Vehicle backward anti-collision early warning device and method

Abstract

The invention discloses a vehicle backward anti-collision early warning device and method. The vehicle backward anti-collision early warning device comprises a sensor module, a data processing module, a communication module and an early warning module. The sensor module is connected with the data processing module, the data processing module is connected with the communication module, the communication module is connected with the early warning module and a CAN bus interface of a vehicle, and the sensor module is integrated in a shark fin structure shell at the top of the vehicle; the sensor module comprises a single-point laser sensor and an angle detection device; according to the invention, high-precision detection of rear large vehicles is realized through a dynamic angle threshold technology and dual-mode judgment logic. The device is integrated in the shark fin shell, is compatible with an original vehicle structure, has the advantages of low cost, high reliability and the like, and can effectively reduce the accident risk of rear-end collision caused by large vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle active safety, and in particular to a vehicle rearward anti-collision warning device and method. Background Art

[0002] The vehicle rear collision warning system is a key technology to improve driving safety. Its core task is to accurately identify large vehicles approaching quickly from behind to reduce the risk of serious rear-end collisions. Among existing technologies, millimeter-wave radar, solid-state laser radar, camera and rotating laser radar have significant limitations in practical applications.

[0003] For example, millimeter-wave radar is easily interfered by signals from vehicles in adjacent lanes in low-speed scenarios, making it difficult to accurately distinguish targets behind the lane from those behind the adjacent lanes; solid-state laser radar has high-precision detection capabilities, but its multi-wire design makes it bulky and expensive, making it difficult to adapt to small and medium-sized vehicles; the camera solution is significantly affected by ambient light and rainy and foggy weather, with a sharp drop in imaging quality and large ranging errors; and although the rotating laser radar can achieve wide-area scanning, its installation requires the modification of the roof structure, consumes too much power and lacks concealment, making it difficult to meet the requirements of economy and vehicle appearance integration. Therefore, it is necessary to propose a vehicle rearward collision warning device and method to solve the above problems. Summary of the invention

[0004] The object of the present invention is to provide a vehicle rearward collision avoidance warning device and method, so as to achieve accurate detection of large vehicles behind the vehicle while ensuring seamless integration with the vehicle appearance.

[0005] In a first aspect, the present invention provides a vehicle rearward collision avoidance warning device, comprising: a sensor module, a data processing module, a communication module and a warning module; the sensor module is connected to the data processing module, the data processing module is connected to the communication module, the communication module is connected to the warning module and a CAN bus interface of the vehicle, and the sensor module is integrated inside a shark fin structure housing on the top of the vehicle;

[0006] The sensor module includes a single-point laser sensor and an angle detection device, wherein the single-point laser sensor is used to emit a 905nm wavelength laser beam and measure the real-time distance S between the vehicle and the target vehicle behind based on the time-of-flight method, and the angle detection device is used to monitor the angle α between the laser beam and the horizontal plane in real time;

[0007] The data processing module is used to obtain the vehicle speed V through the CAN bus. 1 , the speed V of the target vehicle behind is calculated by the difference of the real-time distance S 2 , calculate the dynamic angle threshold α 1 And the collision time TTC, and according to V 1 、V2 , S, α, α 1 , the TTC value executes the warning judgment of the low-speed warning mode and the high-speed warning mode;

[0008] The communication module is used to obtain the vehicle speed V 1 and gear position signal, at the vehicle speed V 1 and the gear position signal meets the preset conditions, activating the warning judgment of the vehicle rearward collision warning device, and transmitting the control command of the data processing module to the warning module;

[0009] The warning module is used to trigger a vehicle rear collision warning according to a control instruction of the data processing module.

[0010] Furthermore, the shark fin structure shell includes a three-layer gradient composite structure:

[0011] The outer layer is a carbon fiber reinforced PEEK layer with a thickness of 0.8mm±0.05mm and a surface roughness of Ra≤0.8μm; the curvature radius of the windward surface is R 1 =120mm±5mm, leeward curvature radius R 2 =80mm±3mm;

[0012] The middle layer is a nano-aerogel insulation layer with a porosity of 92% ± 1% and a thickness of 2.5 mm ± 0.1 mm;

[0013] The inner layer is a 6061-T6 aluminum alloy substrate with an anodized film thickness of 25μm±2μm.

