Trolley following method based on AOA principle in UWB

Abstract

The invention provides a dolly following method based on an AOA principle in UWB, and the method comprises the steps: placing a UWB base station end provided with double antennas on a dolly, and enabling a user end to be provided with a UWB label end provided with a single antenna; converting the phase difference into a distance difference; the flight time between the UWB label end and the UWB base station end is calculated, and then the antenna distance between the single antenna of the UWB label end and the near-end UWB base station end is calculated; calculating the size of the included angle AOA according to the cosine law; the UWB base station end sends the rotating angle and the moving distance to the trolley through a serial port, and the trolley converts data into a moving vector after receiving an instruction and then moves according to the vector. The UWB label ends and the UWB base station ends are independently used in a one-to-one mode, the following effect of the trolley is very ideal, UWB signals are slightly influenced by the surrounding natural environment, and the application scene is wider.

Description

Technical Field

[0001] The invention belongs to the technical field of intelligent car following, and in particular relates to a car following method based on the AOA principle in UWB. Background Art

[0002] The current car following system mainly uses multiple cameras to capture the surrounding environment from multiple angles, and uses special software to systematically analyze environmental changes, and then calculates the trajectory that the car should move forward, and then controls the car to follow the set target. This method requires many cameras to collect the environment of the car from multiple angles for professional analysis, and the technical cost is very high. At the same time, due to the fact that the distance, weather, ambient light and other factors have a great impact on the camera imaging effect, it will also cause the car's following effect to be unsatisfactory. Summary of the invention

[0003] The purpose of the present invention is to provide a car following method based on the AOA principle in UWB, aiming to solve the problem that the existing car following effect is not ideal.

[0004] The present invention is implemented as follows: a car following method based on the AOA principle in UWB, the method comprising the following steps: Step 1: Place a UWB base station with dual antennas on the car. The UWB base station can control the servo motor below it to adjust the direction of the dual antennas and control the movement trajectory of the car. The user end has a UWB tag with a single antenna. The single antenna of the UWB tag and the dual antenna of the UWB base station send signals to each other. Step 2: Every time the UWB tag transmits a signal, the dual antennas on the UWB base station receive signals in a first-come-first-served and last-served manner due to the different distances from the UWB tag. There is a phase difference pdoa. The phase difference is converted into a distance difference b through the wavelength of the UWB signal using the formula b=r*pdoa, where r is the wavelength of the UWB signal. Step 3: The UWB tag end sends signal S1. After the UWB base station end receives the S1 signal, it sends signal S2. After the UWB tag end receives the S2 signal, it sends signal S3. When the UWB base station end receives the S3 signal, a measurement cycle ends. Then, the flight time T between the UWB tag end and the UWB base station end is T = (Tround1 * Tround2 - Treply1 * Treply2) / (Tround1 + Tround2 + Treply1 + Treply2). Tround1 is the time from when the UWB tag end transmits the S1 signal to when it receives the S2 signal from the UWB base station end. Treply2 is the time from when the UWB tag end receives the S2 signal from the UWB base station end to when it transmits the S3 signal. Tround2 is the time from when the UWB base station end transmits the S2 signal to when it receives the S3 signal from the UWB tag end. Treply1 is the time from when the UWB base station end receives the S1 signal from the UWB tag end to when it transmits the S2 signal. Furthermore, the distance a between the single antenna of the UWB tag end and the antenna of the proximal UWB base station end is calculated as a = T * c, where c is the speed of light; Step 4: Set the distance between the two antennas of the UWB base station end as d. Consider the two antennas of the UWB base station end and the single antenna of the UWB tag end as a triangle. The distance between the single antenna of the UWB tag end and the antenna of the proximal UWB base station end is a, and the distance between the single antenna of the UWB tag end and the antenna of the distal UWB base station end is a + b. Then, the cosine value of the angle AOA between the UWB tag end and the UWB base station end is COS(AOA) = (d * d + (a + b) * (a + b) – a * a) / (2 * d * (a + b)). Calculate the magnitude of AOA according to this formula; Step 5: When the UWB base station end measures the valid angle AOA and distance a with the UWB tag end each time, it controls the servo motor to rotate at the AOA angle through the serial port. After the action is completed, the UWB base station end will start the next AOA measurement. If the AOA angle at this time is not close to 0, the UWB base station end will rotate at the AOA angle again and measure again until the AOA angle is close to 0. The UWB base station end counts the total degree of rotation and the direction of rotation. The total rotation angle A = A1 + A2 + A3 + …… Ai, where A1, A2…Ai are the angles of each rotation, which have positive and negative values. The UWB base station end compares the distance a measured each time with the following distance S set inside the UWB base station end. If a > S, the trolley moves forward; if a < S, the trolley moves backward. The forward and backward distances are the difference between a and S. The UWB base station end sends the angle to be rotated and the moving distance to the trolley through the serial port. After receiving the instruction, the trolley converts the data into a moving vector and then moves according to this vector to achieve the effect of the trolley following the UWB tag end.

