Method, system and vehicle for detecting an approach to a vehicle

Abstract

The application discloses a vehicle entering direction identification method and system and a vehicle. The method comprises the following steps: sequentially acquiring first signal strengths of signals received by antennas corresponding to each vehicle door; screening a maximum value and a second maximum value in the first signal strengths; and determining a direction of an antenna corresponding to the maximum value as the vehicle entering direction when a difference between the maximum value and the second maximum value exceeds a judgment threshold. The application can determine the vehicle entering direction by using only one node, greatly reduces the number of node arrangements, saves manufacturing cost, and has low power consumption because the antenna only receives signals. Meanwhile, only one node needs to be powered, which can also reduce static power consumption.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, specifically to an approach vehicle direction detection method, system, and vehicle. Background Technology

[0002] Currently, keyless entry / start systems for automobiles generally employ a multi-node configuration with one master and many slaves. This means that slave nodes are deployed on each car door, and a master node is deployed inside the vehicle. A node is an active electronic device that can connect to a network and send, receive, or forward information via a communication channel. Each slave node obtains its distance from the user and sends it to the master node, which then determines the direction from which the user will enter the vehicle by comparing these distances. In developing this application, the inventors discovered that this master-slave multi-node configuration requires the deployment of multiple nodes, resulting in high costs. Summary of the Invention

[0003] In view of this, this application proposes an approach, system and vehicle for detecting the direction of entry into a vehicle, in order to solve the above-mentioned technical problems.

[0004] This application provides a method for identifying the direction of vehicle entry, comprising: sequentially acquiring the first signal strength of the signal received by the antenna corresponding to each vehicle door; filtering out the maximum and second maximum values ​​among the first signal strengths; and determining the direction of the antenna corresponding to the maximum value as the direction of vehicle entry when the difference between the maximum and second maximum values ​​exceeds a determination threshold. This application requires only one node to determine the direction of vehicle entry, which can greatly reduce the number of nodes required, save manufacturing costs, and since the antenna only receives signals, power consumption is low. Furthermore, supplying power to only one node also reduces static power consumption.

[0005] Optionally, sequentially acquiring the first signal strength of the signal received by the antenna corresponding to each vehicle door includes: repeatedly acquiring the second signal strength of the signal received by the antenna corresponding to each vehicle door; calculating the average signal strength of the signal received by each antenna based on the repeatedly acquired second signal strengths; and using the average signal strength as the first signal strength. By calculating the average signal strength, the accuracy of the first signal strength can be increased, thereby improving the accuracy of identifying the direction of entry into the vehicle.

[0006] Optionally, when the difference between the maximum and the second-highest value exceeds a judgment threshold, the direction of the antenna corresponding to the maximum value is determined as the direction of entering the vehicle. The process then includes: monitoring the distance between the user and the vehicle using the antenna corresponding to the maximum value; opening the door corresponding to the antenna corresponding to the maximum value when the distance is less than a predetermined distance; and stopping the antenna corresponding to the maximum value and activating the antenna corresponding to the driver's side door when a user is detected entering the vehicle or the vehicle starts. After the vehicle is turned off, the antenna on the driver's side door can directly enter the locking distance judgment process for convenient vehicle locking.

[0007] Optionally, the maximum and second-highest values ​​of the first signal strength are selected, which may be further included before amplifying and reducing the noise of the signal received by each antenna to improve the signal-to-noise ratio of the output signal.

[0008] Optionally, the signal received by each antenna is amplified and denoised, which previously included: obtaining the noise figure NFn and gain Gn of each component, where n≥2; according to the formula Calculate the total noise figure NFsys. By calculating the total noise figure, the noise figure of the system can be evaluated for better signal reception.

[0009] This application also provides a vehicle entry direction recognition system, which includes multiple antennas, a communication module, and a main control processor. The multiple antennas are respectively installed on the side where the driver's side door is located and on the side where the passenger side door is located. Each antenna is used to receive signals and transmit the signals to the main control processor via the communication module. The main control processor controls the antennas to receive signals sequentially, receives the signals transmitted by the antennas, and obtains a first signal strength of the signals. It then filters out the maximum and second maximum values ​​from the first signal strength. When the difference between the maximum and second maximum values ​​exceeds a judgment threshold, the direction of the antenna corresponding to the maximum value is determined as the vehicle entry direction. This application requires only one node to determine the vehicle entry direction, which can greatly reduce the number of nodes and save manufacturing costs. Furthermore, the antennas only receive signals, resulting in low power consumption. Additionally, supplying power to only one node also reduces static power consumption.

