JP6188132B2 - Distance measuring system and transceiver - Google Patents

Description

  The present invention relates to a distance measuring system using a mobile terminal.

  Smart entry systems are beginning to spread mainly in automobiles. By using the smart entry system, the user can unlock the door only by approaching the door or touching the door knob without inserting the key into the door of the automobile. A general smart entry system in an automobile uses a dedicated key carried by a user and a transceiver attached to the automobile.

  In Patent Document 1, when a dedicated key receives a transmission signal from a transceiver, a response signal is transmitted. When the transceiver receives the response signal, the door lock is released. The radio signal communication range of the transceiver is limited to a short distance of about 1 m. This solves a security problem such that a user away from the vehicle accidentally releases the door lock and a third party can enter the vehicle. The frequency band of the radio signal varies depending on the automobile manufacturer, but 125 kHz or 300 MHz is used.

  If a mobile terminal such as a mobile phone or a smartphone can be used instead of the dedicated key, the convenience of the user can be improved. Due to the widespread use of mobile terminals, many people usually wear mobile terminals, so there is no need to carry a dedicated key. Mobile terminals are equipped with various wireless communication devices such as Bluetooth (registered trademark) and Wi-Fi. However, the communication range of the radio signal using these is as wide as about 5 m to 100 m, and the communication range may vary depending on the type of smartphone or mobile phone.

  Regarding the security, in Non-Patent Document 1, dedicated hardware is installed in a mobile phone. Communication between automobiles and mobile phones uses radio waves of 125kHz and 300MHz, and the communication range of radio waves is limited to about 1m.

JP 2000-160897 A (Door Handle for Vehicle)

"Mobile phone with intelligent key" by Nissan, DOCOMO, Sharp http://www.itmedia.co.jp/mobile/articles/0810/02/news094.html

  In the prior art described in Patent Document 1, it is necessary to carry a dedicated key. In the prior art described in Non-Patent Document 1, the smart key function is installed in the mobile terminal, thereby eliminating the need to carry a dedicated key and improving convenience. However, dedicated hardware is required to transmit and receive radio waves in the 125 kHz and 300 MHz bands, and it cannot be used only with commercially available mobile terminals such as general mobile phones and smartphones.

  The present invention provides a distance measurement system that can be realized using only a general portable terminal in view of the above-described problems of the prior art, and that enables control according to distance, such as a smart entry system. With the goal.

  In order to achieve the above object, the present invention is a distance measurement system that includes a mobile terminal and a transceiver, measures a distance between the two, and executes a predetermined function based on the distance, An authentication unit that performs authentication between the two by radio, and a ranging signal transmission / reception unit that continuously transmits and receives radio for measuring the distance between the two. A distance calculation unit that calculates a distance between the two based on the transmission / reception time of the transmitted / received radio, and the portable terminal or the transceiver performs a predetermined function based on the calculated distance An execution unit is included.

  In the distance measurement system of the present invention, both authentication and distance measurement can be performed by ordinary radio (radio wave and / or sound wave) that can be used by the mobile terminal. Therefore, a distance measurement system that can be used only by a portable terminal is provided.

It is a figure for demonstrating the structure outline | summary of a distance measurement system. It is a functional block diagram of the transceiver and portable terminal in a distance measurement system. It is a figure for demonstrating the case division of the process procedure by the inside and outside of a wireless communication possible range. It is a figure for demonstrating the process sequence in the radio | wireless communicable range after detecting having entered into the radio | wireless communicable range. It is a figure for demonstrating the 1st method of distance calculation. It is a figure for demonstrating the 2nd method of distance calculation.

  FIG. 1 is a diagram for explaining an outline of the configuration of a distance measuring system 100 according to the present invention. The distance measurement system 100 includes a transceiver 1a and a portable terminal 1b. In FIG. 1, the place where the transceiver 1a is installed in the automobile is conceptually illustrated as an example. When installed in the automobile, the distance measurement system 100 can be used as a smart entry system. The transceiver 1a may also be installed in a bicycle, an office or home door, a personal computer (PC), or the like other than a car. A smart phone or a mobile phone can be used for the mobile terminal 1b.

  In the description of the present invention, in particular, when explaining the exchange between the transceiver 1a and the portable terminal 1b, the transceiver 1a is appropriately abbreviated as the parent 1a as a parent machine, 1b is abbreviated as a child 1b as a child device.

