Multi-radar detection system and method

Abstract

The present invention provides a multi-radar detection system, comprising: an operation unit, at least two radar units respectively connected to the operation unit by signal; the operation unit is provided with an independent trigger signal generating circuit; the radar unit is provided with a trigger signal sampler and a trigger signal register; the trigger signal sampler is used to sample the trigger signal and assign a value to the trigger signal register, and start collecting a frame of data according to the value of the trigger signal register. Multiple radar units can be synchronized by receiving trigger signals at the same time point, and the operation unit can obtain frame-synchronized radar data for processing, so that the azimuth information of the detected object is more accurate, and the improvement of angular resolution does not depend on the physical size of a single radar unit, which can further meet the demand for high angular resolution in applications. The multi-radar detection method provided by the present invention has corresponding advantages.

Description

Technical Field

[0001] The present invention belongs to the field of radar detection technology, and in particular relates to a multi-radar detection system and a detection method. Background Art

[0002] In radar detection applications, angular resolution is a crucial evaluation metric. Assuming an angular resolution of N degrees, two targets must be separated by at least N degrees for the radar to recognize them as two points. For example, a radar with an angular resolution of 5 degrees will produce an image of four points when viewing a target with a 20-degree field of view. If another radar with an angular resolution of 1 degree were to detect the same target, it would produce an image of 20 points, resulting in a higher "pixel count" of the image. The smaller the angular resolution, the greater the target detail and the clearer the image. Therefore, improving radar angular resolution is crucial for radar detection applications.

[0003] However, for a single radar, its angular resolution is limited by the radar antenna's aperture and wavelength. Given a fixed wavelength, practical limitations often prevent the radar antenna's aperture from being too large. Improving angular resolution by increasing the aperture has significant limitations. For example, a 77GHz angular radar typically has an aperture size of 50mm x 50mm. Assuming four receiving antennas, the angular resolution formula is ∆θ = λ / (Ndcosθ). Here, λ is the wavelength, d is the antenna spacing, and N is the number of receiving antennas. This yields an angular resolution of approximately 5 degrees horizontally and 5 degrees vertically. For a 24GHz radar, a 160mm aperture would be required to achieve a 5-degree resolution.

[0004] Existing technologies use MIMO antenna systems for single radars, reducing antenna size and increasing the number of antennas to improve radar angular resolution within a limited aperture. For detection systems composed of multiple radars, a preferred approach is to use synthetic aperture multi-radar systems, leveraging the relative motion of multiple radar units and the target to synthesize a radar with a larger equivalent antenna aperture using data processing methods, thereby improving angular resolution. However, these approaches still require increasing the aperture, resulting in numerous limitations in their implementation, and increasing the aperture size remains limited. With the rapid development of smart transportation and intelligent mobility, applications are now demanding higher requirements for radar angular resolution and other aspects. Advanced driving features, highly accurate traffic condition detection, security monitoring, and monitoring of passing vessels on rivers all require further improvements in radar performance. Taking assisted driving as an example, in the past and present, automotive radars have been limited to low-level assisted driving, which presents at least two limitations: First, low-level assisted driving can only play an auxiliary role and requires low resolution. Existing single radars can only meet the needs of situations where manual driving is the primary reliance. Second, low-level assisted driving automotive radars typically lack a unified computing unit to coordinate data processing across multiple radar units. Clearly, in the current context of the vigorous development of advanced assisted driving features, existing automotive radars no longer meet application requirements. The difficulty in improving radar angular resolution is a bottleneck in the development of advanced assisted driving features. Therefore, it is urgent to develop a method to improve radar angular resolution so that the improvement is not limited by the radar antenna aperture.

[0005] Based on the above, it can be seen that the existing radar detection technology has some shortcomings in application, such as: 1. Methods for improving angular resolution are limited by physical size and difficult to break through; 2. In the existing multi-radar detection system, each radar unit performs detection independently, and different radar units do not support simultaneous scanning. The performance of the multi-radar detection system is limited by the performance of a single radar unit, and its advantages are difficult to fully utilize. Summary of the Invention

[0006] The present invention aims to address all or part of the problems of the prior art described above. In one aspect, the present invention provides a multi-radar detection system that achieves multi-radar frame synchronization and improves angular resolution independent of the radar antenna aperture. In another aspect, the present invention provides a multi-radar detection method that is independent of the performance of a single radar unit, improves radar angular resolution, and optimizes system detection performance.

