A method for suppressing multipath false targets of vehicle-borne millimeter-wave radar based on track management

Abstract

The invention discloses a method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management, and belongs to the technical field of radar tracking system. The method comprises the following steps: obtaining the RD diagram of the current frame, collecting the energy value of each Doppler line, screening the target Doppler line according to its energy value and recording the index; obtaining track information data, screening each new track according to the track information data, and obtaining the initial position and Doppler index of each new track for Doppler information judgment to obtain each target track; marking the tracks in the neighborhood of each target track as each neighboring track of each target track, and extracting the speed of each neighboring track to obtain the similar neighboring track of each target track; judging whether the similar neighboring track is an old track, and obtaining the energy value of the similar neighboring track, comparing the energy value of the similar neighboring track of each target track with the energy value of each target track, judging whether each target track is a multipath false target, obtaining the judgment result and providing feedback.

Description

Technical Field

[0001] The invention relates to the technical field of radar tracking systems, and in particular to a method for suppressing multipath false targets of vehicle-mounted millimeter-wave radars based on track management. Background Art

[0002] Millimeter wave radar detects and measures the distance, speed and direction of surrounding objects by emitting electromagnetic waves of a specific frequency and receiving the reflected signals. However, in some complex environments, electromagnetic waves will be reflected multiple times, and the radar will receive multipath signals, resulting in a difference between the detected target direction and its actual position, resulting in false alarms / false targets, which ultimately affect the target tracking judgment.

[0003] The existing conventional solutions mainly use a variety of technical means such as electromagnetic wave propagation path analysis, echo model establishment, signal matching and elimination of false targets to effectively deal with the multipath effect problem in radar systems, analyze the electromagnetic wave propagation path and establish echo models, and then match and eliminate false targets.

[0004] For example, a method for identifying multipath false targets of a vehicle-mounted millimeter-wave radar is disclosed in a patent application with publication number CN117805802A, which includes: tracking a moving target according to a millimeter-wave radar point cloud of a current frame, and estimating the size and heading angle of the moving target tracking; dividing N straight roads with a width of X meters around the vehicle; retrieving a real target A that meets the reflection condition; matching a multipath ghost B; verifying whether the matched multipath ghost B meets the multiple conditions of the multipath; traversing each divided straight road, repeating steps S4 to S5, and completing the identification of all such multipath false targets in the current frame.

[0005] For example, a method and system for suppressing multipath false targets of a vehicle-mounted millimeter-wave radar is disclosed in a patent application with publication number CN117784137A, which includes: when receiving a radar signal, analyzing the radar signal based on clustering in the range Doppler domain to obtain target information; calculating the maximum Mag value or the number of target points of each type of data after clustering according to the target information; detecting the data classification whose maximum Mag value or the number of target points is greater than a preset threshold, and recording it as a large reflector; if the large reflector exists, traversing all other classified data; if the classified data satisfies the preset standard conditions, determining that the target represented by the classified data that satisfies the standard conditions is a multipath false target.

[0006] However, in the process of implementing the technical solution of the invention in the embodiments of the present application, the present application found that the above technology has at least the following technical problems:

[0007] In the prior art, it is difficult to establish an echo model for the multipath false target problem in a complex scene, resulting in the inability to effectively suppress the multipath false target. Summary of the invention

[0008] The embodiment of the present application provides a method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management, which solves the problem of multipath false targets in the prior art. It is difficult to establish its echo model in complex scenes, resulting in the inability to effectively suppress multipath false targets. It effectively suppresses the spread of target vehicles caused by multipath, resulting in multiple targets, and even the appearance of "clones" in other lanes several meters away.

[0009] The embodiment of the present application provides a method for suppressing multipath false targets of a vehicle-mounted millimeter-wave radar based on track management, comprising the following steps: obtaining an RD diagram of a current frame, and collecting energy values ​​of each Doppler line, and filtering and obtaining target Doppler lines according to the energy values ​​of each Doppler line and recording indexes; obtaining track information data, filtering and obtaining new tracks according to the track information data, and obtaining the initial position and Doppler index of each new track to perform Doppler information judgment to obtain each target track; marking tracks in the neighborhood of each target track as neighboring tracks of each target track, and extracting the speed of each neighboring track, and processing to obtain similar neighboring tracks of each target track; judging whether similar neighboring tracks are old tracks, and obtaining energy values ​​of similar neighboring tracks, and comparing the energy values ​​of similar neighboring tracks of each target track with the energy values ​​of each target track, judging whether each target track is a multipath false target, obtaining a judgment result and providing feedback.

[0010] Furthermore, the steps of screening and obtaining the target Doppler line and recording the index include: extracting the Doppler line from the RD diagram, marking it as each Doppler line, and collecting the signal strength of each distance unit of each Doppler line; summing the signal strength of each distance unit of each Doppler line, and marking the summation result as the energy value of each Doppler line; sorting the Doppler lines from large to small according to the energy value of each Doppler line, and marking the first three Doppler lines as target Doppler lines; and recording the index of the target Doppler line.

