JP2015058773A - Tire position determination system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire position determination system capable of determining a position of a tire in the further early timing.SOLUTION: Rotation information on a corresponding tire is transmitted from a transmitter 4 provided in the respective tires, and the rotation information on the respective tires is received by a vehicle body side receiver 6, and a position of the tire provided with the transmitter 4 for transmitting the rotation information is determined from a correlation with reference rotation information for each tire. The transmitter 4 imparts detection accuracy in four-stage levels on the rotation information of the corresponding tire, and transmits the rotation information on the tire together with level information of detection accuracy. The receiver 6 determines a position of the tire from the correlation with the reference rotation information for each tire, while increasing weighting toward the rotation information of high detection accuracy.

Description

  The present invention relates to a tire position determination system that determines the position of a tire.

  In a vehicle equipped with a tire pressure monitoring system (TPMS: Tire Pressure Monitoring System), the air pressure of each tire is monitored, and when the air pressure of any tire decreases, this is notified. By determining the position of the tire, the air pressure of each tire can be monitored individually.

  In the TPMS of Patent Document 1, a transmitter provided in each tire is provided with a temperature sensor and an acceleration sensor in addition to a pressure sensor, and a detection signal from each sensor is transmitted from each transmitter. It is received by the receiver on the side. The front and rear wheels are determined based on the tire temperature, and the left and right wheels are determined based on the acceleration generated in the tire. As a result, the position of the tire can be determined with a simple configuration that does not use an initiator that outputs a trigger signal for acquiring the ID (identification) of the transmitter.

JP 2006-142873 A

  Although it is desirable that the position of the tire can be determined within a short time from the start of traveling on the assumption that the initiator is not used, in the TPMS of Patent Document 1, a predetermined temperature difference occurs between the tires on the front and rear wheels, and the position of the tire is determined. It takes a certain amount of time to reach a condition that can be confirmed.

  The present invention has been made paying attention to such problems, and an object of the present invention is to provide a tire position determination system capable of determining the position of a tire at an earlier timing.

  The tire position determination system that solves the above problems transmits the rotation information of the corresponding tire from the transmitter provided in each tire, receives the rotation information of each tire by the receiver on the vehicle body side, and performs the reference rotation for each tire. In the tire position determination system for determining the position of the tire provided with the transmitter that transmitted the rotation information from the correlation with the information, the transmitter detects the rotation information of the corresponding tire at three or more levels of accuracy. And the rotation information of the tire is transmitted together with the level information of the detection accuracy, and the receiver determines the position of the tire from the correlation with the reference rotation information for each tire while increasing the weight of the rotation information with higher detection accuracy. The gist is to judge.

  According to this configuration, the receiver on the vehicle body side obtains the reference rotation information of the tire mounted on the wheel from the pulse used for detecting the rotation of the wheel. Reference rotation information unique to each tire is obtained. Under such a premise, the tire rotation information is transmitted from the transmitter when it is at a specific rotation position among the rotation positions of the tire, and the receiver on the vehicle body side receives the rotation information of the tire from each transmitter. Is plotted on the sheet for each reference rotation information. The plot situation is analyzed for each sheet, and it is determined that the transmitter that transmitted the rotation information is a transmitter provided in the tire related to the reference rotation information on the condition that the standard deviation is equal to or less than the reference value. Thereby, the position of the tire is determined. With the configuration in which the weighting is increased as the rotation information has higher detection accuracy, the timing at which the standard deviation falls below the reference value is advanced. Therefore, the position of the tire can be determined at an earlier timing.

About the said tire position determination system, the said receiver is good also as not using the rotation information of the level with the lowest detection accuracy for determination of the position of a tire.
According to this configuration, the tire position can be correctly determined by using the remaining rotation information excluding the rotation information with the lowest detection accuracy.

  According to the present invention, the position of the tire can be determined at an earlier timing.

