Beidou-based highway accident quick response method and system

Abstract

The invention relates to the technical field of intelligent traffic control, in particular to an expressway accident quick response method and system based on Beidou, and the method comprises the following steps: collecting three-axis acceleration and vehicle longitude and latitude, calculating a vector modulus length, comparing the vector modulus length with a threshold value, determining an accident grade state code, and carrying out the calculation; a Beidou accident short message is constructed through serialized data and sent through a satellite link, the message is analyzed to extract information, the spherical distance between an accident point and candidate rescue vehicles is calculated to establish a list, target rescue vehicles are selected in an ascending order, and a rescue task instruction is sent. According to the method, the collision level is judged by calculating the vector modulus length, messages are transmitted through a Beidou satellite link, the coverage limitation of a ground communication network is broken through, it is ensured that a dangerous case is stably reported when a signal blind area or a person is coma, the spherical distance is automatically calculated, the target vehicle is locked, and the tedious link of manual re-check scheduling is eliminated; and automatic matching and quick response of the optimal rescue resources are realized.

Description

Technical Field

[0001] This invention relates to the field of intelligent traffic control technology, and in particular to a rapid response method and system for highway accidents based on BeiDou. Background Technology

[0002] Intelligent traffic control refers to a technological system that utilizes sensors, communication networks, signal controllers, and a central management platform deployed along roads to monitor and dispatch road traffic flow, vehicle operating status, and emergencies. Traditional rapid response methods for highway accidents involve personnel at the accident scene using handheld mobile communication terminals to access the public mobile communication network via roadside cellular base stations. They then transmit voice alarm signals or accident scene image data collected through an application via a terrestrial fiber optic transmission network to the emergency dispatch server at the highway emergency command center. Command center personnel confirm the accident location using a computer-aided dispatch terminal and issue dispatch orders to road patrol vehicles and clearing and rescue teams within their jurisdiction via a dedicated wireless communication trunking system or wired telephone network.

[0003] Current technology relies on on-site personnel using handheld terminals to access the public network for alarms via roadside cellular base stations. However, due to limitations in the coverage of public communication networks and the stability of ground transmission, transmission is easily interrupted in remote areas or extreme environments due to signal blind spots and network congestion. Furthermore, manual alarms heavily depend on active operation by personnel. If a serious accident occurs and a person becomes unconscious, they will be unable to send a distress signal. At the same time, the command center relies on manual confirmation of station numbers and voice dispatch, resulting in complex and inefficient information flow processes. It is difficult to quickly locate the nearest rescue resources, leading to delayed instructions and missed opportunities for optimal rescue. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a rapid response method and system for highway accidents based on BeiDou.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a rapid response method for highway accidents based on BeiDou, comprising the following steps:

[0006] S1: Collect triaxial acceleration data and vehicle latitude and longitude coordinates, calculate the vector magnitude of the triaxial acceleration data to generate a resultant acceleration value, compare the resultant acceleration value with a preset collision judgment threshold, and generate an accident level status code according to a preset interval mapping relationship when the resultant acceleration value is greater than the preset collision judgment threshold.

[0007] S2: Serialize the vehicle's latitude and longitude coordinates and the accident level status code to generate a fixed-length location code and an accident status bit stream, obtain the vehicle identification code and the event occurrence timestamp, concatenate the fixed-length location code, the accident status bit stream, the vehicle identification code and the event occurrence timestamp to construct a Beidou accident short message, and send the Beidou accident short message through a satellite link;

[0008] S3: Parse the Beidou accident short message to extract the vehicle's latitude and longitude coordinates and the accident level status code, obtain the candidate rescue vehicle location set, calculate the spherical distance between the vehicle's latitude and longitude coordinates and the candidate rescue vehicle location set, and establish a rescue distance value list;

[0009] S4: Sort the list of rescue distance values ​​in ascending order and select the first target rescue vehicle. Construct a rescue mission instruction based on the vehicle's latitude and longitude coordinates and the accident level status code, and send the rescue mission instruction to the target rescue vehicle through the ground station.

[0010] As a further aspect of the present invention, step S1 specifically comprises:

[0011] S11: The vehicle-mounted inertial measurement unit collects the three-axis acceleration data of the X-axis, Y-axis and Z-axis in real time at a preset sampling frequency, and obtains the latitude and longitude coordinates of the vehicle at the current moment through the Beidou positioning module. The Kalman filter algorithm is used to denoise and smooth the three-axis acceleration data to generate a standardized acceleration component sequence.

[0012] S12: Extract the three components at the same moment from the normalized acceleration component sequence, calculate the physical vector length at that moment according to the Euclidean norm rule, and correct the calculation result by combining the gravitational acceleration compensation coefficient to generate the resultant acceleration value.

[0013] S13: Obtain the preset collision determination threshold and the preset interval mapping relationship stored in the local control unit, compare the resultant acceleration value with the preset collision determination threshold, and when the determination result is true, retrieve the value interval into which the resultant acceleration value falls in the preset interval mapping relationship, and extract the identifier corresponding to the interval to generate the accident level status code.

[0014] As a further aspect of the present invention, step S2 specifically comprises:

[0015] S21: Obtain the longitude and latitude floating-point values ​​in the vehicle's latitude and longitude coordinates, use a binary space segmentation algorithm to convert the longitude and latitude floating-point values ​​into binary strings with a preset bit length, and perform interleaving and merging processing on the two binary strings to generate the fixed-length position code;

[0016] S22: Parse the accident level status code and extract its corresponding severity level identifier, map the severity level identifier into a binary sequence of target length according to a preset status compression protocol, add parity check bits, and generate the accident status bit stream;

[0017] S23: Obtain the vehicle identification code stored in the vehicle terminal read-only memory and the event occurrence timestamp output by the Beidou timing module. According to the frame structure specified in the Beidou short message communication protocol, fill the fixed-length position code, the accident status bit stream, the vehicle identification code and the event occurrence timestamp into the user data segment in sequence, and add a frame header and a frame tail to construct the Beidou accident short message.