[0005] A further technical solution of the present invention is that the distance d between the two antennas at the UWB base station end is smaller than a half wavelength of the UWB signal.

[0006] A further technical solution of the present invention is: in step 4, after a measurement cycle is completed, the average value of the angle AOA within the cycle is calculated, and the average value of the distance a within the cycle is calculated.

[0007] A further technical solution of the present invention is: in step five, the angle of AOA close to 0 is defined as being within a range of -5 degrees to +5 degrees.

[0008] A further technical solution of the present invention is: the UWB base station end includes a main control chip U1, a UWB chip U3 and a dual antenna ANT1, pin 1 of the main control chip U1 is connected to pin 2 of the UWB chip U3, pin 2 of the main control chip U1 is connected to pin 3 of the UWB chip U3, pin 3 of the main control chip U1 is connected to pin 4 of the UWB chip U3, pin 5 of the main control chip U1 is connected to pin 5 of the UWB chip U3, pin 1 of the dual antenna ANT1 is connected to pin 7 of the UWB chip U3, and pin 2 of the dual antenna ANT1 is connected to pin 8 of the UWB chip U3.

[0009] A further technical solution of the present invention is: the UWB base station also includes a voltage conversion chip U5, pin 3 of the voltage conversion chip U5 is connected to a 5V voltage, pin 2 of the voltage conversion chip U5 outputs a 3.3V voltage, pin 9 of the main control chip U1 is connected to a 3.3V voltage, and pin 1 of the UWB chip U3 is connected to a 3.3V voltage.

[0010] A further technical solution of the present invention is: the UWB base station end also includes a motor chip U2 and a car connection chip U4, pin 2 of the motor chip U2 is connected to pin 20 of the main control chip U1, pin 3 of the motor chip U2 is connected to pin 19 of the main control chip U1, pin 2 of the car connection chip U4 is connected to pin 13 of the main control chip U1, and pin 3 of the car connection chip U4 is connected to pin 12 of the main control chip U1.

[0011] A further technical solution of the present invention is: the UWB tag end includes a main control chip U6, a UWB chip U7 and a single antenna ANT2, pin 1 of the main control chip U6 is connected to pin 2 of the UWB chip U7, pin 2 of the main control chip U6 is connected to pin 3 of the UWB chip U7, pin 3 of the main control chip U6 is connected to pin 4 of the UWB chip U7, pin 5 of the main control chip U6 is connected to pin 5 of the UWB chip U7, and pin 1 of the single antenna ANT2 is connected to pin 7 of the UWB chip U7.

