A vehicle return detection method and system for an electronic post office

Abstract

This invention relates to the field of telecommunications technology and discloses a vehicle return detection method and system for an electronic service station. The method includes: the electronic service station acquiring a dynamic drift compensation vector and establishing a dynamic sub-coordinate system, and broadcasting a Bluetooth signal containing coordinate system information via pulse broadcast; after receiving the Bluetooth signal, the vehicle smart lock sends back a Bluetooth echo packet containing a timestamp; after receiving the Bluetooth echo packet, the electronic service station sends a pre-lock command to the backend system via GPRS; the backend system responds to the pre-lock command and returns a heartbeat seed; the vehicle smart lock performs a validity verification based on the heartbeat seed and its own serial number; after successful verification, the electronic service station detects the Bluetooth signal strength of the vehicle smart lock to confirm its stationary state; after receiving the verification information and the confirmation of the stationary state, the backend system issues a locking permission command, and the vehicle smart lock locks to complete the vehicle return. This method solves the problems of inaccurate positioning, high response delay, and inability to correct drift, achieving a simplified process and drift correction.

Description

Technical Field

[0001] This invention relates to the field of telecommunications technology, and in particular to a vehicle return detection method and system for electronic rest stops. Background Technology

[0002] Existing Bluetooth-only electronic parking station systems establish a stable communication bridge with users' mobile devices and smart locks through Bluetooth signal transmission and reception, enabling smooth data transmission and smart lock opening / closing control. However, this solution faces challenges due to the lack of power and network support, such as frequent disconnections and loss of connectivity. Furthermore, the accuracy of location information is significantly reduced, increasing the risk of positioning errors. More importantly, the system's relatively weak direct control over the smart locks increases the risk of vehicle theft. In another approach, the electronic parking station first receives Bluetooth signals from the smart lock and uploads this crucial data to the backend system. The backend system then performs detailed analysis and judgment on this data to determine whether to perform an unlocking or locking operation, and subsequently issues instructions to the smart lock to take the corresponding action. While this process seems rigorous, it is actually cumbersome and lengthy, significantly reducing system response speed and forcing users to endure long waiting times during vehicle rentals and returns. In addition, the separate design of the Bluetooth module and the GPS / GPRS module further hinders rapid data interaction and overall system performance improvement.

[0003] For example, Chinese patent CN112581697A discloses a method and device for returning shared vehicles, providing the following technical solution: in response to receiving a return instruction, determining whether Bluetooth broadcast information of a valid parking dock can be scanned; if the Bluetooth broadcast information of the valid parking dock can be scanned, detecting whether a locking signal is received; and if the locking signal is received, determining that the return is complete. This method and device for returning shared vehicles can constrain users' return behavior and prevent shared vehicles from being parked haphazardly. However, the aforementioned method and device for returning shared vehicles relies solely on Bluetooth, which has drawbacks such as missing location tracking, the need for cloud relay leading to a lengthy process, inability to correct GPS drift, and high power consumption. Summary of the Invention

[0004] This invention solves the problems of inaccurate positioning, high response delay, complex process, and inability to correct drift in the prior art. It proposes a vehicle return detection method and system for electronic stations, which achieves the goals of accurate positioning, rapid response, simplified process, and drift correction.

[0005] Furthermore, this invention integrates Bluetooth, GPS, and GPRS, and adopts a time-space folding vehicle return protocol, aiming to achieve a fast, accurate, and low-power vehicle return process.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for detecting vehicle return at an electronic rest stop includes: The electronic station acquires the dynamic drift compensation vector and establishes a dynamic sub-coordinate system, then broadcasts a Bluetooth signal containing coordinate system information via pulse broadcast; After receiving the Bluetooth signal, the vehicle smart lock sends back a Bluetooth echo packet containing a timestamp. After receiving the Bluetooth echo packet, the electronic station sends a pre-lock command to the backend system via GPRS. The backend system responds to the pre-lock command and returns a heartbeat seed. The vehicle smart lock verifies its legitimacy based on the heartbeat seed and its own serial number; After verification, the electronic station checks the Bluetooth signal strength of the vehicle's smart lock to confirm that it is stationary; After receiving the verification information and confirmation of the stationary status, the backend system issues a locking permission command, and the vehicle's smart lock is locked to complete the return of the vehicle.

[0007] The system implements a time-space folding vehicle return protocol, compressing the long process into a single positioning, two handshakes, and three confirmations process. The entire process is completed in a very short time, significantly improving the return response speed and user experience. At the same time, multiple verifications ensure security and accuracy.

[0008] A vehicle return detection system for an electronic rest stop includes an electronic rest stop, a smart lock, and a backend system. The electronic rest stop integrates a GPS module, a GPRS module, and an electronic rest stop Bluetooth module. The smart lock is equipped with a smart lock Bluetooth module. The backend system is connected to the GPRS module of the electronic rest stop via a GPRS network. The electronic rest stop communicates wirelessly with the smart lock Bluetooth module via its electronic rest stop Bluetooth module. When the smart lock is within the Bluetooth signal coverage range of the electronic rest stop, it uploads vehicle information and electronic rest stop information to the backend system via the electronic rest stop's GPRS module. After successful verification, the backend system sends a locking command to the smart lock via the GPRS module and the electronic rest stop.

[0009] Integrating Bluetooth, GPS, and GPRS technologies, it overcomes the limitations of pure Bluetooth solutions in positioning and data interaction, achieving accurate real-time positioning, stable data transmission, and rapid remote control. It optimizes the car rental and return process, and enhances the user experience and vehicle monitoring capabilities.

[0010] Preferably, the Bluetooth signal containing coordinate system information broadcast via pulse broadcast specifically includes: the electronic station periodically broadcasting Bluetooth pulse packets with dynamically adjusted power and interval. The broadcast power is dynamically modulated based on the environmental interference level and the broadcast interval is dynamically adjusted according to the communication status. When a smart lock is detected approaching, the interval is shortened to improve the response speed, and the interval is extended to reduce power consumption when no device is present. The Bluetooth pulse packet uses binary encoding, and its structure includes: a protocol header identifying the start of the data packet, a field for the station's dynamic plane coordinate information after drift compensation, a timestamp field for smart lock clock calibration, and a check code field to ensure data integrity.

[0011] The breathing-style pulse broadcast, which dynamically adjusts power and interval, mimics a heartbeat mechanism. It can optimize communication based on environmental interference and device distance, save power consumption of smart lock scanning, and enhance anti-interference capabilities in weak signal environments. The compact binary encoding reduces transmission load and improves data exchange efficiency.

