Door inside and outside distinguishing method based on radio frequency signal interference

Abstract

The invention discloses an inside and outside door distinguishing method based on radio frequency signal interference, which comprises the following steps: an outside door radio frequency module A and an inside door radio frequency module B broadcast I D-W and I D-N signals at the same time, the signals interfere with each other, the I D-W signals are received outside the door, the I D-N signals are received inside the door, if the I D-W signals can be completely received, the door is outside the door, and if the I D-N signals can be received, the door is inside the door; if the I D-W signal intensity is higher than the threshold value and the identification is successful, establishing connection with the door lock and carrying out identity authentication. According to the door interior and exterior distinguishing method based on radio frequency signal interference, through cooperative work of the human body induction radar, the DD activation module, the radio frequency module and the distance measurement module, the high-precision distance measurement capability of the UWB module and signal intensity comparison are utilized, it is guaranteed that the position of a key tag can be accurately judged, the error is smaller than 10 cm, and the safety of a door is guaranteed. Through signal intensity difference judgment, misjudgment caused by single signal fluctuation is effectively avoided, and the reliability of the intelligent door lock in a non-inductive door opening scene is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of smart home, and particularly relates to a method for distinguishing inside and outside a door based on radio frequency signal interference. Background Art

[0002] With the development of smart home technology, smart door locks have gradually become an important device for home security. In the prior art, smart door locks mainly achieve touchless door opening through radio frequency technologies such as Bluetooth and UWB.

[0003] In the prior art, the Bluetooth technology judges inside and outside the door by comparing the RSSI values of two Bluetooth modules, but the RSSI value is easily affected by the environment and leads to misjudgment. The UWB technology measures the distance by time of flight, and the error is about 10 cm. The thickness of the door is usually 5 cm, resulting in a relatively high probability of misjudgment. The prior art cannot reliably distinguish inside and outside the door, and there are certain security risks. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method for distinguishing inside and outside a door based on radio frequency signal interference, which can effectively solve the problems that the existing Bluetooth technology is easily affected by the environment and leads to misjudgment, and the UWB technology has a large error.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: a method for distinguishing inside and outside a door based on radio frequency signal interference, the method comprising:

[0006] S1. The radio frequency module A outside the door broadcasts a data packet with ID-W;

[0007] S2. The radio frequency module B inside the door broadcasts a data packet with ID-N or a carrier signal;

[0008] S3. Since ID-W and IN-N are synchronously transmitted, they interfere with each other. Outside the door, the ID-N signal is attenuated by the door and then interfered by ID-W. Therefore, only the ID-W signal can be received outside the door, and the ID-N signal is interfered into scrambled codes; the situation inside the door is exactly the opposite. If the ID-W signal can be received completely, it is judged to be outside the door. If the ID-N signal can be received completely, it is judged to be inside the door. If neither of them can be received, it is to be determined;

[0009] S4. In step S3, if the intensity of the ID-W signal is higher than a preset threshold and is received and recognized, it establishes a connection with the door lock and performs identity authentication.

[0010] Preferably, the radio frequency module includes but is not limited to a Bluetooth module, a UWB module, a StarFlash module, and a 2.4G module.

[0011] Preferably, the ranging module includes but is not limited to a UWB module, a 24G radar, a 64G radar, a 77G radar, Bluetooth 6.0, and an ultrasonic module.

[0012] Preferably, the human body sensing radar is an infrared sensor and a radio frequency radar.

[0013] Preferably, the installation position of the radio frequency module is horizontally aligned.

[0014] Preferably, the computing unit processes the data of the ranging module in real time to analyze human behavior trends.

[0015] Preferably, the door lock end includes a human body sensing radar, two radio frequency modules, a ranging module and a computing unit.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. In the present invention, the method successfully solves the problem of unreliable distinction between inside and outside the door mentioned in the background technology through the coordinated work of human body sensing radar, radio frequency module and ranging module. The high-precision ranging capability and signal strength comparison of the UWB module are used to ensure that the key tag can accurately determine the position with an error of less than 10 cm. Through signal judgment, the misjudgment caused by single signal fluctuations is effectively avoided. The accuracy of distinguishing between inside and outside the door reaches 100%, and the misjudgment rate is less than 0.1%. The reliability of smart door locks in the scene of non-sensing door opening is significantly improved.