[0007] On one hand, the present invention provides a multi-radar detection system, comprising: an operation unit, and at least two radar units respectively connected to the operation unit by signal; the operation unit is provided with a data processing module, a configuration module, and an independent trigger signal generating circuit; the data processing module is used to receive radar data from the radar unit for processing and obtaining detection results; the configuration module is used to configure the parameters of the trigger signal generating circuit; the trigger signal generating circuit is respectively connected to the radar units by signal, and is used to generate and send a trigger signal; the radar unit is provided with a trigger signal sampler, a trigger signal register, a radar core module and an antenna array; the trigger signal sampler is used to sample the trigger signal and assign a value to the trigger signal register; the antenna array is used to detect multiple objects; and the radar core module is used to start collecting a frame of data according to the value of the trigger signal register.

[0008] The arithmetic unit is configured with an independent trigger signal generation circuit. The radar unit, through a trigger signal sampler and a trigger signal register, can sample the trigger signal and then set the value of the trigger register. The arithmetic unit can send a frame trigger signal to all radar units at the same time, and all radar units can collect data upon receiving the frame trigger signal. The radar units each detect multiple objects through the antenna array to generate data. The radar core module sends a frame of synchronously collected data to the data processing module, enabling data fusion of the simultaneously acquired detection results.

[0009] The multi-radar detection system of the present invention supports frame time synchronization triggered by multiple radar units. Data acquired by different radar units can be fused together through a computing unit. By fusing data acquired by different radar units at the same time, a more accurate angle of the detected object can be calculated, achieving higher angular resolution. Compared to relying on software for synchronization control, the software stack architecture is complex, requiring complex processes to be called for synchronization control, and multiple indirect steps are involved in achieving synchronization. If any step fails, synchronization fails, which is very disadvantageous for multi-radar detection systems that require frequent detection. However, the multi-radar detection system of the present invention, through the configuration of the computing unit and the radar units, directly implements the synchronous acquisition of a frame of radar data controlled by a trigger signal in hardware. This fully determines the time to trigger data acquisition by different radar units, maintains accurate synchronization of each data acquisition during use, and offers high operational stability and a low probability of error.

[0010] The trigger signal generating circuit and the radar unit transmit the trigger signal via a separate line.

[0011] The signal connection method between the operation unit and the radar unit includes: superimposing the trigger signal on the data signal and transmitting them together through the same line; the radar unit is also provided with a signal extraction circuit for extracting the trigger signal and sampling it to the trigger signal sampler; the data signal includes a differential signal, and the trigger signal includes a common mode signal superimposed on the differential signal.

[0012] The signal connection between the operation unit and the radar unit can be flexibly arranged based on the actual product structure design or the spatial layout of multiple radar units. A separate line can be used to transmit the trigger signal generated by the trigger signal generating circuit to the radar unit, while other data signal transmissions between the radar unit and the operation unit are implemented via another line. The radar unit can directly obtain the trigger signal for sampling, thereby improving signal processing efficiency. In some cases, to simplify the design of the signal line, the trigger signal and other conventional data signals are transmitted through the same line. This also facilitates the modification of the existing multi-radar detection system to realize the function of the operation unit sending trigger signals to each radar unit at the same time point for data frame synchronization, making full use of existing equipment and lines.

[0013] The radar units are millimeter-wave radars; different radar units have antenna arrays that emit different scanning signals; these scanning signals include frequency-division signals and code-division signals. Multiple radar units can use different signal formats when performing simultaneous scanning detection, or they can use the same signal format but with different characteristic parameters for the different scanning signals. For example, for a continuously frequency-modulated radar, the different scanning signals have different frequency bands, while for a code-division-modulated radar, different codes can be used. Using different scanning signals can further reduce crosstalk between the data collected by the multiple radar units, thereby improving detection accuracy.

[0014] The radar unit is also equipped with a counting module for counting frames and adding a frame sequence number to each frame of data. When the computing unit receives multiple frames of data from multiple radar units, when performing data fusion, the computing unit needs to match the simultaneously collected frames of data, obtain the frame sequence number through the counter, and add the sequence number to the frame data, so that the computing unit can accurately match the sequence number of each frame of data.