[0012] Preferably, the Bluetooth echo packet containing a timestamp specifically includes: after receiving the Bluetooth pulse packet from the electronic station, the vehicle smart lock triggers an interrupt and replies with a Bluetooth echo packet within a preset time; the structure of the Bluetooth echo packet includes: the unique identifier of the electronic station, the unique hardware serial number of the vehicle smart lock, the relative coordinates of the vehicle smart lock in the dynamic sub-coordinate system calculated by the vehicle smart lock, the current battery information of the vehicle smart lock, the lock tongue status information of the vehicle smart lock, and a verification code field for data verification.

[0013] The smart lock's fast interruption response ensures low end-to-end latency and improves real-time performance. The echo packet contains relative coordinates, battery level, and bolt status, enabling the back-end system to comprehensively monitor the vehicle and enhance operational management capabilities and security.

[0014] Preferably, the confirmation of the stationary state specifically includes: after receiving the Bluetooth echo packet, the electronic station continuously monitors the Bluetooth signal reception strength indicator value returned by the vehicle smart lock; the electronic station determines whether the vehicle is stationary by analyzing the fluctuation of the reception strength indicator value received multiple times; when the standard deviation of the reception strength indicator value for a preset number of consecutive times is less than a preset threshold, the vehicle smart lock is determined to be in a stationary state, and a stationary state confirmation mark is generated.

[0015] By analyzing fluctuations in the received signal strength indicator, the system determines whether the vehicle is stationary, preventing accidental return of the vehicle while it is in motion and improving the accuracy of the return operation. The preset threshold can effectively identify stable states, enhancing system reliability.

[0016] Preferably, the establishment of the dynamic sub-coordinate system specifically includes: the electronic station obtains the current latitude and longitude coordinates through the GPS module and converts them into Cartesian coordinates with the initial position of the station as the origin; the electronic station periodically collects multiple sets of Cartesian coordinates and uses the least squares method to fit the multiple sets of coordinates to calculate the optimal stationary point coordinates; the electronic station compares the optimal stationary point coordinates with the original coordinates collected last time to obtain a two-dimensional drift vector and temporarily stores it in the microcontroller unit of the electronic station, thus establishing a periodically effective dynamic sub-coordinate system.

[0017] The least squares fitting and drift compensation method is used to reduce positioning errors and improve position accuracy. The dynamic sub-coordinate system only needs to be calculated and stored locally, without the need to upload the original GPS data, which saves GPRS traffic and reduces communication costs and latency.

[0018] Preferably, the issuance of the locking permission instruction specifically includes: the backend system receiving combined information including hash verification results and static status confirmation markers uploaded from the electronic station via the GPRS network, performing a second verification of the hash verification results, and making a comprehensive judgment with the static status information; when both verifications pass, the backend system generates and issues a locking permission confirmation code to the electronic station, which then forwards or triggers the vehicle smart lock to perform the locking action.

[0019] The back-end system performs secondary verification and comprehensive judgment, adding security layers to prevent illegal or abnormal vehicle returns. The streamlined confirmation code design results in extremely low GPRS round-trip data, adapting to 2G narrowband networks and ensuring rapid response in weak network environments.

[0020] Preferably, the legitimacy verification specifically includes: the vehicle smart lock uses a preset hash algorithm locally to combine the heartbeat seed returned by the backend system with its own stored unique serial number to generate a hash value; the vehicle smart lock extracts the first preset bytes of the hash value as a hash prefix and compares the hash prefix with the hash prefix recorded in its internally stored legitimate device whitelist; if the comparison is successful, the preliminary legitimacy verification is passed.

[0021] Local hash verification only takes the first two bytes of the prefix, which greatly improves the verification speed while ensuring security and reducing computation and communication overhead. Whitelist comparison can block most illegal requests and enhance the overall security of the system.

[0022] Preferably, the vehicle return detection method also includes an abnormal rolling mechanism, specifically including: when the vehicle smart lock fails to verify its legitimacy, fails to confirm its stationary state, or does not receive a final locking permission instruction, the vehicle smart lock automatically broadcasts an abnormal identifier. After receiving the abnormal identifier, the electronic station uploads abnormal snapshot data to the background system via the GPRS network. The abnormal snapshot data includes the GPS drift vector at that time and the relevant Bluetooth signal reception strength indicator array. The background system generates a no-fault report based on the abnormal snapshot data.

[0023] The abnormal rolling mechanism automatically handles failure scenarios and uploads detailed abnormal snapshot data to facilitate rapid problem diagnosis; the generation of no-fault reports reduces the need for manual customer service intervention, lowers operation and maintenance costs, and improves processing efficiency.

[0024] Preferably, the dynamic sub-coordinate system is a relative coordinate reference that has been compensated for drift during the current vehicle return cycle, and the coordinates received by the smart lock are the relative coordinates in this dynamic sub-coordinate system.

[0025] Relative coordinates are calculated based on the local dynamic sub-coordinate system, avoiding the cumulative error of cloud-based difference calculations, while simplifying the data processing flow and improving system response speed.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0027] 1. This invention constructs an intelligent and efficient vehicle return detection system through the deep integration of Bluetooth, GPS and GPRS. It effectively solves the problems of missing positioning, easy loss of connection and background interaction delay in pure Bluetooth solutions. By utilizing the two-way communication between the electronic station and the smart lock, it not only realizes real-time monitoring of vehicle status and accurate determination of return range, but also greatly improves the overall response speed and operational reliability.

[0028] 2. This invention significantly compresses the traditionally lengthy vehicle return process through a single positioning, two handshakes, and three confirmations, completing verification and locking in a short time. Moving edge computing forward reduces the data processing burden on the cloud, the GPRS simplified frame design adapts to narrowband network environments, and the Bluetooth breathing pulse mechanism balances low power consumption and anti-interference capabilities.

[0029] 3. The accurate GPS positioning function of this invention makes it easier for users to find rest stops and improves the user experience. The optimized signal interaction process reduces the energy consumption of electronic rest stops, while the enhanced vehicle monitoring capability effectively reduces the risk of loss, provides strong support for operation and management, standardizes users' vehicle return behavior, and helps to control the phenomenon of random parking. Attached Figure Description

[0030] Figure 1 This is an overall flowchart of a vehicle return detection method for an electronic rest stop according to the present invention.

