System for monitoring driving state of vehicle on highway in real time and application method

Abstract

The invention discloses a system for monitoring the driving state of vehicles on an expressway in real time and an application method. The system comprises two sets of pulse laser integrated emission subsystems which are oppositely arranged on the whole course of the two sides of the expressway; the data acquisition cards are oppositely arranged on the whole process of the two sides of the expressway and matched with the pulse laser integrated emission subsystem; wherein each set of pulse laser integrated emission subsystem comprises m matrix units, and each matrix unit comprises a pulse laser integrated emission unit and a corresponding laser receiving and detecting module; and each laser receiving and detecting module is in communication connection with the upper computer through the data acquisition card. According to the system for monitoring the driving state of the vehicles on the expressway in real time and the application method, traditional millimeter wave radar and visual radar schemes are abandoned, a tunable laser cluster and an optical fiber transmission system are combined, all-optical-path signal transmission is achieved, laser serves as a monitoring medium, and the transmission speed is increased by at least two orders of magnitude.

Description

Technical Field

[0001] The present invention relates to the field of road monitoring, and more particularly to a system and application method for real-time monitoring of vehicle driving status on a highway. Background Art

[0002] Current highway monitoring systems, whether for road safety monitoring (such as traffic accidents, low-speed vehicles, traffic flow, and passenger and freight lane separation), traffic environment monitoring (such as rainfall and visibility in snowy and foggy weather), or road condition monitoring (such as icy roads and landslides), primarily rely on cameras, lidar, and related sensors installed on the road. Vehicle status monitoring primarily relies on the combination of cameras and lidar. A similar technical solution currently available is the intelligent integrated road pole system proposed by Alibaba's DAMO Academy in 2018. However, this system has the following shortcomings in practical application:

[0003] Vehicle obstruction blind spot: A large vehicle traveling in front of a small vehicle will block the laser and millimeter-wave radar waves, causing the radar waves to be unable to illuminate the small vehicle behind it, and thus unable to monitor the small vehicle behind it.

[0004] Extremely long information latency: Information is transmitted through fiber, 5G, and V2X, resulting in a minimum transmission time of approximately 20 milliseconds. It should be noted that while V2X and fiber-optic backhaul are employed, data processing on road poles and the sheer volume of video and radar data require significant bandwidth. Furthermore, fiber-optic backhaul requires back-end data decoding and other processing, resulting in relatively long latency.

[0005] Short lifespan: Taking Suzhou Holographic Sensing Expressway as an example, the core module has a lifespan of only 6 to 10 years and requires annual inspection, otherwise normal use will be affected;

[0006] Low stability: The core functional components of the solution are exposed to the elements for a long time and are easily affected by rain, snow and other weather conditions, which may cause interference and damage to the core components.

[0007] It is greatly affected by extreme weather: for example, foggy weather may cause the lidar to be inaccurate, the visual radar to be unable to work effectively, and the millimeter-wave radar detection to be limited. Summary of the Invention

[0008] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0009] In order to achieve these objects and other advantages of the present invention, a system for real-time monitoring of the driving status of vehicles on a highway is provided, comprising:

[0010] Two sets of pulse laser integrated emission subsystems are installed on both sides of the highway;

[0011] Data acquisition cards are installed on both sides of the highway and work with the pulse laser integrated emission subsystem;

[0012] Each set of pulse laser integrated emission subsystem includes m matrix units, and each matrix unit includes: a pulse laser integrated emission unit and a corresponding laser receiving and detection module;

[0013] Each laser receiving and detecting module is connected to the host computer through a data acquisition card.

[0014] Preferably, the pulse laser integrated emission unit comprises:

[0015] A tunable laser that generates and emits continuous laser light within a predetermined wavelength range;

[0016] A signal generator that generates corresponding pulse signals based on the pulse frequency instructions of the host computer;

[0017] An acousto-optic modulator that modulates continuous laser light into pulsed laser light based on a received pulse signal;

[0018] A narrow-band optical fiber filter that filters the pulsed laser to make the output pulsed laser a single wavelength.

[0019] 1 / 2 optical splitter I that performs initial optical splitting on the light transmitted by the narrowband optical fiber filter;

[0020] An infrared and ultraviolet cut-off filter for filtering the infrared or ultraviolet laser in the light beam I at the output side of the 1 / 2 beam splitter I;

[0021] a visible light source located downstream of the infrared and ultraviolet cutoff filters;

[0022] 1 / 2 beam splitter II for performing secondary beam splitting on the light beam II at the output side of 1 / 2 beam splitter I;

[0023] The laser receiving and detecting module I is adapted to one output side of the 1 / 2 optical splitter II, and the other output side of the 1 / 2 optical splitter II is adapted to the transmission optical fiber of the receiving side.

[0024] Preferably, it further includes a transmitting side transmission module and a receiving side transmission module that cooperate with the pulse laser integrated transmitting subsystem;

[0025] The transmitting side transmission module includes:

[0026] 1 / n optical splitter group I matched with 1 / 2 optical splitter II;

[0027] A 1 / nx optical splitter group matched with one of the output optical paths of the 1 / n optical splitter group, wherein the value of x is 1, 2, 3, or n-1. When x is n-1, a direct optical fiber connection is adopted;

[0028] collimating optical fiber interface groups respectively matched with the output optical path of the 1 / nx optical splitter group I and the other output optical paths of the 1 / n optical splitter group I;

[0029] A horizontally emitting laser group matched with the collimating fiber interface group;

[0030] The receiving side transmission module includes:

[0031] A horizontal receiving laser group coordinated with the horizontal transmitting laser group;

[0032] Transmit the light beam transmitted by the horizontal receiving laser group to the 1 / n optical splitter group II of the laser receiving and detection module;

[0033] A 1 / nx optical splitter group II is matched with one of the output optical paths of the 1 / n optical splitter group.