[0018] As a further aspect of the present invention, step S3 specifically comprises:

[0019] S31: Demodulate the satellite downlink signal through the ground receiving station and parse the Beidou accident short message. Extract the user data segment content in reverse according to the frame structure definition, separate the vehicle's latitude and longitude coordinates and the accident level status code, and store the parsing result in the accident processing event queue.

[0020] S32: Read the preset rescue resource distribution database, take the vehicle's latitude and longitude coordinates as the center point, take the preset maximum response radius as the search boundary, use the spatial indexing algorithm to filter all idle rescue vehicles located within the boundary, and generate the candidate rescue vehicle location set;

[0021] S33: Traverse each location point in the candidate rescue vehicle location set, call the Earth's great circle distance calculation logic, calculate the spherical arc length between the vehicle's latitude and longitude coordinates and multiple location points respectively, associate the calculated distance values ​​with the corresponding vehicle IDs, and establish the rescue distance value list.

[0022] As a further aspect of the present invention, step S4 specifically comprises:

[0023] S41: Obtain the list of rescue distance values, sort the distance elements in the list in ascending order using a quicksort algorithm, locate the vehicle ID associated with the element with the smallest value in the list, and mark it as the target rescue vehicle that will perform this rescue mission.

[0024] S42: Generate a navigation waypoint for the accident location based on the vehicle's latitude and longitude coordinates, match the corresponding rescue equipment list and medical plan with the rescue demand level indicated by the accident level status code, encapsulate the navigation waypoint, the rescue equipment list and the medical plan into a data packet, and construct the rescue mission instruction;

[0025] S43: Establish a dedicated wireless communication link between the ground station and the target rescue vehicle, modulate the rescue mission command into a radio frequency signal and send it to the vehicle-mounted receiving terminal of the target rescue vehicle, and simultaneously listen for the confirmation receipt signal of the terminal.

[0026] As a further aspect of the present invention, the calculation process of the resultant acceleration value and the generation process of the accident level status code include:

[0027] Obtain the X-axis acceleration components Y-axis acceleration components and Z-axis acceleration components The original modulus length is calculated using the formula for the sum of squares and the square root, and then the gravitational acceleration constant is subtracted. The resultant acceleration value after gravity compensation is obtained. Calculation formula:

[0028] ;

[0029] in, Represents the vehicle's lateral acceleration. Represents the vehicle's longitudinal acceleration. Represents the vehicle's vertical acceleration. Represents the standard gravitational acceleration constant. Represents the net acceleration used for collision detection;

[0030] Get the preset minor collision threshold Severe collision threshold and fatal collision threshold ,like If so, it is determined to be a minor accident and a level 1 status code is generated;

[0031] like If so, it is determined to be a serious accident and a level 2 status code is generated;

[0032] like If the condition is met, it is determined to be a fatal accident and a level 3 status code is generated.

[0033] As a further aspect of the present invention, the generation process of the fixed-length position code includes:

[0034] Obtain the longitude interval where the vehicle's latitude and longitude coordinates are located. and latitude range The longitude interval and the latitude interval are subjected to binary search iterations to determine whether the vehicle's longitude and latitude coordinates fall in the left or right interval after binary search. If it falls in the right interval, the bit is marked as 1; if it falls in the left interval, the bit is marked as 0. The iterations are repeated until the preset precision bits are reached, and longitude binary strings and latitude binary strings are generated respectively.

[0035] Obtain the multiple digits of the longitude binary string and the multiple digits of the latitude binary string, and perform bit-by-bit combination according to the rule of "even-numbered digits for longitude and odd-numbered digits for latitude" to generate a unique binary sequence as the fixed-length position code.

[0036] As a further aspect of the present invention, the calculation process of the spherical distance includes:

[0037] Obtain the latitude of the vehicle's latitude and longitude coordinates. and longitude And the latitude of a certain vehicle location in the candidate rescue vehicle location set. and longitude Convert the angle value to a radian value, and use the semi-versus formula to calculate the spherical distance between the two points. Calculation formula:

[0038] ;

[0039] in, Represents the average radius of the Earth. The latitude radian value representing the accident location. The latitude radian value represents the rescue point. The longitude in radians represents the location of the accident. The longitude in radians represents the location of the rescue point. This represents the calculated spherical distance.

[0040] As a further aspect of the present invention, the process of constructing the rescue mission instruction includes:

[0041] Obtain the current location coordinates of the target rescue vehicle, call the online map service application interface, use the current location coordinates as the starting point and the vehicle's latitude and longitude coordinates as the ending point, combine real-time traffic information to plan the optimal driving route, and generate a route navigation data package;

[0042] Obtain a preset rescue resource configuration table associated with the accident level status code, parse the table to extract the required emergency equipment type code, the required number of medical personnel, and on-site handling operation specifications, encapsulate the path navigation data packet with the extracted information, and generate the rescue mission instruction.

[0043] A BeiDou-based rapid response system for highway accidents, wherein the BeiDou-based rapid response system for highway accidents is used to implement the aforementioned BeiDou-based rapid response method for highway accidents, the system comprising:

[0044] The accident detection and analysis module is used to collect triaxial acceleration data and vehicle latitude and longitude coordinates, calculate the vector magnitude of the triaxial acceleration data to generate a resultant acceleration value, compare the resultant acceleration value with a preset collision judgment threshold, and generate an accident level status code according to a preset interval mapping relationship when the resultant acceleration value is greater than the preset collision judgment threshold.

[0045] The message encoding and sending module is used to serialize the vehicle's latitude and longitude coordinates and the accident level status code to generate a fixed-length location code and an accident status bit stream, obtain the vehicle identification code and the event occurrence timestamp, splice the fixed-length location code, the accident status bit stream, the vehicle identification code and the event occurrence timestamp to construct a Beidou accident short message, and send the Beidou accident short message through a satellite link;

[0046] The rescue matching calculation module is used to parse the Beidou accident short message to extract the vehicle's latitude and longitude coordinates and the accident level status code, obtain a set of candidate rescue vehicle locations, calculate the spherical distance between the vehicle's latitude and longitude coordinates and the set of candidate rescue vehicle locations, and establish a list of rescue distance values.

[0047] The task scheduling and distribution module is used to sort the list of rescue distance values ​​in ascending order and select the first target rescue vehicle. It constructs a rescue task instruction based on the vehicle's latitude and longitude coordinates and the accident level status code, and sends the rescue task instruction to the target rescue vehicle through the ground station.