[0015] Another aspect of the present invention provides a multi-radar detection method, which is performed using the multi-radar detection system of the present invention, including: an operation unit controlling multiple radar units to synchronously collect radar data and obtain frame-synchronized radar data; matching the same target object detected by different radar units; and calculating the target arrival angle of the multi-radar detection system based on the frame-synchronized radar data of the target object and external parameters of at least two of the radar units; wherein the radar data includes image information and motion information.

[0016] By controlling multiple radar units through the operation unit to achieve data frame synchronization, radar data detected by different radar units at the same time point are obtained, and the operation unit obtains the frame-synchronized data for matching, and can match the same target object identified by different radar units one-to-one, thereby obtaining radar data of the same target object detected by different radar units at the same time point. By using the frame-synchronized radar data of the same target object by different radar units and combining the known external parameters of each radar unit, the target arrival angle of the multi-radar detection system when detecting the target object can be more accurately calculated, and the target object can be detected more accurately relative to the multi-radar detection system. The angular resolution of the multi-radar detection system is improved and is not limited by the physical size of a single radar unit. By using the multi-radar detection method of the present invention, the more radar units there are, the more accurate the calculation is, and the angular resolution of the multi-radar detection system can be further improved to meet the needs of practical applications.

[0017] The method of controlling multiple radar units to synchronously collect radar data by the operation unit includes: presetting the time point of each frame scanning; the operation unit is provided with a timing control module to achieve clock synchronization with the multiple radar units; the clock-synchronized radar units scan at the same time point and collect a frame of data.

[0018] The method in which the operation unit controls multiple radar units to synchronously collect radar data includes: the operation unit sends a trigger signal to different radar units at the same time point, and the radar unit scans and collects a frame of data when receiving the trigger signal.

[0019] In some cases, the radar unit receives the trigger signal by extracting the trigger signal and sampling the trigger signal.

[0020] The method of obtaining the frame-synchronized radar data includes: the operation unit sends a handshake signal to the radar unit for handshake, and then sends a startup sequence; after receiving the startup sequence, the radar unit starts counting frames as frame numbers; the radar unit puts the frame number in each frame of radar data and sends it back to the operation unit.

[0021] The operation unit and the radar unit shake hands and send the start sequence according to a preset period. The handshake does not need to be too frequent, and can be once every second or every few seconds, without limitation.

[0022] The computing unit sends a special sequence of trigger signals to each radar for handshake. After the handshake is complete, it issues a special startup sequence. After receiving this startup sequence, each radar begins counting frames, which are used as frame numbers and are included in each frame of radar data and returned to the computing unit. In different application scenarios, when different radar units transmit their radar data to the same computing unit at significantly different times, identifying each frame of data with a frame number can further ensure accurate matching of radar data collected simultaneously by multiple radar units.

[0023] The method of matching the same target object includes: performing point cloud matching based on frame-synchronized image information and motion information collected by different radar units to obtain a one-to-one correspondence between objects detected by different radar units; the image information includes: a point cloud map and a depth map; the motion information includes the object's movement speed.

[0024] When calculating the target arrival angle for the multi-radar detection system, the known extrinsic parameters of the radar units include the orientation of the radar units, the aperture of the antenna array, and the distance between the radar units. The process of calculating the target arrival angle of the multi-radar detection system includes: step S1. calculating the target arrival angle of any of the radar units using frame-synchronized radar data of the target object and the extrinsic parameters of at least two of the radar units; step S2. obtaining the target arrival angle of the multi-radar detection system by coordinate conversion.

[0025] In some embodiments, in step S1, the target arrival angle of the target object relative to any radar unit is calculated based on the distances to the target object detected by different radar units and the distances between the radar units. The angular resolution of a single radar unit is limited by its physical size, an objective limitation that cannot be overcome. However, range resolution is not limited by physical size and other factors, but depends solely on the circuit design and configuration within the radar unit. By designing or configuring the radar units to have a relatively high range resolution, the angular resolution of coordinated detection by multiple radars can be further improved.