  In the present invention, it is assumed that the parent 1a is fixed in place and the child 1b is carried by the user. As shown in FIG. 1, the distance E between the parent and child 1a, 1b is sequentially measured in time series by performing wireless communication. The parent 1a performs a predetermined function based on the measured distance E.

  FIG. 2 is a functional block diagram of the transceiver 1a and the portable terminal 1b constituting the distance measuring system 100. The transceiver 1a includes a range determination unit 2a, an additional information acquisition unit 20a, an authentication unit 3a, a key management unit 30a, a ranging signal transmission / reception unit 4a, a setting unit 40a, a distance calculation unit 5a, and a function execution unit 6a. The portable terminal 1b includes a range determination unit 2b, an additional information acquisition unit 20b, an authentication unit 3b, a key management unit 30b, and a ranging signal transmission / reception unit 4b.

  It should be noted that between the parent and child 1a and 1b, the functional blocks having the same name and the corresponding symbols are attached (for example, the parent 1a range determination unit 2a and the child 1b range determination unit 2b) are the same. Responsible for or corresponding functions.

  The range determination units 2a and 2b periodically transmit beacon signals from the parent 1a side (range determination unit 2a) to the child 1b side (range determination unit 2b). On the child 1b side, when receiving the beacon signal, the child 1b side responds to the parent 1a side. The additional information acquisition units 20a and 20b acquire additional information such as position information when the range determination units 2a and 2b transmit and receive beacon signals.

  In the following, each functional unit will be further described in the same manner as described above for the range determination units 2a and 2b, such as “the parent 1a side” and “the child 1b side”, etc. And "the functional part Xb on the child 1b side". Here, 2, 20, 3, 30, 4, and 40 correspond to X.

  The authentication units 3a and 3b perform authentication between the parent and child 1a and 1b. In order to enable the authentication, the parent and child 1a and 1b set and manage their own key information in advance by the key management units 30a and 30b, respectively.

  The distance measurement signal transmission / reception units 4a and 4b continuously transmit and receive the distance measurement signal between the parent and child 1a and 1b in one or both directions, and record the transmission / reception time of the distance measurement signal. The child 1b side further notifies the parent 1a side of the transmission / reception time of itself. The notification may be performed wirelessly separately from the distance measurement signal, or the distance measurement signal itself transmitted from the child 1b may be configured to have a function of transmitting the transmission / reception time. The setting units 40a and 40b set the transmission intervals and frequencies of the ranging signals transmitted and received by the ranging signal transmitting and receiving units 4a and 4b.

  The distance calculation unit 5a calculates the distance between the parent 1a and the child 1b as a measurement value based on the transmission / reception time of the distance measurement signal acquired by the distance measurement signal transmission / reception unit 4a. Here, since the distance measurement signal is continuously transmitted and received, and the transmission / reception time is also continuously acquired, the distance is also continuously calculated in time series.

  The function execution unit 6a executes a predetermined function based on the distance calculated by the distance calculation unit 5a. If the parent 1a is installed in the automobile, the door of the automobile may be unlocked when the distance is less than or equal to the threshold, and the automobile door may be locked when the distance is greater than the threshold. Furthermore, the engine lock may be released / set in the same manner using another threshold value.

  The function execution unit 6a can release / lock the corresponding key even when the parent 1a is installed on a bicycle, an office or home door, a personal computer (PC), etc., by threshold determination similar to the above. . For example, in the case of a PC, screen lock control may be performed.

  The outline of each part in FIG. 2 has been described above, and supplementary items will be described. When signals and information are exchanged between the parent and child 1a and 1b by the above function units, various types of radio can be used. As radio types, sound waves, ultrasonic waves, and radio waves such as Wi-Fi (registered trademark) and Bluetooth (registered trademark) can be used, and each function unit may use a separate type of radio. In this case, there may be a functional unit that uses the same type of radio.

  Regarding the beacon signal and its response in the range determination unit 2a, 2b and the transmission / reception of the distance measurement signal in the distance measurement signal transmission / reception unit 4a, 4b, the type in which the radio signal directly reaches between the parent / child 1a, 1b. Need to be. In other exchanges, the radio signal does not necessarily reach directly between the parent and child 1a, 1b, and may be via a separate network.