[0048] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0049] In this invention, collision levels are determined by collecting triaxial acceleration data and calculating the vector magnitude, which is then compared with a threshold value. This enables automatic perception of vehicle accident status. By combining the vehicle's latitude and longitude to construct a BeiDou short message and transmitting it via satellite link, the limitations of ground-based public communication network coverage are effectively overcome. This ensures stable reporting of emergencies even in signal blind spots or when personnel are unconscious and unable to operate the system. Simultaneously, the spherical distance to candidate rescue vehicles is automatically calculated based on analytical coordinates and accident levels. By arranging the vehicles in ascending order, the target vehicle is accurately located and commands are directly issued. This eliminates the cumbersome manual review and scheduling process, achieving automatic matching and rapid response of optimal rescue resources. Attached Figure Description

[0050] Figure 1 This is a flowchart of the BeiDou-based rapid accident response method of the present invention;

[0051] Figure 2 This is a flowchart of the accident level determination and status code generation process of the present invention;

[0052] Figure 3 This is a flowchart illustrating the construction and encoding process of BeiDou accident short messages in this invention.

[0053] Figure 4 This is a flowchart of the rescue vehicle screening and distance calculation process of the present invention;

[0054] Figure 5 This is a flowchart illustrating the construction and transmission process of rescue mission instructions in this invention. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the software-based technical solution is described in detail below with reference to system architecture diagrams and embodiments. It should be understood that the specific embodiments described herein are only for explaining the technical solutions of this invention and do not constitute a limitation on the scope of protection.

[0056] In the description of this invention, the system architecture relationships or data processing flows indicated by terms such as "layer," "module," "interface," "data flow," "client," and "server" are all defined based on the architecture diagram or flowchart corresponding to the embodiments. This way of describing is only used to clearly illustrate the logical relationships between the elements in the technical solution, and not to limit the physical deployment form. The term "multiple" includes two or more technical units, including but not limited to multiple data nodes, processing threads, service instances, or functional components and other scalable elements. The specific number is determined according to the actual business scenario and needs to be specifically specified.

[0057] Please see Figure 1 and Figure 2 This invention provides a technical solution: a rapid response method for highway accidents based on BeiDou, comprising the following steps:

[0058] S1: Collect triaxial acceleration data and vehicle latitude and longitude coordinates, calculate the vector magnitude of the triaxial acceleration data to generate a resultant acceleration value, compare the resultant acceleration value with a preset collision judgment threshold, and generate an accident level status code based on a preset interval mapping relationship when the resultant acceleration value is greater than the preset collision judgment threshold.

[0059] The specific steps of S1 are as follows:

[0060] S11: The vehicle-mounted inertial measurement unit collects three-axis acceleration data of X-axis, Y-axis and Z-axis in real time at a preset sampling frequency, and obtains the vehicle's latitude and longitude coordinates at the current moment through the Beidou positioning module. The Kalman filter algorithm is used to denoise and smooth the three-axis acceleration data to generate a standardized acceleration component sequence.

[0061] S12: Extract the three components at the same moment from the normalized acceleration component sequence, calculate the physical vector length at that moment according to the Euclidean norm rule, and correct the calculation result by combining the gravitational acceleration compensation coefficient to generate the resultant acceleration value.

[0062] S13: Obtain the preset collision judgment threshold and preset interval mapping relationship stored in the local control unit, compare the resultant acceleration value with the preset collision judgment threshold, and when the judgment result is true, search the numerical interval in the preset interval mapping relationship to find the numerical interval in which the resultant acceleration value falls, and extract the identifier corresponding to the interval to generate an accident level status code.

[0063] The calculation process for the combined acceleration value and the generation process for the accident level status code include:

[0064] Obtain the X-axis acceleration components Y-axis acceleration components and Z-axis acceleration components The original modulus length is calculated using the formula for the sum of squares and the square root, and then the gravitational acceleration constant is subtracted. The resultant acceleration value after gravity compensation is obtained. Calculation formula:

[0065] ;

[0066] in, Represents the vehicle's lateral acceleration. Represents the vehicle's longitudinal acceleration. Represents the vehicle's vertical acceleration. Represents the standard gravitational acceleration constant. Represents the net acceleration used for collision detection;

[0067] Get the preset minor collision threshold Severe collision threshold and fatal collision threshold ,like If so, it is determined to be a minor accident and a level 1 status code is generated;

[0068] like If so, it is determined to be a serious accident and a level 2 status code is generated;

[0069] like If the condition is met, it is determined to be a fatal accident and a level 3 status code is generated.

[0070] In a BeiDou-based highway operation scenario, the vehicle terminal first initiates a data acquisition thread, using the onboard microelectromechanical system (MEMS) inertial measurement unit (IMU) to sense physical quantities. The IMU's sampling frequency is set to 200Hz, meaning it reads sensor register values ​​every 5 milliseconds to ensure the complete impact waveform is captured at the moment of a high-speed collision. Simultaneously, the processor communicates with the BeiDou-3 satellite navigation and positioning module via a universal asynchronous transceiver (UAST) serial port, reading the positioning data stream in NMEA-0183 protocol format at a frequency of 10Hz, parsing the GNGGA statements, and extracting the vehicle's current latitude and longitude coordinates and Coordinated Universal Time (UTC).

[0071] The aforementioned microelectromechanical system inertial measurement unit refers to a miniature sensor system integrated on a chip, capable of measuring motion parameters such as acceleration and angular velocity of an object in three-dimensional space.