[0011] Furthermore, the step of obtaining each new track based on the track information data includes: the track information data includes the detection time and update times of each track; obtaining the track information data of the preset new track from the vehicle-mounted millimeter-wave radar database; comparing the track information data with the track information data of the preset new track, if a track meets the preset new track information data, then the track is counted to obtain each new track, if a track does not meet the preset new track information data, then the track is not processed.

[0012] Furthermore, the initial position and Doppler index of each new track are obtained to perform Doppler information judgment, and the step of obtaining the target track includes: obtaining the coordinates of the initial position point of each new track, judging whether the coordinates of the initial position point meet the initial position condition, and comparing the Doppler index of each new track with the target Doppler line index; if the coordinates of the initial position point of a new track meet the initial position condition, and the Doppler index of the new track is not equal to the target Doppler line index, then the new track is marked as the target track, and each target track is counted; if the coordinates of the initial position point of a new track do not meet the initial position condition, or the Doppler index of the new track is equal to the target Doppler line index, then the new track is not processed.

[0013] Furthermore, the step of processing to obtain similar neighboring tracks includes: obtaining the coordinates and speed of each target track, and extracting a preset speed resolution from the on-board millimeter-wave radar database; obtaining the neighborhood of each target track according to the coordinate processing of each target track, and marking the tracks in the neighborhood of each target track as neighboring tracks of each target track; performing difference calculations on the speed of each target track and the speed of each neighboring track of each target track, and marking the absolute value of the difference result as the deviation speed of each neighboring track of each target track; comparing the deviation speed of each neighboring track of each target track with the speed resolution, if the deviation speed of a neighboring track of a target track is less than or equal to the speed resolution, then marking the neighboring track as a similar neighboring track of the target track; if the deviation speed of a neighboring track of a target track is greater than the speed resolution, then not processing the neighboring track.

[0014] Furthermore, the step of judging whether a similar adjacent track is an old track includes: obtaining track information data of each similar adjacent track; obtaining track information data of a preset old track from the vehicle-mounted millimeter-wave radar database; comparing the track information data of each similar adjacent track with the track information data of the preset old track, if a similar adjacent track meets the old track management parameters, then judging that the similar adjacent track is an old track, if a similar adjacent track does not meet the old track management parameters, then judging that the similar adjacent track is not an old track.

[0015] Furthermore, the step of judging whether each target track is a multipath false target includes: obtaining the energy value of each similar adjacent track, and comparing the energy value of each target track with the energy value of each similar adjacent track of each target track; for a certain target track, if there is a similar adjacent track whose energy value is greater than the energy value of the target track and the similar adjacent track is an old track, then the target track is judged to be a multipath false target; if there is no similar adjacent track whose energy value is greater than the energy value of the target track or the similar adjacent track is not an old track, then the target track is judged not to be a multipath false target.

[0016] Furthermore, the step of obtaining the judgment result and providing feedback includes: obtaining a preset standard value of track information data from the vehicle-mounted millimeter-wave radar database; if a target track is a multipath false target, deleting the target track; if a target track is not a multipath false target and meets the preset standard value of track information data, outputting the target track; if a target track is not a multipath false target but does not meet the preset standard value of track information data, not processing the track.

[0017] Furthermore, the step of determining whether the coordinates of the initial position point meet the initial position conditions includes: the coordinates of the initial position point include an initial horizontal coordinate and an initial vertical coordinate; obtaining a preset initial coordinate value from the vehicle-mounted millimeter-wave radar database; comparing the coordinates of the initial position point with the preset initial coordinate value. If the coordinates of the initial position point meet the preset initial coordinate value, the track can be further determined. If the coordinates of the initial position point do not meet the preset initial coordinate value, the track will not be processed.

[0018] Furthermore, the step of obtaining the neighborhood of each target track according to the coordinate processing of each target track includes: obtaining a preset neighborhood range deviation value from the vehicle-mounted millimeter-wave radar database; the preset neighborhood range deviation value includes a horizontal coordinate range deviation value and a vertical coordinate range deviation value; performing subtraction and sum operations on the horizontal coordinate of each target track and the horizontal coordinate range deviation value respectively to obtain the lower limit and upper limit of the horizontal coordinate range of the track neighborhood, marking the range of the lower limit and upper limit of the horizontal coordinate range of the track neighborhood as the horizontal coordinate range of each target track, performing subtraction and sum operations on the vertical coordinate of each target track and the vertical coordinate range deviation value respectively to obtain the lower limit and upper limit of the vertical coordinate range of the track neighborhood, marking the range of the lower limit and upper limit of the vertical coordinate range of the track neighborhood as the vertical coordinate range of each target track, and obtaining the neighborhood range of each target track based on the horizontal coordinate range and the vertical coordinate range of each target track.