  The processing procedure according to the present invention will be described below.

  The processing procedure of the present invention is carried out in different cases depending on whether the parent and child 1a, 1b is outside the wireless communication range or the wireless communication range. FIG. 3 is a diagram for explaining the case classification of the processing procedure depending on the inside and outside of the wireless communication possible range.

  In FIG. 3, the radio communicable range R is shown centering on the parent 1a at the fixed position. When the child 1b exists in the range R, the radio directly reaches between the parent 1a and 1b. Communication is possible. In FIG. 3, (2) shows the case where the child 1b exists within the range R, and (1) and (3) show the case where the child 1b exists outside the range R as examples. Based on this distinction, the following procedures are performed in each range.

(1. Outside the wireless communication range)
If it is out of the wireless communication range, only the beacon transmission / reception by the range determination units 2a and 2b is attempted between the parent and child 1a and 1b. In this way, the parent 1a waits for the child 1b to enter the wireless communicable range, and constantly monitors whether the child 1b has entered the range. Specifically, the range determination unit 2a of the parent 1a transmits a beacon signal at a predetermined period and waits for a response from the child 1b. On the other hand, the range determination unit 2b of the child 1b continues to monitor whether or not a beacon signal has been received, and responds if received.

(2. Within the wireless communication range)
FIG. 4 shows a processing procedure between the parent and child 1a, 1b after entering the wireless communication range after being out of the wireless communication range. Here, steps (S1) to (S4) are steps in which it is detected that the wireless communication range is entered as indicated by an arrow A12 in FIG. 3, and authentication is performed. ) To (S8) correspond to a procedure within the wireless communicable range, which is repeatedly performed so as to be enclosed as the block B.

(2-1. Detection and authentication of entering wireless communication range)
In step (S1), since the child 1b has moved within the range R, the beacon signal transmitted by the parent 1a is received by the child 1b. In step (S2), the child 1b sends a response signal to the parent 1a in response to the beacon signal. In this way, the child 1b knows that the child 1b exists within the range R by receiving the beacon signal, and can switch to the processing within the wireless communication range. Similarly, the parent 1a knows that the child 1b exists in the range R by receiving the response signal, and can switch to the processing in the wireless communicable range.

  In step (S3), as described above, the authentication unit 3a, 3b transmits key information from the child 1b side to the parent 1a side to perform authentication processing between the parent 1a, 1b, and in step (S4), The key information received from the child 1b is compared with the key information held by the parent 1a, and the parent 1a authenticates the child 1b. The key information is set in advance in the key management units 30a and 30b as described above. Note that, regarding the mode of transmission / reception of key information between the parent and child 1a and 1b, authentication may be performed by a method other than steps (S3) and (S4), for example, authentication is performed on the child 1b side, mutual authentication, etc. .

  If the authentication in the step (S4) is successful, the process proceeds to the wireless communication range after the step (S5). If the authentication in step (S4) fails, the process does not proceed to step (S5) and subsequent steps, and the process returns to the above (1. Outside the wireless communication range).

(2-2. Processing procedure within wireless communication possible range)
In step (S5), the setting units 40a and 40b set the ranging signals to be transmitted by the ranging signal transmission / reception units 4a and 4b, respectively (such as the radio frequency and transmission interval). By sharing the setting between the parent and child 1a and 1b, the transmission / reception time of the distance measurement signal in the subsequent procedure (S6) can be detected from the recorded wireless reception data. At this time, it is also possible to prevent other unrelated terminals from impersonating the parent 1a by using the predetermined setting information of authentication in step (S4).

  This setting may be set in advance between the parent and child 1a and 1b before actual transmission and reception of the distance measurement signal, and the same setting may be continuously used in the repetitive processing B. Alternatively, the setting is changed based on a history of a series of distances in the time series obtained in the repetitive process B (distance between the parent and child 1a, 1b) so that an appropriate distance measuring process is performed. Also good. Specific examples will be described later.

  In step (S6), according to the settings of the setting units 40a and 40b, the distance measurement signal transmission / reception units 4a and 4b transmit and receive the distance measurement signals and record the transmission / reception times. Further, the ranging signal transmitting / receiving unit 4b of the child 1b notifies the recording to the ranging signal transmitting / receiving unit 4a of the parent 1a. A specific example of transmission / reception of the distance measurement signal will be described later.