[0014] Furthermore, a thermally conductive silicone layer is provided on the aluminum alloy substrate. The thermally conductive silicone layer has a thickness of 3mm±0.2mm, contains 30% volume fraction of aluminum nitride particles, and has a particle size of D50=8μm±1μm. A concentration gradient is formed along the heat dissipation direction, 35%±2% on the laser side and 25%±2% on the shell side.

[0015] Furthermore, the three-layer composite structure is manufactured by a gradient sintering process, and the sintering temperature curve adopts a three-stage heating process of 300°C, 420°C, and 580°C; the thickness of the interlayer transition layer is 50±5μm; and the cooling rate is 8°C / min±0.5°C.

[0016] Further, the single-point laser sensor emits a PRBS9 coded pulse laser with a wavelength of 905nm±5nm, a pulse width of 5ns±0.3ns, and a duty cycle of 1%-3%;

[0017] The laser pulse emission elevation angle range is 1-2.5°; the built-in aspheric lens group has a curvature radius of R 3 =12.5mm±0.1mm, R 4=-18.3mm±0.1mm, ZF52 glass material, refractive index nd=1.6725±0.0002; the resolution of the angle detection device is ±0.1°.

[0018] In a second aspect, the present invention provides a vehicle rearward collision warning method, which is used in the vehicle rearward collision warning device described above, comprising:

[0019] Step 1: When the vehicle is in the D / N / P gear and meets any of the following speed conditions, the vehicle rearward collision warning method is activated: 0km / h≤V1<15km / h, V 1 ≥50km / h;

[0020] Step 2: Get the vehicle speed V 1 , the real-time distance S between the vehicle and the target vehicle behind, the angle α between the laser beam of the single-point laser sensor and the horizontal plane; the speed V of the target vehicle behind is calculated by the difference of the real-time distance S 2 , calculate the dynamic angle threshold α 1 and time to collision TTC;

[0021] Step 3: According to V 1 、V 2 , S, α, α 1 , TTC value executes warning judgment of low-speed warning mode and high-speed warning mode.

[0022] Furthermore, in step 2,

[0023] Calculate the dynamic angle threshold α according to α1=arctan((h_target-H) / S) 1 , where h_target is the maximum height of the car that is expected to be filtered out, h_target ≥ 2.6m, and H is the installation height of the single-point laser sensor, H ≥ 1.5m;

[0024] According to TTC = S / (V 2 -V 1 )Calculate the collision time TTC.

[0025] Furthermore, in step three,

[0026] 0≤V 1 <15km / h is low speed warning mode; in low speed warning mode, if both of the following conditions are met: 40m <S<55m、ΔV> 11.1m / s, α>α 1 When the vehicle rear collision warning is triggered;

[0027] V 1 ≥50km / h is high-speed warning mode; in high-speed warning mode, when both of the following conditions are met: 20m <S<55m、TTC≤4s、α> α1 The vehicle rear collision warning is triggered.

[0028] Furthermore, the data processing module executes a Doppler frequency shift compensation algorithm, and the compensation amount Δf=2V 1 cosα / λ, where λ is the wavelength; and a matched filter is used: h(n)=s(N-1-n)*, where h(n) is the coefficient sequence of the matched filter, N is the total length of the pseudo-random binary sequence PRBS9, n is a discrete time variable representing the sequence number of the signal sampling point, s(n) is the PRBS9 sequence, and * represents a conjugate operation.

[0029] Furthermore, if α≤α for three consecutive times within the sampling period of 100ms 1 , disable the warning for 0.5 seconds.

[0030] The present invention has the following beneficial effects: The present invention realizes lossless integration of the sensor and the vehicle appearance by innovatively integrating the single-point laser sensor with the shark fin housing, significantly reducing the size of the device while avoiding modifications to the vehicle body structure, and combining concealment with vehicle appearance integrity. The lightweight hardware architecture is used to optimize manufacturing costs, and combined with the real-time comparison mechanism of dynamic angle thresholds, it can accurately filter interference signals from low vehicles, effectively solving the problem of misjudgment caused by insufficient target height discrimination capabilities in traditional solutions. Through dual-speed interval division and differentiated warning logic design, the system takes into account multiple scenario requirements such as low-speed parking, high-speed congestion and fast driving, and stably identifies the rapid approaching threat of large vehicles from behind under complex working conditions. At the same time, based on the dynamic calibration of the laser angle and the Doppler compensation algorithm, the system further improves the ranging accuracy and anti-interference capability under different vehicle speeds and road conditions, achieves all-weather high-reliability warnings, and provides an economical and efficient solution for vehicle rear safety protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a schematic diagram of the appearance of the shark fin integrated module;