The block diagram which shows the structure of a tire pressure monitoring system. The graph which shows the change of the acceleration with respect to time when the vehicle is driving on a smooth road surface at a constant speed without acceleration / deceleration. The graph which shows the change of the acceleration with respect to time when the vehicle is drive | working the road surface containing a bad road at constant speed. The graph which shows the change of the acceleration with respect to time when a brake is applied during driving | running | working of a vehicle. The table | surface which shows the relationship between the detection accuracy in a transmitter, and the weighting in a receiver. The figure which shows the sheet | seat of the tire of a right front wheel about a comparative example. The figure which shows the sheet | seat of the tire of the left front wheel about a comparative example. The figure which shows the sheet | seat of the tire of a right rear wheel about a comparative example. The figure which shows the sheet | seat of the tire of a left rear wheel about a comparative example. The table which shows correlation with ID of a transmitter, and the position of a tire about a comparative example. The figure which shows the sheet | seat of the tire of a right front wheel about an Example. The figure which shows the sheet | seat of the tire of the left front wheel about an Example. The figure which shows the sheet | seat of the tire of a right rear wheel about an Example. The figure which shows the sheet | seat of the tire of a left rear wheel about an Example. The table | surface which shows correlation with ID of a transmitter, and the position of a tire about an Example.

Hereinafter, an embodiment of a tire position determination system will be described.
As shown in FIG. 1, the vehicle 1 includes a tire pressure monitor for monitoring the air pressure of each tire 2 (right front wheel tire 2a, left front wheel tire 2b, right rear wheel tire 2c, left rear wheel tire 2d). System 3 is installed. The tire pressure monitoring system 3 includes the tires corresponding to the transmitters 4 (the transmitter 4a of the tire 2a, the transmitter 4b of the tire 2b, the transmitter 4c of the tire 2c, and the transmitter 4d of the tire 2d) provided in each tire 2. 2 is received and received by the receiver 6 on the vehicle body 5 side, and the air pressure of each tire 2 is monitored. The monitoring result is displayed on the display unit 7 on the vehicle body 5 side.

  The transmitter 4 is provided with a controller 11 that performs overall control of the transmitter 4. The controller 11 includes a nonvolatile memory 12. The memory 12 stores an ID unique to the transmitter 4. The controller 11 is electrically connected to a pressure sensor 13 that detects the air pressure of the tire 2, a temperature sensor 14 that detects the internal temperature of the tire 2, and an acceleration sensor 15 that detects acceleration generated in the transmitter 4. ing. The controller 11 is connected to an antenna 16 serving as a medium for transmitting UHF (Ultra High Frequency) radio waves.

  When the controller 11 analyzes the detection signal from the acceleration sensor 15 and detects that the transmitter 4 has reached the upper and lower pole positions as the tire 2 rotates, UHF including the tire 2 air pressure information Stp is triggered by the detection. Send radio waves. The UHF radio wave includes the ID and temperature information of the tire 2 in addition to the air pressure information Stp. When the controller 11 detects that the transmitter 4 has reached the upper and lower pole positions, a UHF radio wave is transmitted. When this UHF radio wave is received by the receiver 6 on the vehicle body 5 side, the UHF radio wave is transmitted. The receiver 6 recognizes that the transmitter 4 is approaching the upper and lower pole positions. That is, the rotation state of the tire 2 is grasped. Therefore, the UHF radio wave from the transmitter 4 is defined as including rotation information of the corresponding tire 2.

  The receiver 6 on the vehicle body 5 side is provided with a TPMS ECU (Electronic Control Unit) 21 for controlling the receiver 6 and an antenna 22 as a medium for receiving UHF radio waves. . When the UHF radio wave from the transmitter 4 is received by the antenna 22, the ECU 21 analyzes the UHF radio wave to understand the rotation state of the tire 2, and the transmitter 4 that has transmitted the UHF radio wave is assigned to any of the tires 2a to 2d. It is determined whether the transmitter 4 is provided. Then, the ECU 21 associates the position of the tire 2 with the ID of the transmitter 4 and stores it in the nonvolatile memory 23. For convenience, the ID of the transmitter 4a for the right front wheel is defined as ID1, and the ID of the transmitter 4b for the left front wheel is defined as ID2. The ID of the right rear wheel transmitter 4c is defined as ID3, and the ID of the left rear wheel transmitter 4d is defined as ID4.

  For example, a display unit 7 installed on an instrument panel in the vehicle is connected to the receiver 6. When the UHF radio wave from the transmitter 4 is received by the antenna 22, the ECU 21 collates the ID included therein with ID 1 to ID 4. When the ID matches any of ID1 to ID4, the ECU 21 compares the pressure value suggested by the air pressure information Stp included in the UHF radio wave with a threshold value. When the pressure value is less than the threshold value, the ECU 21 outputs a control signal for instructing the display unit 7 to display the content indicating that the tire 2 provided with the transmitter 4 having the matched ID has low air pressure. To do. As a result, the above contents are displayed on the display unit 7 and a notification operation for the user is performed.