[0072] For the raw X-axis, Y-axis, and Z-axis acceleration data, direct use can lead to misjudgments due to high-frequency random noise such as engine vibration and road bumps during vehicle movement. Therefore, this embodiment constructs a Kalman filter for a linear discrete system to denoise and smooth the raw data. First, the system state vector is defined. Establish the state transition equation. and observation equations In this scenario, assuming the acceleration is constant within a very short sampling interval, the state transition matrix is... Set as identity matrix Control matrix Set to 0, observation matrix Set as Process noise covariance matrix Set as It is used to characterize the uncertainty within the system; the observation noise covariance matrix. The value is set to 0.15, which is derived from the statistical analysis of the basis noise variance of the sensor in a static state. The filtering iteration process strictly follows the following five sub-steps: First, calculate the prior estimate. and prior error covariance Secondly, calculate the Kalman gain. Next, we introduce the original acceleration observations at the current moment. Calculate the posterior estimate ,this This refers to the denoised standardized acceleration components; subsequently, the error covariance is updated. Finally, the processed X, Y, and Z axis data are stored in a circular buffer queue of length N to generate a standardized acceleration component sequence.

[0073] The aforementioned Kalman filter refers to a highly efficient recursive filter that can estimate the state of a dynamic system from a series of noisy measurements.

[0074] Subsequently, the processor extracts the same timestamp from the normalized acceleration component sequence. The three components below: lateral acceleration Longitudinal acceleration and vertical acceleration To quantify the severity of the impact, the physical vector length is calculated according to the Euclidean norm rule. A gravitational acceleration compensation mechanism needs to be introduced before the calculation because the Z-axis sensor is affected by the gravitational component when stationary. In this embodiment, a standard gravitational acceleration constant is set. for The resultant acceleration after gravity compensation is calculated using the formula. :

[0075] ;

[0076] in, Represents the vehicle's lateral acceleration. Represents the vehicle's longitudinal acceleration. Represents the vehicle's vertical acceleration. Represents the standard gravitational acceleration constant. This represents the net acceleration used for collision detection.

[0077] Suppose that at the instant of a rear-end collision, the acceleration components after Kalman filtering are: for , for , for Substitute into the formula to calculate the original modulus:

[0078] .

[0079] Calculate the resultant acceleration value after gravity compensation. :

[0080] .

[0081] In acquiring Then, the system calls the preset collision judgment threshold table and interval mapping relationship stored in local flash memory. The thresholds are set as follows: minor collision threshold for Severe collision threshold for Fatal collision threshold for The above example Compare with a threshold. The judgment logic is as follows: (i.e., greater than) Continue to make a judgment; (i.e., greater than) Continue to make a judgment; (i.e., less than or equal to) The judgment is complete. The value falls within the range. Based on the preset interval mapping relationship, the accident level corresponding to the interval is found to be a serious accident. The corresponding identifier (e.g., binary code 10) is extracted, and a secondary status code is generated. This result indicates that the current vehicle has experienced a relatively serious collision, and the system triggers the secondary response mechanism. To verify the impact of different filtering parameters and threshold settings on the accident recognition accuracy, multiple real-vehicle collision simulation experiments were conducted, and the data are shown in Table 1.

[0082] Table 1. Collision Detection Algorithm Parameter Verification and Results

[0083] Experiment number Realistic Collision Level Filter R value setting Calculated resultant acceleration (m / s²) Judgment Result Response time (ms) Test-001 slight 0.15 22.4 Minor accident 12 Test-002 serious 0.15 48.3 Serious accident 14 Test-003 serious 0.80 36.1 Minor accident 18 Test-004 fatal 0.15 92.5 fatal accident 13

[0084] As shown in Table 1, when the observed noise covariance When set to 0.15, the calculated resultant acceleration accurately reflects the actual collision intensity, and the system's accuracy reaches 100%. However, in Test-003, due to... The value was set too high (0.80), causing the filter to over-smooth the peak data, pulling the value down from around 48.3 to 36.1, thus misclassifying the incident level from severe to minor. This verifies the parameter settings in this embodiment. The rationality of the selection.

[0085] Please see Figure 1 and Figure 3 S2: Serialize the vehicle's latitude and longitude coordinates and accident level status code to generate a fixed-length location code and accident status bit stream, obtain the vehicle identification code and event timestamp, splice the fixed-length location code, accident status bit stream, vehicle identification code and event timestamp to construct a Beidou accident short message, and send the Beidou accident short message through the satellite link;

[0086] The specific steps of S2 are as follows:

[0087] S21: Obtain the floating-point values ​​of longitude and latitude in the vehicle's latitude and longitude coordinates, use the binary space segmentation algorithm to convert the floating-point values ​​of longitude and latitude into binary strings with a preset bit length, and perform interleaving and merging processing on the two binary strings to generate a fixed-length position code;

[0088] S22: Parse the accident level status code and extract its corresponding severity level identifier. According to the preset status compression protocol, map the severity level identifier into a binary sequence of target length, add parity check bits, and generate an accident status bit stream.

[0089] S23: Obtain the vehicle identification code stored in the vehicle terminal read-only memory and the event occurrence timestamp output by the Beidou timing module. According to the frame structure specified in the Beidou short message communication protocol, fill the fixed-length position code, accident status bit stream, vehicle identification code and event occurrence timestamp into the user data segment in sequence, and add frame header and frame tail to construct the Beidou accident short message.

[0090] The process of generating fixed-length positional codes includes:

[0091] Obtain the longitude interval of the vehicle's latitude and longitude coordinates and latitude range The longitude and latitude intervals are divided into two iterative intervals to determine whether the vehicle's longitude and latitude coordinates fall into the left or right interval after the division. If it falls into the right interval, the flag is set to 1; if it falls into the left interval, the flag is set to 0. The iteration is repeated until the preset precision bits are reached, and longitude binary strings and latitude binary strings are generated respectively.

[0092] Obtain multiple bits of longitude and latitude binary strings, and perform bit-by-bit combination according to the rule of "even-numbered bits for longitude and odd-numbered bits for latitude" to generate a unique binary sequence as a fixed-length position code.

[0093] Once step S1 determines an accident has occurred and generates a status code, the system immediately enters the data packetization phase. First, the vehicle's spatial location information is processed. The processor reads the latest floating-point longitude value (e.g., 114.12345) and floating-point latitude value (e.g., 30.54321). To efficiently transmit high-precision location data within the limited BeiDou short message payload, this embodiment employs a binary spatial segmentation algorithm for data compression. The preset precision bit depth is set to 20 bits.

[0094] The aforementioned binary space partitioning algorithm refers to a method for organizing spatial objects by recursively partitioning space into convex sets, which in this context is used to map continuous latitude and longitude values ​​into discrete binary sequences.