[0033] Figure 2 This is a cross-sectional view of the internal structure of the shark fin integrated module;

[0034] Figure 3 Schematic diagram for filtering low vehicles;

[0035] Figure 4 It is a schematic diagram of the detection range;

[0036] Figure 5 This is a schematic diagram of module connection;

[0037] Figure 6 This is the early warning logic flow chart. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The technical solutions provided by the embodiments of the present invention are described in detail below in conjunction with the drawings.

[0039] See also Figures 1 to 5 A vehicle rearward collision avoidance warning device provided by the present invention includes: a sensor module, a data processing module, a communication module and a warning module; the sensor module is connected to the data processing module, the data processing module is connected to the communication module, the communication module is connected to the warning module and the vehicle's CAN bus interface, and the sensor module 1 is integrated inside the shark fin structure shell on the top of the vehicle.

[0040] The sensor module 1 includes a single-point laser sensor 2 and an angle detection device. The single-point laser sensor is used to emit a 905nm wavelength laser beam and measure the real-time distance S between the vehicle and the target vehicle behind based on the time-of-flight method. The angle detection device is used to monitor the angle α between the laser beam and the horizontal plane in real time. In this embodiment, the shark fin structure is installed behind the center line of the roof, with a height of H = 1.6m ± 0.05m, and the initial calibration of the laser beam elevation angle is 1.5°

[0041] The data processing module includes a timer and a data processor. The data processing module is fixed to the roof interlayer and connected to the vehicle power supply and CAN bus through an IP67 waterproof connector. The data processing module is used to obtain the vehicle speed V through the CAN bus. 1 , the speed V of the target vehicle behind is calculated by the difference of the real-time distance S 2 , calculate the dynamic angle threshold α 1 And the collision time TTC, and according to V 1 、V 2 , S, α, α 1 , TTC value executes warning judgment of low-speed warning mode and high-speed warning mode.

[0042] Communication module, used to obtain the vehicle speed V 1 and gear position signal, at the vehicle speed V 1and the gear position signal meets the preset conditions, activating the warning judgment of the vehicle rearward collision warning device, and transmitting the control command of the data processing module to the warning module;

[0043] The warning module is used to trigger the vehicle rear collision warning according to the control instructions of the data processing module. The warning module has the following functions: visual warning, which can remind the driver of the vehicle that there is a risk of collision behind by flashing the indicator symbol on the display screen; sound warning, which can send out a sound alarm through the buzzer to remind the driver to be careful behind.

[0044] Specifically, the shark fin structure shell includes a three-layer gradient composite structure: the outer layer is a carbon fiber reinforced polyetheretherketone (PEEK) layer with a thickness of 0.8mm±0.05mm and a surface roughness of Ra≤0.8μm; the curvature radius R 1 =120mm±5mm, leeward side B curvature radius R 2 =80mm±3mm; the middle layer is a nano-aerogel insulation layer with a porosity of 92%±1% and a thickness of 2.5mm±0.1mm; the inner layer is a 6061-T6 aluminum alloy substrate with an anodized film thickness of 25μm±2μm. The three-layer composite structure is manufactured using a gradient sintering process, and the sintering temperature curve adopts a three-stage heating of 300℃, 420℃, and 580℃; the thickness of the interlayer transition layer is 50±5μm; the cooling rate is 8℃ / min±0.5℃. A thermal conductive silicone layer is provided on the aluminum alloy substrate, with a thickness of 3mm±0.2mm, containing 30% volume fraction of aluminum nitride particles, with a particle size of D50=8μm±1μm, and a concentration gradient is formed along the heat dissipation direction, 35%±2% on the laser side and 25%±2% on the shell side. The thermal conductive silicone layer works synergistically with the three-layer gradient composite structure to improve the heat dissipation performance and ensure the stable operation of the device in a high temperature environment.

[0045] The laser pulse emission elevation angle range is 1-2.5°. The laser pulse emission elevation angle range refers to the angle of the laser emitted by the shark fin selected within this range according to the different vehicle heights, but it is not dynamically adjustable. The device itself will not automatically adjust this angle, but the angle will change with the bumps and pitch movements of the vehicle; the aspheric lens group is built-in, and the curvature radius of the aspheric lens group is R 3＝ 12.5mm±0.1mm, R 4 =-18.3mm±0.1mm, ZF52 glass material, refractive index nd=1.6725±0.0002; angle detection device resolution ±0.1°.