[0018] 2. In the present invention, the method is comprehensively optimized in terms of system performance and user experience. Through low-power design, the human body sensing radar and key tag are in low-power standby state when no one approaches, which significantly reduces the overall power consumption of the system and extends the battery life. The time from detecting the presence of a human body to waking up the key tag is less than 100 milliseconds, ensuring a quick response of the system. In addition, the precise ranging and real-time behavior trend judgment of the 24G radar make the trigger time of the unlocking action less than 1 second, improving the smoothness of the user experience. The user does not need manual operation when approaching the door lock, especially when both hands are occupied or carrying items, which provides great convenience.

[0019] 3. In the present invention, the method supports a variety of RF modules and ranging modules. Users can choose appropriate modules according to actual needs, which not only improves the applicability of the system, but also reserves space for future technology upgrades and module replacements. By optimizing algorithms and parameters, the adaptability of the system in different environments has been significantly improved, and it can maintain stable and reliable performance regardless of whether it is in an electromagnetic environment with complex signals or under different installation conditions.

[0020] 4. In the present invention, the method optimizes the back recognition algorithm to ensure that the key tag is not accidentally triggered to unlock when it is on the back of the door lock, further enhancing the security of the system. The identity authentication uses an encryption algorithm to prevent illegal key tags from forging, ensuring that only legitimate key tags can complete the identity authentication and trigger the unlocking action. After long-term system-level testing, the stability in various complex environments has been verified, and the false trigger rate is lower than 0.1%. Through algorithm optimization such as adaptive filtering and dynamic threshold adjustment, the system can accurately judge the trend of human behavior, avoid misjudgment caused by environmental interference or signal fluctuations, and ensure the long-term stable operation of the system. Brief Description of the Drawings

[0021] Figure 1 It is a flow framework diagram of the present invention;

[0022] Figure 2 It is a diagram showing the positional relationship between the radio frequency module and the ranging module of the present invention. Detailed Embodiments

[0023] To make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0024] Embodiment 1, System initialization and human body proximity detection. During the implementation process, when the system is initialized, the human body induction radar (infrared sensor) and the DD activation module at the door lock end enter the low-power standby state, and the key tag is in the sleep state. The human body induction radar uses passive infrared technology to detect the presence of a human body by detecting changes in human infrared radiation, and the set induction range is within 1 meter. When a human body enters the induction range and the induction radar continuously detects the presence of a human body for more than 500 milliseconds, the DD activation module is triggered. Subsequently, after receiving the signal from the induction radar, the DD activation module immediately sends a wireless wake-up signal to wake up the key tag. The wake-up signal uses the low-power Bluetooth protocol to ensure stable and low-power signal transmission. After receiving the wake-up signal, the DD detection module of the key tag wakes up from the sleep state. The power consumption in the sleep state is lower than 10 microamps, and the power consumption increases to 50 milliamps after waking up, and the radio frequency scanning function is started to prepare to receive the radio frequency signal from the door lock end.

[0025] After completing the system initialization and human body proximity detection, the system has successfully woken up the key tag and is ready to perform the next radio frequency signal broadcast and signal comparison.

[0026] Through low-power design, the human body induction radar and key tag are in a low-power standby state when no one is approaching, significantly reducing the overall power consumption of the system, extending the battery life, and the time from detecting the presence of a human body to waking up the key tag is less than 100 milliseconds, ensuring the system's quick response. By setting reasonable induction distance and time thresholds, the probability of false triggering caused by a short passing or environmental interference is effectively reduced, ensuring the system's stability.