  The vehicle body 5 is provided with wheel speed sensors 8 (right front wheel sensor 8a, left front wheel sensor 8b, right rear wheel sensor 8c, left rear wheel sensor 8d) corresponding to each wheel. The wheel speed sensor 8 outputs a pulse Spl indicating the rotational speed of the corresponding wheel to an ECU (not shown) of an ABS (Anti lock Brake System). This pulse Spl is also input to the ECU 21 of the TPMS. The ECU 21 obtains reference rotation information of the tire 2 attached to each wheel from the pulse Spl by each wheel speed sensor 8. And ECU21 determines the position of the tire 2 with which the transmitter 4 which transmitted the said rotation information was provided from the correlation with the rotation information of each tire 2, and the reference rotation information for every tire 2. FIG. The ECU 21 individually monitors the air pressure of each tire 2 while reflecting the determination result in the stored contents of the memory 23. The function of determining the position of the tire 2 is defined as an autolocation function, and this function is realized by the autolocation function unit 24.

  As shown in FIG. 2, when the vehicle 1 is traveling on a smooth road surface at a constant speed without acceleration / deceleration, a reference waveform is obtained in which the change in acceleration with respect to time is approximately a sine curve (sine curve). The acceleration is detected by the acceleration sensor 15 of each transmitter 4. The timing at which the transmitter 4 reaches the upper and lower pole positions as the tire 2 rotates is indicated by black circles, and the rotation from the first black circle to the second black circle is equivalent to one rotation. Changes are shown. A UHF radio wave is transmitted from the transmitter 4 at the timing of each black circle. When the UHF radio wave is received by the receiver 6 on the vehicle body 5 side, the rotation state of the tire 2 is grasped from the reception timing.

  As shown in FIG. 3, when the vehicle 1 is traveling on a road surface including a rough road at a constant speed, the waveform is temporarily disturbed when the vehicle 1 passes through the rough road. A reference waveform when traveling on a smooth road surface is indicated by a one-dot chain line for three rotations. On the other hand, a waveform when traveling on a road surface including a rough road is shown by a solid line, and an inflection point appears at a cycle shorter than the reference waveform when passing the rough road. In addition to the timing when the transmitter 4 approaches the upper and lower pole positions as the tire 2 rotates, the inflection point is indicated by a black circle, and UHF radio waves are transmitted from the transmitter 4 at the timing of each black circle. As a result, it is shown that rotation information equivalent to 5 rotations more than the actual 3 rotations can be obtained by the receiver 6 on the vehicle body 5 side.

  As shown in FIG. 4, when a brake is applied while the vehicle 1 is traveling, a state in which the transmitter 4 reaches the upper and lower pole positions at a timing delayed from the reference waveform indicated by the alternate long and short dash line is indicated by a solid line. In addition, the timing at which the UHF radio wave is transmitted from the transmitter 4 is indicated by a black circle.

  With these in mind, since the UHF radio waves when the vehicle 1 is traveling on a smooth road surface at a constant speed without acceleration / deceleration include reliable rotation information of the tire 2 without disturbance, When the position of the tire 2 is determined by the receiver 6 on the vehicle body 5 side, a correct determination can be made quickly. On the other hand, when the vehicle 1 is traveling on a rough road or when the brake is applied during traveling, the UHF radio wave includes rotation information of the tire 2 with low reliability affected by the disturbance. When the position of the tire 2 is determined by the receiver 6 on the vehicle body 5 side using this, the determination performance may be dull.

  Therefore, in this example, the controller 11 of each transmitter 4 detects the certainty that the transmitter 4 has reached the upper and lower pole positions, and provides detection accuracy at four levels according to the certainty. At the same time, the level information of the detection accuracy is added to the UHF radio wave transmitted at the timing when the transmitter 4 detects that it has reached the upper and lower pole positions. When the UHF radio wave to which the level information of the detection accuracy is added is received by the receiver 6 on the vehicle body 5 side, the autolocation function unit 24 of the ECU 21 increases the weight of the rotation information with higher detection accuracy while increasing the weight of the tire 2. The position of the tire 2 is determined from the correlation with each reference rotation information.