[0034] An application method, which uses a system for real-time monitoring of the driving status of vehicles on a highway, includes:

[0035] Step 1: When a vehicle enters a toll booth or acceleration lane, the vehicle's identity information is identified by the ETC system and / or the high-speed acceleration lane violation camera, and then sent to the system for synchronization. The vehicle's starting point and driving duration are recorded to determine whether there is fatigue driving. The vehicle identity information includes: license plate number, vehicle model, vehicle size, vehicle weight, and lane number;

[0036] Step 2: After leaving the corresponding lane and entering the system's monitoring range, the vehicle body will block the pulsed lasers at different positions during driving. The system obtains and records the vehicle's driving status information on the highway based on the persistence of the signals of two adjacent pulsed lasers at different positions to determine whether there are any illegal operations until the vehicle leaves the highway;

[0037] The driving status information includes longitudinal speed, mileage position from the starting point, lateral speed, and lane information.

[0038] Preferably, the longitudinal speed The way to obtain is:

[0039]

[0040] In the above formula, m is the number of lasers of different wavelengths that can be received in a matrix unit element, V 纵i is the average speed between two adjacent monitoring points, and V 纵i Obtained by the following formula:

[0041]

[0042] In the above formula, Δt i is the disappearance time difference between two adjacent monitoring laser beams, λ is the laser wavelength, and λ k+1 ,λ k It is used to characterize two adjacent laser beams with sequentially arranged wavelengths, and d is the distance between the two adjacent laser beams;

[0043] The mileage position H from the starting point is obtained by the following formula:

[0044]

[0045] In the above formula, dt j is the total time of the corresponding segment, dt i The speed is V 纵i When , integrate the distance obtained for the time period.

[0046] Preferably, the lateral speed is the lateral speed of the bicycle during the non-blocking period Lateral velocity during occlusion They are obtained by the following formulas:

[0047]

[0048] In the above formula, Δt i is the disappearance time difference of two adjacent monitoring laser beams, Δtk is the time when a single tire of the vehicle blocks the laser, X 横始 is the lateral position of the vehicle body from the opposite side of the road when the vehicle tire just contacts the laser at the monitoring point in the single-vehicle driving state, and X 横始 It is characterized by the following formula:

[0049]

[0050] In the above formula, t1 is the time when the laser signal on the receiving side disappears during the non-blocking period, t2 is the time when the laser signal on the receiving side disappears during the non-blocking period, L is the total width of the highway, X is the total width of the highway, 轮距 is the wheelbase of the vehicle, is the laser point detected by the unidirectional laser receiving and detection module during the time t1-t2, and n is the distance between two adjacent laser points;

[0051] X 横止 is the lateral position of the vehicle tire from the opposite side of the road when the vehicle leaves the monitoring point laser in the single-vehicle driving state, and X 横止 It is characterized by the following formula:

[0052]

[0053] In the above formula, t3 is the time when the laser signal on the receiving side disappears during the shielding period, t4 is the time when the laser signal on the receiving side disappears during the shielding period, It is the laser point detected by the unidirectional laser receiving and detection module during the time t3-t4.

[0054] Preferably, when the two vehicles are in parallel, the lateral position X of the rear vehicle is 横后 Should be equal to X 横止 , but if X 横后 <X 轮距后 , then it is determined that the two cars collided, X 轮距后 is the wheelbase of the vehicle's rear wheels;

[0055] The safety distance of the rear vehicle must meet the following conditions:

[0056]

[0057] In the above formula, X 轮距前 is the wheelbase of the vehicle in front.

[0058] Preferably, when the front wheel tire of the vehicle blocks the laser, the disappearance time of the two pulse laser signals with different wavelengths on the transmitting side and the receiving side can be used to obtain the length of the vehicle's lateral position from the monitoring point through the speed of light of the laser in this environment, thereby obtaining the current lane position of the vehicle.

[0059] The present invention has at least the following beneficial effects:

[0060] First, the present invention abandons traditional millimeter-wave radar and visual radar solutions and adopts a combination of a tunable laser cluster and an optical fiber transmission system to achieve full optical signal transmission. By using laser as the monitoring medium, the transmission speed is increased by two orders of magnitude (optical fiber replaces traditional wireless communication links, reducing the information transmission delay from the current shortest 20 milliseconds to the longest 166.75 microseconds), making its information transmission time faster than existing technologies. At the same time, through laser transmission, the transmission body does not need to be exposed to natural conditions for a long time, reducing damage to components caused by rain and snow, and ensuring transmission stability. At the same time, the laser can actively melt the snow layer, ensuring the feasibility of detection in heavy snow weather. The use of optical fiber for information transmission can also overcome the problem of radar failure at low temperatures and high altitudes.

[0061] Secondly, the monitoring system of the present invention uses two fully designed "pulse laser integrated emission subsystem" matrices and two "laser spectrum detection subsystems" on the road (that is, one set is set on one side of the road, serving as each other's receiving end and transmitting end), so there are almost no vehicle-blocked blind spots, and the monitoring effect is better.

[0062] Fourthly, the monitoring system of the present invention does not require an external power supply. The laser is generated at the toll station and the power supply is centralized at the toll station.

[0063] Third, the monitoring method of the present invention uses lasers to collect real-time motion information of objects on fixed tracks, completing real-time driving status monitoring of vehicles on highways and roads of the same level. Specifically, the present invention realizes longitudinal positioning of the object position (i.e., vehicle driving speed detection) based on a comparison algorithm of the time difference between the disappearance of two pulses, and realizes lateral positioning (i.e., lane detection) by the difference in the number of pulse laser points when two beams of pulse lasers emitted in opposite directions along the same optical path disappear. Compared with the existing technology, the present invention has low computational cost and better monitoring stability.