[0012] A further technical solution of the present invention is: the UWB tag end also includes a voltage conversion chip U8, pin 3 of the voltage conversion chip U8 is connected to a 5V voltage, pin 2 of the voltage conversion chip U8 outputs a 3.3V voltage, pin 9 of the main control chip U6 is connected to a 3.3V voltage, and pin 1 of the UWB chip U7 is connected to a 3.3V voltage.

[0013] A further technical solution of the present invention is that the dual antenna ANT1 communicates with the single antenna ANT2.

[0014] The beneficial effects of the present invention are: UWB can measure distance with an accuracy of 10 cm, AOA angle can also achieve an accuracy of 1 degree, and the UWB tag end and the UWB base station end are used one-to-one, so the following effect of the car is very ideal. At the same time, UWB signals are little affected by the surrounding natural environment and are applicable to a wider range of scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a flow chart of the method of the present invention; Figure 2 It is a schematic diagram of receiving signals at the front and rear ends of the dual antennas at the UWB base station end of the present invention; Figure 3 It is a schematic diagram of calculating the flight time through two-way and two-sided ranging in the present invention; Figure 4 It is a schematic diagram of a triangle formed by the dual antennas at the UWB base station end and the single antenna at the UWB tag end of the present invention; Figure 5 It is a circuit connection diagram of the UWB base station end of the present invention; Figure 6 It is a circuit connection diagram of the UWB tag end of the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0017] Figure 1 The present invention shows a car following method based on the AOA principle in UWB, which includes the following steps: Step 1: Place a UWB base station with dual antennas on the car. The UWB base station can control the servo motor below it to adjust the direction of the dual antennas and control the movement trajectory of the car. The user end has a UWB tag with a single antenna. The single antenna of the UWB tag and the dual antenna of the UWB base station send signals to each other. Step 2: Every time the UWB tag transmits a signal, the dual antennas on the UWB base station receive signals in a first-come-first-served and last-served manner due to the different distances from the UWB tag. There is a phase difference pdoa. The phase difference is converted into a distance difference b through the wavelength of the UWB signal using the formula b=r*pdoa, where r is the wavelength of the UWB signal. Step 3: The UWB tag sends signal S1, and the UWB base station sends signal S2 after receiving signal S1. The UWB tag sends signal S3 after receiving signal S2. After the UWB base station receives signal S3, a measurement cycle ends. Then the flight time between the UWB tag and the UWB base station is T=(Tround1*Tround2-Treply1*Treply2) / (Tround1+Tround2+Treply1+Treply2), where Tround1 is the flight time of the UWB tag. The time from transmitting the S1 signal to receiving the S2 signal from the UWB base station, Treply2 is the time from the UWB tag receiving the S2 signal from the UWB base station to transmitting the S3 signal, Tround2 is the time from the UWB base station transmitting the S2 signal to receiving the S3 signal from the UWB tag, and Treply1 is the time from the UWB base station receiving the S1 signal from the UWB tag to transmitting the S2 signal. Then, the distance between the single antenna of the UWB tag and the antenna of the near-end UWB base station is calculated as a=T*c, where c is the speed of light; Step 4: Set the distance between the two antennas at the UWB base station to d, and regard the dual antennas at the UWB base station and the single antenna at the UWB tag as a triangle. The distance between the single antenna at the UWB tag and the antenna at the near end of the UWB base station is a, and the distance between the single antenna at the UWB tag and the antenna at the far end of the UWB base station is a+b. The cosine value of the angle AOA between the UWB tag and the UWB base station is COS(AOA)=(d*d+(a+b)*(a+b)–a*a) / 2*d*(a+b). Calculate the size of AOA according to this formula. Step 5: When the UWB base station measures the valid angle of arrival (AOA) A and the distance a from the UWB tag end each time, it controls the servo motor to rotate at the AOA angle through the serial port. After the action is completed, the UWB base station will start the next AOA measurement. If the AOA angle at this time is not close to 0, the UWB base station will rotate the AOA angle again and measure again until the AOA angle is close to 0. The UWB base station counts the total rotation degrees and the rotation direction. The total rotation angle A = A1 + A2 + A3 +... + Ai, where A1, A2... Ai are the angles of each rotation, with positive and negative values. The UWB base station compares the measured distance a each time with the following distance S set inside the UWB base station. If a > S, the trolley moves forward; if a < S, the trolley moves backward. The forward and backward distances are the difference between a and S. The UWB base station sends the angle to be rotated and the moving distance to the trolley through the serial port. After receiving the instruction, the trolley converts the data into a moving vector and then moves according to this vector to achieve the effect of the trolley following the UWB tag end.

