Air conditioner outdoor unit reflection point identification system and method based on millimeter wave radar

Abstract

The invention provides an air conditioner outdoor unit reflection point identification system based on millimeter wave radar, and the system comprises a radar signal processing module, the input data of which is an echo signal of a transmitted signal, and the output data of which is a spectrogram and a point cloud in the spectrogram; the stationary point judgment module is used for extracting the point cloud in the spectrogram to obtain a radar measurement included angle of the target and the radial speed of the target, and determining a stationary target and the point cloud of the stationary target in combination with the instrument speed of the vehicle; and the air conditioner outdoor unit reflection point identification module combines the static target obtained by the static point judgment module according to the relationship between the speed and the distance measured by the spectrogram, and if the position of the static target is attached with the moving target, all the moving targets at the position are air conditioner outdoor unit reflection points. The invention further provides a corresponding method. The recognition system adopts a strategy of searching Doppler unit extension based on the distance unit, can effectively aim at a scene in which the air conditioner outdoor unit is a static object but reflection echo detection has a moving target, and is high in generalization and accuracy.

Description

Technical Field

[0001] The present invention relates to millimeter wave radar signal processing technology, and more specifically, to a system and method for identifying reflection points of an air conditioner outdoor unit in an environment. Background Art

[0002] Today, the field of automotive technology is increasingly moving towards automation and intelligence. On-board millimeter-wave radar is mainly used to detect the distance between the vehicle body and other vehicles and obstacles, which improves driving safety.

[0003] In the application of millimeter-wave radar, speed measurement is a common application scenario of millimeter-wave radar. Due to the influence of the Doppler effect, millimeter-wave radar is sensitive to changes in target speed. In some cases, it may cause unexpected radar reflection echoes (hereinafter referred to as reflection points). When there is an air-conditioning outdoor unit in the environment, when the stationary air-conditioning is working, due to the characteristics of millimeter-wave radar, its electromagnetic waves can pass through its surface material and reach its internal fan blades. Then the Doppler effect generated by the rotation of the fan blades is detected by the radar, generating reflection points.

[0004] Normally, the impact of this reflection point is limited, but in some automotive application scenarios, such as reversing radar, DOW (door opening warning) function, etc., the moving reflection point generated by the fan blade will cause unknown results of the function.

[0005] The common millimeter-wave radar method of identifying moving targets in the environment is not applicable to this scenario. The reason is that for the radar, the air conditioner outdoor unit itself is a stationary object, and the moving reflection points generated by it are generated by the rotating fan blades inside. Its characteristics do not conform to the common moving target model. Usually, millimeter-wave radar determines that the target is in a moving state, and it needs to combine the speed information of all the reflection points of the target. If the main body of the target is divided into a stationary object and has some moving reflection points, it is easy to cause errors in the judgment of the target's motion state. Summary of the invention

[0006] The object of the present invention is to provide an air-conditioning outdoor unit reflection point recognition system based on millimeter-wave radar, so as to realize the air-conditioning outdoor unit reflection point recognition with strong generalization and high accuracy.

[0007] In order to achieve the above-mentioned purpose, the present invention provides an air-conditioning outdoor unit reflection point recognition system based on millimeter wave radar, comprising a radar signal processing module, a stationary point judgment module and an air-conditioning outdoor unit reflection point recognition module; the input data of the radar signal processing module is the echo signal of the transmitted signal, and the output data is the spectrum diagram and the point cloud therein; the stationary point judgment module is configured to extract the point cloud in the spectrum diagram to obtain the radar measurement angle of the target and the radial speed of the target after defuzzification of the speed, and determine the stationary target and its point cloud area in combination with the instrument speed of the vehicle; the air-conditioning outdoor unit reflection point recognition module is configured to determine the stationary target obtained by the stationary point judgment module based on the speed and distance relationship measured by the spectrum diagram, and if the stationary target is located at a position accompanied by a moving target, all moving targets at this position are judged as the air-conditioning outdoor unit reflection point.

[0008] The modulation mode of the millimeter wave radar is linear frequency modulation continuous wave, the input data of the radar signal processing module is the echo signal obtained by using the linear frequency modulation continuous wave as the transmission signal, and the point cloud includes the angle, distance and speed of all real targets.