[0095] The longitude encoding process is as follows: The initial interval is The target value of 114.12345 is greater than the median value of 0 and falls within the right interval. Marked as 1; new interval The median value is 90, and 114.12345 is greater than 90, falling within the right interval. Marked as 1; new interval The median value is 135. 114.12345 is less than 135 and falls within the left interval. The value is marked as 0. This process is repeated 20 times in a binary search to generate the longitude binary string. The latitude encoding process is as follows: the initial interval is... The target value of 30.54321 is greater than the median value of 0 and falls within the right interval. Marked as 1; new interval The median value is 45, and 30.54321 is less than 45, falling within the left interval. The first bit is marked as 0. This process is repeated 20 times to generate a binary string representing latitude. Following the rule of placing even-numbered positions for longitude and odd-numbered positions for latitude (bit indices start from 0), the two 20-bit binary strings are merged into a single 40-bit binary sequence. For example, if the first two bits of the longitude string are 11 and the first two bits of the latitude string are 10, then the first four bits of the merged string are 1110. This constitutes a fixed-length positional encoding.

[0096] Next, the processor parses the accident level status code generated in step S1. It extracts the severity level identifier and converts it according to a preset status compression protocol. The protocol defines: Level 1 is mapped to binary 01; Level 2 to binary 10; and Level 3 to binary 11. In this example, the result of S1 is a Level 2 severe accident, so the binary sequence 10 is extracted. To improve transmission reliability, a parity bit is added at the end. Since the number of 1s is odd, even parity is used, so the parity bit is set to 1, generating the final 3-bit accident status bitstream 101. Simultaneously, the processor reads the unique vehicle identification code from the electrically erasable programmable read-only memory of the vehicle terminal and obtains the Coordinated Universal Time (UTC) timestamp of the accident from the BeiDou time synchronization module.

[0097] The message construction and transmission strictly follow the frame structure of the BeiDou short message communication protocol: the frame header is filled with a fixed synchronization word 0xEB90; the user address field is filled with the sender's BeiDou card ID; the information category is marked as an emergency alarm; the user data field is filled with a fixed-length location code (40 bits, 5 bytes), an accident status bit stream (3 bits, zero-padded to 1 byte), a vehicle identification code (converted to compressed BCD code, 8 bytes), and an event timestamp (4-byte unsigned integer); the checksum is calculated by XORing all bytes from the frame header to the data field and padded to the end; the frame tail is filled with 0x0D0A. After construction, the processor writes the encapsulated binary data packet into the transmission buffer of the BeiDou RF transmitter module through the serial peripheral interface and pulls the transmission enable pin high. When the BeiDou module detects that the satellite signal quality meets the transmission threshold (signal-to-noise ratio greater than 40dBHz), it sends a short message to the geostationary orbit satellite through the L-band. Experimental data shows that, using the binary compression encoding method of this embodiment, the data packet length is reduced by approximately 60% compared to directly transmitting ASCII strings.

[0098] Please see Figure 1 and Figure 4 S3: Parse the Beidou accident short message to extract the vehicle's latitude and longitude coordinates and accident level status code, obtain the candidate rescue vehicle location set, calculate the spherical distance between the vehicle's latitude and longitude coordinates and the candidate rescue vehicle location set, and establish a rescue distance value list;

[0099] The specific steps for S3 are as follows:

[0100] S31: Demodulate the satellite downlink signal and parse the BeiDou accident short message through the ground receiving station. Extract the user data segment content in reverse according to the frame structure definition, separate the vehicle latitude and longitude coordinates and the accident level status code, and store the parsing results in the accident processing event queue.

[0101] S32: Read the preset rescue resource distribution database, take the vehicle's latitude and longitude coordinates as the center point, and the preset maximum response radius as the search boundary. Use the spatial indexing algorithm to filter all idle rescue vehicles located within the boundary and generate a candidate rescue vehicle location set.

[0102] S33: Traverse each location point in the candidate rescue vehicle location set, call the Earth's great circle distance calculation logic, calculate the spherical arc length between the vehicle's latitude and longitude coordinates and multiple location points respectively, associate the calculated distance values ​​with the corresponding vehicle ID, and establish a rescue distance value list.

[0103] The calculation process for spherical distance includes:

[0104] Obtain the latitude of the vehicle's latitude and longitude coordinates and longitude And the latitude of the candidate rescue vehicle locations concentrated at a certain vehicle location. and longitude Convert the angle value to a radian value, and use the semi-versus formula to calculate the spherical distance between the two points. Calculation formula:

[0105] ;

[0106] in, Represents the average radius of the Earth. The latitude radian value representing the accident location. The latitude radian value represents the rescue point. The longitude in radians represents the location of the accident. The longitude in radians represents the location of the rescue point. This represents the calculated spherical distance.

[0107] The ground receiving station receives downlink signals from BeiDou satellites via a high-gain parabolic antenna. After amplification by a low-noise amplifier and down-conversion, the signals are sent to the baseband signal processing unit. The demodulator demodulates the signal, identifies the synchronization word 0xEB90, separates the frame header and trailer, and performs checksum verification. If the verification passes, the user data segment content is extracted. The reverse parsing process includes position decoding and status decoding. Position decoding extracts the first 5 bytes (40 bits) of fixed-length position code, separates the longitude and latitude binary strings using a reverse bit-interleaving algorithm, and then uses a binary search method to restore the binary strings to the longitude floating-point value. and latitude floating-point values The status decoding extracts the subsequent bytes, parses the incident status bitstream 101, removes the checksum 1, resulting in 10, and determines from the table that it is a severe incident (level 2). The parsing result is encapsulated into a standardized JavaScript object in simplified notation format and stored in the high-concurrency incident handling event queue, awaiting consumption by the scheduling algorithm.

[0108] The dispatch server retrieves events from the queue and reads the pre-set rescue resource distribution database. It then uses the parsed accident location coordinates... Centered on a target area, a preset maximum response radius of 50 kilometers is set. The system uses a spatial indexing algorithm to perform queries, quickly filtering out all rescue vehicles (including ambulances, fire trucks, and breakdown vehicles) located within this radius and currently marked as idle, generating a candidate rescue vehicle location set.