[0018] Preferably, the distance d between the two antennas of the UWB base station should be less than half of the wavelength of the UWB signal.

[0019] Preferably, in Step 4, after the end of a measurement cycle, calculate the average value of the AOA angle within the cycle and calculate the average value of the distance a within the cycle.

[0020] Preferably, in Step 5, the definition that the AOA angle is close to 0 is within the range of -5 degrees to +5 degrees.

[0021] In this system, a UWB base station with two antennas will be placed on the trolley. The UWB base station can control the servo motor below it to quickly adjust the direction by 360 degrees and can also control the movement trajectory of the trolley. At the same time, the user also has a UWB tag end with a single antenna to perform real-time distance and AOA measurements with the UWB base station.

[0022] In the measurement of AOA, the main data to be obtained is the distance difference between the UWB tag end and the two antennas of the UWB base station. Due to volume limitations, it is most appropriate to use the phase difference of arrival (pdoa) of the UWB signal to measure the distance. In this design, the two antennas of the UWB base station should be exactly the same, and the distance between them is designed to be slightly less than half of the wavelength of the UWB to ensure that the distance difference between the signals from the UWB tag end to the two antennas of the UWB base station is controlled within half of the wavelength, that is, pdoa is within -90 to 90 degrees, making the data more accurate and effective. Since the front and back of the UWB tag end with respect to the UWB base station are completely symmetric, the AOA measurement angles are exactly the same, and there will be a problem of being unable to distinguish the front and back. Therefore, the antenna design of the UWB base station will also use a directional forward antenna, such as Figure 2As shown, the UWB tag data can only be received from the front. The antenna of the UWB tag is omnidirectional and uniform, ensuring that there is enough power in all directions to meet the measurement effect of the UWB base station.

[0023] Each time the UWB tag transmits a signal, the dual antennas on the base station are at different distances from the tag, so the received signals may arrive first and then later, that is, there will be a phase difference pdoa. The phase difference can be converted into a distance difference b through the wavelength of the UWB signal. b=r*pdoa, where r is the wavelength of the UWB signal. The UWB base station and the UWB tag will also use the two-way two-way ranging (DS-TWR) method to accurately measure the distance between each signal transmission. Figure 3 As shown, the UWB tag sends signal S1, and the UWB base station sends signal S2 after receiving signal S1. The UWB tag sends signal S3 after receiving signal S2, and a measurement cycle ends after the UWB base station receives signal S3. Then the flight time T between the UWB tag and the UWB base station is converted as follows: T=(Tround1xTround2–Treply1xTreply2) / (Tround1+Tround2+Treply1+Treply2).

[0024] Then the distance a between the single antenna at the UWB tag and the antenna at the near UWB base station can be obtained by multiplying T by the speed of light, that is, a=T*c, where c is the speed of light. The distance between the two antennas at the UWB base station is set to d, which should be less than the half wavelength of the UWB signal. The dual antennas at the UWB base station and the single antenna at the UWB tag can be regarded as a triangle, such as Figure 4 As shown, the AOA angle can be calculated by the cosine theorem of the triangle. COS(AOA)=(d*d+(a+b)*(a+b)–a*a) / 2*d*(a+b), so the size of AOA can be calculated, that is, the angle between the UWB tag and the UWB base station.