[0026] The frame-synchronized radar data includes the target arrival angle collected by a single radar unit. After step S1, the calculated target arrival angle of the radar unit is verified to be reasonable using the frame-synchronized radar data. Comparing the detection results of the single radar unit can verify the calculated result, further improving the reliability of the calculated result.

[0027] The multi-radar detection method further includes: performing statistical calculations to establish a distribution curve of target arrival angle calculation errors for the multi-radar detection system using the range resolution of the radar units and external parameters of the radar units as variables; and setting a threshold for the range resolution of the radar units based on the distribution curve. The statistical calculations determine the impact of an error in a variable on the target arrival angle calculation result of the multi-radar detection system. Based on this information and in combination with actual application requirements for the accuracy of the target arrival angle calculation result of the multi-radar detection system, an allowable error range for the variables involved in the calculation is determined. Radar units that meet application requirements can be configured based on the threshold.

[0028] Configuring the range resolution of the radar units of the multi-radar detection system based on the threshold value is beneficial to effectively optimizing the angular resolution of the multi-radar detection system and guiding the design of the multi-radar detection system in practical applications.

[0029] Compared with the prior art, the present invention has the following main beneficial effects:

[0030] 1. A multi-radar detection system of the present invention is provided with an independent trigger signal generating circuit through a computing unit. The radar unit is provided with a trigger signal sampler and a trigger signal register. Each radar unit can synchronize by receiving a trigger signal at the same time point. The computing unit can obtain frame-synchronized radar data for processing, and can more accurately obtain the azimuth information of the detected object. This is independent of the physical size of a single radar unit and can further meet the demand for higher angular resolution in applications.

[0031] 2. The multi-radar detection method of the present invention calculates the target object's position by controlling multiple radar units to synchronize data acquisition and processing frame-synchronized radar data. This method can improve the angular resolution of the multi-radar detection system to meet practical application needs without being limited by the physical size of a single radar unit, providing a solution for the design optimization and effective application of multi-radar detection systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of a multi-radar detection system according to embodiment 1 of the present invention.

[0033] Figure 2 Schematic diagram of a multi-radar detection method according to a second embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of the implementation of the angle enhancement algorithm of the second embodiment of the present invention.

[0035] FIG4 (a) and FIG4 (b) are schematic diagrams of application scenarios of the second embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the specific embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0037] In the following embodiments, the operations of the embodiments are described in a specific order. The description of these orders is for a better understanding of the details in the embodiments so as to fully understand the present invention. However, the description of these orders does not necessarily correspond one-to-one to the methods of the present invention, nor can it be used to limit the scope of the present invention.

[0038] Example 1

[0039] In the first embodiment of the present invention, Figure 1 As shown, the multi-radar detection system provided includes: an operation unit, two radar units respectively connected to the operation unit by signal; the operation unit is provided with a data processing module, a configuration module, and an independent trigger signal generating circuit. The data processing module is used to receive radar data from the radar unit for processing and obtain detection results. The configuration module is used to configure the parameters of the trigger signal generating circuit. The trigger signal generating circuit is respectively connected to the radar units by signal, and is used to generate and send a trigger signal to each radar unit. The radar unit is provided with a trigger signal sampler, a trigger signal register, a radar core module and an antenna array; the trigger signal sampler is used to sample the trigger signal and assign a value to the trigger signal register. The antenna array is used to detect multiple objects. The radar core module starts to collect a frame of data according to the value of the trigger signal register. In order to simplify the drawings, Figure 1 While two radar units are used as an example, in actual applications, more radar units can be used, and their layout is based on the actual application space, and there is no limitation. Multiple radar units are controlled by the computing unit to achieve frame synchronization of trigger signals. The computing unit's data processing module processes the synchronized data from multiple radar units, further optimizing the accuracy of detection results.