  As shown in FIG. 5, level 1, level 2, level 3, and level 4 are assigned to detection accuracy at the transmitter 4 in order of increasing probability. On the other hand, with respect to the weighting at the receiver 6, as the detection accuracy increases in order from level 1, 0 times (not used), 1 time, 2 times, and 4 times are associated.

Next, the operation of the tire position determination system will be described.
As shown in FIG. 6, in the comparative example in which the transmitter 4 does not give the level information of the detection accuracy and the receiver 6 does not weight, the receiver 6 starts the tire from the pulse Spl by the sensor 8a of the right front wheel. The reference rotation information 2a is obtained. Since the number of pulses when the tire 2a makes one rotation is determined, the receiver 6 selects one pulse as a base point, and counts the number of pulses from that pulse as the base point to the number of pulses for one rotation. When it reaches, it knows that the tire 2a has made one revolution. Therefore, the rotational position of the tire 2a is grasped from the pulse Spl of the sensor 8a. A sheet showing such a state is defined as a sheet of the tire 2a.

  Then, when receiving the UHF radio wave from each transmitter 4, the receiver 6 selects and plots the reception timing of the UHF radio wave for each ID of the transmitter 4 while associating the reception timing with the rotation position of the tire 2a. Each time a UHF radio wave is received, one upward arrow is plotted on the sheet. The reason why a plurality of arrows are vertically connected at the same rotation position is that UHF radio waves are received at the same rotation position for each of a plurality of rotation periods (for example, the first rotation and the third rotation).

  Then, the receiver 6 analyzes the plot situation and determines that the transmitter 4 having the ID is the transmitter 4 provided in the tire 2a on the condition that the standard deviation is equal to or less than the reference value. Here, regarding the plot state of ID1, it is assumed that the standard deviation is equal to or less than the reference value, and it is determined that the transmitter 4a having the ID1 is the transmitter 4 provided in the tire 2a.

  As shown in FIG. 7, for the same comparative example as described above, the receiver 6 obtains the reference rotation information of the tire 2b from the pulse Spl by the sensor 8b for the left front wheel. Since the number of pulses when the tire 2b makes one rotation is determined, the receiver 6 selects one pulse as a base point, and counts the number of pulses from the pulse as the base point to the number of pulses for one rotation. When it reaches, it knows that the tire 2b has made one revolution. Therefore, the rotational position of the tire 2b is grasped from the pulse Spl of the sensor 8b. A sheet showing such a state is defined as a sheet of the tire 2b.

  And the receiver 6 will select and plot for every ID of the transmitter 4, correlating the receiving timing of the said UHF radio wave with the rotation position of the tire 2b, if the UHF radio wave from each transmitter 4 is received. Then, the receiver 6 analyzes the plot situation and determines that the transmitter 4 having the ID is the transmitter 4 provided in the tire 2b on the condition that the standard deviation is equal to or less than the reference value. Here, regarding the plot state of ID2, it is assumed that the standard deviation is equal to or less than the reference value, and it is determined that the transmitter 4b having the ID2 is the transmitter 4 provided in the tire 2b.

  As shown in FIG. 8, for the same comparative example as described above, the receiver 6 obtains the reference rotation information of the tire 2c from the pulse Spl by the sensor 8c for the right rear wheel. Since the number of pulses when the tire 2c makes one rotation is determined, the receiver 6 selects one pulse as a base point, and counts the number of pulses from that pulse as a base point to the number of pulses for one rotation. When it reaches, it knows that the tire 2c has made one rotation. Therefore, the rotational position of the tire 2c is grasped from the pulse Spl of the sensor 8c. A seat showing such a state is defined as a seat of the tire 2c.

  When the receiver 6 receives the UHF radio wave from each transmitter 4, the receiver 6 selects and plots the reception timing of the UHF radio wave for each ID of the transmitter 4 while associating the reception timing with the rotation position of the tire 2c. Then, the receiver 6 analyzes the plot situation and determines that the transmitter 4 having the ID is the transmitter 4 provided in the tire 2c on the condition that the standard deviation is equal to or less than the reference value. Here, it is assumed that the standard deviation is equal to or less than the reference value for the plot state of ID3, and it is determined that the transmitter 4c having the ID3 is the transmitter 4 provided in the tire 2c.

