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CN-116261099-B - Bluetooth ranging method and system and vehicle

CN116261099BCN 116261099 BCN116261099 BCN 116261099BCN-116261099-B

Abstract

The invention provides a Bluetooth ranging method, which comprises the steps that a master node sends a first signal to a slave node, the flight time of the first signal reaching the slave node is T1, the strength indication of the first signal is RSSI 1 , the slave node sends a second signal to the master node, the flight time of the second signal reaching the master node is T2, the strength indication of the second signal is RSSI 2 , an equation is constructed, the measurement deviation of the signal flight time of the first signal and the second signal is solved, the distance is obtained according to d= (T1 + delta T 1 ) multiplied by C, and C is the speed of light. The ranging method can effectively combine the two ranging methods, fuse and mutually correct the two kinds of measurement information, improve the overall measurement accuracy of a ranging system, and can be realized by using the existing Bluetooth device without additionally arranging other hardware settings, thereby being convenient and efficient.

Inventors

  • DU LEI
  • DING LIFENG
  • JIANG AIMIN
  • SHI YUXUAN
  • ZHANG YUANTENG

Assignees

  • 上海海拉电子有限公司

Dates

Publication Date
20260512
Application Date
20230314

Claims (8)

  1. 1. A bluetooth ranging method, comprising: The method comprises the steps that a master node sends a first signal to a slave node, the flight time of the signal of the first signal reaching the slave node is T1, and the strength indication of the first signal is RSSI 1 ; The slave node sends a second signal to the master node, the flight time of the signal of the second signal reaching the master node is T2, and the strength indication of the second signal is RSSI 2 ; Constructing a first distance equation of the first signal according to the time of flight T1+Deltat 1 and the intensity indication RSSI 1+ ΔA 1 of the first signal, constructing a second distance equation of the second signal according to the time of flight T2+Deltat 2 and the intensity indication RSSI 2+ ΔA 2 of the second signal, Wherein Δt 1 and Δa 1 are the measured deviations of the signal time of flight and the intensity indication of the first signal, respectively, and Δt 2 and Δa 2 are the measured deviations of the signal time of flight and the intensity indication of the second signal, respectively; solving the first and second distance equations to enable the first and second signals to have the same time of flight Obtaining a minimum delta t 1 、Δt 2 , wherein w 1 、w 2 is a weight ratio and the sum of w 1 and w 2 is 1; The distance d is calculated according to the following formula: d= Wherein C is the speed of light; Solving for deltat 1 、Δt 2 according to the following equation, , Where a is the RSSI of the signal at a distance of 1 meter and n is the path loss index.
  2. 2. The Bluetooth ranging method of claim 1, wherein, The master node sends a first signal to the slave node, the signal flight time of the first signal reaching the slave node is T1, and a formula (1) is constructed: d= formula (1); The slave node sends a second signal to the master node, the flight time of the signal of the second signal reaching the master node is T2, and a formula (2) is constructed: d= formula (2); The strength indication of the first signal is RSSI 1 , equation (3) is constructed, d= Formula (3); the strength indication of the second signal is RSSI 2 , equation (4) is constructed, d= Formula (4); The first distance equation is = ; The second distance equation = 。
  3. 3. The bluetooth ranging method according to any one of claims 1 to 2, wherein, The w 1 is equal to w 2 .
  4. 4. A Bluetooth ranging system is characterized by comprising a master node, a slave node and a computing unit; the master node is configured to send a first signal to a slave node, where a signal flight time of the first signal reaching the slave node is T1, and a strength indication of the first signal is RSSI 1 ; the slave node is configured to send a second signal to the master node, where a signal flight time of the second signal reaching the master node is T2, and a strength indication of the second signal is RSSI 2 ; The calculation unit is configured to construct a first distance equation of the first signal according to the time of flight t1+Δt 1 and the strength indication RSSI 1+ ΔA 1 of the first signal, construct a second distance equation of the second signal according to the time of flight t2+Δt 2 and the strength indication RSSI 2+ ΔA 2 of the second signal, Wherein Δt 1 and Δa 1 are the measured deviations of the signal time of flight and the intensity indication of the first signal, respectively, and Δt 2 and Δa 2 are the measured deviations of the signal time of flight and the intensity indication of the second signal, respectively; The calculation unit is used for solving the problem that when the first distance equation and the second distance equation are simultaneously satisfied and the flight time of the first signal and the flight time of the second signal are equal Obtaining a minimum delta t 1 、Δt 2 , wherein w 1 、w 2 is a weight ratio and the sum of w 1 and w 2 is 1; The calculating unit is used for calculating the distance d according to the following formula: d= Wherein C is the speed of light; The calculation unit is used for solving deltat 1 、Δt 2 according to the following formula, , Where a is the RSSI of the signal at a distance of 1 meter and n is the path loss index.
  5. 5. The Bluetooth ranging system of claim 4, wherein, The master node sends a first signal to the slave node, the signal flight time of the first signal reaching the slave node is T1, and a formula (1) is constructed: d= formula (1); The slave node sends a second signal to the master node, the flight time of the signal of the second signal reaching the master node is T2, and a formula (2) is constructed: d= formula (2); The computing unit is configured to construct formula (3) according to the strength indication RSSI 1 of the first signal, d= Formula (3); The calculating unit is configured to construct formula (4) according to the strength indication RSSI 2 of the second signal, d= Formula (4); constructing a first distance equation = And a second distance equation = 。
  6. 6. The Bluetooth ranging system of claim 4, wherein, The calculation unit is used for solving deltat 1 、Δt 2 according to the following formula, , Wherein w 1 is equal to w 2 .
  7. 7. A Bluetooth ranging system according to any one of claims 4-6, The master node and the slave node are low-power Bluetooth devices.
  8. 8. A vehicle comprising a bluetooth ranging system according to any of claims 4-7.