[0010] Optionally, it also includes a radio frequency switch, and an antenna is also installed on the side where the tailgate is located. Each antenna is connected to the communication module through the radio frequency switch. The main control processor controls the multiple antennas to receive signals in sequence by controlling the radio frequency switch, so as to facilitate the control of each antenna.

[0011] Optionally, it also includes a low-noise amplifier corresponding to each antenna, wherein the antenna is connected to the radio frequency switch in sequence through the low-noise amplifier, the coaxial cable, and the radio frequency switch to improve the signal-to-noise ratio of the signal output.

[0012] Optionally, the communication module is an in-vehicle Bluetooth module or an in-vehicle UWB module, and the antenna is a directional antenna, which not only simplifies the structure and reduces power consumption, but also increases the difference between the maximum and second maximum values, so as to better determine the direction of the approaching vehicle and improve the accuracy of the judgment.

[0013] This application also provides a vehicle including the vehicle direction recognition system described above. This application requires only one node to determine the direction of entry, significantly reducing the number of nodes needed and saving manufacturing costs. Furthermore, the antenna only receives signals, resulting in low power consumption. Additionally, supplying power to only one node also reduces static power consumption.

[0014] The vehicle direction recognition method, system, and vehicle provided in this application receive signals using time-division multiplexing and sequentially acquire the first signal strength. The difference between the maximum and second maximum values ​​of the first signal strength is compared with a judgment threshold to determine the direction of the vehicle entering. Only one node is needed to determine the direction of the vehicle entering, which can greatly reduce the number of nodes and save manufacturing costs. Moreover, the antenna only receives signals and has low power consumption. At the same time, only one node needs to be powered, which can also reduce static power consumption. Attached Figure Description

[0015] Figure 1 This is a flowchart of the vehicle direction recognition method of this application.

[0016] Figure 2 This is a schematic diagram of the antenna installation according to this application.

[0017] Figure 3 This is a schematic diagram of the vehicle direction recognition system of this application. Detailed Implementation

[0018] The technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. Identical components are represented by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, while the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0019] Figure 1 A flowchart of the vehicle direction recognition method of this application is shown, as follows: Figure 1 As shown, the vehicle direction recognition method provided in this application includes:

[0020] S100, sequentially obtain the first signal strength of the signal received by the antenna corresponding to each door;

[0021] like Figure 2 As shown, antenna 1 is installed on the side where the driver's cab door is located, the side where the passenger cab door is located, and the side where the tailgate is located.

[0022] Signals can be received sequentially from the driver's cab door, passenger's cab door, and tailgate to obtain the first signal strength.

[0023] S200, filter out the maximum and second-highest values ​​in the first signal strength;

[0024] Sort the first signal strengths from largest to smallest, and then filter out the maximum and second-largest values. The second-largest value is only less than the maximum value, but greater than all other values.

[0025] S300, when the difference between the maximum value and the second maximum value exceeds the determination threshold, the direction of the antenna corresponding to the maximum value is determined as the direction of entering the vehicle.

[0026] For example, if the first signal strength of the signal received by the antenna on the side where the driver's side door is located is the maximum value, the second maximum value is -60dBm, the second maximum value is -70dBm, the difference is 10dBm, the judgment threshold is 5dBm, and 10>5, then the driver's side door side is considered to be the direction of entering the vehicle.

[0027] The vehicle direction recognition method provided in this application receives signals using time-division multiplexing and sequentially acquires the first signal strength. The difference between the maximum and second maximum values ​​of the first signal strength is compared with a judgment threshold to determine the vehicle direction. Only one node is needed to determine the vehicle direction, which can greatly reduce the number of nodes and save manufacturing costs. Moreover, the antenna only receives signals and has low power consumption. At the same time, only one node needs to be powered, which can also reduce static power consumption.