[0009] The radar signal processing module includes a spectrum diagram generation module, which samples the echo signal received by each transmission signal to obtain N sampling points, performs FFT along the sampling points to obtain distance dimension information, performs FFT processing on the same distance unit of the echo signals of M consecutive transmission signals to obtain speed dimension information, thereby forming a spectrum diagram, and the spectrum diagram includes the distance dimension information and speed dimension information of the radar target; the radar signal processing module also includes a constant false alarm detection module and a wave direction of arrival estimation module.

[0010] The stationary point determination module is configured to perform the following steps: for each point cloud of the spectrum graph, obtain the radar measurement angle M of the target corresponding to the point cloud from the radar signal processing module. R And get the radial velocity V of the target after velocity blurring real , according to the radial velocity V after the target velocity is resolved real and the vehicle's instrument speed V Ego The relationship between the target and the vehicle's horizontal axis is used to obtain the analytical value of the angle M F , according to the radar measurement angle M of the target R The analytical value M of the angle between the target and the vehicle's horizontal axis F To determine the target's motion state.

[0011] The analytical value M of the angle between the target and the horizontal axis of the vehicle F for:

[0012]

[0013] Among them, V Ego is the instrument speed of the vehicle, VReal The radial velocity of the target after velocity blurring.

[0014] According to the radar measurement angle M of the target R The analytical value M of the angle between the target and the vehicle's horizontal axis F To determine the target's motion state, specifically including: obtaining the radar measurement angle M R The analytical value M of the angle between the target and the vehicle's horizontal axis F The angle difference ΔM is used to compare the angle difference ΔM with the preset angle difference empirical threshold M. Thd Compare, if ΔM <M Thd , the target's motion state is judged to be stationary, otherwise the target's motion state is moving.

[0015] The air conditioner outdoor unit reflection point recognition module is configured as follows:

[0016] B1: Take a frame of spectrum, traverse the point cloud, select the stationary target whose echo signal is stronger than a certain intensity threshold as the reference point, and obtain the distance unit R where the reference point is located i ;

[0017] B2: Traverse the point cloud and count all distance units in the point cloud set as R i The number of point clouds N T ;

[0018] B3: Based on the existing empirical threshold N Thre , when the number of point clouds N T >N Thre When Flag =1, otherwise set to 0;

[0019] B4: If the flag is N Flag =1, then the distance unit R is counted i The midpoint cloud belongs to the speed of the moving target, and the distance unit is R i The maximum velocity of a point cloud in the point cloud set is V max , the minimum speed is V min , calculate the speed difference V delta ;

[0020] B5: Based on the existing empirical threshold V Thre , when the speed difference V delta >V Thre When the speed flag is set to V Flag =1;

[0021] B6: If N Flag =1 and V Flag =1, then the distance unit R i All moving targets on the image are reflection points caused by the air conditioner outdoor unit.

[0022] On the other hand, the present invention provides a method for identifying reflection points of an air conditioner outdoor unit based on millimeter wave radar, comprising:

[0023] S100: using a radar signal processing module to receive an echo signal of a transmitted signal, and outputting a spectrum diagram and a point cloud therein;

[0024] S200: extracting the point cloud in the spectrum diagram using the stationary point judgment module to obtain the radar measurement angle of the target and the radial velocity of the target after velocity resolution, and determining the stationary target and its point cloud area in combination with the instrument speed of the vehicle;

[0025] S300: Using the air conditioner outdoor unit reflection point recognition module to measure the speed and distance relationship according to the frequency spectrum, combined with the stationary target obtained by the stationary point judgment module, if the location of the stationary target is accompanied by a moving target, all moving targets at this location are judged as the air conditioner outdoor unit reflection point.

[0026] The step S200 specifically includes: for each point cloud of the spectrum graph, obtaining the radar measurement angle M of the target corresponding to the point cloud from the radar signal processing module R And get the radial velocity V of the target after velocity blurring real , according to the radial velocity V after the target velocity is resolved real and the vehicle's instrument speed V Ego The relationship between the target and the vehicle's horizontal axis is used to obtain the analytical value of the angle M F , according to the radar measurement angle M of the target R The analytical value M of the angle between the target and the vehicle's horizontal axis F To determine the target's motion state.