[0040] In this embodiment, the operation unit is provided with an independent trigger signal generating circuit to ensure that the trigger signal can be stably issued (for example, when the operation unit is busy, the trigger signal is not affected). The operation unit configures the parameters of the trigger signal generating circuit through the configuration module. Figure 1In the example scenario, the signal connection between the operation unit and the radar unit is achieved through a data line, which transmits the radar data signal and the trigger signal. Specifically, the radar data is transmitted using a differential signal, and the common-mode signal superimposed on it is the trigger signal. The radar unit is also provided with a signal extraction circuit for extracting the trigger signal and sampling it to the trigger signal sampler. The original differential data lines of the conventional multi-radar system are reused, and the trigger signal is superimposed. At the receiving end of the radar unit, this common-mode signal is extracted by the signal extraction circuit and then transmitted to the trigger signal sampling module for sampling. In some embodiments, it is also possible to superimpose the trigger signal using a differential signal. For example, if some radar data signals are AC signals, then the trigger signal can be transmitted using a DC signal superimposed on it. The trigger signal data volume is very small and can be transmitted in a relatively slow manner. Therefore, it can be transmitted using one data channel, and the signal superposition method is not limited here.

[0041] In some other examples, a separate trigger signal line is used to transmit the trigger signal between the operation unit and the radar unit. The radar unit does not set a signal extraction circuit, directly samples the trigger signal, and then sets a trigger register to assign a value. Then, the radar core module starts to collect a frame of data according to the value of the trigger register and is not limited.

[0042] In this embodiment, since different radar units scan simultaneously, different scanning signals are used to reduce crosstalk. For continuous frequency modulation radars, different frequency bands can be used, while for code division modulation radars, different codes can be used, though this is not a limitation. In some embodiments, time-division signals can be used, with a slight time offset (for example, 5µs) to reduce crosstalk between different radar units.

[0043] In this embodiment, the radar unit's antenna array can detect multiple objects, and a single radar unit supports multiple antennas. The antenna array can be arranged horizontally with a spacing of half a wavelength. Such an antenna array can maximize the horizontal angular resolution of a single radar unit.

[0044] In this embodiment, the operation unit directly matches the radar data transmitted by each radar unit using the frame sequence number. In the exemplary embodiment, the radar unit is also provided with a counting module for counting frames and adding the frame sequence number to each frame of data. The operation unit sends a preset sequence of trigger signals as a handshake signal to each radar unit for handshake. After the handshake is completed, the operation unit then issues a preset start sequence. After receiving this start sequence, each radar unit begins counting frames and adds the frame sequence number to each frame of radar data and returns it to the operation unit. When specific factors such as the transmission medium or transmission space between different radar units and the operation unit affect the time when data arrives at the operation unit, even if the data arrival time varies significantly, the accuracy of the frame matching in the exemplary embodiment will not be affected, and the reliability is good.

[0045] In some examples, the computing unit matches the data transmitted by each radar unit by determining the arrival time of the data. If the arrival times are similar, they are considered to be a frame of data at the same time. The specific method is not limited.

[0046] Example 2

[0047] The second embodiment is used to illustrate a detection method using the multi-radar detection system of the first embodiment, so as to facilitate a comprehensive understanding of the present invention by those skilled in the art, but does not limit the present invention in any form.

[0048] The multi-radar detection method of this embodiment is as follows: Figure 2 As shown, the system includes: a computing unit controlling multiple radar units to synchronously collect radar data and obtain frame-synchronized radar data; matching the same target object detected by different radar units; and calculating the target arrival angle of the multi-radar detection system based on the frame-synchronized radar data of the target object and the external parameters of the two radar units. Matching can be performed between more radar units. The illustrative method uses a minimum of two radar units. Using more radar units, other conditions being equal, can achieve more accurate detection results. The number of radar units is not limited.

[0049] In some embodiments, the computing unit controls multiple radar units to synchronously collect radar data by presetting a scanning time for each frame. The computing unit includes a timing control module to synchronize clocks with the multiple radar units. The clock-synchronized radar units scan at the same time and collect a frame of data.

[0050] In this embodiment, the computing unit controls multiple radar units to synchronously collect radar data by sending a trigger signal to each radar unit at the same time. Upon receiving the trigger signal, each radar unit scans and collects a frame of data. The radar units receive the trigger signal by first extracting the trigger signal, then sampling the trigger signal and assigning a value to a trigger signal register. In some implementations, the trigger signal is transmitted via a separate data line, eliminating the extraction process and directly acquiring the trigger signal for sampling. This is not a limitation here.

