An apparatus and method for improving the AoA measurement accuracy of UWB

Abstract

The present invention discloses a device and method for improving the AoA measurement accuracy of UWB. The device includes a UWB chip, three external antennas, three internal antennas, a main control MCU, and a power supply. The three external antennas and the three internal antennas are both distributed in an equilateral triangle. The distance between the internal antennas is less than λ / 2, the distance between the external antennas is greater than λ / 2, and the connecting lines between the internal antennas and the connecting lines between the external antennas are parallel, and the distance between the external antennas is twice the distance between the internal antennas. When working, the azimuth angle is calculated by using the external antenna measurement received phase difference obtained by the external antenna with an antenna spacing d greater than half the wavelength λ / 2 of the signal, which can improve the accuracy of the final calculation. By using the internal antenna measurement received phase difference obtained by the internal antenna with an antenna spacing d less than half the wavelength λ / 2 of the signal to correct the external antenna measurement received phase difference obtained by the external antenna, the ambiguity can be avoided, thereby achieving the design purpose.

Description

Technical Field

[0001] The present invention relates to the technical field of UWB positioning, and particularly relates to a device and method for improving the AoA measurement accuracy of UWB. Background Art

[0002] Most of the traditional UWB AoA base stations adopt an antenna array composed of three antennas, and the antennas are arranged in an equilateral triangle. To avoid the ambiguity of measuring the received phase difference pdoa, the antenna spacing d needs to be equal to or less than half of the signal wavelength λ / 2.

[0003] In actual use, the positioning calculation calculates the azimuth angle through the measured received phase difference pdoa between the three antennas. The relationship between the measured received phase difference pdoa and the antenna spacing d is: φ = (2π * d * cosα) / λ. It can be seen from the formula that when the antenna spacing d is reduced, in actual use, due to the limitation of floating-point numbers, the value range of pdoa will be reduced, and thus the accuracy of pdoa will decrease. Therefore, a device and method for improving the AoA measurement accuracy of UWB that takes into account both the pdoa accuracy and the avoidance of ambiguity are needed. Summary of the Invention

[0004] The main object of the present invention is to provide a device and method for improving the AoA measurement accuracy of UWB that takes into account both the pdoa accuracy and the avoidance of ambiguity.

[0005] The present invention provides a device and method for improving the AoA measurement accuracy of UWB, including a UWB chip, three external antennas, three internal antennas, a main control MCU, and a power supply;

[0006] The three external antennas and the three internal antennas are all distributed in an equilateral triangle. The spacing between the internal antennas is less than λ / 2, the spacing between the external antennas is greater than λ / 2. The connection lines between the internal antennas and the connection lines between the external antennas are parallel, and the spacing of the external antennas is twice the spacing between the internal antennas;

[0007] One external antenna and one internal antenna form an antenna group. The external antenna and the internal antenna in the same antenna group are connected to the UWB chip through a radio frequency switch, and the UWB chip is connected to the main control MCU;

[0008] When the device communicates with the tag, when the device receives the poll frame of the tag, the internal antenna is used to calculate the measured received phase difference of the internal antenna of the tag, and the initial azimuth angle α is calculated through the measured received phase difference of the internal antenna;

[0009] When the device receives the final frame of the tag, it uses the outer antenna with a larger spacing between the antennas to calculate the measured value of the received phase difference of the outer antenna, and calculates the actual value range of the received phase difference of the outer antenna through the initial azimuth angle α to obtain the actual value of the received phase difference of the outer antenna, so as to achieve the design purpose of deblurring, and calculate the high-precision final azimuth angle β through the actual value of the received phase difference of the outer antenna.

[0010] Preferably, the spacing between the inner antennas is 2λ / 5, and the spacing between the outer antennas is 4λ / 5.