[0027] The step S300 specifically includes:

[0028] B1: Take a frame of spectrum, traverse the point cloud, select the stationary target whose echo signal is stronger than a certain intensity threshold as the reference point, and obtain the distance unit R where the reference point is located i ;

[0029] B2: Traverse the point cloud and count all distance units in the point cloud set as R i The number of point clouds N T ;

[0030] B3: Based on the existing empirical threshold N Thre , when the number of point clouds N T >N Thre When Flag =1, otherwise set to 0;

[0031] B4: If the flag is N Flag=1, then the distance unit R is counted i The midpoint cloud belongs to the speed of the moving target, and the distance unit is R i The maximum velocity of a point cloud in the point cloud set is V max , the minimum speed is V min , calculate the speed difference V delta ;

[0032] B5: Based on the existing empirical threshold V Thre , when the speed difference V delta >V Thre When the speed flag is set to V Flag =1;

[0033] B6: If N Flag =1 and V Flag =1, then it is considered that the distance unit R i All moving targets on the image are reflection points caused by the air conditioner outdoor unit.

[0034] The air-conditioning outdoor unit reflection point recognition module of the air-conditioning outdoor unit reflection point recognition system based on millimeter-wave radar of the present invention adopts a strategy based on distance unit search and Doppler unit expansion, which can effectively target the scenario where the air-conditioning outdoor unit is a stationary object but there is a moving target in the reflected echo detection. It has strong generalization and high accuracy, and is effective for automobile application scenarios such as preventing reversing radar from misidentifying and the presence of moving targets in the FOV that cause abnormal vehicle functions.

[0035] In addition, the maximum speed difference algorithm proposed in the present invention utilizes the accurate characteristic of radar speed measurement and the characteristic that stationary objects and moving targets in the spectrum can be clearly distinguished, thereby reducing the probability of misidentification. When updating and maintaining the algorithm, only the algorithm parameters need to be updated, and the algorithm has strong maintainability.

[0036] The air conditioner outdoor unit reflection point recognition system based on millimeter wave radar of the present invention only detects the point cloud of the target screened by the CFAR module, rather than the detection based on the spectrum, which simplifies the signal processing steps and greatly reduces the calculation and storage pressure of the lower computer under the condition of limited computing power of the current vehicle-mounted millimeter wave radar. If the target before CFAR screening is directly detected, the input at this time is the entire spectrum, the data storage pressure is large, and because the spectrum information contains useless information such as noise, the calculation efficiency is greatly reduced without CFAR screening, and the noise may cause misidentification. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural block diagram of the air conditioner outdoor unit reflection point recognition system based on millimeter wave radar of the present invention.

[0038] Figure 2 It is a waveform diagram of the transmitted signal and the echo signal of a single cycle.

[0039] Figure 3 It is a schematic diagram of the spectrum obtained by processing the echo signal.

[0040] Figure 4 It is a relationship diagram between the angle between the target and the vehicle's horizontal axis, the radial velocity and the instrument speed of the ego vehicle.

[0041] Figure 5 is a spectrogram of a typical scene showing a stationary object along with a moving object. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0043] The radar hardware based on which the air conditioner outdoor unit reflection point identification method based on millimeter wave radar of the present invention is implemented is not targeted at a specific millimeter wave radar, but due to the requirements of the actual scene and the signal processing method, in this embodiment, the modulation mode of the radar used in the air conditioner outdoor unit reflection point identification method based on millimeter wave radar is frequency modulated continuous wave, and has horizontal angle measurement capability, distance resolution not less than 0.2m, distance accuracy not less than 0.1m, speed resolution not less than 0.1m / s, speed accuracy not less than 0.05m / s, angle measurement accuracy not less than 3°, and the number of sampling frames after radar signal processing is not less than 16 frames per second. In other embodiments, any radar that meets the above performance can apply the air conditioner outdoor unit reflection point identification method based on millimeter wave radar of the present invention to identify the air conditioner outdoor unit.

[0044] In addition, since the radar's FOV (field of view), installation location and the maximum distance at which the radar can detect a target jointly determine the effective range of the radar in identifying the air conditioner outdoor unit, it is necessary to adjust the radar's installation location according to the actual application scenario.

[0045] The working principle of the air conditioner outdoor unit reflection point recognition method based on millimeter wave radar of the present invention is as follows:

[0046] like Figure 1 FIG. 1 is a schematic diagram of a structure of a reflection point recognition system for an air conditioner outdoor unit based on a millimeter wave radar according to an embodiment of the present invention. Figure 1 As shown, the air-conditioner outdoor unit reflection point recognition system based on millimeter-wave radar includes a radar signal processing module 10 , a stationary point judgment module 20 , and an air-conditioner outdoor unit reflection point recognition module 30 .