[0064] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a block diagram of the pulse laser integrated emission subsystem in the present invention;

[0066] Figure 2 This is a block diagram of the pulse laser integrated emission subsystem of the present invention;

[0067] Figure 3 It is a block diagram of the system composition of the present invention;

[0068] Figure 4 This is a schematic diagram of the connection between the data acquisition card and the laser receiving and detection module of the present invention;

[0069] Figure 5 This is a diagram showing the distance measurement principle of the present invention;

[0070] Figure 6 This is a schematic diagram of the layout of the matrix monitoring device of the present invention on the road;

[0071] Figure 7 This is a flow chart of synchronizing vehicle identity information using solution 1 of the present invention;

[0072] Figure 8 This is a schematic diagram of vehicle identity information in the acceleration lane when the second solution of the present invention is adopted;

[0073] Figure 9 This is a flow chart of synchronizing vehicle identity information using solution 2 of the present invention;

[0074] Figure 10 This is a schematic diagram of the distribution of cars A, B, and C on the road when they are traveling in the same direction;

[0075] Figure 11 This is a schematic diagram of the trajectory of the vehicle A simulating continuous driving in the present invention;

[0076] Figure 12 Schematic diagrams of several possible distributions of cars A, B, C, D, E, F, and G on the road when they are traveling in the same direction;

[0077] Figure 13 This is a schematic diagram showing that the front edge of the tire of vehicle C is completely tangent to the rear edge of the tire of vehicle D;

[0078] Figure 14 This is a schematic diagram of the tire of car G blocking the front edge of the surface, and the tire of car E blocking the rear edge of the surface and not being tangent;

[0079] Figure 15 A simplified diagram of the entire system when a car is driving on the road. DETAILED DESCRIPTION

[0080] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0081] A system for real-time monitoring of the driving status of vehicles on a highway, comprising:

[0082] Two sets of pulse laser integrated emission subsystems are installed on both sides of the highway;

[0083] Data acquisition cards are installed on both sides of the highway and work with the pulse laser integrated emission subsystem;

[0084] It also includes a transmitting side transmission module and a receiving side transmission module that cooperate with the pulse laser integrated transmitting subsystem;

[0085] Among them, each set of pulse laser integrated emission subsystem includes m matrix units, and each matrix unit includes: a pulse laser integrated emission unit and a corresponding laser receiving and detection module. It should be noted that the functions of the laser receiving and detection module include calibrating and resolving laser wavelength information, collecting laser light intensity signals of different wavelengths, detecting and recording the change information of different wavelength light signals of the system (light intensity, disappearance time, appearance time), the number of pulse laser points collected within a period of time, and gain amplification of weak light signals (equal proportion or unequal proportion). This module contains all hardware devices that may have the above functions or the same or similar functions as the spectrometer in this system, including but not limited to: spectrometer, multi-channel photoelectric sensor, integrated photoelectric sensor chip, multi-beam array photoelectric sensor, photon detector, etc.

[0086] Each laser receiving and detecting module is communicatively connected to the host computer through a data acquisition card. In this solution, the complete system design consists of two sets of "pulsed laser integrated emission subsystems" and two sets of "data acquisition cards". The two sets of "pulsed laser integrated emission subsystems" achieve bidirectional laser emission and reception under the action of the emission-side transmission module and the reception-side transmission module, so that in later applications, calculations are performed by adopting the method of bidirectional laser emission calculation to complete the monitoring of the vehicle driving state (such as speed measurement, etc.). Among them, as Figure 6 shown, each pulsed laser integrated emission subsystem consists of m matrix units to form a complete matrix monitor on one side (emission side or reception side). The monitoring task is completed through two sets of matrix monitors, and each matrix unit includes: a pulsed laser integrated emission unit and a corresponding laser receiving and detecting module.

[0087] Specifically, as Figure 1 shown, when a single pulsed laser integrated emission unit is applied in road monitoring, in order to distinguish the installation methods with the emission side and the reception side at both ends of the road, the pulsed laser integrated emission units on one side of the road are all simply referred to as "device Am", and the other side is simply referred to as "device Bm", where m = 1, 2, 3... m; a single pulsed laser integrated emission unit mainly includes the following components:

[0088] Tunable laser 1: Generate and emit laser with a wavelength range of a0 - b0 nm and emit it;

[0089] Ordinary visible light source 2: Generate and emit high-brightness visible ordinary visible light, mix it with the laser to facilitate the alignment of the pulsed laser integrated emission unit on the emission side and the pulsed laser integrated emission unit on the receiving side when installing the horizontal laser transmitter and the horizontal laser receiver, and outline the road range under night and foggy weather (Tyndall effect);

[0090] Signal generator 3: Receive the computer's instruction on the pulse frequency of the laser, and after processing, send it to the acousto-optic modulator 4 to modulate the continuous laser into pulsed laser;

[0091] Acousto-optic modulator 4: Receive the pulsed signal transmitted by the signal generator 3, and modulate the a0 - b0 nm wavelength continuous laser generated by the tunable laser into pulsed laser with a pulse frequency of x Hz according to the instruction. It should be noted that in actual applications, the acousto-optic modulator 4 can be set at the front or rear end of the narrowband fiber filter 5 according to needs;

[0092] Narrowband fiber filter 5: Filter the laser modulated by the acousto-optic modulator 4, so that the pulsed laser integrated emission system only emits laser with a wavelength of c0 nm (a0 < c0 < b0) and a pulse frequency of x Hz (determined by the required lateral position accuracy), and mix it with the visible light through a splitter in the same optical fiber;

[0093] Optical splitter I 6: In this solution, a 1 / 2 optical splitter is used to integrate the tuned frequency-modulated laser and visible light into the same optical fiber. (It should be noted that the optical splitter involved in this invention mainly applies the principle of optical path reversibility. Depending on its location, the optical splitter can either split light or converge pulsed laser and visible light).

[0094] Infrared and ultraviolet cut-off filter 7: Filters infrared or ultraviolet lasers transmitted in the optical fiber towards the visible light source to prevent it from burning the visible light source.