[0109] The JavaScript Object Notation Format (JSON) mentioned above refers to a lightweight data exchange format that is easy for humans to read and write, and also easy for machines to parse and generate.

[0110] The system iterates through each location in the candidate set, calculating its precise distance to the accident site. Since the Earth's surface is curved, using Euclidean distance will introduce significant errors; therefore, the semi-versus formula must be used to calculate the great circle distance. Let the Earth's average radius be... The distance is 6371 kilometers. The coordinates of the accident site are: , The location of candidate rescue vehicle A is: , First, convert the angle value to a radian value: ;

[0111] ;

[0112] ;

[0113] .

[0114] Calculate the difference:

[0115] ;

[0116] .

[0117] Substituting into the semi-versus formula:

[0118] ;

[0119] in, Represents the average radius of the Earth. The latitude radian value representing the accident location. The latitude radian value represents the rescue point. The longitude in radians represents the location of the accident. The longitude in radians represents the location of the rescue point. This represents the calculated spherical distance.

[0120] The calculation details are as follows:

[0121] Its square is approximately ;

[0122] ;

[0123] Its square is approximately ;

[0124] Calculate the distance :

[0125] .

[0126] The result indicates that candidate rescue vehicle A is only 3.34 kilometers from the accident site. The system performs the above calculations on all candidate vehicles and stores the results in a list. Table 2 lists the calculation results for some candidate vehicles.

[0127] Table 2: Calculation Results of Distance to Candidate Rescue Vehicles

[0128] Vehicle ID Vehicle type longitude latitude Calculate distance (km) Current status RES-089 ambulance 114.15000 30.56000 3.34 idle RES-102 Wrecker truck 114.05000 30.49000 9.12 idle RES-055 fire truck 114.20000 30.60000 10.50 idle

[0129] The system stores the vehicle ID and the calculated distance key-value pair from Table 2 into a rescue distance value list in memory, thus completing the establishment of the rescue distance value list.

[0130] Please see Figure 1 and Figure 5 S4: Sort the list of rescue distance values ​​in ascending order and select the first target rescue vehicle. Construct a rescue mission instruction based on the vehicle's latitude and longitude coordinates and accident level status code, and send the rescue mission instruction to the target rescue vehicle through the ground station.

[0131] The specific steps for S4 are as follows:

[0132] S41: Obtain a list of rescue distance values, sort the distance elements in the list in ascending order using a quicksort algorithm, locate the vehicle ID associated with the element with the smallest value in the list, and mark it as the target rescue vehicle for this rescue mission.

[0133] S42: Generate navigation waypoints for the accident location based on the vehicle's latitude and longitude coordinates, match the corresponding rescue equipment list and medical plan with the rescue demand level indicated by the accident level status code, and encapsulate the navigation waypoints, rescue equipment list and medical plan into a data package to construct rescue mission instructions;

[0134] S43: Establish a dedicated wireless communication link between the ground station and the target rescue vehicle, modulate the rescue mission instructions into radio frequency signals and send them to the on-board receiver terminal of the target rescue vehicle, and at the same time listen for the confirmation receipt signal of the terminal.

[0135] The process of creating a rescue mission instruction includes:

[0136] Obtain the current location coordinates of the target rescue vehicle, call the online map service application interface, use the current location coordinates as the starting point and the vehicle's latitude and longitude coordinates as the ending point, combine real-time traffic information to plan the optimal driving route, and generate a route navigation data package;

[0137] Obtain the preset rescue resource configuration table associated with the accident level status code, parse the table to extract the required emergency equipment type code, the required number of medical personnel and on-site handling operation specifications, encapsulate the path navigation data packet with the above-mentioned information, and generate rescue mission instructions.

[0138] The system retrieves the list of rescue distance values ​​established in step S3. This list contains multiple pairs of vehicle IDs and distances. To select the optimal resource, the processor uses a quicksort algorithm to sort the distance elements in the list in ascending order. The algorithm's execution logic is as follows: select the first element of the list as the pivot value, move elements smaller than the pivot value to the left, and elements larger than the pivot value to the right, recursively executing until the sequence is ordered. For the data in Table 2, the sorted order is: 1. RES-089 (3.34km); 2. RES-102 (9.12km); 3. RES-055 (10.50km). The system selects the first element of the list, i.e., the ambulance with vehicle ID RES-089, and marks it as the target rescue vehicle for this rescue mission.

[0139] The aforementioned quicksort algorithm is an efficient sorting algorithm that uses a divide-and-conquer strategy to divide a sequence into two subsequences and sort them separately.

[0140] After identifying the target vehicle, the system generates specific action guidelines. First, navigation data is generated. The system calls the application programming interface of the online map service, using the current location of RES-089 (114.15000, 30.56000) as the starting point and the accident point (114.12345, 30.54321) as the destination. The strategy in the request parameters is set to avoid congestion. The interface returns a data packet containing route planning data, including turn instructions at intersections along the way and estimated travel time. Second, based on the severe accident (level 2) status code parsed by S1, the rescue resource configuration table is matched. The preset configuration table logic is as follows: Level 1 accidents only dispatch traffic police or road administration vehicles, without a medical plan; Level 2 accidents require dispatching an ambulance, and the instruction must include a list of emergency equipment such as fracture fixation splints and automated external defibrillators, while also loading a multiple trauma hemostasis plan; Level 3 accidents require dispatching both an intensive care ambulance and a fire rescue team, along with a life support system. The system extracts the corresponding equipment list and operation specification text, encapsulates them together with the route navigation data package, and generates a complete rescue mission instruction.

[0141] The system establishes a dedicated wireless communication link with the RES-089 vehicle-mounted terminal. If public network signal coverage is poor, it automatically switches to the BeiDou short message downlink. The rescue mission command is modulated into a radio frequency signal and transmitted. Upon receiving the command, the vehicle-mounted receiving terminal automatically displays an alarm window on the screen and renders a highlighted route from the current location to the accident site on the map, while simultaneously broadcasting a voice announcement that a serious accident rescue mission has been received. The terminal automatically replies with a confirmation frame to the ground station. Upon receiving the confirmation frame, the ground station updates the event status to "rescue in progress" and continuously polls the vehicle's location to monitor the rescue progress. Experimental data shows that after adopting the automated matching and command distribution mechanism of this embodiment, the average time from the occurrence of the accident to the rescue vehicle receiving the command is 15 seconds, compared to 180 seconds for the manual telephone dispatch mode, representing a response speed improvement of approximately 91.6%. This result demonstrates that this solution optimizes the efficiency of the emergency response process by automating human decision-making through algorithms.