[0031] Figure 2 This is a system block diagram of a vehicle return detection system for an electronic rest stop according to the present invention. Detailed Implementation

[0032] See Figures 1-2 As shown, a vehicle return detection method for an electronic rest stop includes: The electronic station acquires the dynamic drift compensation vector and establishes a dynamic sub-coordinate system, then broadcasts a Bluetooth signal containing coordinate system information via pulse broadcast; After receiving the Bluetooth signal, the vehicle smart lock sends back a Bluetooth echo packet containing a timestamp. After receiving the Bluetooth echo packet, the electronic station sends a pre-lock command to the backend system via GPRS. The backend system responds to the pre-lock command and returns a heartbeat seed. The vehicle smart lock verifies its legitimacy based on the heartbeat seed and its own serial number; After verification, the electronic station checks the Bluetooth signal strength of the vehicle's smart lock to confirm that it is stationary; After receiving the verification information and confirmation of the stationary status, the backend system issues a locking permission command, and the vehicle's smart lock is locked to complete the return of the vehicle.

[0033] A vehicle return detection system for an electronic rest stop includes an electronic rest stop, a smart lock, and a backend system. The electronic rest stop integrates a GPS module, a GPRS module, and an electronic rest stop Bluetooth module. The smart lock is equipped with a smart lock Bluetooth module. The backend system is connected to the GPRS module of the electronic rest stop via a GPRS network. The electronic rest stop communicates wirelessly with the smart lock Bluetooth module via its electronic rest stop Bluetooth module. When the smart lock is within the Bluetooth signal coverage range of the electronic rest stop, it uploads vehicle information and electronic rest stop information to the backend system via the electronic rest stop's GPRS module. After successful verification, the backend system sends a locking command to the smart lock via the GPRS module and the electronic rest stop.

[0034] like Figure 1 In one embodiment shown, Figure 1 This is an overall flowchart of a vehicle return detection method for an electronic rest stop according to the present invention. The present invention mainly includes the following steps: First, the electronic rest stop periodically obtains its own location information via GPS module, converts latitude and longitude coordinates into Cartesian coordinates, and uses the least squares method to fit multiple sets of coordinates to calculate the drift compensation vector, constructing a dynamic sub-coordinate system that is only valid within the current return cycle. This coordinate system, after drift correction, provides a high-precision relative reference for vehicle positioning.

[0035] The electronic relay station periodically broadcasts Bluetooth pulse packets containing its dynamic coordinate information with dynamically adjustable power and intervals. The pulse packets adopt a compact binary structure, containing a protocol header, drift-compensated coordinate data, a timestamp for time synchronization, and a checksum, ensuring the integrity and timeliness of data transmission.

[0036] When the vehicle's smart lock enters the signal coverage area of ​​the electronic service station and receives the pulse packet, it will immediately reply with a Bluetooth echo packet. The echo packet contains the electronic service station identifier, the smart lock's unique hardware serial number, its relative coordinates calculated in the dynamic sub-coordinate system, battery level, bolt status, and verification information. This interaction completes the initial handshake.

[0037] After receiving the echo packet, the electronic station immediately sends a simplified pre-lock command to the backend system via GPRS. The backend system responds and generates a random number with a short validity period as a "heartbeat seed," which is then returned to the electronic station, completing the second handshake.

[0038] The vehicle smart lock uses the heartbeat seed and its built-in unique serial number locally to generate a verification code through a hash algorithm. It extracts the first few bytes as a hash prefix and quickly compares it with the locally stored whitelist of legitimate devices to achieve preliminary legitimacy verification.

[0039] Meanwhile, the electronic station continuously monitors the Bluetooth signal strength (RSSI) returned by the smart lock. By analyzing the fluctuations of multiple consecutive RSSI values, such as determining whether its standard deviation is lower than a set threshold, it confirms whether the vehicle is stationary and generates a corresponding status flag.

[0040] After receiving the combined information from the electronic station, which includes the hash verification result and the static status marker, the backend system performs comprehensive verification and secondary review. If both verifications pass, the final locking authorization command is issued via the GPRS network.

[0041] After receiving the authorization command, the vehicle's smart lock drives the actuator to complete the locking action and prompts the user with sound and light to indicate that the vehicle has been successfully returned. The entire process is usually completed in a very short time.

[0042] In addition, the method also includes an anomaly handling mechanism: if any stage of legality verification, static state judgment or final instruction reception fails, the smart lock will broadcast an anomaly flag, the electronic station will collect the current GPS drift vector and Bluetooth signal strength snapshot and report it to the background, and the background will generate a report based on this, which will facilitate problem tracing and responsibility determination and reduce manual intervention.

[0043] like Figure 2 In one embodiment shown, Figure 2This is a system block diagram of a vehicle return detection system for an electronic rest stop according to the present invention. The basic technical framework of the present invention is built upon the organic integration of Bluetooth, GPS, and GPRS modules. In the interaction system between the smart lock and the electronic rest stop, the Bluetooth module plays a crucial information bridging role. On the one hand, through a dedicated Bluetooth signal receiving mechanism, it accurately captures the Bluetooth signal emitted by the smart lock, thereby comprehensively analyzing and obtaining detailed information about the smart lock of the associated vehicle, and simultaneously initiating a timed inspection process to ensure real-time monitoring and data collection of the vehicle's status.

[0044] On the other hand, the smart lock also has the ability to receive Bluetooth signals emitted by the electronic service station. By analyzing and processing multi-dimensional data such as signal strength and characteristics, it accurately determines whether the smart lock, i.e., the vehicle, is within a preset specific geographical range for returning the vehicle. At the electronic service station, the GPS module uses satellite positioning technology to accurately determine the geographical coordinates of the station, providing a precise spatial positioning reference for the entire system. The GPRS module, based on its mature mobile communication network technology, efficiently builds a stable and reliable data transmission channel between the electronic service station and the back-end management system, enabling two-way data interaction and covering various types of data flow, including vehicle status information uploading and back-end control command issuance. Through the coordinated operation and close cooperation of this entire technical process, the core objective of automatically verifying the vehicle status and executing the locking and returning operation is ultimately achieved, effectively improving the intelligence and operational efficiency of the entire vehicle management system.

[0045] During scheduled inspections, the smart lock emits Bluetooth signals. Once these signals are received by the electronic service station, the station periodically uploads the received vehicle data to the system backend. This process ensures real-time updates and accurate recording of vehicle information.