[0011] A method for improving the AoA measurement accuracy of UWB, based on the device for improving the AoA measurement accuracy of UWB according to claim 1, the specific method is as follows:

[0012] 1) Device initialization, set the inner antenna as the transmitting and receiving antenna through the RF switch;

[0013] 2) The tag sends a poll frame. After the device receives the poll frame sent by the tag through the inner antenna, it calculates the measured received phase differences pdoa12, pdoa23, and pdoa31 of the inner antenna, and through the formula: Calculate the initial azimuth angle α of the tag;

[0014] 3) The device replies to the tag Response frame through the inner antenna for DS-TWR ranging. After the transmission is completed, the device sets the outer antenna as the transmitting and receiving antenna through the RF switch;

[0015] 4) The tag sends a Final frame. After the device receives the Response frame through the outer antenna, it calculates the measured values pdoa54a, pdoa65a, and pdoa46a of the received phase difference of the outer antenna;

[0016] 5) The main control MCU calculates the value range of the actual value of the received phase difference of the outer antenna through the initial azimuth angle α, so as to eliminate the ambiguity and obtain the actual values pdoa54b, pdoa65b, and pdoa46b of the received phase difference of the accurate outer antenna;

[0017] 6) The main control MCU uses the actual values pdoa54b, pdoa65b, and pdoa46b of the received phase difference of the outer antenna through the formula Calculate the high-precision azimuth angle β of the tag.

[0018] Preferably, the calculation method in step 5 is as follows:

[0019] ① Since the three external antennas are distributed in an equilateral triangle, and the three internal antennas are respectively arranged at the midpoints between every two of the three external antennas, thus also in an equilateral triangle distribution, and the distance between the external antennas is twice the distance between the internal antennas, d 54 = 2 * d 31 , and at the same time, since φ 54 = φ 31 * (d 54 / d 31 ), by the same token, φ 54 = 2 * φ 31 , by the same token: φ 65 = 2 * φ 12 , φ 46 = 2 * φ 23 ;

[0020] ② Set the measurement error to be ε. The measured value pdoa54a of the received phase difference measured by the external antenna is between [2φ 31 - ε, 2φ 31 + ε], pdoa65a is between [2φ 12 - ε, 2φ 12 + ε], and pdoa46a is between [2φ 23 - ε, 2φ 23 + ε];

[0021] ③ If the measured values pdoa54a, pdoa65a, and pdoa46a of the received phase difference measured by the external antenna are not within the interval, then rotate them by +2π or -2π to obtain the actual values pdoa54b, pdoa65b, and pdoa46b of the received phase difference measured by the final external antenna.

[0022] Preferably, the magnitude of the measurement error ε is related to the accuracy that needs to be improved during design.

[0023] The beneficial effects of the device and method for improving the AoA measurement accuracy of UWB of the present invention are:

[0024] 1. By calculating the azimuth angle using the received phase difference measured by the external antenna with the antenna spacing d greater than half the wavelength λ / 2 of the signal, the accuracy of the final calculation can be improved.

[0025] 2. By correcting the received phase difference measured by the external antenna with the received phase difference measured by the internal antenna with the antenna spacing d less than half the wavelength λ / 2 of the signal, the ambiguity can be avoided, thus achieving the design purpose. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the device for the device and method for improving the AoA measurement accuracy of UWB of the present invention;

[0027] Figure 2 Layout diagram of the external antenna and internal antenna of the device and method for improving the AoA measurement accuracy of UWB according to the present invention;

[0028] Figure 3 Flowchart of the method for the device and method for improving the AoA measurement accuracy of UWB according to the present invention;

[0029] Reference numerals in the figure: 1, the first internal antenna; 2, the second internal antenna; 3, the third internal antenna; 4, the first external antenna; 5, the second external antenna; 6, the third external antenna; 7, the RF switch; 8, the UWB chip; 9, the main control MCU; 10, the power supply.