  In step (S7), the distance calculation unit 5a on the parent 1a side, based on the transmission / reception times of both the parent 1a side and the child 1b side obtained by the distance measurement signal transmission / reception unit 4a, the parent / child 1a, 1b at the time point Calculate the distance between them. The calculation will be described later when a specific example of the distance measurement signal is described later.

  In step (S8), based on the distance calculated in step (S7), the function execution unit 6a executes a predetermined function on the parent 1a side. As the predetermined function, for example, as described above, the control for setting the lock / unlock state by the threshold determination for the distance may be executed.

  As described above, steps (S5) to (S8) are repeatedly executed so as to be surrounded by the block B. At this time, in accordance with the interval T (i) of each time i (i = 1, 2, 3, ...) of the distance measurement signal transmission / reception in step (S6), the block B also has an interval T (i). Repeatedly executed. That is, steps (S5), (S7), and (S8) other than step (S6) may be regarded as substantially instantaneously determining or processing steps.

  Therefore, the interval T (i) is an interval of each transmission / reception of the distance measurement signal by the distance measurement signal transmission / reception units 4a, 4b, a distance calculation interval by the distance calculation unit 5a, and the calculated distance This is also the interval of function execution by the function execution unit 6a based on the above.

(3. Judgment when moving from within the wireless communicable range to outside the wireless communicable range)
Within the wireless communicable range, the processing of block B in FIG. 4 described above is repeated. As the process is repeated, the child terminal 1b moves to move out of the wireless communicable range as indicated by arrow A23 in FIG. There is also a case to move to. In this case, the following may be performed.

  That is, in step (S6) in FIG. 4, when the distance measurement signal that should be transmitted from the partner side is not received on the parent 1a side and the child 1b side for a predetermined number of times or for a predetermined period, Both of the parent and child 1a and 1b may determine that they are out of the wireless communication range, and shift to the above processing (1. outside the wireless communication range). The determination may be performed independently on the parent 1a side and the child 1b side.

  The number of times for the determination may be counted on the time axis using the repetition interval T (i). The predetermined period for the determination may be set in advance in the setting units 40a and 40b.

  Here, an example of setting the above-described repetition interval T (i) will be described. The setting may be performed by the setting unit 40a on the parent 1a side, and the setting may be shared with the setting unit 40b on the child 1b side as necessary.

  In one example, T (i) may be a fixed value regardless of the number of times i. In one example, assuming a smart entry system or the like, it is suitable when the function execution unit 6a executes door lock / unlock control based on a comparison between the distance Eth of a predetermined threshold and the calculated distance E. The following may be used.

  That is, the distance between the parent and child 1a, 1b acquired for the i-th time may be set by dynamically changing T (i) according to E (i). For example, when the difference between the threshold distance Eth and the acquired distance E (i) is small, by reducing the interval T (i), the timing across the threshold distance Eth is within the interval T (i). It is possible to detect and reduce the delay in unlocking and locking the door lock. On the contrary, when the difference between the threshold distance Eth and the calculated distance E (i) is large, the power consumption due to frequent distance calculation can be reduced by increasing the interval T (i).

An example of calculating the interval T (i) based on the above consideration is shown in the following equation.
I = MAX (Tmin, | Eth-E (i) | / Vmax)
Here, MAX (X, Y) is a function that returns the larger of X and Y.
Tmin is a setting value of the minimum value of the interval. This prevents waste of power consumption due to the interval becoming smaller than necessary.
Vmax is a set value of the maximum moving speed assumed when the user (child 1b) approaches or moves away from the automobile (parent 1a).

  In the above formula, i in the interval T (i) represents the interval from the acquisition of the distance E (i) until the next acquisition of the distance E (i + 1). .

  In addition to determining the interval T (i) based on the calculated distance E (i) in consideration of the difference from the threshold distance Eth used in the function execution unit 6a as described above, the threshold Eth = The interval T (i) may be determined based on only the calculated distance E (i). For example, the interval T (i) is set so as to be approximately proportional to the distance E (i), and when the distance E (i) between the parent 1a and 1b is small, the distance is frequently calculated, and the distance E (i) When is large, the distance calculation may be performed sparsely or vice versa. Various methods according to the implementation mode of the function execution unit 6a are possible.