[0019] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0020] 1. The present invention provides a method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management, outputs information of all current valid tracks, and thus effectively suppresses the spread of target vehicles caused by multipath, resulting in multiple targets, and even "clones" appearing in other lanes several meters away;

[0021] 2. In the whole radar signal processing process, the present invention only needs to process the data in the track management link according to the data characteristics of multipath false targets, which not only significantly improves the portability and compatibility of the system, but also ensures that it can be effectively applied in vehicle-mounted millimeter-wave radars of different configurations and types;

[0022] 3. The identification of multipath false targets by the present invention does not rely on the judgment of reflection points and reflection paths, does not require the construction of path models, has a small amount of algorithm calculation, is easy to implement in engineering, and has high availability. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management provided in an embodiment of the present application;

[0024] Figure 2 A schematic diagram of calculating and selecting the strongest three Doppler dimensions of the RD diagram for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of a multipath false target scenario for a vehicle-mounted millimeter-wave radar provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The embodiment of the present application provides a method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management, which solves the problem of multipath false targets in the prior art. It is difficult to establish its echo model in complex scenes, resulting in the inability to effectively suppress multipath false targets. By selecting the Doppler line with the strongest energy, then screening out the new track and detecting whether there are neighboring tracks with the same speed in its neighborhood, identifying and deleting multipath false targets based on energy values ​​and track information data, and finally outputting valid track information based on the set track information data, it is possible to effectively suppress the spread of target vehicles caused by multipath, resulting in multiple targets, and even the appearance of "clones" in other lanes a few meters away.

[0027] The technical solution in the embodiment of the present application is to solve the problem of multipath false targets in the above-mentioned prior art. It is difficult to establish its echo model in complex scenes, resulting in the inability to effectively suppress multipath false targets. The overall idea is as follows:

[0028] By obtaining the RD diagram of the current frame and collecting the energy value of each Doppler line, the target Doppler line is screened and the index is recorded according to the energy value of each Doppler line; the track information data is obtained, and each new track is screened according to the track information data, and the initial position and Doppler index of each new track are obtained to perform Doppler information judgment to obtain each target track; the tracks in the neighborhood of each target track are marked as each neighboring track of each target track, and the speed of each neighboring track is extracted to obtain the similar neighboring track of each target track; it is judged whether the similar neighboring track is an old track, and the energy value of the similar neighboring track is obtained, and the energy value of the similar neighboring track of each target track is compared with the energy value of each target track to judge whether each target track is a multipath false target, and the judgment result is obtained and fed back, so as to effectively suppress the spread of target vehicles caused by multipath to appear multiple targets, and even "clones" appear in other lanes a few meters away.

[0029] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0030] like Figure 1 As shown, it is a flow chart of a method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management provided by an embodiment of the present application, and the method includes the following steps: S1, obtaining the RD diagram of the current frame, and collecting the energy value of each Doppler line, according to the energy value of each Doppler line, screening to obtain the target Doppler line and recording the index; S2, obtaining track information data, screening to obtain each new track according to the track information data, and obtaining the initial position and Doppler index of each new track to perform Doppler information judgment to obtain each target track; S3, marking the tracks in the neighborhood of each target track as each neighboring track of each target track, and extracting the speed of each neighboring track, and processing to obtain similar neighboring tracks of each target track; S4, judging whether the similar neighboring tracks are old tracks, and obtaining the energy value of similar neighboring tracks, comparing the energy value of the similar neighboring tracks of each target track with the energy value of each target track, judging whether each target track is a multipath false target, obtaining the judgment result and providing feedback; S5, outputting all tracks that meet the standard value of the track information data.

[0031] In this embodiment, the radar system periodically transmits electromagnetic waves and receives reflected signals, and each transmission and reception cycle is called a frame. The range-Doppler diagram (RD diagram) is obtained by performing a two-dimensional fast Fourier transform (FFT) (2D-FFT) on the echo received by the millimeter-wave radar. It is a signal processing and analysis technology widely used in the fields of radar, sonar, medical imaging (such as color ultrasound), etc., which combines distance information and Doppler information to characterize the characteristics of the target object. The RD diagram is a two-dimensional spectrum diagram, the horizontal axis represents the distance (usually represented by the distance index or range gate), and the vertical axis represents the Doppler frequency or speed (represented by the Doppler index, which is proportional to the speed or Doppler frequency shift). It shows the intensity distribution of the reflected signal of the target object under different combinations of distance and speed (or Doppler frequency shift). Each Doppler line in the RD diagram represents a signal reflected by a target at a specific speed. The energy value of the Doppler line reflects the reflection intensity of the target at that speed, that is, the intensity of the echo signal. The higher the energy value, the stronger the reflection of the target at that speed. Due to the relative motion between targets and the interference of environmental factors in a complex multi-target environment, the Doppler lines of different targets may overlap or interfere with each other, greatly increasing the difficulty of separating and identifying target signals. By selecting the three Doppler lines with the strongest energy, it is easier to distinguish and separate different targets, which not only helps to reduce the complexity and calculation of signal processing, but also significantly improves the accuracy and efficiency of target identification, providing strong support for subsequent target classification, identification and other processing.

[0032] In addition, the vehicle-mounted millimeter-wave radar database is used to store relevant data of the method of suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management, including: initial coordinate values ​​(initial horizontal coordinate values ​​and initial vertical coordinate values), speed resolution, track information data detection time threshold and update number threshold, etc. The vehicle-mounted millimeter-wave radar database can be constructed and optimized by utilizing existing public databases or existing systems, such as multi-target tracking systems, signal processing and suppression systems, or intelligent perception and decision-making systems, etc. At the same time, academic paper databases (such as CNKI, Wanfang, PubMed, etc.) include a large number of academic papers and research reports related to vehicle-mounted millimeter-wave radars, and the vehicle-mounted millimeter-wave radar database can extract valuable information and data from them.