[0030] The realization, functional features and advantages of the object of the present invention will be further described in conjunction with the embodiments with reference to the accompanying drawings. Detailed implementation manners

[0031] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] Referring to Figures 1 to 3 , an embodiment of the device and method for improving the AoA measurement accuracy of UWB according to the present invention is proposed:

[0033] A device for improving the AoA measurement accuracy of UWB includes a UWB chip 8, three external antennas, three internal antennas, a main control MCU 9 and a power supply 10;

[0034] The three external antennas are distributed in an equilateral triangle, namely the first external antenna 4, the second external antenna 5 and the third external antenna 6. The three internal antennas are respectively arranged at the midpoints between every two of the three external antennas, thus also being distributed in an equilateral triangle, namely the first internal antenna 1, the second internal antenna 2 and the third internal antenna 3. The distance between the internal antennas is 2λ / 5, and the distance between the external antennas is 4λ / 5.

[0035] Among them, the first internal antenna 1 and the first external antenna 4, the second internal antenna 2 and the second external antenna 5, and the third internal antenna 3 and the third external antenna 6 respectively form the first antenna group, the second antenna group and the third antenna group. The external antenna and the internal antenna in each antenna group are connected to the UWB chip 8 through the RF switch 7, and the UWB chip 8 is connected to the main control MCU 9. The main control MCU 9, the three internal antennas, the three external antennas and the UWB chip 8 are powered by the power supply 10.

[0036] A method for improving the AoA measurement accuracy of UWB, the specific method is as follows:

[0037] 1) Device initialization, setting the internal antenna as a transmitting and receiving antenna through the RF switch 7;

[0038] 2) The tag sends a poll frame to the device. After the device receives the poll frame sent by the tag through the internal antenna, it calculates the measured received phase differences pdoa12, pdoa23, and pdoa31 of the internal antenna, and through the formula: Calculate the initial azimuth angle α of the tag;

[0039] 3) The device replies to the tag with a Response frame through the internal antenna for DS-TWR ranging. After the transmission is completed, the device sets the external antenna as the transmit-receive antenna through the RF switch 7;

[0040] 4) The tag sends a Final frame. After the device receives the Response frame through the external antenna, it calculates the measured values pdoa54a, pdoa65a, and pdoa46a of the measured received phase difference of the external antenna;

[0041] 5) The main control MCU9 calculates the value range of the actual value of the measured received phase difference of the external antenna based on the initial azimuth angle α, thereby eliminating the ambiguity to obtain the accurate actual values pdoa54b, pdoa65b, and pdoa46b of the measured received phase difference of the external antenna;

[0042] The calculation method is:

[0043] ① Since the three external antennas are distributed in an equilateral triangle, and the three internal antennas are respectively set at the midpoints between every two of the three external antennas and are also distributed in an equilateral triangle, the distance between the external antennas is twice the distance between the internal antennas, d 54 = 2 * d 31 , and at the same time, since φ 54 = φ 31 *(d 54 / d 31 ), similarly, φ 54 = 2 * φ 31 , similarly, it can be obtained that: φ 65 = 2 * φ 12 , φ 46 = 2 * φ 23 ;

[0044] ② Set the measurement error as ε. The measured value pdoa54a of the measured received phase difference of the external antenna is between [2φ 31 -ε, 2φ 31 +ε], pdoa65a is between [2φ 12 -ε, 2φ 12 +ε], and pdoa46a is between [2φ 23 -ε, 2φ 23 +ε];

[0045] ③ If the measured values pdoa54a, pdoa65a, and pdoa46a of the received phase difference measured by the external antenna are not within the interval, rotate them by +2π or -2π to obtain the actual values pdoa54b, pdoa65b, and pdoa46b of the received phase difference measured by the external antenna finally;

[0046] 6) The main control MCU uses the actual values pdoa54b, pdoa65b, and pdoa46b of the received phase difference measured by the external antenna through the formula to calculate the high-precision azimuth angle of the tag;

[0047] 7) When the ranging is completed, set the internal antenna as the transmitting and receiving antenna through the RF switch.