[0025] In fact, the measurement period of AOA is about 20 ms each time. To ensure the accuracy and reliability of the data, an algorithm processing method of taking the average value after collecting 20 data each time is adopted to make the result of AOA more reliable. AOA = (AOA1 + AOA2 + AOA3 + …… + AOA20) / 20; the corresponding distance a will also be processed using the same algorithm, a = (a1 + a2 + a3 + …… + a20) / 20; when the UWB base station measures the effective included angle AOA and distance a with the UWB tag end each time. It will control the high-speed servo motor to rotate at the AOA angle through the serial port, and basically this rotation action can be completed within 10 ms. After the action is completed, the UWB base station will start the next AOA measurement. If the AOA result at this time is not close to 0, the base station will perform another AOA angle rotation and measurement until the AOA angle is as close to 0 as possible, defined within the range of -5 to +5 degrees. At this time, the UWB base station will count how many degrees it has rotated in total and the rotation direction. The total rotation angle A = A1 + A2 + A3 + …… Ai, where A1, A2…Ai are the angles of each rotation, with positive and negative values. At the same time, the base station will also compare the measured distance a each time with the following distance S set inside the base station. If a > S, the trolley should move forward; if a < S, the trolley should move backward, and the difference between the forward and backward distances a and S. At this time, the UWB base station will send the angle to be rotated and the moving distance to the trolley through the serial port. After receiving this instruction, the trolley converts this data into a moving vector and then moves according to this vector, thus achieving the effect of the trolley following the UWB tag end.

[0026] The ranging of UWB can reach an accuracy of 10 cm, and the AOA angle can also achieve an accuracy of 1 degree. Moreover, the UWB tag end and the UWB base station end are used separately in a one-to-one manner, so the following effect of the trolley is very ideal. At the same time, the UWB signal is little affected by the surrounding natural environment and has a wider applicable scenario.

[0027] Preferably, the UWB base station end includes a main control chip U1, a UWB chip U3 and a dual antenna ANT1, pin 1 of the main control chip U1 is connected to pin 2 of the UWB chip U3, pin 2 of the main control chip U1 is connected to pin 3 of the UWB chip U3, pin 3 of the main control chip U1 is connected to pin 4 of the UWB chip U3, pin 5 of the main control chip U1 is connected to pin 5 of the UWB chip U3, pin 1 of the dual antenna ANT1 is connected to pin 7 of the UWB chip U3, and pin 2 of the dual antenna ANT1 is connected to pin 8 of the UWB chip U3; the UWB base station end also includes a voltage conversion chip U5, Pin 3 of the voltage conversion chip U5 is connected to a 5V voltage, pin 2 of the voltage conversion chip U5 outputs a 3.3V voltage, pin 9 of the main control chip U1 is connected to a 3.3V voltage, and pin 1 of the UWB chip U3 is connected to a 3.3V voltage; the UWB base station end also includes a motor chip U2 and a car connection chip U4, pin 2 of the motor chip U2 is connected to pin 20 of the main control chip U1, pin 3 of the motor chip U2 is connected to pin 19 of the main control chip U1, pin 2 of the car connection chip U4 is connected to pin 13 of the main control chip U1, and pin 3 of the car connection chip U4 is connected to pin 12 of the main control chip U1.

[0028] like Figure 5 As shown, the main control chip U1 controls the UWB chip U3, communicates with the UWB tag end through the dual antenna ANT1, receives instructions from the UWB tag end, and then transmits the signal to the motor chip U2 and the car connection chip U4 to drive the servo motor to rotate and the car to move forward and backward. The voltage conversion chip U5 provides 3.3V voltage for the UWB chip U3 and the main control chip U1.