[0027] Example 2: RF signal broadcasting and signal strength comparison. During the implementation process, the RF module A (UWB module) outside the door starts broadcasting data packets with a unique identifier ID-W at a frequency of 10 times per second. The RF module B (UWB module) inside the door simultaneously broadcasts data packets with a different identifier ID-N at the same frequency of 10 times per second. The broadcast signals cover the area in front of the door, ensuring that the key tag receives signals of different strengths at different positions inside and outside the door. The two broadcasts of ID-W and ID-N are simultaneous. When outside the door, if the key tag can receive the complete ID-W data, it establishes a secure connection with the door lock end for identity authentication (such as AES-256 encryption authentication), and the identity authentication process is completed within 500 milliseconds to ensure a smooth unlocking process.

[0028] The system has successfully identified the position of the key tag and established a secure connection. Next, ranging and behavior trend judgment are required to further confirm whether to perform the unlocking action.

[0029] High-precision positioning is achieved through a high-precision UWB module, with an error less than 10 centimeters, ensuring that the key tag can accurately judge its position. The UWB signal has strong anti-interference ability in a complex electromagnetic environment, ensuring the stability of signal transmission. Through signal judgment, false judgment caused by a single signal fluctuation is effectively avoided, ensuring the accuracy of distinguishing inside and outside the door, with a false judgment rate lower than 0.1%.

[0030] Example 3: Ranging and behavior trend judgment. During the implementation process, the ranging module (24G radar) at the door lock end measures the distance from the human body to the door lock in real time at a sampling frequency of 20 times per second. The 24G radar calculates the distance by transmitting and receiving millimeter-wave signals and using the Doppler effect and signal phase difference. The operation unit processes the received distance data in real time, including filtering, denoising, and trend analysis. The Kalman filter algorithm is used to smooth the distance data to remove noise interference. If the operation unit determines that the human body is approaching the door lock (such as the distance decreasing continuously for 3 consecutive samples), the unlocking action is triggered. If the human body is moving away from the door lock, the unlocking is not performed. The behavior judgment algorithm is based on moving average and trend analysis to ensure the accuracy of judgment. By optimizing the algorithm of the ranging module, it is ensured that the human behavior trend can be accurately judged in different environments. The algorithm optimization includes adaptive filtering and dynamic threshold adjustment to improve the adaptability of the system.

[0031] After completing the ranging and behavior trend judgment, the system can already accurately judge the behavior intention of the human body. Next, the entire system needs to be integrated and optimized to ensure its high performance and stability in various complex environments.

[0032] Through precise 24G radar ranging with centimeter-level accuracy and an error of less than 2 cm, the accuracy of distance measurement is ensured. By analyzing the real-time trend of distance changes, the system can intelligently judge the behavior intention of the human body, avoid false door openings, with a false trigger rate of less than 0.1%. The time from detecting the approach of the human body to triggering the unlocking action is less than 1 second, enhancing the user experience and ensuring a smooth unlocking process.

[0033] Example 4: System integration and optimization. During the implementation process, all modules of the door lock end and the key tag end are integrated into a complete system, including a human body sensing radar, a DD activation module, RF modules A / B, a ranging module, an arithmetic unit, as well as a DD detection module, an RF module, and a main control module of the key tag. Communication between modules is carried out through standardized interfaces to ensure the compatibility and expandability of the system.

[0034] Subsequently, system-level tests are conducted, including functional tests, performance tests, and stability tests. Functional tests ensure that each module works properly in coordination. Performance tests include response time, recognition accuracy, and power consumption tests. Stability tests are carried out under different environmental conditions to ensure the long-term stable operation of the system.

[0035] Finally, system parameters and algorithms are optimized based on the test results to ensure the best overall performance. The optimized parameters include signal strength thresholds, broadcast frequencies, sampling frequencies, and filtering parameters. It supports multiple RF modules (such as Bluetooth modules, UWB modules, XingShan modules, 2.4G modules) and ranging modules (such as UWB modules, 24G radars, 64G radars, 77G radars, Bluetooth 6.0, ultrasonic modules). Users can select appropriate modules according to actual needs to enhance the applicability and flexibility of the system. The recognition effect of the key tag at different angles is tested, and the algorithm is optimized to ensure reliable recognition within a wide angle range of 170 degrees. The optimized algorithms include signal strength weighting and multipath signal processing. The recognition effect of the key tag when it is behind the door lock is tested, and the signal strength of the RF module B inside the door and the algorithm of the arithmetic unit are optimized to ensure that there is no false trigger for unlocking when it is behind the door. The optimization measures include adjusting the transmission power of the module inside the door and optimizing the signal processing algorithm.