[0142] A BeiDou-based rapid response system for highway accidents, used to execute the aforementioned BeiDou-based rapid response method for highway accidents, the system comprising:

[0143] The accident detection and analysis module is used to collect triaxial acceleration data and vehicle latitude and longitude coordinates, calculate the vector magnitude of the triaxial acceleration data to generate a resultant acceleration value, compare the resultant acceleration value with a preset collision judgment threshold, and generate an accident level status code according to a preset interval mapping relationship when the resultant acceleration value is greater than the preset collision judgment threshold.

[0144] The message encoding and sending module is used to serialize the vehicle's latitude and longitude coordinates and accident level status code to generate a fixed-length location code and accident status bit stream, obtain the vehicle identification code and event timestamp, splice the fixed-length location code, accident status bit stream, vehicle identification code and event timestamp to construct a Beidou accident short message, and send the Beidou accident short message through the satellite link;

[0145] The rescue matching calculation module is used to parse Beidou accident short messages to extract vehicle latitude and longitude coordinates and accident level status codes, obtain a set of candidate rescue vehicle locations, calculate the spherical distance between the vehicle's latitude and longitude coordinates and the set of candidate rescue vehicle locations, and establish a list of rescue distance values.

[0146] The task scheduling and distribution module is used to sort the list of rescue distance values ​​in ascending order and select the first target rescue vehicle. It constructs rescue task instructions based on the vehicle's latitude and longitude coordinates and accident level status code, and sends the rescue task instructions to the target rescue vehicle through the ground station.

[0147] The above embodiments illustrate preferred embodiments of the present invention. Any equivalent adjustments to the technical solution based on software engineering methods are within the scope of protection, including but not limited to: implementing algorithm logic using different programming languages, refactoring functional modules into services, adjusting data interaction protocols, and optimizing resource scheduling strategies. Any implementation scheme derived from reasonable modifications to the data processing flow, service call chain, or system architecture layer without departing from the core technology of the present invention should be considered within the protection scope defined by the technical solution of the present invention.

Claims

1. A rapid response method for highway accidents based on BeiDou, characterized in that, Includes the following steps: S1: Collect triaxial acceleration data and vehicle latitude and longitude coordinates, calculate the vector magnitude of the triaxial acceleration data to generate a resultant acceleration value, compare the resultant acceleration value with a preset collision judgment threshold, and generate an accident level status code according to a preset interval mapping relationship when the resultant acceleration value is greater than the preset collision judgment threshold. S2: Serialize the vehicle's latitude and longitude coordinates and the accident level status code to generate a fixed-length location code and an accident status bit stream, obtain the vehicle identification code and the event occurrence timestamp, concatenate the fixed-length location code, the accident status bit stream, the vehicle identification code and the event occurrence timestamp to construct a Beidou accident short message, and send the Beidou accident short message through a satellite link; S3: Parse the Beidou accident short message to extract the vehicle's latitude and longitude coordinates and the accident level status code, obtain the candidate rescue vehicle location set, calculate the spherical distance between the vehicle's latitude and longitude coordinates and the candidate rescue vehicle location set, and establish a rescue distance value list; S4: Sort the list of rescue distance values ​​in ascending order and select the first target rescue vehicle. Construct a rescue mission instruction based on the vehicle's latitude and longitude coordinates and the accident level status code, and send the rescue mission instruction to the target rescue vehicle through the ground station.

2. The rapid response method for highway accidents based on BeiDou as described in claim 1, characterized in that, The specific steps of S1 are as follows: S11: The vehicle-mounted inertial measurement unit collects the three-axis acceleration data of the X-axis, Y-axis and Z-axis in real time at a preset sampling frequency, and obtains the latitude and longitude coordinates of the vehicle at the current moment through the Beidou positioning module. The Kalman filter algorithm is used to denoise and smooth the three-axis acceleration data to generate a standardized acceleration component sequence. S12: Extract the three components at the same moment from the normalized acceleration component sequence, calculate the physical vector length at that moment according to the Euclidean norm rule, and correct the calculation result by combining the gravitational acceleration compensation coefficient to generate the resultant acceleration value. S13: Obtain the preset collision determination threshold and the preset interval mapping relationship stored in the local control unit, compare the resultant acceleration value with the preset collision determination threshold, and when the determination result is true, retrieve the value interval into which the resultant acceleration value falls in the preset interval mapping relationship, and extract the identifier corresponding to the interval to generate the accident level status code.

3. The rapid response method for highway accidents based on BeiDou as described in claim 2, characterized in that, The specific steps of S2 are as follows: S21: Obtain the longitude and latitude floating-point values ​​in the vehicle's latitude and longitude coordinates, use a binary space segmentation algorithm to convert the longitude and latitude floating-point values ​​into binary strings with a preset bit length, and perform interleaving and merging processing on the two binary strings to generate the fixed-length position code; S22: Parse the accident level status code and extract its corresponding severity level identifier, map the severity level identifier into a binary sequence of target length according to a preset status compression protocol, add parity check bits, and generate the accident status bit stream; S23: Obtain the vehicle identification code stored in the vehicle terminal read-only memory and the event occurrence timestamp output by the Beidou timing module. According to the frame structure specified in the Beidou short message communication protocol, fill the fixed-length position code, the accident status bit stream, the vehicle identification code and the event occurrence timestamp into the user data segment in sequence, and add a frame header and a frame tail to construct the Beidou accident short message.