[0047] The radar signal processing module 10 is a common part of current radar signal processing and is not original to the present invention.

[0048] In this embodiment, since the modulation method of the millimeter wave radar is linear frequency modulation continuous wave, the input data of the radar signal processing module 10 is the echo signal obtained by using the linear frequency modulation continuous wave as the transmitting signal (i.e., the chirp signal), and the output data is the spectrum diagram and the point cloud therein, and the point cloud includes the angle, distance and speed of all real targets.

[0049] In other embodiments, the input data of the radar signal processing module 10 may be the echo signal of other types of transmission signals, as long as the echo signal can meet the required angle, distance and speed resolutions.

[0050] The waveform diagram of the single-cycle transmission signal (i.e. chirp signal) and the echo signal is as follows: Figure 2 As shown, f0 is the starting frequency of the transmitted signal, f sw is the sweep bandwidth of the transmitted signal, T chirp is the pulse period of the transmitted signal. τ is the time delay of the echo signal caused by the target distance. The frequency change caused by the echo signal shifting along the time axis caused by the target distance is defined as the frequency offset caused by the target distance f R (f R That is, the height of a right triangle with τ as the base and the waveform of the transmitted signal as the hypotenuse), the target speed v r The frequency change caused by the translation of the echo signal along the frequency axis is defined as the frequency change caused by the target velocity f D , the received target echo signal is mixed with the transmitted signal to obtain the difference frequency f B From this, we can see that for a stationary target, the difference frequency f B It is only affected by the target distance R, and for moving targets, the difference frequency f B It includes not only the frequency offset f caused by the target distance R , including the frequency change f caused by the target speed D , as shown below:

[0051]

[0052] Among them, f R is the frequency offset caused by the target distance, f D is the frequency change caused by the target speed, f sw is the sweep bandwidth of the transmitted signal, T chirp is the pulse period of the transmitted signal, c is the propagation speed of the radar signal, R is the target distance, λ is the wavelength of the radar antenna, v r is the target speed.

[0053] like Figure 3As shown, the radar signal processing module 10 includes a spectrum diagram generation module, which samples the echo signal received by each transmission signal (i.e., chirp signal) to obtain N sampling points, and performs FFT along the sampling points to obtain distance dimension information. Performing FFT processing on the same distance unit of the echo signal of M consecutive transmission signals can obtain speed dimension information, thereby forming a spectrum diagram (Range-Dopper), which includes the distance dimension information and speed dimension information of the radar target.

[0054] In addition, the radar signal processing module 10 also includes a constant false alarm detection (CFAR) module and a direction of arrival estimation (DOA) module, wherein the constant false alarm detection module is configured to obtain the distance and speed information of all real targets according to the spectrum diagram, and the direction of arrival estimation module is configured to obtain the angle information of all real targets according to the phase difference of the echo signal.

[0055] Since the road surface media where the vehicles are parked in different environments are different, the environmental noise in the radar irradiation area is different. In order to eliminate the influence of environmental noise on the real target in the spectrum diagram, the constant false alarm detection (CFAR) module usually performs a CFAR process to extract the distance and speed information of all real targets (the CFAR process is a universal process, which is not described in detail in the present invention). Subsequently, the radar signal processing module 10 forms target point cloud data according to the angle, distance and speed of all real targets obtained through the direction of arrival estimation (DOA) module. Therefore, the present invention only detects the point cloud of the target screened out by the constant false alarm detection (CFAR) module.

[0056] The target distance and speed information are extracted, specifically including: for each target, assuming that the radar distance resolution is Res, the radar speed resolution is Ves, its distance index in the N distance units in the spectrum graph is R, and its speed index in the M speed units in the spectrum graph is D, then the target distance Range and speed Velocity are obtained as shown in Formula 1:

[0057] Range=Res*R,Velocity=Ves*D (1)

[0058] Among them, Range is the distance of the target, Velocity is the speed of the target, Res is the range resolution of the radar, Ves is the speed resolution of the radar, R is the range index in the N range units in the spectrum graph, and D is the speed index in the M speed units in the spectrum graph.

[0059] The stationary point determination module 20 is configured to extract the radar measurement angle of the target and the radial velocity of the target after velocity resolution from the point cloud in the spectrum diagram, and determine the stationary target and its point cloud area in combination with the instrument speed of the vehicle.

[0060] The area of ​​the stationary target in the spectrum diagram will form the point cloud area of ​​the stationary target. The target that is not a stationary target is identified as a moving target.