  As shown in FIG. 9, for the same comparative example as described above, the receiver 6 obtains the reference rotation information of the tire 2d from the pulse Spl by the sensor 8d for the left rear wheel. Since the number of pulses when the tire 2d makes one rotation is determined, the receiver 6 selects one pulse as a base point, and counts the number of pulses from that pulse as the base point to the number of pulses for one rotation. When it reaches, it knows that the tire 2d has made one revolution. Therefore, the rotational position of the tire 2d is grasped from the pulse Spl of the sensor 8d. A seat showing such a state is defined as a seat of the tire 2d.

  And the receiver 6 will select and plot for every ID of the transmitter 4, correlating the reception timing of the said UHF radio wave with the rotation position of the tire 2d, if the UHF radio wave from each transmitter 4 is received. Then, the receiver 6 analyzes the plot situation and determines that the transmitter 4 having the ID is the transmitter 4 provided in the tire 2d on the condition that the standard deviation is equal to or less than the reference value. Here, regarding the plot state of ID4, it is assumed that the standard deviation is equal to or less than the reference value, and it is determined that the transmitter 4d having the ID4 is the transmitter 4 provided in the tire 2d.

The receiver 6 analyzes the plot state for each sheet, and determines the position of the tire 2 when the ID of the transmitter 4 and the position of the tire 2 correspond in a one-to-one relationship.
As shown in FIG. 10, in this comparative example, the transmitter 4 having ID1 is the transmitter 4 for the right front wheel, the transmitter 4 having ID2 is the transmitter 4 for the left front wheel, and the transmitter 4 having ID3 is the right As the rear wheel transmitter 4, the transmitter 4 having ID 4 is registered in the memory 23 as the left rear wheel transmitter 4.

  As shown in FIG. 11, for the present example in which level information of detection accuracy is given by the transmitter 4 and weighting is performed by the receiver 6, the receiver 6 receives the rotation information of level 1 with the lowest detection accuracy. When the UHF radio wave including the UHF radio wave is received, the reception timing of the UHF radio wave is not plotted on the seat of the tire 2a. That is, the rotation information is not used for determining the position of the tire 2. On the other hand, when receiving a UHF radio wave including rotation information other than level 1, the receiver 6 plots the reception timing on the sheet while performing weighting according to the level information included in the UHF radio wave. The point that one upward arrow is plotted on the sheet each time a UHF radio wave is received is the same as in FIG. 6, but differs from FIG. 6 in that the length of the arrow is defined according to a multiple of weighting. . For example, when a UHF radio wave including level 4 rotation information is received, an arrow four times longer is plotted.

  Then, the receiver 6 analyzes the plot situation and determines that the transmitter 4 having the ID is the transmitter 4 provided in the tire 2a on the condition that the standard deviation is equal to or less than the reference value. Here, regarding the plot state of ID1, it is assumed that the standard deviation is equal to or less than the reference value, and it is determined that the transmitter 4a having the ID1 is the transmitter 4 provided in the tire 2a.

  As shown in FIG. 12, in this example, when receiving the UHF radio wave from each transmitter 4, the receiver 6 plots the reception timing on the seat of the tire 2b while performing weighting in the same manner as described above. Then, the receiver 6 analyzes the plot situation and determines that the transmitter 4 having the ID is the transmitter 4 provided in the tire 2b on the condition that the standard deviation is equal to or less than the reference value. Here, regarding the plot state of ID2, it is assumed that the standard deviation is equal to or less than the reference value, and it is determined that the transmitter 4b having the ID2 is the transmitter 4 provided in the tire 2b.

  As shown in FIG. 13, in this example, when receiving the UHF radio wave from each transmitter 4, the receiver 6 plots the reception timing on the seat of the tire 2 c while performing weighting in the same manner as described above. Then, the receiver 6 analyzes the plot situation and determines that the transmitter 4 having the ID is the transmitter 4 provided in the tire 2c on the condition that the standard deviation is equal to or less than the reference value. Here, it is assumed that the standard deviation is equal to or less than the reference value for the plot state of ID3, and it is determined that the transmitter 4c having the ID3 is the transmitter 4 provided in the tire 2c.

  As shown in FIG. 14, in this example, when the receiver 6 receives the UHF radio wave from each transmitter 4, the receiver 6 plots the reception timing on the seat of the tire 2d while performing weighting in the same manner as described above. Then, the receiver 6 analyzes the plot situation and determines that the transmitter 4 having the ID is the transmitter 4 provided in the tire 2d on the condition that the standard deviation is equal to or less than the reference value. Here, regarding the plot state of ID4, it is assumed that the standard deviation is equal to or less than the reference value, and it is determined that the transmitter 4d having the ID4 is the transmitter 4 provided in the tire 2d.