[0046] The present invention creatively hides the single-point laser sensor inside the shark fin housing, achieving a high degree of integration between the two. The volume is significantly reduced compared to millimeter-wave radar and solid-state laser radar, and there is no need to modify the vehicle body structure. It is visually concealed and maintains the integrity of the vehicle appearance. The present invention adopts a lightweight combination of a single-point laser sensor + an angle detection device, and the hardware cost is significantly reduced compared to the millimeter-wave radar solution and the solid-state laser radar solution.

[0047] See also Figure 6 The embodiment of the present invention further provides a vehicle rearward collision warning method, which is used in the above vehicle rearward collision warning device, comprising:

[0048] Step 1: Activate the vehicle rearward collision warning method when the vehicle is in D / N / P gear and meets any of the following speed conditions: 0km / h≤V 1 <15km / h, V 1 ≥50km / h.

[0049] The vehicle rearward collision avoidance warning method of the present invention is activated only in a specified speed range, and can significantly reduce power consumption compared to a solution that works around the clock.

[0050] Step 2: Get the vehicle speed V 1 , the real-time distance S between the vehicle and the target vehicle behind, the angle α between the laser beam of the single-point laser sensor and the horizontal plane; the speed V of the target vehicle behind is calculated by the difference of the real-time distance S 2 , calculate the dynamic angle threshold α 1 And the collision time TTC.

[0051] Specifically, according to α 1 =arctan((h_target-H) / S) to calculate the dynamic angle threshold α 1 , where h_target is the maximum height of the car to be filtered out, h_target ≥ 2.6m, H is the installation height of the single-point laser sensor, H ≥ 1.5m; according to TTC = S / (V 2 -V 1 )Calculate the collision time TTC.

[0052] Step 3: According to V 1 、V 2 , S, α, α 1 , TTC value executes warning judgment of low-speed warning mode and high-speed warning mode.

[0053] 0≤V 1 <15km / h is low speed warning mode; in low speed warning mode, if both of the following conditions are met: 40m <S<55m、ΔV> 11.1m / s, α>α 1When ΔV=V 2 -V 1 .

[0054] V 1 ≥50km / h is high-speed warning mode; in high-speed warning mode, when both of the following conditions are met: 20m <S<55m、TTC≤4s、α> α 1 The vehicle rear collision warning is triggered.

[0055] The present invention introduces the laser angle α and the dynamic angle threshold α 1 The real-time comparison mechanism is used to filter low vehicles, solving the problem of misjudgment of traditional technologies. The dual-speed interval division differentiates the collision judgment logic, effectively covering the red light waiting scene, highway traffic jam scene and high-speed driving scene. This solution uses a single-point laser tilt emission and an angle dynamic calibration technology to significantly reduce the risk of being rear-ended by a large vehicle behind in an economical but highly reliable way. Strong scalability: supports adjusting the warning thresholds, such as S and speed difference ΔV, through software upgrades to adapt to road safety standards in different countries / regions. The present invention is suitable for a variety of small and medium-sized vehicles, especially for vehicles such as SUVs, MPVs, small and medium-sized trucks with a body height of more than 1.6 meters.

[0056] The data processing module executes the Doppler frequency shift compensation algorithm, and the compensation amount Δf = 2V 1 cosα / λ, where λ is the wavelength. The formula means: the Doppler frequency shift compensation is 2V 1 · cosα divided by wavelength λ, which is in line with the radar speed measurement principle, V 1 The speed of the vehicle is the vehicle speed, and α is the laser angle. The present invention adopts a matched filter: h(n)=s(N-1-n)*, wherein h(n) is the coefficient sequence of the matched filter. In signal processing, h(n) represents the coefficient of the digital filter at the discrete time variable n, which is used to perform convolution matching with the received signal s(n) to extract target features, such as echo signals. N is the total length of the pseudo-random binary sequence PRBS9. The specific value is based on the definition of s(n). s(n) is the PRBS9 sequence, N=9, that is, the sequence contains 9 discrete points. s(N-1-n) represents a reverse traversal of the PRBS9 sequence, from the last element to the first element, to generate a matching relationship symmetrical to h(n). n is a discrete time variable, representing the sequence number of the signal sampling point, and the value range of n is: n=0,1,2,...,N-1, with a total of N points. Both h(n) and s(n) rely on n to dynamically generate filter coefficients and sequence values ​​to achieve real-time signal processing. * represents a conjugate operation. If α≤α for three consecutive times within the sampling period of 100ms 1 , disable the warning for 0.5 seconds to avoid misjudgment due to bumps.