[0028] Furthermore, if the method of measuring time of flight is used to identify the direction of the approaching vehicle, each node needs to send a signal to the user once and receive a signal twice, involving at least three information exchanges, resulting in high power consumption. In contrast, this application only requires antenna 1 to receive the signal, which can greatly reduce power consumption.

[0029] Further, in step S100, the first signal strength of the signal received by the antenna corresponding to each door is sequentially acquired, including:

[0030] S110, repeatedly and sequentially acquire the second signal strength of the signal received by the antenna corresponding to each door;

[0031] That is, step S100 is repeated multiple times to obtain multiple second signal strengths. In this embodiment, it can be repeated 10 times.

[0032] S120, calculate the average signal strength of the signal received by each antenna based on the second signal strength obtained multiple times;

[0033] The arithmetic mean of the second signal strengths received multiple times by each antenna is calculated and used as the average signal strength.

[0034] S130, the average signal strength is used as the first signal strength.

[0035] By calculating the average signal strength, the accuracy of the first signal strength can be increased, thereby improving the accuracy of identifying the direction of the approaching vehicle.

[0036] In one specific embodiment, S300, when the difference between the maximum value and the second maximum value exceeds a determination threshold, the direction of the antenna corresponding to the maximum value is determined as the direction of entering the vehicle, and then the process further includes:

[0037] S310 uses the antenna corresponding to the maximum value to monitor the distance between the user and the vehicle;

[0038] For example, if a user enters the vehicle from the passenger side door, only antenna 1 on the passenger side door will be activated to monitor the distance between the user and the vehicle.

[0039] S320, when the distance is less than the predetermined distance, open the door corresponding to the antenna corresponding to the maximum value;

[0040] For example, if the spacing is 20cm and the predetermined distance is 30cm, then the passenger side door will be opened.

[0041] S330, when a user enters the vehicle or the vehicle starts, the antenna corresponding to the maximum value stops working and the antenna corresponding to the driver's side door is turned on.

[0042] When a user enters the vehicle or the vehicle starts, antenna 1 on the passenger side door stops working, while antenna 1 on the driver's side door starts working. After the vehicle is turned off, antenna 1 on the driver's side door can directly enter the locking distance determination process for easy vehicle locking. The vehicle is locked when the user moves further away than a set distance.

[0043] Furthermore, in S200, the maximum and second-highest values ​​of the first signal strength are selected, which also includes amplifying and reducing the noise of the signal received by each antenna to improve the signal-to-noise ratio of the output signal.

[0044] like Figure 3 As shown, this application also provides an entry vehicle direction recognition system, which includes multiple antennas 1, a communication module 4, and a main control processor 5;

[0045] like Figure 2 As shown, multiple antennas 1 are respectively installed on the side where the driver's cab door is located and on the side where the passenger cab door is located.

[0046] The antennas 1 are all used to receive signals and send the signals to the main control processor via the communication module 4.

[0047] The main control processor 5 is used to control the antenna 1 to receive signals sequentially, receive the signals sent by the antenna 1 and obtain the first signal strength of the signals, and filter out the maximum value and the second maximum value in the first signal strength; when the difference between the maximum value and the second maximum value exceeds the judgment threshold, the direction of the antenna corresponding to the maximum value is determined as the direction of entering the vehicle.

[0048] The vehicle direction recognition system provided in this application receives signals using time-division multiplexing and sequentially acquires the first signal strength. The difference between the maximum and second maximum values ​​of the first signal strength is compared with a judgment threshold to determine the direction of the vehicle entering. Only one node is needed to determine the direction of the vehicle entering, which can greatly reduce the number of nodes and save manufacturing costs. Moreover, the antenna only receives signals and has low power consumption. At the same time, only one node needs to be powered, which can also reduce static power consumption.

[0049] Furthermore, the vehicle orientation recognition system also includes an RF switch 3, and an antenna 1 is installed on the side where the tailgate is located. Each antenna 1 is connected to the communication module 4 via the RF switch 3.

[0050] The main control processor 5 is connected to the control port of the radio frequency switch 3, and controls multiple antennas 1 to receive signals in sequence by controlling the radio frequency switch 3.

[0051] By setting up the radio frequency switch 3, each antenna 1 can be easily controlled.

[0052] like Figure 3 As shown, the default connection method of the radio frequency switch 3 is: to connect to the antenna 1 located on the side of the driver's cab door.