[0046] When returning a vehicle, the user must first push it to the designated station. At this point, the Bluetooth signal emitted by the station will be received by the Bluetooth module on the smart lock, indicating that the vehicle has entered the return range. It's worth noting that the Bluetooth signal transmission range of the station is unilateral and fan-shaped, with an effective distance of up to 30 meters. When the user manually triggers the return process, the smart lock immediately checks the return range and vehicle status. If the check fails, the smart lock's buzzer will immediately sound a warning sound indicating a failed return; if the check succeeds, the smart lock will upload the vehicle information and the station information to the system backend. The system backend will then verify the validity of the uploaded data to determine if the return was successful. If the data validity passes the verification, the smart lock will automatically lock, and the backend will push a successful return message to the user's app. However, if the data validity fails the verification, it will be considered an abnormal return, and the user will need to contact customer service to resolve the issue.

[0047] The electronic service station inspection process of this invention is as follows: First, information about the vehicle's smart lock is obtained by scanning Bluetooth signals, and then this information is uploaded to the electronic charging station. The electronic charging station acts as a relay station, transmitting the information to the backend system. After processing this information, the backend system can remotely manage and control smart lock 1 and smart lock 2, as well as subsequent smart locks, where smart lock 1 and smart lock 2 correspond to vehicle 1 and vehicle 2, respectively.

[0048] Users first enter the system by scanning a smart lock. The system then collects vehicle and charging station information and sends this information to the backend. Upon receiving this information, the backend immediately verifies the validity of the data. If the data is valid, the process continues; if the data is invalid, it is rejected.

[0049] In the next steps, the server will perform a locking operation or verify the return function. If the return is successful, the server will lock the vehicle and push a return success message to the user. However, if an abnormal return occurs, such as the vehicle being out of range or the vehicle being in an abnormal state, the server will determine that the return has failed, push a failure message to the user, and simultaneously issue a vehicle alarm.

[0050] If a user receives a return failure warning, they can contact customer service through the app for inquiries or assistance. The entire process ensures the accuracy of vehicle and charging station information and a smooth return process.

[0051] The traditional process is a long, single-threaded chain from lock arrival to background arrival and back to lock. This invention compresses it into three steps of space-time folding: Once the GPS is located, it performs self-coordinate drift compensation within the electronic station, generating a dynamic sub-coordinate system that is only valid for this return cycle. The process involves two handshakes. The first handshake involves the electronic station's Bluetooth beacon broadcasting breathing pulses to the surrounding area, and the smart lock immediately sends back a timestamp echo upon receiving it. The second handshake involves the electronic station receiving the echo and immediately sending a pre-lock command to the backend system via GPRS, with the backend system only replying with a 4-byte heartbeat seed. Three confirmations: The smart lock performs a lightweight hash of the heartbeat seed with its own serial number to verify its legitimacy; the electronic station monitors the smart lock's Bluetooth strength again to confirm that it is stationary (RSSI fluctuation ≤ 3dBm); after receiving the hash and the stationary condition via GPRS, the backend system issues the final locking permission. The entire process is completed within 1.2 seconds, which is more than 70% shorter than the traditional scan-to-upload-to-analysis-to-backhaul method.

[0052] Dynamic coordinates and drift compensation: The coordinate type is GPS raw data in WGS84 latitude and longitude, but before drift compensation, it is first converted to a plane rectangular coordinate system (X / Y, unit: meters) with the initial coordinates of the station as the origin, reducing the computational complexity of spherical coordinates.

[0053] The least squares method takes 10 sets of non-original latitude and longitude plane coordinates as input and removes obvious noise through Kalman filtering preprocessing.

[0054] The optimal stationary point is calculated as the current true coordinates. The drift vector (ΔX, ΔY) is equal to the true coordinates minus the last original coordinates. Specifically, ΔX is equal to Σ(wᵢ multiplied by xᵢ) divided by Σwᵢ, and ΔY is equal to Σ(wᵢ multiplied by yᵢ) divided by Σwᵢ. The weight wᵢ is 1 / σᵢ. 2 σᵢ represents the single-point variance.

[0055] The drift vector is temporarily stored in the local RAM of the station MCU. It is periodically cleared and the RAM usage is ≤64 bytes to avoid frequent Flash read and write.

[0056] The algorithm has a complexity of O(n) (n=10) and can be processed in real time with an MCU main frequency of ≥100MHz. This embodiment adopts a lightweight design and is compatible with mainstream low-cost chips.

[0057] Bluetooth interaction and relative coordinate calculation: Broadcast content, i.e., pulse packet structure: [Protocol Header (2B)][Station Dynamic Coordinates (X / Y, 4B)][Timestamp (4B)][Checksum (2B)] / / Total 12 bytes (breathing packet) [Station ID (4B)][Lock ID (4B)][Hash Prefix (2B)][Status Code (1B)] / / Echo packet (8 bytes).

[0058] The breathing-like feature specifically refers to the dynamic modulation of broadcast power, which is adjusted according to environmental interference, with an average interval of 100ms. This mimics a heartbeat mechanism to reduce the scanning power consumption of the smart lock, and the smart lock only periodically wakes up to listen when it is in sleep mode.

[0059] Dynamic coordinate transmission: The station broadcasts "origin and drift vector (ΔX, ΔY)" via Bluetooth. After receiving the data, the smart lock calculates its own relative coordinates: relative X equals (smart lock's original X minus origin X minus ΔX), rounded after planarization; relative Y equals (smart lock's original Y minus origin Y minus ΔY), rounded after planarization; the final relative coordinate error is <1m, avoiding the cumulative error of cloud-based difference calculation due to local processing.

[0060] Collaborative closed-loop and anomaly handling: GPRS communication only uploads the hash prefix and static status mark to the cloud, which is about 2-4 bytes. The cloud synchronizes the data to the management platform after verifying its legality through a whitelist.

[0061] Security verification is layered. A local whitelist stores the hash prefix of legitimate lock serial numbers. Based on a balance between performance and security, the first two bytes are selected. If a match fails, the request is rejected directly, which can block 90% of illegal requests. Full serial number verification is performed on abnormal requests marked at the edge, such as hash mismatch but stable RSSI. The local MCU processes anomalies such as weak signal (RSSI < 1.5dBm threshold) and coordinate drift exceeding limits in real time, prioritizing the triggering of local alarms (LED flashing) and caching logs. The alarms are then synchronized to the cloud after the network is restored.

[0062] The electronic station's dynamic sub-coordinate system collects 10 sets of coordinates every 30 minutes using the station's GPS module, and calculates the drift vector using the least squares method. This vector is used as the coordinate correction value for the current cycle and is stored only in the station's local RAM. It is automatically cleared to zero after the cycle ends. The coordinates received by the smart lock are the relative coordinates in this dynamic sub-coordinate system, with an error of less than 1 meter. There is no need to upload the original GPS data again, saving 50% of GPRS traffic.