[0095] The working principle of the single pulsed laser integrated emission unit is as follows:

[0096] A continuous laser in the range of a0 - b0 nm is generated by the tunable laser 1 and connected to the acousto-optic modulator 4. The acousto-optic modulator 4 receives the modulation signal from the signal generator 3 to modulate the laser into a pulsed laser with a pulse frequency of x Hz, and is filtered by the narrowband optical fiber filter 5 to only output a pulsed laser with a wavelength of c0 (nm) (a0 < c0 < b0), and is mixed with the visible light generated by the ordinary visible light source 2 through the optical splitter 6, and then transmitted to the horizontal laser transmitter of the roadside laser ranging and speed measuring subsystem through the laser emission side transmission subsystem;

[0097] It should be noted that as Figure 2 shown, since the system for real-time monitoring of the driving state of highway vehicles in this invention needs to emit lasers with several different wavelength ranges, a set of pulsed laser integrated emission subsystems needs to consist of a laser emission cluster composed of more than m independent pulsed laser integrated emission units cooperating with corresponding laser receiving and detection modules to provide pulsed lasers with m different wavelength ranges. Usually, in the above working principle, since the laser cannot emit a laser with a strictly cnm wavelength, it can first emit an a - bnm laser including the cmn wavelength laser, and then be filtered by the laser filter to obtain a cnm wavelength laser. Among them, the first pulsed laser integrated emission system emits a cnm wavelength laser, and each subsequent system emits a c + ynm wavelength laser (ynm is the optical resolution of the laser receiving and detection module) until the mth pulsed laser is integrated into the emission subsystem.

[0098] xHz is mainly determined by the required measurement accuracy of the lateral position (lane) of the vehicle. That is, if the vehicle lane position accuracy requirement is d (cm), then the required laser pulse frequency f is:

[0099] f = c / d

[0100] In the above formula, c is the speed of light. When the accuracy is 1 cm, x = 10 billion Hz, which is much lower than the current world limit level and is practically feasible because the current lasers can reach the level of hundreds of GHz.

[0101] like Figure 3 As shown, the transmitting side transmission module of the present invention mainly includes:

[0102] Spectrum Splitter II 8( Figure 3 The middle beam splitter II uses a 1 / n beam splitter): it splits the light generated by the pulse laser integrated emission unit into a 1 / n portion of light from the optical fiber, and then enters the horizontal light emitter through the collimated optical fiber interface 9;

[0103] Collimated fiber interface I9: converts the scattered light from point 1 / n obtained from the beam splitter II8 into concentrated collimated light, and converges the laser emitted from the other side into the optical fiber;

[0104] Horizontal laser transmitter 10: Receives laser light from beam splitter II 8, adjusts the level of the laser light to emit horizontally, transmits it to the receiving side, and then converges it into the optical fiber. Finally, it is transmitted to the laser receiving and detection module to detect the optical signal.

[0105] The receiving side transmission module of the present invention mainly includes:

[0106] Beam splitter III 11: collects the laser light from the horizontal laser receiver and transmits it to the laser receiving and detection module to centrally detect whether the laser light is still present;

[0107] Collimated laser interface II 12: converts the scattered light from point 1 / n obtained from the beam splitter III 11 into concentrated collimated light, and converges the laser emitted from the opposite side into the optical fiber (in actual application, the optical fiber connected to the laser receiving and detection module not only converges the laser on the opposite side, but also transmits the laser emitted by the laser on this side).

[0108] Horizontal laser receiver 13: The horizontal laser transmitter 10 and the horizontal laser receiver 13 are used for roadside laser ranging and speed measurement. It should be noted that roadside laser ranging and speed measurement refers to transmitting and receiving laser at the edge of the road to measure the speed and distance of the vehicle;

[0109] like Figure 4 As shown, each matrix unit also includes:

[0110] Laser receiving and detection module 14: mainly includes the corresponding laser receiving and detection module coordinated with "device Am" called "laser receiving and detection module Am", and the corresponding laser receiving and detection module coordinated with "device Bm" called "laser receiving and detection module Bm". It mainly receives m lasers of different wavelengths emitted by the pulsed laser integrated emission unit through the laser receiving side transmission module for detection (determines whether the laser is still present by detecting the light intensity of the m laser wavelengths), and generates analog signals in real time and transmits them to the data acquisition card 15;

[0111] like Figure 4As shown, the data acquisition card 15 converts the analog signal from the laser receiving and detection module 14 into a digital signal and transmits it to the computer terminal 16. The computer terminal generates real-time information of speed, distance and vehicle position through calculation to monitor the vehicle's driving status;

[0112] The monitoring system of the present invention has the following effects when applied:

[0113] 1. Real-time information has low latency. Monitoring information is transmitted to the monitoring center at the speed of light, which is at least 125 times faster than traditional wireless communications. Based on a 100km transmission line, the transmission time is only 0.00016675 seconds (approximately 166.75 microseconds). Traditional solutions, such as Alibaba, take at least 20 milliseconds.

[0114] 2. High stability and low failure rate. No wires are laid along the highway curbs. Optical fiber is used for transmission, which is minimally affected by weather.

[0115] 3. Small blind spots. This solution uses the method of measuring the position of vehicle tires to obtain overall real-time information about the vehicle. The blind spot only exists when two identical vehicles are permanently parallel.

[0116] 4. It is less affected by extreme climate. For example, heavy rain or fog will be only slightly affected due to the good penetration of laser. Heavy snow will not be affected because the laser itself has energy that can burn through the snow layer.

[0117] 5. Long service life. This solution uses optical fiber as the main component exposed to the natural environment. The optical fiber has a minimum service life of 10 years under natural conditions.