[0057] The following is an example of a typical application scenario of the present invention:

[0058] Scenario 1: When waiting for a red light, the vehicle speed is 0 km / h.

[0059] A 2.9-meter-high dump truck was approaching from behind at a speed of 60km / h. When it was 49 meters away from the vehicle, the system triggered a dynamic warning icon + sound alarm on the vehicle's onboard display screen, reminding the driver of the vehicle to be careful of the vehicles behind.

[0060] Scenario 2: Highway congestion, low-speed driving scenario, vehicle speed 10km / h.

[0061] There is an ordinary car 5 meters behind the vehicle, and behind it is a 3-meter-high large truck approaching at a speed of 60km / h. When the large truck is about 53 meters away from the vehicle, the system triggers the dynamic warning icon + sound alarm on the vehicle's on-board display screen to remind the driver of the vehicle to be careful of the vehicle behind.

[0062] Scenario 3: High-speed driving scene when driving from the main highway to the right ramp, with a speed of 70km / h.

[0063] A 3.2-meter-high truck was approaching from behind at a speed of 105km / h. When it was 39 meters away from the vehicle, the system triggered a dynamic warning icon + sound alarm on the vehicle's onboard display screen, reminding the driver of the vehicle to be careful of the vehicles behind.

[0064] Scenario 4: Anti-false alarm verification, low-speed driving scenario, vehicle speed 10km / h.

[0065] Assuming that the vehicle itself is 10km / h, the real-time angle α between the laser beam and the horizontal plane changes due to the bumps of the vehicle, decreasing from the initial value to 1°.

[0066] At the same time, a vehicle with a height of 2.5 meters is approaching the vehicle at a speed of 55 km / h, and the distance between the two vehicles is 45 meters. According to the dynamic angle threshold technology, the angle threshold α at this time is calculated. 1 It is 1.27°.

[0067] Since the real-time angle α between the laser beam and the horizontal plane is less than the angle threshold α 1 , that is, α<α 1 , so the system does not issue an alarm. In summary, the anti-false alarm verification in this scenario has passed.

[0068] The embodiment of the present invention further provides a storage medium, wherein a computer program is stored in the storage medium, and when the computer program is executed by a processor, some or all of the steps in each embodiment of the vehicle rearward collision warning method provided by the present invention are implemented. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM).

[0069] Those skilled in the art can clearly understand that the technology in the embodiments of the present invention can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution in the embodiments of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention or some parts of the embodiments.

[0070] The above-described embodiments of the present invention do not limit the protection scope of the present invention.

Claims

1. A vehicle rearward collision warning device, characterized in that: include: A sensor module, a data processing module, a communication module and an early warning module; the sensor module is connected to the data processing module, the data processing module is connected to the communication module, the communication module is connected to the early warning module and the CAN bus interface of the vehicle, and the sensor module is integrated inside the shark fin structure shell on the top of the vehicle; The sensor module includes a single-point laser sensor and an angle detection device, wherein the single-point laser sensor is used to emit a 905nm wavelength laser beam and measure the real-time distance S between the vehicle and the target vehicle behind based on the time-of-flight method, and the angle detection device is used to monitor the angle α between the laser beam and the horizontal plane in real time; The data processing module is used to obtain the vehicle speed V1 through the CAN bus, calculate the rear target vehicle speed V2 by differential calculation of the real-time distance S, calculate the dynamic angle threshold α1 and the collision time TTC, and perform the warning judgment of the low-speed warning mode and the high-speed warning mode according to the values ​​of V1, V2, S, α, α1, and TTC; The communication module is used to obtain the vehicle speed V1 and the gear signal, activate the warning judgment of the vehicle rearward collision warning device when the vehicle speed V1 and the gear signal meet the preset conditions, and transmit the control command of the data processing module to the warning module; The warning module is used to trigger a vehicle rear collision warning according to a control instruction of the data processing module.