[0051] In this embodiment, the process of acquiring frame-synchronized radar data includes: the operation unit sends a handshake signal to the radar unit, followed by a startup sequence; upon receiving the startup sequence, the radar unit begins counting frames, which serve as frame numbers; and the radar unit includes the frame numbers in each frame of radar data and transmits them back to the operation unit. In the example, the handshake between the operation unit and the radar unit and the sending of the startup sequence occur at a preset interval, exemplified by a 5-second period. Through the handshake and startup sequence, the operation unit can accurately match the received radar data. Accurately matching frame-synchronized radar data improves the reliability of subsequent data processing.

[0052] In this embodiment, matching the same target object involves performing point cloud matching based on frame-synchronized image information and motion information collected by different radar units, thereby obtaining a one-to-one correspondence between the objects detected by the different radar units. Image information includes a point cloud image and a depth map. Motion information includes the object's velocity.

[0053] In an example scenario, two radar units scan the physical world together. The distance between the two radar units, their orientation, and the aperture of the antenna array are known. The distance between the radar units in the example refers to the distance between the edge antennas in the two antenna arrays. The orientation of the radar units represents the relative angle between the radar receiving surfaces. The radar unit in the example is a 77GHz millimeter-wave radar. The aperture of a single radar unit is 50mm, which has the ability to detect multiple objects. The collected radar data contains information such as the angle, distance, and movement speed of the object. The specific frequency band of the millimeter-wave radar is not limited here.

[0054] The radar core modules of the two radar units each generate a point cloud map based on their antenna array scans. The point cloud map can be either two-dimensional or three-dimensional. The frame-synchronized images captured by the two radar units are matched to identify one-to-one correspondences between objects. The point cloud matching algorithm used in this example is the Iterative Closest Point (ICP) algorithm or the Normal Distribution Transform (NDT) algorithm. In this embodiment, velocity is also considered a matching dimension during point cloud matching. Each millimeter-wave radar can rank each detected object in its point cloud map. For example, if one radar unit detects objects A1 through AN, and another radar unit detects objects B2 through BN, then after the ranking is complete, the closest object in A1 and B2 through BN is considered the same object. In the case of multiple radar units, a target object in one point cloud map can be matched to objects in multiple point clouds.

[0055] The matched objects, their distances to the respective radar units, and their target arrival angles are combined with the radar unit's external parameters (in this example, the distance and orientation between radar units, and the aperture of the antenna array) to calculate a more accurate target arrival angle for the target object for any radar unit. This example uses an angle enhancement algorithm that fully utilizes the advantage of the radar unit's high range resolution. This algorithm requires relatively low computing power resources to implement, and only requires synchronization of radar unit scanning frames. Figure 3 As shown, the calculation uses the formula: . Step S1. Using the distance c between the two radar units P and Q, and the distances b and c from the target object to the two radar units P and Q respectively, the target arrival angle β of the target object detected by the radar unit P is calculated to be equal to 90°-α by the formula. Step S2. Given the distance between the radar unit P and the radar unit Q, the target arrival angle of the target object detected by the dual radar detection system can be obtained by performing coordinate transformation. In the example case, the target arrival angle β of the target object detected by the radar unit P is calculated for coordinate transformation. The target arrival angle of the target object detected by the radar unit Q can also be calculated for coordinate transformation, and the coordinate transformation is not limited thereto.

[0056] The angular resolution of a multi-radar detection system consisting of radar units P and Q can be further improved. By performing point cloud matching based on the frame-synchronized imagery and motion information collected by the different radar units, a more accurate target arrival angle can be calculated. For example, if the derivative of the formula is calculated with respect to b, the value obtained is minimized when b = c. This means that for a single target object, the optimal radar unit position is one where the distance from the target to one of the radar units is equal to the distance between the two radar units. The formula in the above example is simplified for ease of understanding. In actual applications, the calculation may involve more parameters and calculation steps. For example, the antenna array designs of the radar units may vary, with some having larger apertures and others smaller. When radar units with different antenna array designs are combined to achieve improved resolution, the antenna array aperture must be considered as a calculation parameter. In this example, the two radar units P and Q are relatively stationary, and the target object's velocity relative to each radar unit is the same. In other cases, where multiple radar units are in relative motion, the velocity of the target detected by each radar unit must also be calculated as a parameter.