[0061] The target's motion state and distance from the radar will lead to changes in the number of strong energy units on the spectrum diagram, unit energy changes, the distance of the units and Doppler coordinates. Therefore, by using the stationary point judgment module 20 to process the point cloud in the spectrum diagram, the target's motion state can be determined, and then the stationary target can be determined.

[0062] The stationary point determination module 20 is configured to perform the following step A1:

[0063] For each point cloud of the target 101 in the spectrum diagram, the radar measurement angle M of the target 101 corresponding to the point cloud is obtained from the radar signal processing module 10. R And get the radial velocity V of the target after velocity blurring real , according to the radial velocity V after the target velocity is resolved real and the vehicle's instrument speed V Ego The relationship between the target and the vehicle's horizontal axis is used to obtain the analytical value of the angle M F , according to the radar measurement angle M of the target R The analytical value M of the angle between the target and the vehicle's horizontal axis F To determine the target's motion state.

[0064] like Figure 4 As shown, the direction of the vehicle's speed is V Ego The direction of the radar normal is the direction of the dotted line marked as the normal in the figure, and the speed direction of the radial speed of the target after speed resolution (i.e., the radial relative speed between the target and the vehicle) is the direction of the line connecting the vehicle 102 and the target 101.

[0065] exist Figure 4 In the embodiment, the radar measurement angle obtained by the radar signal processing module 10 is represented as M R (M R That is, the radar angle measurement result of the angle M between the target 101 and the horizontal axis of the vehicle), the radial relative speed of the target and the vehicle is V, V = V Ego sin(M), the vehicle's instrument speed is V Ego , the radial velocity of the target after velocity blurring is V real (ie, the relative speed between a stationary target and a moving vehicle). Generally, there is ambiguity in the speed measurement of FMCW radar, and this patent does not elaborate on the speed deambiguation process.

[0066] According to the radial relative speed between the target and the vehicle 102, the angle analysis value M between the target and the vehicle lateral axis can be calculated: F The analytical value of the angle between the target and the vehicle's horizontal axis is M F for:

[0067]

[0068] Among them, V Ego is the vehicle's instrument speed, V Real The radial velocity of the target after velocity blurring.

[0069] It should be noted that only when the target is stationary, the angle analysis value M between the target and the vehicle's horizontal axis F The actual result is equal to the angle M between the target 101 and the vehicle's transverse axis.

[0070] Therefore, in step A1, according to the radar measurement angle M of the target R The analytical value M of the angle between the target and the vehicle's horizontal axis F To determine the target's motion state, specifically including: obtaining the radar measurement angle M R The analytical value M of the angle between the target and the vehicle's horizontal axis F The angle difference ΔM is used to compare the angle difference ΔM with the preset angle difference empirical threshold M. Thd Compare, if ΔM <M Thd , the target's motion state is judged to be stationary, otherwise the target's motion state is moving.

[0071] The air conditioner outdoor unit reflection point identification module 30 is configured to determine whether it is an air conditioner outdoor unit reflection point based on the speed and distance relationship measured by the spectrum diagram and the stationary target obtained by the stationary point judgment module 20; if there is a moving target at the location of the stationary target, all moving targets at that location are judged as air conditioner outdoor unit reflection points.

[0072] Since the typical characteristics of the reflection point of the air conditioner outdoor unit are a static target with a moving target, such as Figure 5 As shown in the spectrum diagram shown (here the brightness reflects the echo intensity, the horizontal axis is the velocity dimension, i.e. the Doppler unit, and the vertical axis is the distance dimension, i.e. the distance unit).

[0073] Figure 5It is a spectrum diagram of a typical scene, which shows a stationary target with a moving target. After the stationary point judgment module 20, the area of ​​the stationary target in the spectrum diagram will form a point cloud area. The Doppler unit coordinates of the point cloud area of ​​the target are located near 510, and the distance unit is located around 21, which is the echo generated by the air conditioner itself; that is, in the stationary point judgment module, the point cloud target corresponding to the point cloud area is judged as a stationary point. Around the distance unit 21, the point cloud targets formed on the remaining Doppler units are judged as moving points, such as distance unit 21 and Doppler unit 499. That is to say, in the distance unit 21, only the area near Doppler unit 510 is a stationary target, and the rest are moving targets; Doppler unit 499 is a moving point attached to the stationary target.