[0063] GPS coordinates use WGS84 latitude and longitude. In practical applications, since WGS84 latitude and longitude is a spherical coordinate system, it is quite complicated to calculate drift compensation directly using latitude and longitude. Therefore, it is usually converted to planar coordinates first.

[0064] The 10 sets of coordinates processed by the least squares method are transformed planar coordinates, not direct latitude and longitude coordinates. Specifically, the 10 sets of WGS84 latitude and longitude coordinates are converted into coordinates (X, Y) in a Cartesian coordinate system with the initial coordinates of the electronic station as the origin through a specific coordinate transformation algorithm (such as the common Mercator projection). This makes it easier to perform subsequent drift compensation calculations on the plane and reduces the complexity of spherical coordinate calculations.

[0065] Calculation of drift vector (ΔX, ΔY): The main calculation is the drift vector (ΔX, ΔY) on the two-dimensional plane. ΔZ is not involved for now, because in the electronic station inspection scenario, the focus is mainly on the positional offset on the horizontal plane. The offset in the vertical direction has little impact on the vehicle return positioning and can be ignored.

[0066] The calculation steps and formulas are as follows: First, convert the 10 sets of WGS84 latitude and longitude coordinates into coordinates (xi, yi) (i=1,2,…,10) in a Cartesian coordinate system, using the initial coordinates of the electronic station as the origin. Then, use the least squares method to fit these coordinate points to find an optimal stationary point (x0, y0) that minimizes the sum of squared errors from these points to that point. The coordinates (x0, y0) of the optimal stationary point are obtained through the least squares calculation. Finally, the drift vector ΔX is equal to x0 minus xlast, and ΔY is equal to y0 minus ylast, where (xlast, ylast) are the original planar coordinates collected last time.

[0067] Location of drift vector storage: The drift vector is stored only in local RAM, which refers to the MCU of the electronic station. As the core control component of the electronic station, the MCU is responsible for processing various data and executing corresponding algorithms. Storing the drift vector in its RAM facilitates subsequent calculations and use.

[0068] The algorithm complexity and RAM space requirements for processing 10 sets of coordinates are as follows: the algorithm complexity for processing 10 sets of coordinates is O(n), where n=10. When performing the least squares calculation, it mainly involves simple addition, multiplication, and summation operations on these 10 sets of planar coordinate data, without requiring complex iterations or recursion, resulting in relatively low computational cost.

[0069] Regarding RAM space requirements, since only 10 sets of planar coordinates and some intermediate calculation results need to be stored, each set of coordinates consists of 2 floating-point numbers. Assuming each floating-point number occupies 4 bytes, the total is 8 bytes, and 10 sets are approximately 80 bytes. The intermediate calculation results include summation variables, which occupy relatively little space. The total required RAM space does not exceed 64 bytes. Within the RAM capacity range of the Electronic Station MCU, the MCU usually has enough RAM to meet this requirement.

[0070] The resource requirements for the MCU at the station are not high. From the CPU perspective, processing 10 sets of coordinates for least squares calculations mainly involves simple numerical operations and does not require powerful computing capabilities. A mainstream low-cost MCU with a clock speed of 100MHz can handle these calculations in real time. From the memory perspective, as mentioned earlier, the required RAM space is no more than 64 bytes, which consumes very little memory resources from the MCU.

[0071] A key factor in choosing this algorithm is its lightweight nature. Since electronic stations are typically deployed outdoors, there are certain requirements regarding the cost, power consumption, and size of the equipment. Using this lightweight algorithm, which has low requirements for MCU resources and low algorithm complexity, can reduce the hardware cost and power consumption of the equipment while meeting the drift compensation function, thereby improving the reliability and stability of the equipment. It also facilitates the implementation and maintenance of the algorithm.

[0072] The Bluetooth breathing pulse and echo mechanism works as follows: the breathing pulse beacon sends a 16-byte short packet every 250 ms, containing the current sub-coordinate system origin and drift vector; the smart lock immediately replies with an 8-byte echo, including its own battery level, latch status, and received signal strength; the electronic station uses the gradient descent algorithm of the echo RSSI to determine whether the vehicle has come to a complete stop: if the standard deviation of RSSI is less than 1.5 dBm for 3 consecutive times, it is considered stationary.

[0073] The structure of the pulse packet includes the following key fields, which are encoded using compact binary code to reduce transmission load: The protocol header (2B) is a fixed identifier (such as 0xAA55) used to identify the start of a valid data packet; The dynamic coordinate information (4B) of the station is a two-dimensional plane coordinate (ΔX, ΔY, 2B each, unit: meters, 16-bit signed integer based on origin offset, with an accuracy of ±0.1m) after drift compensation. The timestamp (4B) is a UTC timestamp, Unix millisecond-level, lower 32 bits, used by the smart lock to calibrate the local clock offset; The checksum (2B) is a CRC-16 checksum that covers the protocol header to the timestamp field to ensure data integrity.

[0074] The broadcast power and scanning interval are as follows: The broadcast power uses dynamic modulation, with a default initial power of 0dBm. It automatically adjusts the ±3dBm range according to environmental interference and optimizes the coverage range through RSSI feedback. The typical effective distance is 5-10 meters. The scanning interval is not fixed and is dynamically adjusted in a breathing manner. The average interval is 100ms, which is shortened to 50ms during busy periods and extended to 200ms during idle periods to balance power consumption and response speed.

[0075] By dynamically adjusting the broadcast strength and frequency, energy saving and anti-interference are synergistically optimized. The power modulation is based on the real-time environmental noise, and the MCU dynamically adjusts the transmission power. In this embodiment, the power is increased by 3dBm when the interference is high and decreased by 3dBm when the interference is low, reducing the energy consumption of invalid broadcasts. When the interval changes, the station extends the broadcast interval to 200ms when the smart lock is in sleep mode, reducing power consumption. When the smart lock is detected to be close (RSSI>-70dBm), the interval is shortened to 50ms, improving the response speed and mimicking the on-demand wake-up mechanism of a heartbeat.

[0076] Its core advantage is that compared with fixed power / interval broadcasting, it saves more than 30% of the power consumption of smart lock end scanning, while enhancing the anti-interference capability in weak signal environments and reducing the bit error rate to below 0.5%.

[0077] Smart lock response timing and echo packet: After receiving the pulse packet, the smart lock triggers an interrupt response within 10ms, uses hardware-level priority scheduling, and transmits the echo packet back via Bluetooth Low Energy, with an end-to-end latency of ≤50ms.