[0053] When a user enters the vehicle, starts the vehicle, or locks the vehicle, the radio frequency switch 3 is reset to its default state, that is, connected to the antenna 1 located on the side of the driver's side door.

[0054] Since RF switch 3 introduces additional insertion loss, typically around 0.5 dB, and the distance from RF switch 3 to each antenna 1 is approximately 2 m, the insertion loss of the coaxial cable 6 for this length is approximately 3.5 dB, the total insertion loss of the entire link is approximately 4 dB. Because the insertion loss of passive components can be considered equivalent to the noise figure, the noise figure introduced by the coaxial cable 6 and RF switch 3 in this link is approximately 4 dB.

[0055] To compensate for the increased noise figure and improve receiving sensitivity, a low-noise amplifier 2 was added between antenna 1 and RF switch 3. The low-noise amplifier 2 corresponds one-to-one with antenna 1. Antenna 1 is connected to RF switch 3 sequentially via the low-noise amplifier 2 and coaxial cable 6.

[0056] By setting up a low-noise amplifier 2, not only can the signal-to-noise ratio be improved, but the impact of the coaxial cable length on the total noise figure can also be greatly reduced, allowing the node to be placed at any location on the vehicle.

[0057] In one specific embodiment, the signal received by each antenna is amplified and noise-reduced, which is further included before:

[0058] Obtain the noise figure NFn and gain Gn for each component, where n≥2;

[0059] like Figure 2-3 As shown, the noise figures and gains of the low-noise amplifier 2, coaxial cable 6, and RF switch 3 are obtained. The noise figure of the low-noise amplifier 2 is 0.5dB, and its gain is 20dB; the noise figure of the coaxial cable 6 is 3.5dB, and its gain is 0; and the noise figure of the RF switch 3 is 0.5dB, and its gain is 0.

[0060] According to the formula Calculate the total noise figure NFsys.

[0061] Based on the above data, NFsys = 0.55dB.

[0062] By calculating the total noise figure, the noise figure of the system can be evaluated in order to better receive signals.

[0063] In one specific embodiment, the communication module 4 may be an in-vehicle Bluetooth module or an in-vehicle UWB (UltraWide Band) module to simplify the structure and reduce power consumption.

[0064] Furthermore, the antenna 1 is a directional antenna, which can increase the difference between the maximum and the second maximum value in order to better determine the direction of the approaching vehicle.

[0065] In this embodiment, antenna 1 can be a linearly polarized directional antenna, typically with a beam angle of 120 degrees and a gain of approximately 5 to 10 dBi, such as a planar antenna.

[0066] The selection of the judgment threshold is an important prerequisite for accurately determining the direction of entry of the key carrier. The installation position of antenna 1 and the type of antenna will affect the selection of the judgment threshold.

[0067] According to Friis's law of transmission, the signal strength Pr received at a free space distance Dr can be calculated using formula (1):

[0068]

[0069] Where Pt is the transmit power intensity, Gt is the transmit antenna gain, Gr is the receive antenna gain, and lambda is the wireless signal wavelength.

[0070] by Figure 2 Taking the two antennas 1 located on the side of the driver's and passenger's side doors as an example, assuming the key is located on the side of the driver's side door, the difference in signal strength received at the positions of the two antennas 1 can be obtained according to formula (1):

[0071]

[0072] The relationship between Dr2 and Dr1 is as follows:

[0073] Dr2=Dr1+W (3)

[0074] Where W is the distance between the two antennas 1.

[0075] Therefore, formula (3) can be simplified to:

[0076]

[0077] The larger ΔPr(dB) is, the easier it is to distinguish the signal strength difference between the received signals on the two antennas 1. Therefore, during installation, the distance between the two antennas 1 should be as large as possible to ensure that... The larger the item, the better.

[0078] but, The value will decrease as the required distance increases. For example, in an automatic parking scenario, it's required to determine whether the key carrier is on the driver's side or the passenger side when they are 6 meters away from the vehicle. Let W be the typical vehicle width of 2 meters. It can only provide an error of about 2dB, making it difficult to determine the direction of the approaching vehicle.

[0079] This application employs a directional antenna, and the difference between Gr1 and Gr2 can reach at least approximately 10 dB. Therefore, relying on the characteristics of the directional antenna, a sufficiently large ΔPr (dB) can still be obtained at a relatively long decision distance, which helps in setting an appropriate decision threshold.