[0033] S1. Obtain the RD map of the current frame, collect the energy value of each Doppler line, and filter out the target Doppler line according to the energy value of each Doppler line and record the index.

[0034] The steps of screening and obtaining the target Doppler line and recording the index include: extracting the Doppler line from the RD diagram, marking each Doppler line, and collecting the signal strength of each distance unit of each Doppler line; summing the signal strength of each distance unit of each Doppler line, and marking the summation result as the energy value of each Doppler line; sorting the Doppler lines from large to small according to the energy value of each Doppler line, and marking the first three Doppler lines as the target Doppler lines; and recording the index of the target Doppler line.

[0035] In this embodiment, the RD graph is usually a two-dimensional matrix, in which the rows represent Doppler frequencies (corresponding to different speeds), the columns represent distance units, and the value of each element represents the signal strength at the distance and speed, that is, the energy value. Each row of Doppler frequencies represents a Doppler line. According to the energy value of the Doppler line, the radar can sort all the Doppler lines from large to small. Because strong energy usually means that the signal reflected by the target is strong and is more likely to be a real target, the first three Doppler lines with the largest energy values ​​are selected as the focus of attention, which helps to quickly identify the most significant targets in the scene and the speed information of these targets. By selecting the Doppler line with the largest energy value, the radar can more accurately detect the main targets in the scene. These targets often have stronger reflection capabilities, so they appear as Doppler lines with higher energy values ​​in the RD graph; when multiple targets coexist, selecting the Doppler line with the largest energy value helps the radar to prioritize the most important targets. This is of great significance for subsequent tasks such as target classification, tracking and decision-making; by selecting the first three Doppler lines with the largest energy values ​​for focus, the calculation burden can be reduced while ensuring the detection effect, and the processing efficiency can be improved. For the three selected Doppler lines, the radar will record their index information. The index information usually includes the position of the Doppler line in the RD diagram (such as the distance information represented by the horizontal axis and the speed information represented by the vertical axis), the energy value, and possible other related parameters (such as signal-to-noise ratio, target amplitude, etc.), which are crucial for subsequent target tracking, identification and analysis. Among them, recording the index means assigning a unique identifier or index value to the selected target Doppler line so that these Doppler lines can be easily referenced and identified in the subsequent data processing, analysis or storage process. By recording the index, the radar can accurately locate and identify the most prominent target in the scene. This is of great significance for improving the precision and accuracy of target detection, especially in complex environments or multi-target scenes; the recorded Doppler line index information provides an important basis for subsequent target tracking, classification and identification. For example, in the process of target tracking, these index information can be used to establish the target's track and update the target's position and velocity information in real time. In order to facilitate subsequent processing and intuitive understanding, these three Doppler lines can be marked as: MaxDopplerLine1, MaxDopplerLine2 and MaxDopplerLine3.

[0036] Depend on Figure 2 As shown, it is a schematic diagram of calculation and selection of the strongest three Doppler dimensions of the RD diagram for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management provided in an embodiment of the present application. In the figure, the horizontal axis is the distance index, and its minimum number of distance units is 256. The vertical axis is the Doppler index, and its index number is 64. The sum of the values ​​in each row of the figure is the sum of the energy values ​​of each Doppler line.

[0037] S2. Acquire track information data, filter and obtain each new track according to the track information data, and obtain the initial position and Doppler index of each new track to perform Doppler information judgment to obtain each target track.

[0038] The steps of obtaining each new track by screening the track information data include: the track information data includes the detection time and update times of each track; obtaining the track information data of the preset new track from the vehicle-mounted millimeter-wave radar database; comparing the track information data with the track information data of the preset new track, if a track meets the preset new track information data, then the track is counted to obtain each new track, if a track does not meet the preset new track information data, then the track is not processed.

[0039] In this embodiment, before screening to obtain a new track, the RD graph can be subjected to CFAR, DOA angle resolution, clustering, and tracking to obtain track information. It should be understood that a new track represents a newly emerged, unconfirmed track, and a track with an update count of 0 and a detection time of 1 is a new track. The update count is usually used to indicate the time or number of times the track has been successfully associated or updated since the last time it was successfully associated or updated. It records the number of consecutive times or time intervals that the track has lost effective association (such as the target point detected by the radar). The main function of the update count is to help the system determine the validity of the track. When the number of updates is 0, it means that the track was just created recently, or no valid association has been lost since the last successful association, which usually means that the track is new, active, and has a high degree of credibility; the detection time is usually associated with the system's update cycle or time step, which is used to record the number of time steps or cycles since the track was created or last updated. Its main function is to provide a reference in a time dimension to help the system understand the activity and update frequency of the track. By monitoring the changes in the detection time, the system can evaluate the stability and reliability of the track. The detection time of 1 means that the track has gone through a time step or cycle since it was created or last updated. Since the value of the detection time is very small, this further confirms that the track is new because it has just been created or updated. Therefore, by identifying tracks with a track information data update number of 0 and a detection time of 1, the status of newly created, active, and not yet fully verified tracks can be queried. By analyzing the track information data, new tracks can be screened out, which may represent new targets or new motion states of existing targets. This helps the radar system identify and track targets more accurately, reducing false alarms and missed alarms. By obtaining the initial position and Doppler index of each new track, the target's motion characteristics can be further analyzed, which helps to distinguish between stationary targets, slow-moving targets, and fast-moving targets, thereby improving the accuracy of target identification.