[0078] The relay station sets a timeout window, which is 100ms by default. If no echo packet is received, the pulse packet will be retransmitted (up to 3 times, with exponential backoff intervals) to ensure reliability in weak signal scenarios.

[0079] Echo packet (8B) field: The station ID (4B) is a unique identifier used to associate the smart lock with the target station, such as the lower 32 bits of the MAC address; The lock ID (4B) is the smart lock hardware serial number, which is matched with the whitelist in the background. The relative coordinates (2B) are 16 signed integers (unit: decimeter, accuracy ±0.1m, range ±327.6m). Battery information (1B) is quantified as 0-100% (0x00=0%, 0x64=100%, step 1%, low battery threshold, LED flashes fast when ≤20%). The latch status (1B) is a 4-bit code: 0x0 = locked, 0x1 = unlocked, 0x2 = fault, 0x3 = unknown, and the remaining 4 bits are reserved. The check (2B) is CRC-16, overriding the lock ID to the latch status field.

[0080] The gradient descent algorithm does not calculate the standard deviation or variance of continuous RSSI values, but is used to optimize the RSSI-based positioning accuracy between smart locks and electronic stations by iteratively adjusting parameters to minimize positioning errors.

[0081] Specifically, the goal is to find an optimal set of parameters, such as the positional offset of the smart lock relative to the electronic rest stop, to minimize the error between the distance calculated from the RSSI value and the actual distance. The basic algorithm flow is as follows: Randomly initialize the estimated parameters of the smart lock's relative position, such as the offset x and y coordinates. Based on the RSSI value and combined with a wireless signal propagation model, such as a free-space propagation model or a logarithmic distance path loss model, calculate the predicted distance and the actual distance under the current estimated parameters. This can be further determined using other methods, such as the error between known approximate ranges. This error is defined as the loss function. For example, if the predicted distance is dpred and the actual distance is dactual, the loss function L can be simply defined as L equal to (dpred minus dactual). 2 .

[0082] The gradient vector is obtained by taking the partial derivatives of the loss function with respect to each estimated parameter. The direction of the gradient vector represents the direction in which the loss function increases the fastest, and its opposite direction is the direction in which the loss function decreases the fastest. A learning rate, specifically a small positive number, is used to control the step size of each parameter update. The estimated parameters are then updated along the opposite direction of the gradient. This process is iterated until the loss function converges to a small value. The parameters obtained at this point are the relatively better estimates, thereby improving the positioning accuracy based on RSSI. It does not simply calculate the standard deviation or variance of continuous RSSI values. Standard deviation or variance mainly describes the dispersion of RSSI values, while the gradient descent algorithm focuses on reducing positioning errors through iterative parameter optimization.

[0083] The 1.5 dBm threshold is usually an empirical value derived from a large amount of experimental data. Statistical analysis was conducted on a large number of RSSI measurements between smart locks and electronic stations under different real-world scenarios (such as indoor, outdoor, different weather conditions, different interference environments, etc.).

[0084] By collecting numerous sample data, the fluctuations in RSSI values ​​and their corresponding positioning accuracy were observed. When the RSSI value changes by more than 1.5 dBm, it is often accompanied by a significant increase in positioning error or a marked decrease in communication stability. For example, in a series of comparative experiments, when the RSSI fluctuation was within 1.5 dBm, the positioning error could be kept within a small range of ±0.5m. However, when it exceeded 1.5 dBm, the positioning error may expand to ±1m or even larger, and the probability of communication anomalies such as data packet loss and connection interruption increased significantly. Therefore, 1.5 dBm was used as a threshold to determine whether the current RSSI state was within an acceptable stable range, thereby triggering corresponding processing mechanisms such as recalibration and broadcast power adjustment to ensure the reliability and positioning accuracy of the system.

[0085] The pre-lock instruction is only 12 bytes (Header 2 B, Station ID 4 B, Lock ID 4 B, Verification 2 B); the heartbeat seed backend system returns a 4-byte random number with a lifespan of 5 seconds, which expires and becomes invalid; finally, the lock-closing permission backend system sends a 1-byte confirmation code (0xA5). The entire GPRS round trip is only 17 bytes, which is suitable for 2G narrowband scenarios.

[0086] The verification algorithm is Header (2B), where the header is the protocol header of the data packet, fixed at 2 bytes. It serves as the start identifier of the data packet, allowing the receiver to quickly identify whether the received data is a valid protocol data packet. Its specific encoded content can be a predefined fixed binary sequence, such as "0xAA55". When the receiver receives data, it first checks if the first two bytes match this fixed sequence. If they do, the subsequent data is considered valid protocol data, and further parsing processing begins; otherwise, the data packet is considered invalid and discarded.

[0087] The station ID is a unique identifier for an electronic station, encoded using 4 bytes. Typically, the lower 32 bits of the electronic station's MAC address are used as its ID. This ensures that each electronic station has a globally unique identifier within the network, facilitating accurate identification of the specific station that the smart lock is communicating with. In the data packet, these 4 bytes are transmitted directly as the binary value of the lower 32 bits of the MAC address.

[0088] The lock ID is a unique identifier for a smart lock, also encoded using 4 bytes. It typically uses the smart lock's hardware serial number, which is uniquely assigned during the smart lock's manufacturing process and is globally unique. During data transmission, the 4 bytes of binary data corresponding to the hardware serial number are placed into the lock ID field, ensuring the unique identifiability of each smart lock within the system and facilitating the management and differentiation of different smart locks by the service station.

[0089] The checksum field uses the CRC-16 checksum algorithm. CRC is a widely used error detection technique in data communication, and CRC-16 is one specific implementation. It generates a 16-bit (2-byte) checksum by performing a specific polynomial operation on key data in the data packet (Header, station ID, lock ID, related status information, etc.) excluding the checksum field. Upon receiving the data packet, the receiving end uses the same CRC-16 algorithm to recalculate the received data (excluding the checksum) and then compares the result with the received checksum. If they match, it indicates that no errors occurred during data transmission; if they do not match, it indicates that a transmission error may have occurred. The receiving end can choose to discard the data packet or request a retransmission, thus ensuring the accuracy and reliability of data transmission.