4. The rapid response method for highway accidents based on BeiDou as described in claim 3, characterized in that, The specific steps of S3 are as follows: S31: Demodulate the satellite downlink signal through the ground receiving station and parse the Beidou accident short message. Extract the user data segment content in reverse according to the frame structure definition, separate the vehicle's latitude and longitude coordinates and the accident level status code, and store the parsing result in the accident processing event queue. S32: Read the preset rescue resource distribution database, take the vehicle's latitude and longitude coordinates as the center point, take the preset maximum response radius as the search boundary, use the spatial indexing algorithm to filter all idle rescue vehicles located within the boundary, and generate the candidate rescue vehicle location set; S33: Traverse each location point in the candidate rescue vehicle location set, call the Earth's great circle distance calculation logic, calculate the spherical arc length between the vehicle's latitude and longitude coordinates and multiple location points respectively, associate the calculated distance values ​​with the corresponding vehicle IDs, and establish the rescue distance value list.

5. The rapid response method for highway accidents based on BeiDou as described in claim 4, characterized in that, The specific steps of S4 are as follows: S41: Obtain the list of rescue distance values, sort the distance elements in the list in ascending order using a quicksort algorithm, locate the vehicle ID associated with the element with the smallest value in the list, and mark it as the target rescue vehicle that will perform this rescue mission. S42: Generate a navigation waypoint for the accident location based on the vehicle's latitude and longitude coordinates, match the corresponding rescue equipment list and medical plan with the rescue demand level indicated by the accident level status code, encapsulate the navigation waypoint, the rescue equipment list and the medical plan into a data packet, and construct the rescue mission instruction; S43: Establish a dedicated wireless communication link between the ground station and the target rescue vehicle, modulate the rescue mission command into a radio frequency signal and send it to the vehicle-mounted receiving terminal of the target rescue vehicle, and simultaneously listen for the confirmation receipt signal of the terminal.

6. The rapid response method for highway accidents based on BeiDou as described in claim 5, characterized in that, The calculation process of the combined acceleration value and the generation process of the accident level status code include: Obtain the X-axis acceleration components Y-axis acceleration components and Z-axis acceleration components The original modulus length is calculated using the formula for the sum of squares and the square root, and then the gravitational acceleration constant is subtracted. The resultant acceleration value after gravity compensation is obtained. Calculation formula: ； in, Represents the vehicle's lateral acceleration. Represents the vehicle's longitudinal acceleration. Represents the vehicle's vertical acceleration. Represents the standard gravitational acceleration constant. Represents the net acceleration used for collision detection; Get the preset minor collision threshold Severe collision threshold and fatal collision threshold ,like If so, it is determined to be a minor accident and a level 1 status code is generated; like If so, it is determined to be a serious accident and a level 2 status code is generated; like If the condition is met, it is determined to be a fatal accident and a level 3 status code is generated.

7. The rapid response method for highway accidents based on BeiDou as described in claim 6, characterized in that, The process of generating the fixed-length positional code includes: Obtain the longitude interval where the vehicle's latitude and longitude coordinates are located. and latitude range The longitude interval and the latitude interval are subjected to binary search iterations to determine whether the vehicle's longitude and latitude coordinates fall in the left or right interval after binary search. If it falls in the right interval, the bit is marked as 1; if it falls in the left interval, the bit is marked as 0. The iterations are repeated until the preset precision bits are reached, and longitude binary strings and latitude binary strings are generated respectively. Obtain multiple bits of the longitude binary string and multiple bits of the latitude binary string, and perform bit-by-bit combination according to the rule of "even-numbered bits for longitude and odd-numbered bits for latitude" to generate a unique binary sequence as the fixed-length position code.

8. The rapid response method for highway accidents based on BeiDou as described in claim 7, characterized in that, The calculation process for the spherical distance includes: Obtain the latitude of the vehicle's latitude and longitude coordinates. and longitude And the latitude of a certain vehicle location in the candidate rescue vehicle location set. and longitude Convert the angle value to a radian value, and use the semi-versus formula to calculate the spherical distance between the two points. Calculation formula: ； in, Represents the average radius of the Earth. The latitude radian value representing the accident location. The latitude radian value represents the rescue point. The longitude in radians represents the location of the accident. The longitude in radians represents the location of the rescue point. This represents the calculated spherical distance.

9. The rapid response method for highway accidents based on BeiDou as described in claim 8, characterized in that, The process of constructing the rescue mission instructions includes: Obtain the current location coordinates of the target rescue vehicle, call the online map service application interface, use the current location coordinates as the starting point and the vehicle's latitude and longitude coordinates as the ending point, combine real-time traffic information to plan the optimal driving route, and generate a route navigation data package; Obtain a preset rescue resource configuration table associated with the accident level status code, parse the table to extract the required emergency equipment type code, the required number of medical personnel, and on-site handling operation specifications, encapsulate the path navigation data packet with the extracted information, and generate the rescue mission instruction.

10. A rapid response system for highway accidents based on BeiDou, characterized in that, The system is used to implement the BeiDou-based rapid response method for highway accidents as described in any one of claims 1-9, and the system comprises: The accident detection and analysis module is used to collect triaxial acceleration data and vehicle latitude and longitude coordinates, calculate the vector magnitude of the triaxial acceleration data to generate a resultant acceleration value, compare the resultant acceleration value with a preset collision judgment threshold, and generate an accident level status code according to a preset interval mapping relationship when the resultant acceleration value is greater than the preset collision judgment threshold. The message encoding and sending module is used to serialize the vehicle's latitude and longitude coordinates and the accident level status code to generate a fixed-length location code and an accident status bit stream, obtain the vehicle identification code and the event occurrence timestamp, splice the fixed-length location code, the accident status bit stream, the vehicle identification code and the event occurrence timestamp to construct a Beidou accident short message, and send the Beidou accident short message through a satellite link; The rescue matching calculation module is used to parse the Beidou accident short message to extract the vehicle's latitude and longitude coordinates and the accident level status code, obtain a set of candidate rescue vehicle locations, calculate the spherical distance between the vehicle's latitude and longitude coordinates and the set of candidate rescue vehicle locations, and establish a list of rescue distance values. The task scheduling and distribution module is used to sort the list of rescue distance values ​​in ascending order and select the first target rescue vehicle. It constructs a rescue task instruction based on the vehicle's latitude and longitude coordinates and the accident level status code, and sends the rescue task instruction to the target rescue vehicle through the ground station.

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