[0040] The steps of obtaining the initial position and Doppler index of each new track to judge the Doppler information and obtain the target track include: obtaining the coordinates of the initial position point of each new track, judging whether the coordinates of the initial position point meet the initial position condition, and comparing the Doppler index of each new track with the target Doppler line index; if the coordinates of the initial position point of a new track meet the initial position condition, and the Doppler index of the new track is not equal to the target Doppler line index, then the new track is marked as the target track, and each target track is counted; if the coordinates of the initial position point of a new track do not meet the initial position condition, or the Doppler index of the new track is equal to the target Doppler line index, then the new track is not processed.

[0041] In this embodiment, the primary task of the radar system is to accurately locate the target. If the initial position of the new track is far from the expected one, it may be due to noise, interference, false detection or other factors. Checking whether the initial position of the new track is consistent with the expected one is because if the initial position does not meet the expectations, then the target may be the result of false detection rather than a real target. Therefore, by checking the initial position, false tracks caused by false alarms can be reduced; and the Doppler index is closely related to the speed information of the target. By verifying whether the Doppler index corresponding to the new track matches the previously selected Doppler line, it can be confirmed whether the target represented by the new track has a speed consistent with the expected one. In a multi-target environment, different targets may have similar distance information but different speed information. By verifying the Doppler index, these targets with similar distances but different speeds can be distinguished to avoid confusion. The multipath effect is one of the common interference sources in radar systems. By verifying the Doppler index, false tracks caused by the multipath effect can be identified, because these false tracks often have Doppler characteristics different from those of real targets. Therefore, by verifying whether the Doppler index corresponding to the new track matches the index of the selected Doppler line, that is, whether MaxDopplerLine1, MaxDopplerLine2 and MaxDopplerLine3, it can be further confirmed whether the track is a new track. By verifying the initial position and Doppler index of the new track, those false tracks that do not meet expectations can be excluded, thereby improving the accuracy of target tracking. If the initial position and Doppler index of the new track meet the conditions, it means that it is a new track and can be processed in the next step; otherwise, the track is determined to be a false track or a track that does not meet the tracking requirements, and no further processing is performed on it.

[0042] S3. Mark the tracks in the neighborhood of each target track as the neighboring tracks of each target track, extract the speed of each neighboring track, and process to obtain the similar neighboring tracks of each target track.

[0043] The steps of processing to obtain similar neighboring tracks include: obtaining the coordinates and speed of each target track, and extracting a preset speed resolution from the vehicle-mounted millimeter-wave radar database; obtaining the neighborhood of each target track according to the coordinate processing of each target track, and marking the tracks in the neighborhood of each target track as neighboring tracks of each target track; performing difference calculations on the speed of each target track and the speed of each neighboring track of each target track, and marking the absolute value of the difference result as the deviation speed of each neighboring track of each target track; comparing the deviation speed of each neighboring track of each target track with the speed resolution, if the deviation speed of a neighboring track of a target track is less than or equal to the speed resolution, then marking the neighboring track as a similar neighboring track of the target track; if the deviation speed of a neighboring track of a target track is greater than the speed resolution, then not processing the neighboring track.