[0090] Each packet includes an accompanying checksum and sequence number, with checksum fields present in both pulse and echo packets. Both pulse and echo packets employ the CRC-16 checksum algorithm to verify critical information within their respective data packets. For example, the pulse packet performs a CRC-16 checksum on the protocol header to the timestamp field, while the echo packet performs a CRC-16 checksum on the lock ID to the latch status field. By calculating the checksum of the data and comparing it with the received checksum, errors can be detected during data transmission, ensuring data integrity.

[0091] Under a typical 2G network, the actual round-trip time for a data interaction between the smart lock and the backend is approximately 3-5 seconds. This includes the entire process of the smart lock sending data to the backend, the backend processing the data, and the backend returning response data to the smart lock. This time is affected by various factors such as the limited bandwidth of the 2G network, signal transmission delay, and the backend processing capacity.

[0092] In traditional solutions, smart locks upload raw GPS data to the cloud, where complex calculations such as coordinate difference calculations and security verification are performed before the results are returned. The entire process typically has a latency of 2-3 seconds, but this can increase to 5-10 seconds under high concurrency or poor network conditions. This solution moves edge computing forward, performing some drift compensation and relative coordinate calculations locally at the electronic lock station. Only necessary verification digests and other information are uploaded to the cloud, significantly reducing data transmission volume and processing complexity. Compared to the traditional process under 2G networks, this solution reduces round-trip time to 1-2 seconds on a typical 2G network, lowering latency by approximately 50%-60%.

[0093] The SN (Signal Token) is stored in the hardware chip of the smart lock, typically in read-only memory or flash memory. These storage areas offer high security and are not easily modified or accessed from the outside.

[0094] The hardware chip of the smart lock employs encryption technology to protect the serial number (SN), such as using encryption algorithms like AES (Advanced Encryption Standard) to encrypt and store the SN. Only with a specific decryption key and algorithm can the SN be read and verified. Strict access control is implemented for the SN; only authorized programs or modules can access it. For example, when the smart lock communicates with an electronic service station or backend system, both reading and transmitting the SN are encrypted and authenticated to prevent unauthorized access. When transmitting SN-related information, digital signature technology is used to sign the data, ensuring its integrity and authenticity. The recipient can verify the digital signature to confirm whether the SN information has been tampered with.

[0095] A three-stage, confirmed safety loop: The smart lock calculates the hash locally: SHA-1(heartbeat seed|| SN)[0:2], and compares it with the internal whitelist; The electronic station monitors for stationary conditions. Once the conditions are met, the local LED flashes twice to remind the user "Do not move". After receiving the hash and the static flag, the backend system sends back 0xA5 within 0.3 seconds. The smart lock immediately drives the motor to lock, and the buzzer sounds briefly for 0.2 seconds to indicate success.

[0096] An internal whitelist stores the serial number (SN) hash prefixes of all legitimate locks. It's not just for the current session, but a long-term set of legitimate lock identifiers maintained at the electronic service station or backend system. This whitelist is used for quickly verifying the legitimacy of smart locks. When a smart lock communicates with the electronic service station, by comparing the hash prefix of the smart lock's SN with the records in the whitelist, it can quickly determine whether the smart lock is a legitimate device. This improves verification efficiency, reduces unnecessary computation and communication overhead, and also enhances system security, preventing unauthorized smart lock access.

[0097] Using only the first two bytes of the hash is a result of a comprehensive consideration of performance and security: during communication between the smart lock and the electronic station, the hash value of the serial number (SN) needs to be quickly compared and verified. A shorter hash length (such as 2 bytes) can reduce data processing and transmission time, and improve verification speed. For example, during hash comparison, a 2-byte hash value only requires a simple byte comparison operation, which is less computationally intensive than a longer hash value, and can yield verification results faster, meeting the fast response requirements of smart locks. Although the 2-byte hash length is relatively short, it still provides sufficient security when combined with other security mechanisms such as encrypted storage, digital signatures, and access control. By converting the SN into a fixed-length hash value through the characteristics of the hash algorithm, the original SN information is effectively protected. At the same time, the whitelist mechanism further restricts the range of legitimate devices; only legitimate locks with matching hash prefixes can pass the initial verification, greatly reducing the risk of unauthorized device access. In practical applications, through testing with a large number of legitimate and illegitimate devices, the 2-byte hash prefix can achieve efficient device verification while ensuring a certain false positive rate (within an acceptable range).

[0098] There are two main triggering situations for LED flashing: Abnormal situation trigger: When the smart lock detects an abnormal situation, such as an RSSI value lower than a set threshold (e.g., 1.5dBm), a drift vector exceeding the allowable range, or a communication error such as a checksum mismatch, the LED will flash rapidly. This fast-flashing mode is an intuitive way to indicate abnormalities, allowing users or maintenance personnel to quickly identify potential problems with the smart lock.

[0099] Specific operation triggers: When performing certain operations, such as returning a vehicle using a smart lock or exchanging critical data with an electronic service station, the LED will flash rapidly to indicate that the operation is in progress. The flashing pattern of the LED may differ depending on whether the operation is successful or failed; for example, it may flash rapidly a few times and then turn off when successful, while it may flash continuously when unsuccessful, so that the user can understand the result of the operation.

[0100] After receiving the hash and static information, the backend will perform the following specific verifications: First, the backend will look up the SN hash prefix of all legitimate locks in the internal whitelist based on the received hash value. The received hash value is then compared with the hash prefixes in the whitelist. If a match is found, the smart lock is preliminarily determined to be a legitimate device; if the match fails, the smart lock is deemed potentially illegitimate, subsequent operations are rejected, and a corresponding security warning is issued.

[0101] For stationary information, the backend will determine whether the smart lock is in a reasonable stationary state based on its historical location information and current time information. For example, by analyzing the smart lock's previous movement trajectory and speed, if the smart lock suddenly stops moving within a short period of time and the change in position conforms to the characteristics of stationary state, such as remaining stationary for a long time within a fixed area, then the stationary state is considered reasonable. If the stationary state does not match the historical behavior pattern, such as having just been moving rapidly and suddenly stopping in an unreasonable position, further investigation and verification will be conducted, which may require the smart lock to resend data or perform additional authentication.

[0102] Combining the results of hash verification and static state verification, the backend performs a comprehensive evaluation of the smart lock's overall status. If both verifications pass, the smart lock's return operation or current status is approved, and subsequent business processing is carried out, such as updating the vehicle status and recording return information. If either verification fails, corresponding measures are taken, such as refusing the operation, issuing an alarm, or requiring the smart lock to re-verify, to ensure the system's security and reliability.

