A method for quickly extracting target data from radar raw data

Abstract

The present application relates to a kind of radar raw data in the quick extraction method of test target data, comprising the following steps: from radar raw data, the inertial navigation and radar information of each CPI of radar are read in turn, the information recorded by GPS device installed on test target is read, the time information of two devices is found simultaneously working time period, the data in the common time period of low rate test target is interpolated to the same update rate with radar, the intersection point of the information of test target after interpolation and radar NED azimuth is found, the radar information and radar raw data index value of the pointing of 4 radar beams in the vicinity of the intersection point are found, the real distance and the relative speed of the illumination of radar beam to test target are calculated, the radar raw data information corresponding to original data index value, test target information, real distance and relative speed are stored in text file, the information containing test target is extracted from original data and stored in new file, as the data input of subsequent radar system analysis and index analysis.

Description

Technical Field

[0001] This application belongs to the field of signal processing, and specifically designs a method for rapid extraction of test target data from raw radar data. Background Technology

[0002] The radar searches and reconnoiters the surrounding 360° airspace / ground. To verify the radar's range and angle detection accuracy, GPS devices are typically installed on the radar and the test target (aircraft / ground vehicle) to record the target's spatial position, velocity, and attitude in real time. During the test, the radar continuously transmits CPI beams for circular scanning, illuminating the test target only in one or multiple consecutive beam directions during the scan.

[0003] Radar raw data typically ranges from several hundred GB to several TB. If the raw data is analyzed sequentially, the beams that did not illuminate the test target during the radar's 360° circumferential scan also need to be analyzed. Assuming a 2° radar beam and a 360° circumferential scan, this means that 179 / 180% of the recorded echo data would not have illuminated the test target. Therefore, extracting raw data containing only the test target and performing rapid analysis is a pressing problem in engineering practice. Summary of the Invention

[0004] Technical problems to be solved

[0005] To avoid the shortcomings of existing technologies, this invention provides a method for rapidly extracting test target data from raw radar data.

[0006] Technical solution

[0007] A method for rapidly extracting test target data from raw radar data, characterized by the following steps:

[0008] Step 1: Read the CPI number, three-dimensional velocity information, three-dimensional position information, three-dimensional attitude information, GPS time information, beam spatial pointing azimuth angle and elevation angle of the current CPI sequentially from the radar raw data, record the byte offset of each CPI data in the raw data file and the data volume of each CPI into a temporary array;

[0009] Step 2: Read the velocity information, attitude information, three-dimensional spatial position information, and GPS time information of the test target sequentially from the GPS device installed on the test target to obtain the velocity information, attitude information, position information, and time information of the test target;

[0010] Step 3: Find the time period when both devices are working simultaneously from the time information of the two devices, and interpolate the longitude, latitude, altitude, east velocity, north velocity, and sky velocity data of the low-rate test targets during the common time period to the same update rate as the radar.

[0011] Step 4: Calculate the NED spatial azimuth, elevation, and range of the test target at each moment in a spatial coordinate system with the radar as the origin, based on the interpolated test target position information and radar position information;

[0012] Step 5: Using the NED azimuth of the radar beam at each CPI moment and the NED azimuth of the test target in the radar coordinate system, sequentially search for the index value of the CPI count value that the radar beam has scanned over the test target from the radar NED azimuth, and take 4 adjacent CPI index values ​​near each index value as the final data index value containing the test target.

[0013] Step 6: Using the NED spatial azimuth, elevation, and range of the test target in a spatial coordinate system with the radar as the origin, and the index value from Step 5, obtain the true range value of the test target in the radar coordinate system using the same method as in Step 4; using the radar velocity information, the interpolated velocity information of the test target, and the NED azimuth and elevation angles of the test target in the radar coordinate system, decompose the two velocity components of the radar velocity and the test target velocity using spatial vector decomposition, calculate the beamline velocity between the two, and then use the Doppler formula to calculate the Doppler frequency of the test target, which is taken as the true Doppler value of the test target;

[0014] Step 7: Using the index value of the test target in the radar raw data obtained in Step 5, store the information of the test target in the raw data into an Excel file as the raw data text information; at the same time, extract the CPI raw data pointing to the test target from the raw data to reduce the amount of data for subsequent data analysis.

[0015] Step 4 uses the geodetic2aer function for calculation.

[0016] In step 6, the Doppler formula is f d =2V los / λ, where V los λ represents the beam velocity along the line of sight, and λ represents the wavelength.

[0017] The raw data text information mentioned in step 7 includes: CPI number, three-dimensional velocity information, three-dimensional spatial position, three-dimensional attitude information, GPS time information, beam spatial pointing azimuth angle and elevation angle of the current CPI, and byte offset of each CPI data in the raw data file extracted from the radar raw data in step 1; position information and velocity information of the test target after interpolation in step 4; and storage of the true value of the distance to the test target and the true value of Doppler calculated in step 6.

[0018] A computer system is characterized by comprising: one or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method described above.

[0019] A computer-readable storage medium is characterized by storing computer-executable instructions, which, when executed, are used to implement the above-described method.