[0029] Preferably, the UWB tag end includes a main control chip U6, a UWB chip U7 and a single antenna ANT2, pin 1 of the main control chip U6 is connected to pin 2 of the UWB chip U7, pin 2 of the main control chip U6 is connected to pin 3 of the UWB chip U7, pin 3 of the main control chip U6 is connected to pin 4 of the UWB chip U7, pin 5 of the main control chip U6 is connected to pin 5 of the UWB chip U7, and pin 1 of the single antenna ANT2 is connected to pin 7 of the UWB chip U7; the UWB tag end also includes a voltage conversion chip U8, pin 3 of the voltage conversion chip U8 is connected to a 5V voltage, pin 2 of the voltage conversion chip U8 outputs a 3.3V voltage, pin 9 of the main control chip U6 is connected to a 3.3V voltage, and pin 1 of the UWB chip U7 is connected to a 3.3V voltage; the dual antenna ANT1 communicates with the single antenna ANT2.

[0030] like Figure 6As shown, the main control chip U6 controls the UWB chip U7, communicates with the UWB base station through the single antenna ANT2, and sends instructions to the UWB base station, so that the car can follow the movement of the UWB tag. The voltage conversion chip U8 provides 3.3V voltage for the UWB chip U7 and the main control chip U6.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A car following method based on the AOA principle in UWB, characterized in that: The method comprises the following steps: Step 1: Place a UWB base station with dual antennas on the car. The UWB base station can control the servo motor below it to adjust the direction of the dual antennas and control the movement trajectory of the car. The user end has a UWB tag with a single antenna. The single antenna of the UWB tag and the dual antenna of the UWB base station send signals to each other. Step 2: Every time the UWB tag transmits a signal, the dual antennas on the UWB base station receive signals in a first-come-first-served and last-served manner due to the different distances from the UWB tag. There is a phase difference pdoa. The phase difference is converted into a distance difference b through the wavelength of the UWB signal using the formula b=r*pdoa, where r is the wavelength of the UWB signal. Step 3: The UWB tag sends signal S1, and the UWB base station sends signal S2 after receiving signal S1. The UWB tag sends signal S3 after receiving signal S2. After the UWB base station receives signal S3, a measurement cycle ends. Then the flight time between the UWB tag and the UWB base station is T=(Tround1*Tround2-Treply1*Treply2) / (Tround1+Tround2+Treply1+Treply2), where Tround1 is the flight time of the UWB tag. The time from transmitting the S1 signal to receiving the S2 signal from the UWB base station, Treply2 is the time from the UWB tag receiving the S2 signal from the UWB base station to transmitting the S3 signal, Tround2 is the time from the UWB base station transmitting the S2 signal to receiving the S3 signal from the UWB tag, and Treply1 is the time from the UWB base station receiving the S1 signal from the UWB tag to transmitting the S2 signal. Then, the distance between the single antenna of the UWB tag and the antenna of the near-end UWB base station is calculated as a=T*c, where c is the speed of light; Step 4: Set the distance between the two antennas at the UWB base station to d, and regard the dual antennas at the UWB base station and the single antenna at the UWB tag as a triangle. The distance between the single antenna at the UWB tag and the antenna at the near end of the UWB base station is a, and the distance between the single antenna at the UWB tag and the antenna at the far end of the UWB base station is a+b. The cosine value of the angle AOA between the UWB tag and the UWB base station is COS(AOA)=(d*d+(a+b)*(a+b)–a*a) / 2*d*(a+b). Calculate the size of AOA according to this formula. Step 5: When the UWB base station detects the valid angle of arrival (AOA) A and distance a with the UWB tag each time, it controls the servo motor to rotate at the AOA angle through the serial port. After the action is completed, the UWB base station will start the next AOA measurement. If the AOA angle at this time is not close to 0, the UWB base station will rotate the AOA angle again and measure again until the AOA angle is close to 0. The UWB base station counts the total degree of rotation and the direction of rotation. The total rotation angle A = A1 + A2 + A3 + …… + Ai, where A1, A2, ……, Ai are the angles of each rotation, which can be positive or negative. The UWB base station compares the distance a measured each time with the following distance S set inside the UWB base station. If a > S, the trolley moves forward; if a < S, the trolley moves backward. The forward and backward distances are the difference between a and S. The UWB base station sends the angle to be rotated and the moving distance to the trolley through the serial port. After receiving the instruction, the trolley converts the data into a moving vector and then moves according to this vector to achieve the effect of the trolley following the UWB tag.