  Next, each example (first method and second method) of distance calculation by the distance calculation unit 5a will be described together with transmission / reception processing of the corresponding distance measurement signal transmission / reception units 4a and 4b. FIG. 5 is a diagram for explaining the first method, and FIG. 6 is a diagram for explaining the second method. 5 and 6 correspond to excerpts of the parts related to steps (S6) and (S7) among the parts repeated as block B in FIG. 4, both of which are pulsed ranging signals. Is being sent and received.

  The first method is based on the premise that the time synchronization between the parents 1a and 1b is performed in advance by the setting units 40a and 40b, as shown as step (T0) in FIG. In this way, after setting the clocks in both, as shown in step (T1), a pulse-shaped ranging signal is transmitted from the child 1b side to the parent 1a side. At this time, as shown as [B1], the transmission time tb1 is acquired on the child 1b side. On the other hand, as shown as [A1], the reception time ta1 is acquired on the parent 1a side. Furthermore, as shown as step (T1-1), the child 1b side notifies the acquired transmission time tb1 to the parent 1a side.

  Thus, on the parent 1a side, as shown in step (T1-2), the difference between the reception time ta1 acquired by itself and the transmission time tb1 on the child 1b side is multiplied by the speed of a known distance measurement signal in advance. Thus, the distance between the parent and child 1a, 1b is calculated. The above is the process for one time as shown as block T10, and the same process is continued after the second time as shown as block T20.

  In the first method, time synchronization is possible by using a GPS (Global Positioning System) signal or the like. The required accuracy of time synchronization depends on the required accuracy of distance calculation and the type of radio of the ranging signal. For example, when the required accuracy of distance calculation is 50 cm, the required accuracy of time synchronization of radio waves is 1.67 ns, and the required accuracy of time synchronization of sound waves / ultrasound is about 0.15 ms.

  In the first method, the parent 1a may be the ranging signal transmitting side and the child 1b may be the receiving side.

  On the other hand, unlike the first method, the second method shown in FIG. 6 is a method that does not require time synchronization. The second method uses a method similar to NTP (Network Time Protocol) widely used on the Internet.

Specifically, each of the parent and child 1a, 1b transmits a distance measurement signal, and each of them measures the transmission time of its own transmission signal and the reception time of the other party's transmission signal. The transmission time and reception time of the child 1b are Tm_s and Tm_r. The transmission time and reception time of the parent 1a are Tc_s and Tc_r. Also, the clock error between the parent and child 1a, 1b is Δt. Similar to NTP, the propagation time P_T is calculated by the following equation. Accordingly, the propagation time can be calculated without being affected by the time difference Δt.
P_T = ((Tm_r-(Tc_s + Δt)) + ((Tc_r + Δt)-Tm_s)) / 2
= ((Tm_r-Tm_s) + (Tc_r-Tc_s)) / 2

  FIG. 6 conceptually explains each time of the above formula. (1) shows the time from the viewpoint on the time axis, and (2) shows the time from the viewpoint on the transmission / reception device. In (2), the distance measurement signal transmitters (speakers for sound waves) of the parent 1a and child 1b are 1aS and 1bS, respectively, and the distance measurement signal receivers of the parent 1a and child 1b (for sound waves) And microphone) are 1aM and 1bM, respectively. For example, Tm_s is the time when 1bM receives 1bS transmission, and Tm_r is the time when 1bM receives 1aS transmission.

  In the second method, the child 1b that has received the transmission of the distance measurement signal from the parent 1a side immediately transmits the distance measurement signal toward the parent 1a side using the reception as a trigger. The interval T (i) described above is managed only on the parent 1a side, and there is no need to notify the child 1b side. However, in this case, it is necessary to set in advance in the setting unit 40b on the child 1b side what kind of ranging signal is transmitted (configuration frequency, etc.).

  Hereinafter, supplementary items (Supplement 1) to (Supplement 6) in the present invention will be described. Regarding (Supplement 2) to (Supplement 4), in particular, the mobile terminal 1b is a mobile terminal, and in view of the limited resources, a reduction in power consumption and the like is achieved.