[0057] In the example case, after step S1, the target arrival angle calculated by the radar unit is verified to be reasonable through the frame-synchronized radar data. The three dimensions of information in the frame-synchronized radar data, namely the distance from the target object to the single radar unit, the speed of movement, and the target arrival angle detected by the single radar unit, are crucial when performing point cloud matching. After the matching is completed, in the example case, only the distance from the target object to the single radar unit and the distance between the radar units are needed to further calculate a more accurate target arrival angle. The target arrival angle detected by a single radar unit can be used for quality control. Although the angular resolution of the target arrival angle detected by radar units P and Q is not optimal compared to the entire multi-radar detection system, the approximate direction of the target object can be known through the target arrival angle detected by radar units P and Q, thereby verifying whether the calculation result is reasonable.

[0058] In this embodiment, the multi-radar detection method further includes: performing statistical calculations to establish a distribution curve for the target arrival angle calculation error of the multi-radar detection system using the range resolution of the radar units and the external parameters of the radar units as variables; and setting a threshold for the range resolution of the radar units based on the distribution curve. Statistical analysis can be used to determine the impact of the layout of individual radar units and the range resolution settings of the individual radar units on the overall angular resolution of the multi-radar detection system. By setting the range resolution threshold for individual radar units, radar units that meet the threshold can be configured to optimize the detection accuracy of the multi-radar detection system, given a fixed layout of individual radar units.

[0059] In this example, using the above angle formula, we add an evenly distributed error to the distances b and c. The statistical method uses an evenly distributed error: for example, if the error is between + / - 1 cm, then a evenly distributed error means that any point between +1 and -1 cm is equally likely. In this example, the range error of a single radar unit is evenly distributed within half of the radar unit's range resolution. Statistical calculations then yield the resulting calculated error distribution for the target arrival angle of the multi-radar system, as shown in Table 1 below.

[0060] Table 1. Calculation error data

[0061]

[0062] Taking the calculation error less than 5 degrees as an example, when the distance between radar units is 1 meter, the radar units with a distance resolution that satisfies the distance error within 0.015 meters are configured, and the angular resolution of the multi-radar detection system can be further optimized.

[0063] Referring to Figures 4(a) and 4(b), in practical applications, when the exemplary multi-radar detection method is applied to a corner radar system on a vehicle, the radar units are generally arranged as shown in Figure 4(a). The distance X between the forward corner radars is generally about 2 meters, and the distance Y between the side corner radars is generally 4 meters. This limits the distance error of a single radar unit to within 0.015 meters, and the forward resolution can reach 0.8 degrees and the side resolution can reach 0.4 degrees.

[0064] An example multi-radar detection method is applied in traffic detection. As shown in Figure 4(b), the distance D between two radar units installed on an overpass or aerial suspension can be set larger, typically greater than 10 meters. This allows the angular resolution of the multi-radar detection system composed of two radar units to be improved to 0.2 degrees. In some cases, the radar units use mainstream continuous frequency modulation radars. The radar's range resolution is related to the radar's frequency modulation bandwidth. Increasing the radar's frequency modulation bandwidth allows for faster frequency modulation of individual radar units. Given a fixed distance between radar units, the multi-radar detection system can achieve higher angular resolution and more accurate detection. By rationally arranging the positions of multiple radar units and adjusting their range resolution, the angular resolution of the multi-radar detection system can be further improved to meet practical application requirements. This improvement in angular resolution is not limited by the physical size of a single radar unit.

[0065] The above embodiments are only intended to help understand the method and core concept of the present invention. For those skilled in the art, without departing from the principles of the present invention, several improvements and modifications may be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A multi-radar detection system comprising: An operation unit and at least two radar units respectively connected to the operation unit; characterized in that: the operation unit is provided with a data processing module, a configuration module, and an independent trigger signal generating circuit; The data processing module is used to receive radar data from the radar unit for processing and obtaining detection results; the configuration module is used to configure parameters of the trigger signal generating circuit; the trigger signal generating circuit is signal-connected to the radar unit and is used to generate and send a trigger signal; The radar unit is provided with a trigger signal sampler, a trigger signal register, a radar core module and an antenna array; the trigger signal sampler is used to sample the trigger signal and assign a value to the trigger signal register; the antenna array is used to detect multiple objects; the radar core module is used to start collecting a frame of data according to the value of the trigger signal register.