[0036] The recognition of the key tag at different angles is tested, and the test results are shown in the following table:

[0037]

[0038] Among them, at an angle of 0°, the key tag can unlock when it is 0.6 - 0.8 meters away from the door lock, and the reaction time is 1 - 2 seconds when it reaches 0 meters from the lock.

[0039] At a 45° angle, the key tag can unlock the door lock when it is 1.0 - 1.2 meters away from the door lock. However, in some cases (such as the second test), it can unlock at 0.8 meters.

[0040] At a 90° angle, the key tag can unlock the door lock when it is 1.3 - 1.5 meters away from the door lock, showing a good recognition effect.

[0041] At a 135° angle, the key tag can unlock within the distance range of 1.0 - 1.2 meters and 1.3 - 1.5 meters. However, in the fourth test, it can unlock at 0.6 meters.

[0042] At a 180° angle, the key tag can unlock the door lock when it is 0.6 - 0.8 meters away from the door lock, and the response time is 1 - 2 seconds when approaching 0 meters from the lock.

[0043] Through system integration, the accuracy rate of distinguishing inside and outside the door reaches 100%, and the response time is 1 - 2 seconds, ensuring that users can unlock the door smoothly at different angles and positions. After long-term testing, the stability of the system in various complex environments is verified, and the false trigger rate is less than 0.1%, ensuring the reliability of the system. The touchless unlocking process is smooth, and users do not need to operate manually when approaching the door lock, improving the user experience, especially when both hands are occupied or carrying items, providing great convenience. It supports multiple radio frequency modules and ranging modules, and users can select appropriate modules according to actual needs, improving the applicability and flexibility of the system to adapt to different user scenarios. By optimizing the back recognition algorithm, it is ensured that the key tag does not accidentally trigger unlocking when it is on the back of the door lock, further enhancing the system security and preventing illegal unlocking.

[0044] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A method for distinguishing inside and outside of a door based on radio frequency signal interference, characterized in that The method includes: S1. The external radio frequency module A broadcasts a data packet with ID-W. S2. The internal radio frequency module B broadcasts a data packet with ID-N or a carrier signal. S3. Since ID-W and ID-N are transmitted synchronously, they interfere with each other. Outside the door, the ID-N signal is attenuated by the door and then interfered by ID-W, so only the ID-W signal can be received outside the door, and the ID-N signal is interfered and becomes scrambled. Inside the door, it is exactly the opposite. If the ID-W signal can be received completely, it is judged as outside the door; if the ID-N signal can be received completely, it is judged as inside the door; if neither can be received, it is pending. S4. In step S3, if the strength of the ID-W signal is higher than the preset threshold and is received and recognized, it establishes a connection with the door lock and performs identity authentication.

2. The method for distinguishing inside and outside a door based on radio frequency signal interference according to claim 1, wherein: The radio frequency module includes, but is not limited to, a Bluetooth module, a UWB module, a XingShan module, and a 2.4G module.

3. A method for distinguishing inside and outside of a door based on radio frequency signal interference according to claim 1, characterized in that: The ranging module includes, but is not limited to, a UWB module, a 24G radar, a 64G radar, a 77G radar, Bluetooth 6.0, and an ultrasonic module.

4. A method for distinguishing inside and outside a door based on radio frequency signal interference according to claim 1, characterized in that: The human body sensing radar is an infrared sensor and a radio frequency radar.

5. A method for distinguishing inside and outside a door based on radio frequency signal interference according to claim 1, characterized in that: The installation positions of the radio frequency modules are horizontally aligned.

6. The method for distinguishing inside and outside the door based on radio frequency signal interference according to claim 1, wherein: The operation unit processes the data of the ranging module in real time and analyzes the human behavior trend.

7. A method for distinguishing inside and outside the door based on radio frequency signal interference according to claim 1: The door lock end includes a human body sensing radar, two radio frequency modules, a ranging module, and an operation unit.

Images