[0020] Beneficial effects

[0021] This invention provides a method for rapidly extracting test target data from radar raw data. It utilizes inertial navigation information, GPS information, radar information, and GPS information installed on the test target stored in the radar raw data to extract the information and raw data of the test target in the radar raw data. The test target information can be used as the basis for analyzing the raw data. The extracted data is significantly reduced in size compared to the original data, thereby improving the speed of subsequent data processing. Attached Figure Description

[0022] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0023] Figure 1 This is a schematic diagram of the radar beam circular scanning and target motion of the present invention;

[0024] Figure 2 In this embodiment of the invention, the radar beam pointing to the NED azimuth angle for each CPI is extracted from the raw data.

[0025] Figure 3 This is a schematic diagram illustrating the extraction of a common data segment from two data sources in an embodiment of the present invention;

[0026] Figure 4 This is a comparison of the target test data before and after interpolation in an embodiment of the present invention;

[0027] Figure 5 This refers to the NED azimuth angle of the test target in the radar coordinate system in this embodiment of the invention.

[0028] Figure 6 This refers to the NED azimuth angles of the radar and the test target during the common time period in this embodiment of the invention.

[0029] Figure 7 This refers to the CPI number of the test target extracted from the original radar data in this embodiment of the invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only a part of the embodiments of this application, not all of them. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0031] This invention provides a method for rapidly extracting target data from raw radar data, comprising the following steps:

[0032] Step 1: Read the CPI number (CPI_CNT), three-dimensional velocity information (east speed, north speed, sky speed), three-dimensional position information (longitude, latitude, altitude), three-dimensional attitude information (heading angle, roll angle, pitch angle), GPS time information (year, month, day, hour, minute, second, millisecond), beam spatial pointing azimuth (NED azimuth), and pitch angle (NED pitch angle) of each CPI sequentially from the radar raw data. Record the byte offset of each CPI data in the raw data file and the data volume of each CPI into a temporary array. The NED azimuth of each CPI is shown in Figure 2.

[0033] Step 2: Read the speed information (east speed, north speed, sky speed), attitude information (heading angle, roll angle, pitch angle), three-dimensional spatial position information (longitude, latitude, altitude), and GPS time information (year, month, day, hour, minute, second, millisecond) of the test target from the GPS device installed on the test target in sequence, so as to obtain the speed information, attitude information, position information, and time information of the test target.

[0034] Step 3: Since the radar and the test equipment are two relatively independent devices, it is necessary to find the time period during which the two devices work simultaneously from the time information of the two devices. The result of processing the common time period is shown in step 3.

[0035] Step 4: Due to the different data update rates of each inertial navigation device, the number of sampling points output by different devices within the same time period varies. In this embodiment, the radar inertial navigation update rate is 50Hz, while the target inertial navigation update rate is 10Hz (from...). Figure 3As can be seen, there are 819 sampling points for the test targets within the same time period, while the original radar data has 4096 sampling points. Therefore, it is necessary to interpolate the longitude, latitude, altitude, east velocity, north velocity, and sky velocity data of the low-rate test targets within the common time period to a data volume of 50Hz, which is the same as the radar update rate (e.g., Figure 4 In this embodiment, linear interpolation is used to interpolate the sampling point data.

[0036] Step 5: Based on the interpolated target location information (longitude, latitude, altitude) and radar location information (longitude, latitude, altitude), calculate the NED spatial azimuth, elevation, and range of the target at each moment in a spatial coordinate system with the radar as the origin (the calculation method can use the geodesic2aer function). The calculated NED azimuth of the target in the radar coordinate system is shown below. Figure 5 .

[0037] Step 6: In Figure 6 In this process, the NED azimuth angle of the radar beam at each CPI moment and the NED azimuth angle of the test target in the radar coordinate system obtained in step 5 are used to sequentially search for the index value of the CPI count value of the test target scanned by the radar beam from the radar NED azimuth angle. The index value search method utilizes the periodicity of the radar scanning beam. The NED azimuth angle difference is obtained by subtracting the NED angle of the target in the radar coordinate system from the radar NED angle. The sign of the azimuth angle difference is determined, and then the sign value is subtracted. The index value of the position where the absolute value of the sign value difference is equal to 2 plus 1 is the index value of the test target scanned by the radar beam.

[0038] Step 7: The radar beamwidth was not considered when calculating the angle index value in the above steps. In actual engineering applications, the beam angles between two adjacent CPIs spatially overlap. To ensure that all original data of the scanned targets are extracted, the azimuth error of one CPI is retained. The original data of four CPIs (±2 adjacent CPIs) are taken around the index value of the target. Therefore, if... Figure 7 The four adjacent CPI index values ​​near the index value in step 6 are used as the final data index values ​​containing the matching target.