2. The multi-radar detection system according to claim 1, characterized in that: The trigger signal generating circuit and the radar unit transmit the trigger signal via a separate line.

3. The multi-radar detection system according to claim 1, characterized in that: The signal connection method between the operation unit and the radar unit includes: superimposing the trigger signal on the data signal and transmitting them together through the same line; The radar unit is further provided with a signal extraction circuit for extracting the trigger signal and sampling it to the trigger signal sampler; the data signal includes a differential signal, and the trigger signal includes a common mode signal superimposed on the differential signal.

4. The multi-radar detection system according to claim 1, characterized in that: The radar unit is further provided with a counting module for counting frames and adding the frame sequence number to each frame of data.

5. The multi-radar detection system according to any one of claims 1 to 4, characterized in that: The radar unit is a millimeter-wave radar; the antenna arrays of different radar units emit different scanning signals; the scanning signals include frequency-division signals and code-division signals.

6. A multi-radar detection method, characterized in that: The method is carried out by using the multi-radar detection system according to any one of claims 1 to 5, comprising: a computing unit controlling the multiple radar units to synchronously collect radar data and obtaining frame-synchronized radar data; matching the same target object detected by different radar units; Calculating a target arrival angle of the multi-radar detection system based on the frame-synchronized radar data of the target object and extrinsic parameters of at least two of the radar units; The radar data includes image information and motion information.

7. The multi-radar detection method according to claim 6, characterized in that: The method of controlling multiple radar units to synchronously collect radar data by the operation unit includes: presetting the time point of each frame scanning; the operation unit is provided with a timing control module to achieve clock synchronization with the multiple radar units; the clock-synchronized radar units scan at the same time point and collect a frame of data.

8. The multi-radar detection method according to claim 6, characterized in that: The method in which the operation unit controls multiple radar units to synchronously collect radar data includes: the operation unit sends a trigger signal to different radar units at the same time point, and the radar unit scans and collects a frame of data when receiving the trigger signal.

9. The multi-radar detection method according to claim 8, characterized in that: The method of the radar unit receiving the trigger signal includes: extracting the trigger signal and sampling the trigger signal.

10. The multi-radar detection method according to claim 8, characterized in that: The method of obtaining the frame-synchronized radar data includes: the operation unit sends a handshake signal to the radar unit for handshake, and then sends a startup sequence; after receiving the startup sequence, the radar unit starts counting frames as frame numbers; the radar unit puts the frame number in each frame of radar data and sends it back to the operation unit.

11. The multi-radar detection method according to claim 10, characterized in that: The handshake between the operation unit and the radar unit and the sending of the start sequence are performed according to a preset cycle.

12. The multi-radar detection method according to claim 6, characterized in that: The method of matching the same target object includes: performing point cloud matching based on frame-synchronized image information and motion information collected by different radar units to obtain a one-to-one correspondence between objects detected by different radar units; the image information includes: a point cloud map and a depth map; the motion information includes the object's movement speed.

13. The multi-radar detection method according to claim 6, characterized in that: When calculating the target arrival angle of the multi-radar detection system, the known external parameters of the radar units include the orientation of the radar units, the aperture of the antenna array, and the distance between the radar units; The process of calculating the target arrival angle of the multi-radar detection system includes: step S1. calculating the target arrival angle of any radar unit using frame-synchronized radar data of the target object and external parameters of at least two radar units; Step S2: coordinate conversion to obtain the target arrival angle of the multi-radar detection system.

14. The multi-radar detection method according to claim 13, characterized in that: The frame-synchronized radar data includes a target arrival angle collected by a single radar unit; after step S1, the target arrival angle of the radar unit calculated is verified to be reasonable using the frame-synchronized radar data.

15. The multi-radar detection method according to claim 13, characterized in that: Also includes: Perform statistical calculations to establish a distribution curve of a target arrival angle calculation error of the multi-radar detection system using the range resolution of the radar unit and an external parameter of the radar unit as variables; and set a threshold value of the range resolution of the radar unit based on the distribution curve.

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