[0118] Furthermore, the principle of the present invention using the monitoring system of the present invention to monitor the real-time position of a vehicle is as follows:

[0119] 1. Speed measurement principle (i.e. measuring vehicle speed)

[0120] The speed of vehicles passing through different sections of road is measured by the time between two laser blockages and the distance between the two detection piles. Assuming that the linear distance between the P and Q detection piles (also called monitoring points, where the monitoring points refer to two adjacent monitoring laser beams) is d (m), and the time interval between the disappearance of the P and Q laser signals is t (s), the monitoring formula for the vehicle speed V is:

[0121] V=d / t=x / s

[0122] For example: There are P and Q monitoring piles, and the two monitoring piles simultaneously emit lasers with the same pulse width, the same pulse frequency, and different wavelengths. If a car Figure 1 If the position blocks the laser of the P monitoring pile, the laser receiving and detection module loses the P laser signal, but the Q laser signal remains, and the position of vehicle 1 can be obtained from the Q signal;

[0123] 2. Distance measurement principle (i.e. measuring the lane)

[0124] like Figure 5 As shown, two pulsed lasers ( Figure 5 The two different dotted lines and short lines in the figure represent that the wavelengths of the two pulsed lasers are different and they are in the same optical path. 轮距 The pulse signal disappearance time is calculated based on the wheelbase of the vehicle, a is the distance between the vehicle and the edge of the road on the transmitting side, and b is the distance between the vehicle and the edge of the road on the receiving side. Based on the light speed of the pulse laser in this environment, the distance between the vehicle's lateral position and the monitoring pile can be obtained, and thus its current lane position can be obtained.

[0125] Example: Assume the lane position error can be set to n (cm) (n is also the distance between two adjacent laser points), and the total lane width L (m). Then, there are M equally spaced laser points on the road. A pair of monitoring piles emit two horizontal laser beams of different wavelengths in opposite directions (eliminating interference and crosstalk). The vehicle's wheelbase is d. When the vehicle's front tire blocks the laser, the distances received by the transmitting and receiving sides are a and b, respectively. The vehicle's distance x on the receiving side of the road is then calculated as follows:

[0126] x=(L-|ab|*nd) / 2

[0127] In the above formula, when ab<0, the vehicle is considered to be at a distance x from the transmitting side of the road; when ab>0, the vehicle is considered to be at a distance x from the receiving side of the road; when ab=0, the vehicle is considered to be in the middle of the road, at a distance x from both sides of the road. Therefore, there is no need to measure the speed, and the lateral position of the vehicle on the road can be obtained by simply comparing the disappearance time of the signals from different monitoring piles (when the lateral position is fixed and the total lane width L and the width of each lane are known, it is easy to determine which lane the current vehicle is in).

[0128] The system working principle of the present invention mainly includes:

[0129] 1. Information synchronization stage when entering the highway

[0130] Because the system of the present invention does not have the function of directly identifying vehicle information at the physical level, it is necessary to use the ETC system of the toll station or the violation camera of the high-speed acceleration lane to jointly identify the vehicle identity information. The system marks the vehicle by receiving the identification information of the ETC or the violation camera of the high-speed acceleration lane and tracks the driving trajectory in real time (the marking here means: at this time, the ETC system or camera and the system of the present invention simultaneously recognize that there is a vehicle at the same location, and the ETC or camera synchronizes the monitored vehicle identity information to the system). The system of the present invention has two solutions for vehicle information identification based on the different locations of vehicle information synchronization. The specific principles are as follows:

[0131] Solution 1: Synchronize vehicle identity information upon entering the toll station

[0132] This solution synchronizes vehicle information recorded at toll booths, including but not limited to: license plate number, vehicle model, basic dimensions, and, in the case of trucks, weight. When a vehicle passes through an ETC lane (e.g., the fourth ETC lane), the ETC system sends a notification that the vehicle is about to pass through the fourth lane, along with the vehicle's license plate and model information. Once the vehicle leaves the fourth ETC lane, it begins blocking the laser beam, and the system simultaneously begins recording the vehicle's real-time information until it leaves the highway.

[0133] like Figure 7 As shown, the specific synchronization method for synchronizing vehicle identity information at the toll station is as follows:

[0134] Step 1: When a vehicle passes through a toll station (ETC or manual channel), its license plate and vehicle model information will be synchronized with the toll collection system. For trucks, this includes its full weight.

[0135] Step 2: Start recording the starting point and driving duration of the vehicle as a criterion for determining driver fatigue.

[0136] Step 3: The vehicle enters the ramp, the tires begin to block the laser, and monitoring begins.

[0137] Option 2: Synchronize vehicle identity information in the acceleration lane

[0138] This solution uses the vehicle information captured by the high-position camera at the acceleration lane when the vehicle enters the acceleration lane from the ramp, including but not limited to: license plate number, vehicle model, basic vehicle size information, etc. If it is a truck, it also includes the vehicle weight. Figure 8 As shown, when a vehicle enters the acceleration lane from the ramp, due to the single-lane characteristic of the acceleration lane, all passing vehicles need to queue up physically. This principle can be used to synchronize vehicle information. The high-position camera in the acceleration lane takes a photo of each vehicle passing through the highway to detect violations in the acceleration lane. The high-position camera recognizes vehicle information and synchronizes vehicle identity information with the monitoring system, and the monitoring system begins to monitor the vehicle's driving status in real time.

[0139] like Figure 9 As shown, the specific synchronization method for synchronizing vehicle identity information in the acceleration lane is as follows:

[0140] Step 1: The vehicle leaves the ramp and enters the acceleration lane, and the high-position camera in the acceleration lane captures the vehicle information.

[0141] Step 2: The system starts to synchronize its information and begins to record its driving starting point and driving duration as a criterion for determining driver fatigue driving.

[0142] Step 3: The vehicles simultaneously enter the acceleration lane, begin blocking the laser, and start monitoring.

[0143] Both of the above methods detect the location of the vehicle through its physical irreplaceability and non-superposition. The specific idea is that when a vehicle enters the area, the laser in that area is blocked, and by comparing the reception of two adjacent pulsed lasers, its location is obtained.

[0144] 2. Normal high-speed driving stage

[0145] In the free driving stage of the system, since the vehicle identity information has been recorded in the information synchronization stage and its physical location is irreplaceable, its identity information can be synchronized while monitoring the vehicle's driving status without a camera.