[0048] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A device for improving the AoA measurement accuracy of UWB, characterized in that it includes a UWB chip, three external antennas, three internal antennas, a main control MCU and a power supply; The three external antennas and the three internal antennas are all distributed in an equilateral triangle. The distance between the internal antennas is less than λ / 2, the distance between the external antennas is greater than λ / 2. The connecting lines between the internal antennas and the connecting lines between the external antennas are parallel, and the distance between the external antennas is twice the distance between the internal antennas. The three internal antennas are respectively arranged at the midpoints between every two of the three external antennas; One external antenna and one internal antenna form an antenna group. The external antenna and the internal antenna in the same antenna group are connected to the UWB chip through a radio frequency switch, and the UWB chip is connected to the main control MCU; When the device communicates with the tag, when the device receives the poll frame of the tag, it uses the internal antenna to calculate the internal antenna measurement received phase difference of the tag, and calculates the initial azimuth angle α through the internal antenna measurement received phase difference; When the device receives the final frame of the tag, it uses the external antenna with a larger distance between antennas to calculate the measured value of the external antenna measurement received phase difference, and calculates the actual value range of the external antenna measurement received phase difference through the initial azimuth angle α to obtain the actual value of the external antenna measurement received phase difference, so as to achieve the design purpose of deblurring, and calculate the high-precision final azimuth angle β through the actual value of the external antenna measurement received phase difference.

2. The device for improving the AoA measurement accuracy of UWB according to claim 1, wherein The distance between the internal antennas is 2λ / 5, and the distance between the external antennas is 4λ / 5.

3. A method for improving the AoA measurement accuracy of UWB, characterized in that Based on the device for improving the AoA measurement accuracy of UWB described in claim 1, the specific method is: 1) Device initialization, set the internal antenna as the transmitting and receiving antenna through the radio frequency switch; 2) The tag sends a poll frame. After the device receives the poll frame sent by the tag through the internal antenna, it calculates the internal antenna measured reception phase differences pdoa12, pdoa23, and pdoa31, and through the formula: calculate the initial azimuth angle α of the tag; 3) The device replies to the tag Response frame through the internal antenna to perform DS-TWR ranging. After the transmission is completed, the device sets the external antenna as the transmitting and receiving antenna through the radio frequency switch; 4) The tag sends the Final frame. After the device receives the Response frame through the external antenna, it calculates the measured values of the external antenna measurement received phase difference pdoa54a, pdoa65a and pdoa46a; 5) The main control MCU calculates the actual value range of the external antenna measurement received phase difference through the initial azimuth angle α, so as to eliminate the ambiguity and obtain the actual values pdoa54b, pdoa65b and pdoa46b of the external antenna measurement received phase difference; 6) The actual values pdoa54b, pdoa65b, and pdoa46b of the received phase difference measured by the external antenna of the main control MCU are calculated through the formula to calculate the high-precision azimuth angle β of the tag; 7) The ranging ends, and the internal antenna is set as the transmitting and receiving antenna through the radio frequency switch.

4. According to the method for improving the AoA measurement accuracy of UWB described in claim 3, characterized in that The calculation method in step 5 is: ①Since the three external antennas are distributed in an equilateral triangle, and the three internal antennas are respectively arranged at the midpoints between every two of the three external antennas, thus also in an equilateral triangle distribution, and the distance between the external antennas is twice the distance between the internal antennas, d 54 = 2*d 31 , and since φ 54 = φ 31 *(d 54 / d 31 ), similarly, φ 54 = 2*φ 31 , and similarly: φ 65 = 2*φ 12 , φ 46 = 2*φ 23 ; ② Set the measurement error to ε. The measured value pdoa54a of the received phase difference measured by the external antenna is within [2φ 31 -ε, 2φ 31 +ε], pdoa65a is within [2φ 12 -ε, 2φ 12 +ε], and pdoa46a is within [2φ 23 -ε, 2φ 23 +ε]; ③ If the measured values pdoa54a, pdoa65a, and pdoa46a of the received phase difference measured by the external antenna are not within the interval, rotate them by +2π or -2π to obtain the actual values pdoa54b, pdoa65b, and pdoa46b of the received phase difference measured by the external antenna finally.

5. The method for improving the AoA measurement accuracy of UWB according to claim 4, characterized in that, The magnitude of the measurement error ε is related to the accuracy that needs to be improved during design.

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