[0044] In this embodiment, the speed resolution refers to the minimum value of the speed difference between two targets that the system can distinguish, which depends on the performance of the radar system, the signal processing algorithm, and the accuracy of the target tracking algorithm. The vehicle-mounted millimeter wave radar transmits high-frequency electromagnetic waves through its antenna system. When the electromagnetic waves encounter the target, part of the energy will be reflected back to form an echo signal. These echoes contain information such as the distance, speed, and angle of the target. The coordinates of each target track can obtain the distance between the target and the radar by using the time delay of the echo signal (i.e., the time from the emission to the reception of the electromagnetic wave) and the propagation speed of the electromagnetic wave (the speed in the air is close to the speed of light). The coordinates of each target track are obtained by converting the extracted distance into the two-dimensional coordinates of the target in the radar coordinate system by converting the polar coordinates to the rectangular coordinates; the speed of each target track is obtained by using the Doppler effect (when there is relative motion between the target and the radar, the frequency of the echo signal will change, and the frequency change of the echo signal is proportional to the radial speed of the new track), according to the relationship between the frequency change and the radial speed of the new track, which can be the Doppler formula. When obtaining the coordinates and speed of neighboring tracks, the radar system needs to continuously scan the surrounding environment, detect and track targets. Each detected target will form a track, which contains the target's historical position, speed, acceleration and other information. The system will store all detected tracks in the track database or track management module, and these tracks will be updated according to time to reflect the latest status of the target. When performing neighbor track analysis, the tracks adjacent to the new track position are retrieved from the track database or management module according to the above-mentioned neighborhood range. This usually involves spatial query algorithms, such as nearest neighbor search, range query, etc., to quickly find neighbor tracks that meet the conditions. Once the neighbor track is found, the system can extract the coordinate information of the neighbor track from the track data, including the position of the neighbor track in the previous time step, the current predicted position or the position after smoothing, etc. The deviation speed of each adjacent track refers to the speed difference between a target track and one of its adjacent tracks; the speed resolution is 0.7, which is obtained from the vehicle-mounted millimeter-wave radar database. It is the minimum difference between two different speeds that can be distinguished in the vehicle-mounted millimeter-wave radar system, representing the system's sensitivity and accuracy to speed changes. When the deviation speed of an adjacent track of a target track is less than or equal to the speed resolution, it means that the difference in speed between the two tracks is so small that within the system's resolution capability, they can be regarded as similar or close in speed, so they are marked as similar adjacent tracks of the target track; on the contrary, if the deviation speed of the adjacent track is greater than the speed resolution, then the difference in speed between the two tracks is large enough that the system can clearly distinguish them and does not regard the two tracks as similar or perform further association processing, because they may correspond to different physical targets or have significantly different motion characteristics.Since in this embodiment, more emphasis is placed on describing the sensitivity or resolution of the radar system to speed differences, the main focus is on the difference in speed magnitude, and the direction of the speed is not directly involved. Therefore, the speed difference between the new track and the adjacent track only considers the speed magnitude of the new track and the adjacent track, and does not consider the direction. When the speed difference between the new track and the adjacent track is less than or equal to the speed resolution, it is considered that the new track and the adjacent track are consistent in speed, and further operations can be performed. If the speed difference between the new track and the adjacent track is greater than the speed resolution, it is considered that they are inconsistent in speed, which may represent different physical targets or have other differences, and no processing is performed.

[0045] S4. Determine whether the similar adjacent track is an old track, and obtain the energy value of the similar adjacent track, compare the energy value of the similar adjacent track of each target track with the energy value of each target track, determine whether each target track is a multipath false target, obtain the judgment result and provide feedback.

[0046] The steps of judging whether a similar neighboring track is an old track include: obtaining track information data of each similar neighboring track; obtaining track information data of a preset old track from a vehicle-mounted millimeter-wave radar database; comparing the track information data of each similar neighboring track with the track information data of a preset old track, and if a similar neighboring track meets the old track management parameters, then judging that the similar neighboring track is an old track, and if a similar neighboring track does not meet the old track management parameters, then judging that the similar neighboring track is not an old track.

[0047] In this embodiment, the preset old track information data condition is: the detection time is greater than 60 and the update number is less than 20. When the detection time is greater than 60, those tracks that have been stably tracked for a period of time can be screened out. This is because if the detection time of the track is very high, it means that it has been continuously tracked and updated for multiple time steps or cycles, so it is more likely to be a real, persistent target. At the same time, when the update number is less than 20, those tracks that may no longer be relevant or exceed the radar detection range although the tracking time is long can be excluded. The limit on the number of updates ensures that the track is still active and its information is valid for the current radar detection. After determining that the adjacent track is an old track, by comparing the energy values ​​of the adjacent track points and the new track points, it can be further determined whether the new track may be a multipath false target of the old track. If the adjacent track is an old track (i.e., a track that has been tracked for a period of time), it is more likely to be real; if the energy of the adjacent track is higher than that of the new track, and the speeds of the two are the same, the new track is likely to be a multipath false target of the old track and should be deleted. Finally, the system will manage the track according to the preset track information data. The output track is both stable and relatively new, so it is more likely to be the track of the real target. Such a track has been sufficiently verified to ensure its reliability, but is not outdated to the extent that it is no longer relevant.

[0048] The step of judging whether each target track is a multipath false target comprises: obtaining the energy value of each similar adjacent track, and comparing the energy value of each target track with the energy value of each similar adjacent track of each target track; for a certain target track, if there is a similar adjacent track whose energy value is greater than the energy value of the target track and the similar adjacent track is an old track, then the target track is judged to be a multipath false target; if there is no similar adjacent track whose energy value is greater than the energy value of the target track or the similar adjacent track is not an old track, then the target track is judged not to be a multipath false target.

[0049] In this embodiment, the multipath false target considered is a false target generated by the multipath effect, which is displayed on the radar display as a false target with the same distance and speed as the real target but at a different angle. The multipath effect is a common phenomenon in radar systems. It causes the radar to receive signals from the same target but reflected through different paths, thereby generating multiple seemingly independent echoes. These multipath false targets may interfere with the radar's tracking and identification of the real target. After determining that the adjacent track is the old track, by comparing the energy values ​​of the adjacent track and the new track, those false targets with low energy that are likely to be generated by the multipath effect can be identified and eliminated, thereby improving the system's anti-interference ability and the accuracy of target tracking.

[0050] S5. Output all tracks that meet the standard values ​​of track information data.

[0051] The steps of obtaining the judgment result and providing feedback include: obtaining a preset standard value of track information data from a vehicle-mounted millimeter-wave radar database; if a target track is a multipath false target, deleting the target track; if a target track is not a multipath false target and meets the preset standard value of track information data, outputting the target track; if a target track is not a multipath false target but does not meet the preset standard value of track information data, not processing the track.