[0074] It should be noted that Figure 5 It is only used to exemplarily illustrate the phenomenon from the perspective of the spectrum diagram. The stationary target and the moving target attached to the stationary target can be intuitively seen in the spectrum, so as to introduce how to make judgments based on the logic of distance units and speed units; the point cloud area of ​​the stationary target is specifically obtained based on judging the motion state of the target in the stationary point judgment module 20 and obtaining the stationary target, without directly using the spectrum data.

[0075] Therefore, the air conditioner outdoor unit reflection point identification module 30 is set as:

[0076] Step B1: Take a frame of spectrum, traverse the point cloud, select a stationary target whose echo signal is stronger than a certain intensity threshold as the reference point, and obtain the distance unit R where the reference point is located i ;

[0077] Step B2: Traverse the point cloud and count all distance units in the point cloud set as R i The number of point clouds N T ;

[0078] It should be noted that this is not based on Figure 5 The spectrum graph is not used for statistics, but there are point sets in the spectrum graph. Each point set represents the point cloud formed after the current frame is processed by the previous modules. Each point cloud carries distance unit information, speed unit information, angle information, stationary point judgment information, etc.

[0079] Step B3: Based on the existing empirical threshold N Thre , when the number of point clouds N T >N Thre When Flag =1, otherwise set to 0;

[0080] N Flag =1 means there are multiple point cloud targets at this distance, N Flag =0 means that the condition of multiple point cloud targets is not met on this distance unit;

[0081] Step B4: If the flag is N Flag =1, then the distance unit R is counted i The midpoint cloud belongs to the speed of the moving target, and the distance unit is R i The maximum velocity of a point cloud in the point cloud set is V max , the minimum speed is V min , calculate the speed difference V delta ;

[0082] Specifically, Figure 5 In the example of , most of the points in the distance unit 21 form a point cloud, but except for the point cloud near the Doppler unit 510, the rest of the point clouds are judged as moving targets.

[0083] Step B5: Based on the existing empirical threshold V Thre , when the speed difference V delta >V Thre When the speed flag is set to V Flag =1;

[0084] Step B6: If N Flag =1 and V Flag =1, then the distance unit R i All moving targets on the image are reflection points caused by the air conditioner outdoor unit.

[0085] On the other hand, the present invention provides a method for identifying reflection points of an air conditioner outdoor unit based on millimeter wave radar, characterized in that it includes:

[0086] Step S100: using the radar signal processing module 10 to receive the echo signal of the transmitted signal, and outputting the spectrum diagram and the point cloud therein;

[0087] Step S200: extracting the point cloud in the spectrum diagram using the stationary point determination module 20 to obtain the radar measurement angle of the target and the radial velocity of the target after velocity defuzzification, and combining the instrument speed of the vehicle to determine the stationary target and its point cloud area;

[0088] Step S300: Use the air conditioner outdoor unit reflection point identification module 30 to determine whether it is an air conditioner outdoor unit reflection point based on the speed and distance relationship measured by the spectrum diagram and the stationary target obtained by the stationary point judgment module 20. If there is a moving target at the location of the stationary target, all moving targets at this location are determined to be air conditioner outdoor unit reflection points.

[0089] The step S200 specifically includes: for each point cloud of the spectrum graph, obtaining the radar measurement angle M of the target corresponding to the point cloud from the radar signal processing module 10 R And get the radial velocity V of the target after velocity blurring real, according to the radial velocity V after the target velocity is resolved real and the vehicle's instrument speed V Ego The relationship between the target and the vehicle's horizontal axis is used to obtain the analytical value of the angle M F , according to the radar measurement angle M of the target R The analytical value M of the angle between the target and the vehicle's horizontal axis F To determine the target's motion state.

[0090] The step 300 specifically includes:

[0091] Step B1: Take a frame of spectrum, traverse the point cloud, select a stationary target whose echo signal is stronger than a certain intensity threshold as the reference point, and obtain the distance unit R where the reference point is located i ;

[0092] Step B2: Traverse the point cloud and count all distance units in the point cloud set as R i The number of point clouds N T ;

[0093] Step B3: Based on the existing empirical threshold N Thre , when the number of point clouds N T >N Thre When Flag =1, otherwise set to 0;

[0094] Step B4: If the flag is N Flag =1, then the distance unit R is counted i The midpoint cloud belongs to the speed of the moving target, and the distance unit is R i The maximum velocity of a point cloud in the point cloud set is V max , the minimum speed is V min , calculate the speed difference V delta ;

[0095] Step B5: Based on the existing empirical threshold V Thre , when the speed difference V delta >V Thre When the speed flag is set to V Flag =1;

[0096] Step B6: If N Flag =1 and V Flag =1, then it is considered that the distance unit R i All moving targets on the image are reflection points caused by the air conditioner outdoor unit.