[0146] like Figure 10 As shown, by comparing the duration of the two pulsed laser signals, the system can determine the lane information of the vehicles. It can also know that Car A is currently in Area A. Whether Car B is driving in the lane to the left or right of Car A, it cannot interfere with the system's determination of Car A's current physical location. Similarly, Car A cannot interfere with the physical location determination of Car B. Therefore, as long as Car A (Car B) leaves the toll station (at the end of the ramp) and enters the monitoring area, the system can continuously monitor it and ensure accurate identification of Car A (Car B)'s identity and driving status without the need for subsequent camera recognition.

[0147] Furthermore, the real-time tracking state method during driving is also based on the irreplaceable physical location. Figure 11 To simulate the continuous lane change trajectory of car A, it can be seen that Figure 9 Vehicle A changes lanes roughly along the direction of the yellow line. Due to the continuity and irreplaceability of its physical location, its identity information can be synchronized in real time and its driving can be monitored.

[0148] Furthermore, when two vehicles of the same model run absolutely side by side for a long time (i.e., absolutely aligned in the geometric sense), e.g. Figure 12 As shown in the figure, there is a monitoring blind spot between car A and car B. However, according to relevant Chinese traffic regulations, in this case, car A can be deemed to have illegally occupied the highway lane. This situation is almost impossible to occur in reality (because the vehicles involved are different in model, length, tire position, height, etc.). As long as it is not Figure 12 In the case of cars A and B, their identity information and driving status can definitely be distinguished. For example, for cars C and D, since the laser surfaces blocked by their tires do not completely overlap, the lane information of the vehicles can be monitored even if they are driving at the same speed.

[0149] When the lane is a two-way six-lane, three vehicles may run parallel for a long time, such as Figure 12 As shown in the G, F and E cars (It should be noted that Figure 12 In the figure, z is the occlusion surface of the three vehicles' tires, x is the distance between the actual occlusion surface of vehicle F and the rear of the total occlusion surface, y is the distance between the actual occlusion surface of vehicle F and the front of the total occlusion surface, and s is the total length of the occlusion surface of the tires of a single vehicle. The overlap of the occlusion surfaces of the three vehicles has no effect on vehicles G and E, but puts vehicle F in the blind spot. Figure 12 The error range of positioning the front end of the occluding surface can be obtained from the middle mark:

[0150] s≤y≤z-2s

[0151] That is, in this case, we can only determine if car F Figure 13 The afb region in Figure 13 In the example, when the front edge of car C's tire is completely tangent to the rear edge of car D's tire, the possible positions of the entire tire occlusion surface of car F in the middle are as follows: the possible position range of the front edge of car F is a), f is its absolute existence area, and it is only uncertain whether it is in area af or area bf. According to calculations, the maximum error range in this case is 20-2

[0152] 5cm, the specific situation is as follows Figure 14 The fa area in (when the front edge of the occlusion surface of the G car's tire is not tangent to the rear edge of the occlusion surface of the E car's tire (that is, there is a distance), the afb area is the possible location of the entire occlusion surface of the F car's tire, and the b area is the possible location of the front edge of the occlusion surface of the F car's tire).

[0153] The above is the error that may occur in the parallel situation during normal driving of this solution. To achieve the above situation, the following conditions must be met:

[0154] 1. The vehicles involved must be identical in model and size, including but not limited to identical tire wear, identical wheel alignment standards, identical steering wheel positions, and identical tire replacements. This means they are physically identical vehicles.

[0155] 2. The driving speed involved is exactly the same

[0156] 3. The vehicle tire obstruction surface perfectly overlaps

[0157] 4. The vehicles must run in perfect parallel in this state for a long time without any deviation in the middle

[0158] Based on the system's monitoring of its position, its driving status information can be known, such as speeding, slow driving, repeated weaving, etc., and information on accidents such as rear-end collisions and scratches can also be obtained (when the system monitors the minimum distance of the distance effect on both sides is 0).

[0159] 3. Exiting the highway

[0160] When a vehicle is about to reach its destination and is preparing to exit the highway, it enters the deceleration lane. The system can end monitoring directly at the deceleration lane and the ramp entrance. If necessary, monitoring piles can continue to be arranged on the ramp until the toll station. However, this behavior is of little significance. At this stage, it is already known that the vehicle is about to leave the highway, and it makes little difference whether the monitoring is ended in the deceleration lane or at the toll station.

[0161] The vehicle's speed (longitudinal speed), lateral speed, and lateral position are calculated as follows:

[0162] 1. Speed and mileage position

[0163] The time difference between the vehicle crossing two adjacent laser beams and the mapping relationship between spectrum and position can be used to obtain its speed and current position. Let the time difference between the two laser beams disappearing be Δt i , the distance covered by m wavelength lasers (one) in a matrix unit is L1, and the laser wavelength is λ, λ k+1 ,λ k It is used to characterize two adjacent laser beams arranged in sequence and with wavelengths changing in sequence. The number of L1s traveled from the starting point H is w, and V 纵i is the average speed between the two monitoring piles, is the average speed of all B corresponding segments traversed, dt j is the total time of the corresponding segment, dt i The speed is V 纵i When , the distance obtained by integrating the time period is j, which represents the jth segment L1 that has been traveled;

[0164]

[0165] 2. The lateral position can be obtained by the number of pulse lasers received by the receiver after the vehicle blocks the laser, such as Figure 15 As shown ( Figure 15 This is a rough layout diagram of the entire system when a car is driving on the road. Its driving speed is obtained by the disappearance time of the two light paths AB, and its lateral position is obtained by the pulse laser point contained in the distance between the ends a1 and a2. Figure 15 L represents the road width, and X represents the vehicle's wheelbase. It should be noted that: Figure 15The system only includes two sets of bidirectional laser monitoring systems. In actual applications, there may be hundreds of bidirectional laser monitoring systems on a certain distance to form a monitoring network. Let a1 and a2 be two laser beams with the same optical path on the receiving and transmitting sides, respectively. The time when the a1 signal disappears is t1, and the time when the a2 signal disappears is t2. The laser point detected by the unidirectional laser receiving and detection module during the time t1-t2 (if it is not blocked, the bidirectional laser receiving and detection module can detect the laser point) is n. A1 and B1 are two monitoring laser beams with different wavelengths. Z1 and Z2 are the distances from the transmitting point and the laser receiving and detection module to the monitoring laser beam.