[0052] In this embodiment, the preset track information data standard value condition is: the detection time is greater than 8 and the update number is less than 20. When the detection time is greater than 8, it is ensured that the track has been stably tracked for a period of time, thereby reducing the possibility of false tracks caused by noise, short-term interference or misdetection. The track is considered reliable only when it is detected in multiple consecutive frames and the parameters are stable; and when the update number is less than 20, the maximum duration of the track is limited. Although tracks tracked for a long time are more likely to be real, too long a duration may also mean that the target has exceeded the detection range of the radar or is no longer relevant. Therefore, setting an upper limit can ensure that the output track is a target that is still active within the current radar field of view. When the track information data of the remaining track meets the preset track information data standard value, it means that the track is an accurate, continuous and smooth motion trajectory of the real target after multipath false target elimination processing.

[0053] The step of judging whether the coordinates of the initial position point meet the initial position conditions includes: the coordinates of the initial position point include an initial horizontal coordinate and an initial vertical coordinate; obtaining a preset initial coordinate value from the vehicle-mounted millimeter-wave radar database; comparing the coordinates of the initial position point with the preset initial coordinate value, if the coordinates of the initial position point meet the preset initial coordinate value, the track can be further judged, if the coordinates of the initial position point do not meet the preset initial coordinate value, the track will not be processed.

[0054] In this embodiment, the preset initial coordinate value includes an initial horizontal coordinate value and an initial vertical coordinate value, wherein the value range of the initial horizontal coordinate value is [-9,9], and the value range of the initial vertical coordinate value is [20,90]. If the coordinates of the initial position point meet the preset initial coordinate values, it means that the track meets the initial position condition, indicating that the radar system or related sensors accurately locate the initial position of the target, and the system has successfully identified the target; if the coordinates of the initial position point do not meet the preset initial coordinate values, it means that the track does not meet the initial position condition, the system does not identify the target, and no further operation can be performed.

[0055] A preset neighborhood range deviation value is obtained from the on-board millimeter-wave radar database; the preset neighborhood range deviation value includes a horizontal coordinate range deviation value and a vertical coordinate range deviation value; the horizontal coordinate of each target track is subtracted and summed with the horizontal coordinate range deviation value to obtain the lower limit and upper limit of the horizontal coordinate range of the track neighborhood, and the range of the lower limit and upper limit of the horizontal coordinate range of the track neighborhood is marked as the horizontal coordinate range of each target track; the vertical coordinate of each target track is subtracted and summed with the vertical coordinate range deviation value to obtain the lower limit and upper limit of the vertical coordinate range of the track neighborhood, and the range of the lower limit and upper limit of the vertical coordinate range of the track neighborhood is marked as the vertical coordinate range of each target track, and the neighborhood range of each target track is comprehensively obtained according to the horizontal coordinate range and the vertical coordinate range of each target track.

[0056] In this embodiment, according to the detection range, resolution and continuity of target motion of the radar, an area with the new track as the center and a certain distance and angle as the boundary is defined. Within the defined neighborhood range, all existing tracks are traversed. These tracks are called neighboring tracks. In the vehicle-mounted millimeter-wave radar scenario, the neighborhood range centered on the new track is: the horizontal coordinate range deviation value of other tracks and the current target track is 7, and the vertical coordinate range deviation value of other tracks and the current target track is 6.

[0057] Depend on Figure 3 As shown, it is a schematic diagram of a multipath false target scenario of a vehicle-mounted millimeter-wave radar provided in an embodiment of the present application, Figure 3 It can be seen from the multipath scenario that the characteristics of this type of multipath false target are consistent with the real target in terms of distance and speed, but the angle is different.

[0058] In summary, the embodiment of the present application selects the Doppler line with the strongest energy, then filters out the new track and detects whether there are neighboring tracks with the same speed in its neighborhood, identifies and deletes multipath false targets based on energy values ​​and track information data, and finally outputs valid track information based on the set track information data, thereby effectively suppressing the spread of target vehicles caused by multipath, resulting in the appearance of multiple targets, and even "clones" appearing in other lanes a few meters away.

[0059] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0060] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0061] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0062] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0063] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0064] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management, characterized in that: The following steps are involved: Obtain the RD map of the current frame, and collect the energy value of each Doppler line. According to the energy value of each Doppler line, filter out the target Doppler line and record the index; Acquire track information data, filter and obtain each new track according to the track information data, and obtain the initial position and Doppler index of each new track to perform Doppler information judgment to obtain each target track; The tracks in the neighborhood of each target track are marked as the neighboring tracks of each target track, and the speed of each neighboring track is extracted to obtain the similar neighboring tracks of each target track; Determine whether the similar adjacent track is an old track, obtain the energy value of the similar adjacent track, compare the energy value of the similar adjacent track of each target track with the energy value of each target track, determine whether each target track is a multipath false target, obtain the judgment result and provide feedback; The steps of screening and obtaining the target Doppler line and recording the index include: Extract Doppler lines from the RD graph, mark them as various Doppler lines, and collect the signal strength of each distance unit of each Doppler line; The signal strength of each distance unit of each Doppler line is summed, and the summation result is marked as the energy value of each Doppler line; According to the energy value of each Doppler line, the Doppler lines are sorted from large to small, and the first three Doppler lines are marked as target Doppler lines; Record indexing of target Doppler lines; The step of obtaining the initial position and Doppler index of each new track to perform Doppler information judgment and obtain the target track includes: Obtain the coordinates of the initial position point of each new track, determine whether the coordinates of the initial position point meet the initial position conditions, and compare the Doppler index of each new track with the target Doppler line index; If the coordinates of the initial position point of a new track meet the initial position conditions, and the Doppler index of the new track is not equal to the target Doppler line index, then the new track is marked as the target track, and each target track is counted; If the coordinates of the initial position point of a new track do not meet the initial position conditions, or the Doppler index of the new track is equal to the target Doppler line index, the new track will not be processed.

