-wave of all array elements is MeanMM, the minimum value is MeanMM, and the average value is MeanMM. i N max min mean ;​​​​ The amplitude consistency of each array element of the three-dimensional ground penetrating radar array antenna is: Step 5, calculation of amplitude correction coefficient of each array element: The correction coefficient corresponding to the i-th array element of the three-dimensional ground penetrating radar array antenna is: After the reverse compensation, the amplitude correction is performed.

2. The method for evaluating and correcting the consistency of the array elements of the three-dimensional GPR array antenna according to claim 1, characterized in that: In step 1, the cross section of the top of the cubic foam is larger than the bottom surface of the array antenna.

3. The method of claim 1, wherein the method further comprises: determining the amplitude consistency of the array elements of the three-dimensional GPR array antenna. In step 1, the height of the cubic foam is 2λ, and λ is the wavelength corresponding to the center frequency of the array antenna in air medium.

4. The method for evaluating and correcting the consistency of the array elements of the three-dimensional GPR array antenna according to claim 3, characterized in that: In step 1, in the length and width directions, the laying range of the copper foil exceeds the edge of the bottom surface of the cubic foam by 4λ.

5. The method of claim 1, wherein the method further comprises: determining the amplitude consistency of the array elements of the three-dimensional GPR array antenna. In step 2, select the corresponding array antenna default parameters, preheat for ten minutes first, check and confirm that all array elements are in working condition, time trigger mode, and can normally transmit and receive signals.

Images