[0103] If any confirmation fails, the smart lock automatically broadcasts an "abnormal UUID". Upon receiving this, the electronic station uploads an abnormal snapshot via GPRS, which includes the GPS drift vector and Bluetooth RSSI array. The backend system then generates a no-fault report based on this information, reducing the need for customer service intervention.

[0104] All data collection and extraction in this invention are carried out under compliant and legal conditions.

Claims

1. A method for detecting vehicle return at an electronic rest stop, characterized in that, include: The electronic station acquires the dynamic drift compensation vector and establishes a dynamic sub-coordinate system, then broadcasts a Bluetooth signal containing coordinate system information via pulse broadcast; After receiving the Bluetooth signal, the vehicle smart lock sends back a Bluetooth echo packet containing a timestamp. After receiving the Bluetooth echo packet, the electronic station sends a pre-lock command to the backend system via GPRS. The backend system responds to the pre-lock command and returns a heartbeat seed. The vehicle smart lock verifies its legitimacy based on the heartbeat seed and its own serial number; After verification, the electronic station checks the Bluetooth signal strength of the vehicle's smart lock to confirm that it is stationary; After receiving the verification information and confirmation of the stationary status, the backend system issues a locking permission command, and the vehicle's smart lock is locked to complete the return of the vehicle.

2. The vehicle return detection method for an electronic rest stop according to claim 1, characterized in that, The Bluetooth signal containing coordinate system information broadcast via pulse broadcast specifically includes: the electronic station periodically broadcasting Bluetooth pulse packets with dynamically adjusted power and interval. The broadcast power is dynamically modulated based on the environmental interference level and the broadcast interval is dynamically adjusted according to the communication status. When a smart lock is detected approaching, the interval is shortened to improve the response speed, and the interval is extended to reduce power consumption when no device is present. The Bluetooth pulse packet uses binary encoding, and its structure includes: a protocol header identifying the start of the data packet, a field of dynamic plane coordinate information of the station after drift compensation, a timestamp field for smart lock clock calibration, and a check code field to ensure data integrity.

3. A vehicle return detection method for an electronic rest stop according to claim 1 or 2, characterized in that, The Bluetooth echo packet containing a timestamp specifically includes: after receiving the Bluetooth pulse packet from the electronic station, the vehicle smart lock triggers an interrupt and replies with a Bluetooth echo packet within a preset time; the structure of the Bluetooth echo packet includes: the unique identifier of the electronic station, the unique hardware serial number of the vehicle smart lock, the relative coordinates of the vehicle smart lock in the dynamic sub-coordinate system calculated by the vehicle smart lock, the current battery information of the vehicle smart lock, the lock tongue status information of the vehicle smart lock, and a verification code field for data verification.

4. The vehicle return detection method for an electronic rest stop according to claim 3, characterized in that, The confirmation of the stationary state specifically includes: after receiving the Bluetooth echo packet, the electronic station continuously monitors the Bluetooth signal reception strength indicator value returned by the vehicle smart lock; the electronic station determines whether the vehicle is stationary by analyzing the fluctuation of the reception strength indicator value received multiple times; when the standard deviation of the reception strength indicator value for a preset number of consecutive times is less than a preset threshold, it is determined that the vehicle smart lock is in a stationary state and a stationary state confirmation mark is generated.

5. The vehicle return detection method for an electronic rest stop according to claim 4, characterized in that, The establishment of the dynamic sub-coordinate system specifically includes: the electronic station obtains the current latitude and longitude coordinates through the GPS module and converts them into plane rectangular coordinates with the initial position of the station as the origin; the electronic station periodically collects multiple sets of plane rectangular coordinates and uses the least squares method to fit the multiple sets of coordinates to calculate the optimal stationary point coordinates; the electronic station compares the optimal stationary point coordinates with the original coordinates collected last time to obtain a two-dimensional drift vector and temporarily stores it in the microcontroller unit of the electronic station, thus establishing a periodically effective dynamic sub-coordinate system.

6. A vehicle return detection method for an electronic rest stop according to claim 4 or 5, characterized in that, The issuance of the locking permission instruction specifically includes: the backend system receiving combined information including hash verification results and static status confirmation markers uploaded from the electronic station via the GPRS network, performing a second verification of the hash verification results, and making a comprehensive judgment with the static status information; when both verifications pass, the backend system generates and issues a locking permission confirmation code to the electronic station, which then forwards or triggers the vehicle smart lock to perform the locking action.

7. The vehicle return detection method for an electronic rest stop according to claim 6, characterized in that, The legitimacy verification specifically includes: the vehicle smart lock uses a preset hash algorithm locally to combine the heartbeat seed returned by the backend system with its own stored unique serial number to generate a hash value; the vehicle smart lock extracts the first preset bytes of the hash value as a hash prefix and compares the hash prefix with the hash prefix recorded in its internally stored list of legitimate devices; if the comparison is successful, the preliminary legitimacy verification is passed.

8. The vehicle return detection method for an electronic rest stop according to claim 1, characterized in that, The vehicle return detection method also includes an abnormal rolling mechanism, specifically: when the vehicle smart lock fails to verify its legitimacy, fails to confirm its stationary state, or does not receive a final locking permission instruction, the vehicle smart lock automatically broadcasts an abnormal identifier. After receiving the abnormal identifier, the electronic station uploads abnormal snapshot data to the background system via the GPRS network. The abnormal snapshot data includes the GPS drift vector at that time and the relevant Bluetooth signal reception strength indicator array. The background system generates a no-fault report based on the abnormal snapshot data.

9. A vehicle return detection method for an electronic rest stop according to claim 1 or 5, characterized in that, The dynamic sub-coordinate system is a relative coordinate reference that has been compensated for drift during this vehicle return cycle, and the coordinates received by the smart lock are the relative coordinates in this dynamic sub-coordinate system.

10. A vehicle return detection system for an electronic rest stop, employing the vehicle return detection method for an electronic rest stop as described in any one of claims 1-9, characterized in that, include: The system includes an electronic rest stop, a smart lock, and a backend system. The electronic rest stop integrates a GPS module, a GPRS module, and an electronic rest stop Bluetooth module. The smart lock has a smart lock Bluetooth module. The backend system connects to the GPRS module of the electronic rest stop via a GPRS network. The electronic rest stop communicates wirelessly with the smart lock Bluetooth module via its electronic rest stop Bluetooth module. When the smart lock is within the Bluetooth signal coverage range of the electronic rest stop, it uploads vehicle information and electronic rest stop information to the backend system via the electronic rest stop's GPRS module. After successful verification, the backend system sends a locking command to the smart lock via the GPRS module and the electronic rest stop.

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