2. The vehicle rearward collision warning device according to claim 1, characterized in that: The shark fin structure shell includes a three-layer gradient composite structure: The outer layer is a carbon fiber reinforced PEEK layer with a thickness of 0.8mm±0.05mm and a surface roughness of Ra≤0.8μm; the curvature radius of the windward surface is R1=120mm±5mm, and the curvature radius of the leeward surface is R2=80mm±3mm; The middle layer is a nano-aerogel insulation layer with a porosity of 92% ± 1% and a thickness of 2.5 mm ± 0.1 mm; The inner layer is a 6061-T6 aluminum alloy substrate with an anodized film thickness of 25μm±2μm.

3. The vehicle rearward collision warning device according to claim 2, characterized in that: A thermally conductive silicone layer is provided on the aluminum alloy substrate. The thermally conductive silicone layer has a thickness of 3mm±0.2mm, contains 30% volume fraction of aluminum nitride particles, and has a particle size of D50=8μm±1μm. A concentration gradient is formed along the heat dissipation direction, 35%±2% on the laser side and 25%±2% on the shell side.

4. The vehicle rearward collision warning device according to claim 3, characterized in that: The three-layer composite structure is manufactured by a gradient sintering process, and the sintering temperature curve adopts a three-stage heating of 300° C., 420° C., and 580° C.; the thickness of the interlayer transition layer is 50±5 μm; and the cooling rate is 8° C. / min±0.5° C.

5. The vehicle rearward collision warning device according to claim 4, characterized in that: The single-point laser sensor emits a PRBS9 coded pulse laser with a wavelength of 905nm±5nm, a pulse width of 5ns±0.3ns, and a duty cycle of 1%-3%; The laser pulse emission elevation angle range is 1-2.5°; the aspheric lens group is built-in, the curvature radius of the aspheric lens group is R3=12.5mm±0.1mm, R4=-18.3mm±0.1mm, ZF52 glass material, refractive index nd=1.6725±0.0002; the angle detection device has a resolution of ±0.1°.

6. A vehicle rearward collision warning method, used in the vehicle rearward collision warning device according to any one of claims 1 to 5, characterized in that: include: Step 1: activating the vehicle rearward collision warning method when the vehicle is in the D / N / P gear and meets any of the following speed conditions: 0km / h≤V1<15km / h, V1≥50km / h; Step 2: Obtain the vehicle speed V1, the real-time distance S between the vehicle and the target vehicle behind, and the angle α between the laser beam of the single-point laser sensor and the horizontal plane; calculate the speed V2 of the target vehicle behind by differential calculation of the real-time distance S, and calculate the dynamic angle threshold α1 and the collision time TTC; Step 3: Execute warning judgment of low-speed warning mode and high-speed warning mode according to the values ​​of V1, V2, S, α, α1, and TTC.

7. The vehicle rearward collision warning method according to claim 6, characterized in that: In step 2, The dynamic angle threshold α1 is calculated according to α1=arctan((h_target-H) / S), where h_target is the maximum height of the car to be filtered out, h_target≥2.6m, and H is the installation height of the single-point laser sensor, H≥1.5m; The collision time TTC is calculated according to TTC=S / (V2-V1).

8. The vehicle rearward collision warning method according to claim 6, characterized in that: In step three, 0≤V1<15km / h is low speed warning mode; in low speed warning mode, when both of the following conditions are met: 40m <S<55m、ΔV> 11.1m / s, α>α1, the vehicle rear collision warning is triggered; V1≥50km / h is high-speed warning mode; in high-speed warning mode, if both of the following conditions are met: 20m <S<55m、TTC≤4s、α> When α1, the vehicle rear collision warning is triggered.

9. The vehicle rearward collision avoidance warning method according to claim 6, characterized in that: The data processing module executes a Doppler frequency shift compensation algorithm, with a compensation amount of Δf=2V1cosα / λ, where λ is the wavelength; and uses a matched filter: h(n)=s(N-1-n)*, where h(n) is the coefficient sequence of the matched filter, N is the total length of the pseudo-random binary sequence PRBS9, n is a discrete time variable representing the serial number of the signal sampling point, s(n) is the PRBS9 sequence, and * represents a conjugate operation.

10. The vehicle rearward collision avoidance warning method according to claim 6, characterized in that: If α≤α1 for three consecutive times within a sampling period of 100ms, the warning is disabled for 0.5 seconds.

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