The receiver 6 analyzes the plot state for each sheet, and determines the position of the tire 2 when the ID of the transmitter 4 and the position of the tire 2 correspond in a one-to-one relationship.
As shown in FIG. 15, in this example, the transmitter 4 having ID1 is the right front wheel transmitter 4, the transmitter 4 having ID2 is the left front wheel transmitter 4, and the transmitter 4 having ID3 is the right rear wheel. As the wheel transmitter 4, the transmitter 4 having ID 4 is registered in the memory 23 as the left rear wheel transmitter 4.

As described above, according to the present embodiment, the following effects can be obtained.
(1) With the configuration in which the weighting is increased as the rotation information has higher detection accuracy, the timing at which the standard deviation becomes less than the reference value is advanced. Therefore, the position of the tire 2 can be determined at an earlier timing.

(2) The position of the tire 2 can be correctly determined by using the remaining rotation information excluding level 1 rotation information with the lowest detection accuracy.
In addition, the said embodiment can also be changed and actualized as follows.

-About the rotation information of the tire 2, you may provide a detection accuracy in the level of three steps or five steps or more.
-You may determine the position of the tire 2 using all the rotation information including the rotation information of the level with the lowest detection accuracy.

A configuration may be adopted in which both the rotation information with the lowest detection accuracy and the rotation information with the second lowest level are not used for determining the position of the tire 2.
-You may determine the position of the tire 2 only using the rotation information of the level with the highest detection accuracy.

The position of the tire 2 may be determined using both the rotation information with the highest detection accuracy and the rotation information with the second highest level.
For levels 1 to 4 according to the above embodiment, the weighting of level 1 (lowest level) is 0 times (not used), the weighting of levels 2 and 3 is 1 time, and the weighting of level 4 (highest level) is 4 You may unify the weighting of intermediate levels, such as double.

Next, a technical idea that can be grasped from the above embodiment and another example will be described.
(A) The rotation information of the corresponding tire is transmitted from the transmitter provided in each tire, the rotation information of each tire is received by the receiver on the vehicle body side, and the rotation information is obtained from the correlation with the reference rotation information for each tire. In a transmitter applied to a tire position determination system that determines the position of a tire provided with a transmitter that has transmitted
A transmitter characterized by providing detection accuracy at three or more levels with respect to rotation information of the corresponding tire, and transmitting the rotation information of the tire together with level information of the detection accuracy.

(B) The rotation information of the corresponding tire is transmitted from the transmitter provided in each tire, the rotation information of each tire is received by the receiver on the vehicle body side, and the rotation information is obtained from the correlation with the reference rotation information for each tire. In a receiver applied to a tire position determination system that determines the position of a tire provided with a transmitter that has transmitted
With regard to tire rotation information, detection accuracy is defined at three or more levels, and the rotation position with higher detection accuracy is weighted and the tire position is determined from the correlation with the reference rotation information for each tire. Receiver.

  (C) In the receiver, the rotation information with the lowest detection accuracy should not be used for determining the tire position.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2, 2a-2d ... Tire, 3 ... Tire pressure monitoring system, 4, 4a-4d ... Transmitter, 5 ... Vehicle body, 6 ... Receiver, 7 ... Display part, 8, 8a-8d ... Wheel speed Sensor, 11 ... Controller, 12 ... Memory, 13 ... Pressure sensor, 14 ... Temperature sensor, 15 ... Acceleration sensor, 16 ... Antenna, 21 ... ECU, 22 ... Antenna, 23 ... Memory, 24 ... Autolocation function part.

Claims (2)

The rotation information of the corresponding tire is transmitted from the transmitter provided in each tire, the rotation information of each tire is received by the receiver on the vehicle body side, and the rotation information is transmitted from the correlation with the reference rotation information for each tire. In a tire position determination system for determining the position of a tire provided with a transmitter,
The transmitter provides detection accuracy at three or more levels for rotation information of the corresponding tire, and transmits tire rotation information together with level information of detection accuracy.
The receiver determines a tire position from a correlation with reference rotation information for each tire while increasing the weight of rotation information with higher detection accuracy. The tire position determination system according to claim 1, wherein the receiver does not use the rotation information with the lowest detection accuracy for determining the position of the tire.