2. The car following method based on the AOA principle in UWB according to claim 1 is characterized in that: The distance d between the two antennas of the UWB base station should be less than half of the wavelength of the UWB signal.

3. The car following method based on the AOA principle in UWB according to claim 1 is characterized in that: In Step 4, after the end of a measurement cycle, calculate the average value of the angle of arrival (AOA) within the cycle and calculate the average value of the distance a within the cycle.

4. The car following method based on the AOA principle in UWB according to claim 1 is characterized in that: In Step 5, the definition that the AOA angle is close to 0 is within the range of -5 degrees to +5 degrees.

5. The car following method based on the AOA principle in UWB according to claim 1 is characterized in that: The UWB base station includes a main control chip U1, a UWB chip U3, and a dual antenna ANT1. The 1st pin of the main control chip U1 is connected to the 2nd pin of the UWB chip U3. The 2nd pin of the main control chip U1 is connected to the 3rd pin of the UWB chip U3. The 3rd pin of the main control chip U1 is connected to the 4th pin of the UWB chip U3. The 5th pin of the main control chip U1 is connected to the 5th pin of the UWB chip U3. The 1st pin of the dual antenna ANT1 is connected to the 7th pin of the UWB chip U3. The 2nd pin of the dual antenna ANT1 is connected to the 8th pin of the UWB chip U3.

6. The car following method based on the AOA principle in UWB according to claim 5 is characterized in that: The UWB base station also includes a voltage conversion chip U5. The 3rd pin of the voltage conversion chip U5 is connected to a 5V voltage. The 2nd pin of the voltage conversion chip U5 outputs a 3.3V voltage. The 9th pin of the main control chip U1 is connected to the 3.3V voltage. The 1st pin of the UWB chip U3 is connected to the 3.3V voltage.

7. The car following method based on the AOA principle in UWB according to claim 5 is characterized in that: The UWB base station also includes a motor chip U2 and a trolley connection chip U4. The 2nd pin of the motor chip U2 is connected to the 20th pin of the main control chip U1. The 3rd pin of the motor chip U2 is connected to the 19th pin of the main control chip U1. The 2nd pin of the trolley connection chip U4 is connected to the 13th pin of the main control chip U1. The 3rd pin of the trolley connection chip U4 is connected to the 12th pin of the main control chip U1.

8. The car following method based on the AOA principle in UWB according to claim 5 is characterized in that: The UWB tag end includes a main control chip U6, a UWB chip U7 and a single antenna ANT2. Pin 1 of the main control chip U6 is connected to pin 2 of the UWB chip U7, pin 2 of the main control chip U6 is connected to pin 3 of the UWB chip U7, pin 3 of the main control chip U6 is connected to pin 4 of the UWB chip U7, pin 5 of the main control chip U6 is connected to pin 5 of the UWB chip U7, and pin 1 of the single antenna ANT2 is connected to pin 7 of the UWB chip U7.

9. The car following method based on the AOA principle in UWB according to claim 8, characterized in that: The UWB tag end also includes a voltage conversion chip U8, pin 3 of the voltage conversion chip U8 is connected to a 5V voltage, pin 2 of the voltage conversion chip U8 outputs a 3.3V voltage, pin 9 of the main control chip U6 is connected to a 3.3V voltage, and pin 1 of the UWB chip U7 is connected to a 3.3V voltage.

10. The car following method based on the AOA principle in UWB according to claim 8, characterized in that: The dual antenna ANT1 communicates with the single antenna ANT2.

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