[0166] 1. Contact starts occlusion

[0167]

[0168] In the above formula, X 横始 is the lateral position of the vehicle body from the opposite side of the road when the vehicle tire just contacts the laser at the monitoring point in the single-vehicle driving state, t1 is the time when the laser signal on the receiving side disappears during the non-blocking period, t2 is the time when the laser signal on the receiving side disappears during the non-blocking period, L is the total width of the highway available, X 轮距 is the wheelbase of the vehicle, is the laser point detected by the unidirectional laser receiving and detection module during the time t1-t2, and n is the distance between two adjacent laser points; when t1-t2<0—the vehicle is on the road near the transmitting and receiving side X 横 At the distance, when t1-t2>0—the vehicle is on the road near the receiving side X 横 At the distance, when t1-t2=0, the vehicle is in the middle of the road, and the distance from both sides of the road is X 横 , thus, the lateral position of the vehicle on the road can be obtained without having to compare the disappearance time of the signals of different monitoring piles as required for speed measurement.

[0169] 2. Leave and stop blocking

[0170]

[0171] In the above formula, X 横止 is the lateral position of the vehicle tire from the opposite side of the road when the vehicle leaves the monitoring point laser in the single-vehicle driving state, t3 is the time when the laser signal on the receiving side disappears during the occlusion period, and t4 is the time when the laser signal on the receiving side disappears during the occlusion period. is the laser point detected by the unidirectional laser receiving and detection module during the time t3-t4. Specifically, the a1 signal appears at t3, and the a2 signal appears at t4. During the time t3-t4, the unidirectional laser receiving and detection module monitors w laser points (if there is no obstruction, the bidirectional laser receiving and detection modules can monitor the laser points).

[0172] 3. Lateral speed of the bicycle during occlusion and non-occlusion

[0173] The lateral velocity during the occlusion period is mainly the lateral displacement of the occluding tire, so Expressed as:

[0174]

[0175] Lateral velocity during non-occlusion period for:

[0176]

[0177] In the above formula, Δt i is the disappearance time difference between two adjacent monitoring laser beams, and Δtk is the time when a single tire of the vehicle blocks the laser;

[0178] 4. The lateral position of the rear vehicle when the two vehicles are parallel (same as the above error situation)

[0179] Let the vehicle tire occlusion surface be X 轮遮面 , then the lateral position X of the rear vehicle can be obtained from the tire occlusion surface of the two vehicles. 横后 for:

[0180]

[0181] If X 横后 <X 轮距后 , the two vehicles are judged to have collided, and the safety zone of the rear vehicle needs to meet the following conditions:

[0182]

[0183] 5. Minimum deceleration distance

[0184] The vehicle's resistance F can be obtained from the vehicle's friction coefficient and wind resistance coefficient, and its deceleration acceleration a can be obtained. μ0 is the zero-speed rolling friction coefficient, k r is the rolling friction velocity gradient coefficient, C d is the drag coefficient, ρ is the air density, A' is the frontal area, and f is the maximum braking force of the vehicle. When the distance between two vehicles is too close, the minimum deceleration distance is obtained by the following formula to predict whether it will collide with the vehicle in front. The minimum deceleration distance X can be obtained to assist in the measurement of the automatic emergency braking system AEB on the vehicle:

[0185]

[0186]

[0187] In the above formula, m′ is the mass of the vehicle, g is the acceleration due to gravity, v is the velocity, and d is the integral sign;

[0188] The application method of the system of the present invention can be linked with other systems to achieve the following effects:

[0189] Monitor the speed and lane information of vehicles traveling on highways;

[0190] Based on the changes in the vehicle's position and speed, it helps control illegal behaviors such as slow driving, speeding, illegal weaving, malicious cutting, and illegal occupation of emergency lanes on highways;

[0191] When two vehicles collide or encounter an accident, the background computer can display it in real time. The accident will be reflected on the page immediately, so as to facilitate the monitoring of highway accident information and immediately report it to the traffic management department, fire department and emergency department for processing;

[0192] Based on the positional relationship between vehicles, it is used to predict possible accidents such as rear-end collisions, cross-traffic interruptions, speeding rollovers, etc.

[0193] This invention provides the most basic road vehicle information for the Internet of Vehicles, promoting the implementation of L4 autonomous driving on highways;

[0194] In fog and rainstorms, the laser light intensity varies, and the presence of fog and rainstorms can be determined based on this change in light intensity. When a road collapses, the optical fiber will also be torn, indicating a road collapse. This invention can be used to monitor natural disasters such as fog, rainstorms, and road collapses on highways and provide timely feedback to relevant departments and vehicles on the road to prevent serious traffic accidents.

[0195] The above solution is only an illustration of a preferred embodiment, but is not limited thereto. When implementing the present invention, appropriate replacements and / or modifications can be made according to user needs.

[0196] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and exemplary embodiments. They can be applied to a variety of fields suitable for the present invention. Further modifications will be readily apparent to those skilled in the art. Therefore, the present invention is not limited to the specific details and illustrations shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims

1. A system for real-time monitoring of vehicle driving status on highways, characterized in that: include: Two sets of pulse laser integrated emission subsystems are installed on both sides of the highway; Data acquisition cards are installed on both sides of the highway and work with the pulse laser integrated emission subsystem; Each set of pulse laser integrated emission subsystem includes m matrix units, and each matrix unit includes: a pulse laser integrated emission unit and a corresponding laser receiving and detection module; Each laser receiving and detecting module is connected to the host computer through a data acquisition card.