Description

Bluetooth ranging method and system and vehicle Technical Field The invention relates to the field of communication, in particular to a Bluetooth ranging method and system and a vehicle. Background In the prior art, measuring distance using bluetooth low energy devices generally includes two measurement methods, namely inter-node ranging based on time of arrival (ToF) and Received Signal Strength Indication (RSSI), respectively. The ToF ranging basic flow comprises the steps of measuring the time required by the initiator to transmit signals to the reflector and the initiator to transmit signals to the reflector respectively, and then calculating the average value of the two ranging results. The ranging method is easily affected by factors such as clock frequency deviation, antenna delay, multipath and the like of the receiving and transmitting parties, so that the ranging accuracy is reduced. In addition, when the distance between the transmitting and receiving parties is relatively short, the negative effect caused by the interference factors is more obvious. Another ranging method is to model according to the propagation loss of the wireless signal, i.e. calculate according to the following formula: Wherein, the AndRepresenting the actual distance and the reference distance respectively,AndThe RSSI at the actual distance and the reference distance are shown respectively,Is the path loss index (pathloss) of the optical system,Is random noise. In practice, the larger the true distance is,The greater the fluctuation. Therefore, the distance measuring method is more suitable for being used when the distance between the transmitting and receiving parties is relatively short. Based on the above, both ranging methods are difficult to apply to all distance ranges, and there are advantages and disadvantages in different distance ranges. Therefore, there is a need to provide a ranging method and system that can cover all distance ranges and has high accuracy. Disclosure of Invention In order to improve the accuracy of measuring distance, the invention aims to provide a Bluetooth ranging method. Specifically, the invention discloses a Bluetooth ranging method, which comprises the following steps: The method comprises the steps that a master node sends a first signal to a slave node, the flight time of the signal of the first signal reaching the slave node is T1, and the strength indication of the first signal is RSSI 1; The slave node sends a second signal to the master node, the flight time of the signal of the second signal reaching the master node is T2, and the strength indication of the second signal is RSSI 2; Constructing a first distance calculation equation of the first signal according to the time of flight T1+Deltat 1 and the intensity indication RSSI 1+ΔA1 of the first signal, constructing a second distance calculation equation of the second signal according to the time of flight T2+Deltat 2 and the intensity indication RSSI 2+ΔA2 of the second signal, Wherein Δt 1 and Δa 1 are the measured deviations of the signal time of flight and the intensity indication of the first signal, respectively, and Δt 2 and Δa 2 are the measured deviations of the signal time of flight and the intensity indication of the second signal, respectively; Solving the first and second distance calculation equations to enable the first and second signals to have the same time of flight Obtaining a minimum delta t 1、Δt2, wherein w 1、w2 is a weight ratio and the sum of w 1 and w 2 is 1, and calculating the distance d according to the following formula: d= wherein C is the speed of light. Preferably, deltat 1、Δt2 is solved according to the following formula, , Where a is the RSSI of the signal at a distance of 1 meter and n is the path loss index. Preferably, the master node sends a first signal to the slave node, the signal flight time of the first signal reaching the slave node is T1, and formula (1) is constructed: d= formula (1); The slave node sends a second signal to the master node, the flight time of the signal of the second signal reaching the master node is T2, and a formula (2) is constructed: d= equation (2). Preferably, the strength indication of the first signal is RSSI 1, equation (3) is constructed, d=Formula (3); the strength indication of the second signal is RSSI 2, equation (4) is constructed, d=Formula (4); The first distance equation is =The second distance equation is=。 Preferably, w 1 is equal to w 2. In another aspect of the present invention, a bluetooth ranging system is provided, including a master node, a slave node, and a computing unit; the master node is configured to send a first signal to a slave node, where a signal flight time of the first signal reaching the slave node is T1, and a strength indication of the first signal is RSSI 1; the slave node is configured to send a second signal to the master node, where a signal flight time of the second signal reaching the master node is T2, and a strength