2. A method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management as claimed in claim 1, characterized in that: The step of obtaining each new track by screening the track information data comprises: The track information data includes the detection time and update times of each track; Acquire the track information data of the preset new track from the vehicle-mounted millimeter-wave radar database; The track information data is compared with the track information data of the preset new track. If a track meets the preset new track information data, the track is counted to obtain each new track. If a track does not meet the preset new track information data, the track is not processed.

3. A method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management as claimed in claim 1, characterized in that: The step of processing to obtain similar adjacent tracks comprises: Obtain the coordinates and speed of each target track and extract the preset speed resolution from the vehicle-mounted millimeter-wave radar database; The neighborhood of each target track is obtained according to the coordinate processing of each target track, and the tracks in the neighborhood of each target track are marked as the neighboring tracks of each target track; Perform difference calculation on the speed of each target track and the speed of each adjacent track of each target track, and mark the absolute value of the difference result as the deviation speed of each adjacent track of each target track; The deviation speed of each adjacent track of each target track is compared with the speed resolution. If the deviation speed of an adjacent track of a target track is less than or equal to the speed resolution, the adjacent track is marked as a similar adjacent track of the target track; if the deviation speed of an adjacent track of a target track is greater than the speed resolution, the adjacent track is not processed.

4. A method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management as claimed in claim 1, characterized in that: The step of judging whether the similar adjacent track is an old track comprises: Obtain track information data of each similar adjacent track; Acquire the track information data of the preset old track from the vehicle-mounted millimeter-wave radar database; The track information data of each similar adjacent track is compared with the track information data of the preset old track. If a similar adjacent track meets the old track management parameters, it is judged that the similar adjacent track is an old track. If a similar adjacent track does not meet the old track management parameters, it is judged that the similar adjacent track is not an old track.

5. A method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management as claimed in claim 1, characterized in that: The step of judging whether each target track is a multipath false target comprises: Obtaining energy values ​​of each similar adjacent track, and comparing the energy value of each target track with the energy values ​​of each similar adjacent track of each target track; For a certain target track, if there is a similar neighbor track whose energy value is greater than the energy value of the target track and the similar neighbor track is an old track, then the target track is judged to be a multipath false target; if there is no similar neighbor track whose energy value is greater than the energy value of the target track or the similar neighbor track is not an old track, then the target track is judged not to be a multipath false target.

6. A method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management as claimed in claim 1, characterized in that: The steps of obtaining the judgment result and providing feedback include: Obtaining preset track information data standard values ​​from the vehicle-mounted millimeter-wave radar database; If a target track is a multipath false target, the target track is deleted; if a target track is not a multipath false target and meets the preset track information data standard value, the target track is output; if a target track is not a multipath false target but does not meet the preset track information data standard value, the track is not processed.

7. A method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management as claimed in claim 1, characterized in that: The step of determining whether the coordinates of the initial position point meet the initial position conditions comprises: The initial position point coordinates include an initial horizontal coordinate and an initial vertical coordinate; Obtaining a preset initial coordinate value from the vehicle-mounted millimeter-wave radar database; The coordinates of the initial position point are compared with the preset initial coordinate values. If the coordinates of the initial position point meet the preset initial coordinate values, the track is further judged. If the coordinates of the initial position point do not meet the preset initial coordinate values, the track is not processed.

8. A method for suppressing multipath false targets of vehicle-mounted millimeter-wave radar based on track management as claimed in claim 3, characterized in that: The step of obtaining the neighborhood of each target track according to the coordinate processing of each target track comprises: Obtaining a preset neighborhood range deviation value from the vehicle-mounted millimeter-wave radar database; The preset neighborhood range deviation value includes a horizontal coordinate range deviation value and a vertical coordinate range deviation value; The abscissa of each target track is subtracted and summed from the abscissa range deviation value to obtain the lower and upper limits of the abscissa range of the track neighborhood, and the range of the lower and upper limits of the abscissa range of the track neighborhood is marked as the abscissa range of each target track. The ordinate of each target track is subtracted and summed from the ordinate range deviation value to obtain the lower and upper limits of the ordinate range of the track neighborhood, and the range of the lower and upper limits of the ordinate range of the track neighborhood is marked as the ordinate range of each target track. The neighborhood range of each target track is obtained based on the abscissa range and ordinate range of each target track.

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