[0097] The air-conditioning outdoor unit reflection point recognition module of the air-conditioning outdoor unit reflection point recognition system based on millimeter-wave radar of the present invention adopts a strategy based on distance unit search and Doppler unit expansion, which can effectively target the scenario where the air-conditioning outdoor unit is a stationary object but there is a moving target in the reflected echo detection, and effectively target automobile application scenarios such as: preventing the reversing radar from misidentifying and the presence of moving targets in the FOV causing abnormal vehicle functions.

[0098] In addition, the maximum speed difference algorithm proposed in the present invention utilizes the accurate characteristic of radar speed measurement and the characteristic that stationary objects and moving targets in the spectrum can be clearly distinguished, thereby reducing the probability of misidentification. When updating and maintaining the algorithm, only the algorithm parameters need to be updated, and the algorithm has strong maintainability.

[0099] The air conditioner outdoor unit reflection point recognition system based on millimeter wave radar of the present invention only detects the point cloud of the target screened by the CFAR module, rather than the detection based on the spectrum, which simplifies the signal processing steps and greatly reduces the calculation and storage pressure of the lower computer under the condition of limited computing power of the current vehicle-mounted millimeter wave radar. If the target before CFAR screening is directly detected, the input at this time is the entire spectrum, the data storage pressure is large, and because the spectrum information contains useless information such as noise, the calculation efficiency is greatly reduced without CFAR screening, and the noise may cause misidentification.

[0100] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiments of the present invention can also be modified in various ways. All simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A millimeter-wave radar-based air conditioner outdoor unit reflection point recognition system, characterized in that: It includes a radar signal processing module, a stationary point judgment module and an air conditioner outdoor unit reflection point recognition module; The input data of the radar signal processing module is the echo signal of the transmitted signal, and the output data is the spectrum diagram and the point cloud therein; The stationary point determination module is configured to extract the radar measurement angle of the target and the radial velocity of the target after velocity resolution from the point cloud in the spectrum diagram, and determine the stationary target and its point cloud area in combination with the instrument speed of the vehicle; The air conditioner outdoor unit reflection point identification module is configured to measure the speed and distance relationship based on the frequency spectrum diagram, combined with the stationary target obtained by the stationary point judgment module. If the stationary target is located at a moving target, all moving targets at that location are judged as the air conditioner outdoor unit reflection point.

2. The air conditioner outdoor unit reflection point recognition system based on millimeter wave radar according to claim 1, characterized in that: The modulation mode of the millimeter wave radar is linear frequency modulation continuous wave, the input data of the radar signal processing module is the echo signal obtained by using the linear frequency modulation continuous wave as the transmission signal, and the point cloud includes the angle, distance and speed of all real targets.

3. The air conditioner outdoor unit reflection point recognition system based on millimeter wave radar according to claim 1, characterized in that: The radar signal processing module includes a spectrum diagram generation module, which samples the echo signal received by each transmission signal to obtain N sampling points, performs FFT along the sampling points to obtain distance dimension information, performs FFT processing on the same distance unit of the echo signals of M consecutive transmission signals to obtain speed dimension information, thereby forming a spectrum diagram, and the spectrum diagram includes the distance dimension information and speed dimension information of the radar target; the radar signal processing module also includes a constant false alarm detection module and a wave direction of arrival estimation module.

4. The air conditioner outdoor unit reflection point recognition system based on millimeter wave radar according to claim 1, characterized in that: The stationary point determination module is configured to perform the following steps: For each point cloud of the spectrum graph, the radar measurement angle M of the target corresponding to the point cloud is obtained from the radar signal processing module. R And get the radial velocity V of the target after velocity blurring real , according to the radial velocity V after the target velocity is resolved real and the vehicle's instrument speed V Ego The relationship between the target and the vehicle's horizontal axis is used to obtain the analytical value of the angle M F , according to the radar measurement angle M of the target R The analytical value M of the angle between the target and the vehicle's horizontal axis F To determine the target's motion state.