2. The system for real-time monitoring of vehicle driving status on a highway according to claim 1, characterized in that: The pulse laser integrated emission unit comprises: A tunable laser that generates and emits continuous laser light within a predetermined wavelength range; A signal generator that generates corresponding pulse signals based on the pulse frequency instructions of the host computer; An acousto-optic modulator that modulates continuous laser light into pulsed laser light based on a received pulse signal; A narrow-band optical fiber filter that filters the pulsed laser to make the output pulsed laser a single wavelength; 1 / 2 optical splitter I that performs initial optical splitting on the light transmitted by the narrowband optical fiber filter; An infrared and ultraviolet cut-off filter for filtering the infrared or ultraviolet laser in the light beam I at the output side of the 1 / 2 beam splitter I; a visible light source located downstream of the infrared and ultraviolet cutoff filters; 1 / 2 beam splitter II for performing secondary beam splitting on the light beam II at the output side of 1 / 2 beam splitter I; The laser receiving and detecting module I is adapted to one output side of the 1 / 2 optical splitter II, and the other output side of the 1 / 2 optical splitter II is adapted to the transmission optical fiber of the receiving side.

3. The system for real-time monitoring of vehicle driving status on a highway as claimed in claim 1, characterized in that: It also includes a transmitting side transmission module and a receiving side transmission module that cooperate with the pulse laser integrated transmitting subsystem; The transmitting side transmission module includes: 1 / n optical splitter group I matched with 1 / 2 optical splitter II; A 1 / nx optical splitter group matched with one of the output optical paths of the 1 / n optical splitter group, wherein the value of x is 1, 2, 3, or n-1. When x is n-1, a direct optical fiber connection is adopted; collimating optical fiber interface groups respectively matched with the output optical path of the 1 / nx optical splitter group I and the other output optical paths of the 1 / n optical splitter group I; A horizontally emitting laser group matched with the collimating fiber interface group; The receiving side transmission module includes: A horizontal receiving laser group coordinated with the horizontal transmitting laser group; Transmit the light beam transmitted by the horizontal receiving laser group to the 1 / n optical splitter group II of the laser receiving and detection module; A 1 / nx optical splitter group II is matched with one of the output optical paths of the 1 / n optical splitter group.

4. An application method, which uses the system for real-time monitoring of the driving status of vehicles on a highway according to any one of claims 1 to 3, characterized in that: include: Step 1: When a vehicle enters a toll booth or acceleration lane, the vehicle's identity information is identified by the ETC system and / or the high-speed acceleration lane violation camera, and then sent to the system for synchronization. The vehicle's starting point and driving duration are recorded to determine whether there is fatigue driving. The vehicle identity information includes: license plate number, vehicle model, vehicle size, vehicle weight, and lane number; Step 2: After leaving the corresponding lane and entering the system's monitoring range, the vehicle body will block the pulsed lasers at different positions during driving. The system obtains and records the vehicle's driving status information on the highway based on the persistence of the signals of two adjacent pulsed lasers at different positions to determine whether there are any illegal operations until the vehicle leaves the highway; The driving status information includes longitudinal speed, mileage position from the starting point, lateral speed, and lane information.

5. The system for real-time monitoring of vehicle driving status on a highway as claimed in claim 1, characterized in that: The longitudinal speed The way to obtain is: In the above formula, m is the number of lasers of different wavelengths that can be received in a matrix unit element, V 纵i is the average speed between two adjacent monitoring points, and V 纵i Obtained by the following formula: In the above formula, Δt i is the disappearance time difference between two adjacent monitoring laser beams, λ is the laser wavelength, and λ k+1 ,λ k It is used to characterize two adjacent laser beams arranged in sequence with wavelengths changing sequentially, and d is the distance between the two adjacent laser beams; The mileage position H from the starting point is obtained by the following formula: In the above formula, dt j is the total time of the corresponding segment, dt i The speed is V 纵i When , integrate the distance obtained for the time period.

6. The system for real-time monitoring of vehicle driving status on a highway as claimed in claim 1, characterized in that: The lateral speed is the lateral speed of the bicycle during the non-blocking period Lateral velocity during occlusion They are obtained by the following formulas: In the above formula, Δt i is the disappearance time difference of two adjacent monitoring laser beams, Δtk is the time when a single tire of the vehicle blocks the laser, X 横始 is the lateral position of the vehicle body from the opposite side of the road when the vehicle tire just contacts the laser at the monitoring point in the single-vehicle driving state, and X 横始 It is characterized by the following formula: In the above formula, t1 is the time when the laser signal on the receiving side disappears during the non-blocking period, t2 is the time when the laser signal on the receiving side disappears during the non-blocking period, L is the total width of the highway, X is the total width of the highway, 轮距 is the wheelbase of the vehicle, is the laser point detected by the unidirectional laser receiving and detection module during the time t1-t2, and n is the distance between two adjacent laser points; X 横止 is the lateral position of the vehicle tire from the opposite side of the road when the vehicle leaves the monitoring point laser in the single-vehicle driving state, and X 横止 It is characterized by the following formula: In the above formula, t3 is the time when the laser signal on the receiving side disappears during the shielding period, t4 is the time when the laser signal on the receiving side disappears during the shielding period, It is the laser point detected by the unidirectional laser receiving and detection module during the time t3-t4.

7. The system for real-time monitoring of vehicle driving status on a highway as claimed in claim 6, characterized in that: The lateral position X of the rear vehicle when the two vehicles are parallel 横后 Should be equal to X 横止 , but if X 横后 <X 轮距后 , then it is determined that the two cars collided, X 轮距后 is the wheelbase of the vehicle's rear wheels; The safety distance of the rear vehicle must meet the following conditions: In the above formula, X 轮距前 is the wheelbase of the vehicle in front.

8. The system for real-time monitoring of vehicle driving status on a highway as claimed in claim 1, characterized in that: Assume that when the front wheel tire of the vehicle blocks the laser, the disappearance time of the two pulse laser signals with different wavelengths on the transmitting and receiving sides can be used to obtain the length of the vehicle's lateral position from the monitoring point through the speed of light of the laser in this environment, and thus the current lane position of the vehicle can be obtained.

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