[0039] Step 8: Using the NED spatial azimuth, elevation, and range of the test target in a spatial coordinate system with the radar as the origin, calculated in Step 5, and the index value obtained in Step 7, the true range value of the test target in the radar coordinate system is obtained using the same method as in Step 5. Using the radar velocity information, the interpolated velocity information of the test target, and the NED azimuth and elevation angles of the test target in the radar coordinate system, the two velocity components—radar velocity and test target velocity—are decomposed using spatial vector decomposition to calculate the beamline velocity V between them.los Then, using the Doppler formula f d =2V los / λ, calculate the Doppler frequency of the test target, and use this value as the true Doppler value of the test target. In this embodiment, the steps are as follows:

[0040]

[0041] in V is the NED azimuth angle of the test target in the radar coordinate system, θ is the NED elevation angle of the test target in the radar coordinate system, and V is the NED elevation angle of the test target in the radar coordinate system. rn V re V ru V tn V te V tu These are the north velocity, east velocity, and sky velocity output by the radar inertial navigation system, and the north velocity, east velocity, and sky velocity after interpolation by the inertial navigation system of the test target.

[0042] Step 9: Using the index value of the test target in the original radar data obtained in Step 7, store the information of the test target in the original data into an Excel file. The information stored for each CPI includes: the CPI number (CPI_CNT) extracted from the original radar data in Step 1, three-dimensional velocity information, three-dimensional spatial position, three-dimensional attitude information, GPS time information, beam spatial pointing azimuth angle and elevation angle of the current CPI, and the byte offset of each CPI data in the original data file; the position information and velocity information of the test target after interpolation in Step 4; and the true value of the distance to the test target and the true value of Doppler calculated in Step 8.

[0043] Step 10: Using the radar beam scan obtained in Step 7, scan the index value of the test target and the byte offset of the CPI data in the original data file. Use file read and write to store all the CPI data of the test target as a new data. This data is used as the original data containing only the test target extracted from the radar original data for subsequent radar detection and system performance analysis.

[0044] This application can quickly extract the original data and information of the test target from the radar raw data, reduce the amount of raw data, and improve the speed of subsequent data processing.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for rapidly extracting test target data from raw radar data, characterized in that... The steps are as follows: Step 1: Read the CPI number, three-dimensional velocity information, three-dimensional position information, three-dimensional attitude information, GPS time information, beam spatial pointing azimuth angle and elevation angle of the current CPI sequentially from the radar raw data, record the byte offset of each CPI data in the raw data file and the data volume of each CPI into a temporary array; Step 2: Read the velocity information, attitude information, three-dimensional spatial position information, and GPS time information of the test target sequentially from the GPS device installed on the test target to obtain the velocity information, attitude information, position information, and time information of the test target; Step 3: Find the time period when both devices are working simultaneously from the time information of the two devices, and interpolate the longitude, latitude, altitude, east velocity, north velocity, and sky velocity data of the low-rate test targets during the common time period to the same update rate as the radar. Step 4: Calculate the NED spatial azimuth, elevation, and range of the test target at each moment in a spatial coordinate system with the radar as the origin, based on the interpolated test target position information and radar position information; Step 5: Using the NED azimuth of the radar beam at each CPI moment and the NED azimuth of the test target in the radar coordinate system, sequentially search for the index value of the CPI count value that the radar beam has scanned over the test target from the radar NED azimuth, and take 4 adjacent CPI index values ​​near each index value as the final data index value containing the test target. Step 6: Using the NED spatial azimuth, elevation, and range of the test target in a spatial coordinate system with the radar as the origin, and the index value from Step 5, obtain the true range value of the test target in the radar coordinate system using the same method as in Step 4. Using radar velocity information, interpolated velocity information of the test target, and NED azimuth and NED elevation angles of the test target in the radar coordinate system, the two velocity components of radar velocity and test target velocity are decomposed using spatial vector decomposition to calculate the beamline velocity between them. Then, the Doppler frequency of the test target is calculated using the Doppler formula, and this value is used as the true Doppler value of the test target. Step 7: Using the index value of the test target in the radar raw data obtained in Step 5, store the information of the test target in the raw data into an Excel file as the raw data text information; at the same time, extract the CPI raw data pointing to the test target from the raw data to reduce the amount of data for subsequent data analysis.

2. The method for rapid extraction of test target data from raw radar data according to claim 1, characterized in that: Step 4 uses the geodetic2aer function for calculation.

3. The method for rapid extraction of test target data from raw radar data according to claim 1, characterized in that: In step 6, the Doppler formula is f d =2V los / λ, where V los λ represents the beam velocity along the line of sight, and λ represents the wavelength.

4. The method for rapid extraction of test target data from raw radar data according to claim 1, characterized in that: The raw data text information mentioned in step 7 includes: CPI number, three-dimensional velocity information, three-dimensional spatial position, three-dimensional attitude information, GPS time information, beam spatial pointing azimuth angle and elevation angle of the current CPI, and byte offset of each CPI data in the raw data file extracted from the radar raw data in step 1; position information and velocity information of the test target after interpolation in step 4; and storage of the true value of the distance to the test target and the true value of Doppler calculated in step 6.

5. A computer system, characterized in that... include: One or more processors, a computer-readable storage medium for storing one or more programs, wherein, when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method of claim 1.

6. A computer-readable storage medium, characterized in that... The device stores computer-executable instructions, which, when executed, are used to implement the method of claim 1.

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