5. The air conditioner outdoor unit reflection point recognition system based on millimeter wave radar according to claim 4, characterized in that: The analytical value M of the angle between the target and the horizontal axis of the vehicle F for: Among them, V Ego is the instrument speed of the vehicle, V Real The radial velocity of the target after velocity blurring.

6. The air conditioner outdoor unit reflection point recognition system based on millimeter wave radar according to claim 4, characterized in that: According to the radar measurement angle M of the target R The analytical value M of the angle between the target and the vehicle's horizontal axis F To determine the target's motion state, specifically including: obtaining the radar measurement angle M R The analytical value M of the angle between the target and the vehicle's horizontal axis F The angle difference ΔM is used to compare the angle difference ΔM with the preset angle difference empirical threshold M. Thd Compare, if ΔM <M Thd , the target's motion state is judged to be stationary, otherwise the target's motion state is moving.

7. The air conditioner outdoor unit reflection point recognition system based on millimeter wave radar according to claim 1, characterized in that: The air conditioner outdoor unit reflection point recognition module is configured as follows: Step B1: Take a frame of spectrum, traverse the point cloud, select a stationary target whose echo signal is stronger than a certain intensity threshold as the reference point, and obtain the distance unit R where the reference point is located i ; Step B2: Traverse the point cloud and count all distance units in the point cloud set as R i The number of point clouds N T ; Step B3: Based on the existing empirical threshold N Thre , when the number of point clouds N T >N Thre When Flag =1, otherwise set to 0; Step B4: If the flag is N Flag =1, then the distance unit R is counted i The midpoint cloud belongs to the speed of the moving target, and the distance unit is R i The maximum velocity of a point cloud in the point cloud set is V max , the minimum speed is V min , calculate the speed difference V delta ; Step B5: Based on the existing empirical threshold V Thre , when the speed difference V delta >V Thre When the speed flag is set to V Flag =1; Step B6: If N Flag =1 and V Flag =1, then the distance unit R i All moving targets on the image are reflection points caused by the air conditioner outdoor unit.

8. A method for identifying reflection points of an air conditioner outdoor unit based on millimeter wave radar, characterized in that: include: Step S100: using a radar signal processing module to receive an echo signal of a transmitted signal, and outputting a spectrum diagram and a point cloud therein; Step S200: extracting the point cloud in the spectrum diagram using the stationary point determination module to obtain the radar measurement angle of the target and the radial velocity of the target after velocity defuzzification, and determining the stationary target and its point cloud area in combination with the instrument speed of the vehicle; Step S300: using the air conditioner outdoor unit reflection point identification module to measure the speed and distance relationship according to the spectrum diagram, combined with the static target obtained by the static point judgment module, if the static target is located at a location with a moving target, all moving targets at that location are judged as air conditioner outdoor unit reflection points.

9. The method for identifying reflection points of an air conditioner outdoor unit based on millimeter wave radar according to claim 8, characterized in that: The step S200 specifically includes: for each point cloud of the spectrum graph, obtaining the radar measurement angle M of the target corresponding to the point cloud from the radar signal processing module R And get the radial velocity V of the target after velocity blurring real , according to the radial velocity V after the target velocity is resolved real and the vehicle's instrument speed V Ego The relationship between the target and the vehicle's horizontal axis is used to obtain the analytical value of the angle M F , according to the radar measurement angle M of the target R The analytical value M of the angle between the target and the vehicle's horizontal axis F To determine the target's motion state.

10. The method for identifying reflection points of an air conditioner outdoor unit based on millimeter wave radar according to claim 8, characterized in that: The step S300 specifically includes: Step B1: Take a frame of spectrum, traverse the point cloud, select a stationary target whose echo signal is stronger than a certain intensity threshold as the reference point, and obtain the distance unit R where the reference point is located i ; Step B2: Traverse the point cloud and count all distance units in the point cloud set as R i The number of point clouds N T ; Step B3: Based on the existing empirical threshold N Thre , when the number of point clouds N T >N Thre When Flag =1, otherwise set to 0; Step B4: If the flag is N Flag =1, then the distance unit R is counted i The midpoint cloud belongs to the speed of the moving target, and the distance unit is R i The maximum velocity of a point cloud in the point cloud set is V max , the minimum speed is V min , calculate the speed difference V delta ; Step B5: Based on the existing empirical threshold V Thre , when the speed difference V delta >V Thre When the speed flag is set to V Flag =1; Step B6: If N Flag =1 and V Flag =1, then the distance unit R i All moving targets on the image are reflection points caused by the air conditioner outdoor unit.

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