[0080] This application also provides a vehicle that includes the vehicle direction recognition system described above.

[0081] The vehicle provided in this application receives signals by using time-division multiplexing and sequentially obtains the first signal strength. The difference between the maximum and second maximum values ​​of the first signal strength is compared with a decision threshold to determine the direction of the entering vehicle. Only one node is needed to determine the direction of the entering vehicle, which can greatly reduce the number of nodes and save manufacturing costs. Moreover, the antenna only receives signals and has low power consumption. At the same time, only one node needs to be powered, which can also reduce static power consumption.

[0082] The technical solution of this application has been described in detail above with reference to specific embodiments. The specific embodiments described are used to help understand the ideas of this application. Derivations and modifications made by those skilled in the art based on the specific embodiments of this application also fall within the protection scope of this application.

Claims

1. A method for recognizing the direction of entry into a vehicle, characterized in that, include: The first signal strength of the signal received by the antenna corresponding to each car door is obtained sequentially, wherein the antenna is disposed inside or outside the car door; Filter out the maximum and second-highest values ​​in the first signal strength; When the difference between the maximum value and the second maximum value exceeds the determination threshold, the direction of the antenna corresponding to the maximum value is determined as the direction of entering the vehicle.

2. The vehicle direction recognition method as described in claim 1, characterized in that, The first signal strength of the signal received by the antenna corresponding to each car door is obtained sequentially, including: The second signal strength of the signal received by the antenna corresponding to each car door is obtained multiple times in sequence; Calculate the average signal strength received by each antenna based on the second signal strength obtained multiple times; The average signal strength is taken as the first signal strength.

3. The vehicle direction recognition method as described in claim 1, characterized in that, When the difference between the maximum value and the second maximum value exceeds a judgment threshold, the direction of the antenna corresponding to the maximum value is determined as the direction of entering the vehicle, and then the process further includes: The distance between the user and the vehicle is monitored using the antenna corresponding to the maximum value. When the distance is less than the predetermined distance, the door corresponding to the antenna with the maximum value is opened; When a user enters the vehicle or the vehicle starts, the antenna corresponding to the maximum value stops working, and the antenna corresponding to the driver's side door is turned on.

4. The method for identifying the direction of an approaching vehicle as described in any one of claims 1-3, further comprising, before filtering out the maximum and second-highest values ​​of the first signal strength: The signal received by each antenna is amplified and noise reduced.

5. The vehicle direction recognition method as described in claim 4, characterized in that, The signal received by each antenna is amplified and noise reduced, which previously included: Obtain the noise figure NF of each component n and gain G n , n≥2; According to the formula Calculate the total noise figure NFsys.

6. A vehicle direction recognition system, characterized in that, Includes multiple antennas, a communication module, and a main control processor; Multiple antennas are installed on the side where the driver's cab door is located and on the side where the passenger's cab door is located; The antennas are all used to receive signals and send the signals to the main control processor via the communication module; The main control processor is used to control the antenna to receive signals sequentially, receive signals sent by the antenna and obtain the first signal strength of the signal, and filter out the maximum and second maximum values ​​of the first signal strength; when the difference between the maximum and second maximum values ​​exceeds the judgment threshold, the direction of the antenna corresponding to the maximum value is determined as the direction of entering the vehicle.

7. The vehicle direction recognition system as described in claim 6, characterized in that, It also includes a radio frequency switch, and an antenna is installed on the side where the tailgate is located. Each antenna is connected to the communication module through the radio frequency switch. The main control processor controls the multiple antennas to receive signals in sequence by controlling the radio frequency switch.

8. The vehicle direction recognition system as described in claim 7, characterized in that, It also includes a low-noise amplifier corresponding to each antenna, and the antenna is connected to the radio frequency switch in sequence through the low-noise amplifier, coaxial cable and so on.

9. The vehicle direction recognition system as described in claim 8, characterized in that, The communication module is a vehicle-mounted Bluetooth module or a vehicle-mounted UWB module, and the antenna is a directional antenna.

10. A vehicle, characterized in that, Including the vehicle direction recognition system as described in any one of claims 6-9.

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