  (Supplement 1) As described above, when signals and information are exchanged between the parent and child 1a and 1b by each functional unit, various radios can be used. In one example, a sound wave is used as a distance measurement signal. Otherwise, radio waves may be used.

  In this way, for example, by using Wi-Fi (registered trademark) with a high communication speed for transmission and reception of control signals (signals other than ranging signals between the parent and child 1a and 1b), key information and other high-speed transmission and reception, High-precision distance measurement can be achieved by using sound waves having a low propagation speed for transmission and reception of distance measurement signals.

  (Supplement 2) From the viewpoint of not wasting power consumption and the like, the following may be performed. That is, in the case of the above-mentioned (1. out of wireless communicable range), only the range determination units 2a and 2b are operated between the parent and child 1a and 1b, and the authentication units 3a and 3b and distance measurement signal transmission / reception units 4a and 4b are operated. In addition, the distance calculation unit 5a and the function execution unit 6a on the parent 1a side are not operated. Conversely, in the above-described (2. Within the wireless communicable range), when the beacon signal arrives and a response is obtained, the operation of the range determination units 2a and 2b is stopped.

  (Supplement 3) When the range determination units 2a and 2b are attempting to reach the beacon signal according to the above (1. Out of radio communicable range), the transmission interval of the beacon signal is set to a fixed interval. In addition, the following control may be performed.

  For this reason, the additional information acquisition units 20a and 20b acquire and use their own positions by the parent 1a and the child 1b, respectively. For location acquisition, GPS, mobile phone network and Wi-Fi (registered trademark) connection destination information can be used. The child 1b side notifies the position information to the parent 1a side. In the case of the notification, since it is out of the direct wireless reachable range, the notification is performed via a separate network or the like.

  On the side of the parent 1a, the distance X between the parent and child 1a, 1b is obtained from the acquired own position and the position of the child 1b. When the distance X exceeds a predetermined value R2 that is larger than the radio communicable range R as illustrated in FIG. 3, the range determination units 2a and 2b interrupt the attempt to reach the beacon signal. The child 1b may be notified of the interruption via the Internet or the like.

  On the parent 1a side, the distance X between the parent and child 1a, 1b is periodically acquired based on the respective position information, and the attempt to reach the beacon signal is resumed when the distance becomes equal to or less than the predetermined value R2. May be.

  Alternatively, the distance X may be obtained, and the beacon signal may be transmitted from the parent 1a side at a predetermined cycle that is set longer as the distance X is longer. By notifying the child 1b side of a predetermined period set from the distance X, it is possible to grasp the small period that the beacon signal may reach next, and to receive the beacon signal only during the small period. You may make it start.

The predetermined period P may be obtained as follows. Here, V_max2 is the maximum value of the moving speed of the user (the user who holds the child 1b).
P = X / V_max2

  Note that when the position information is acquired again and the distance X is updated before the predetermined period P elapses, the predetermined period P may be updated at the same time.

  (Supplement 4) One embodiment of setting the transmission / reception interval T (i) by the distance measurement signal transmission / reception units 4a, 4b may be as follows. Here, it is assumed that the parent 1a is stationary. On the child 1b side, as an additional process, it is determined whether or not it is moving. For this reason, the acceleration is acquired from the acceleration sensor provided in the portable terminal 1b, or the position information is acquired by GPS or the like similar to (Supplement 3).

  On the child 1b side, the acceleration or position information is accumulated as a history at a predetermined interval, and if it is determined that the child 1b remains stationary for a certain period by referring to the history, the transmission / reception interval T ( i) is changed to a larger set value (for example, by multiplying by a predetermined value greater than 1) than the set value when the determination is not made. The change may be performed by the setting unit 40b, and the setting unit 40a may be notified to share the setting.

  In the case of the smart entry system, for example, the car (transmitter / receiver 1a) and the portable terminal 1b exist within a communicable range by a ranging signal, but the car is in a parking lot at home, and the user When the user is resting at home and does not plan to use the car for a while, it is possible to prevent the ranging signal from being continuously transmitted and received.

  (Supplement 5) In the present invention, as shown in FIG. 2, the distance calculation unit 5a and the function execution unit 6a have been described as existing on the side of the transceiver (parent) 1a. At least one of them may exist as the distance calculation unit 5b and / or the function execution unit 6b on the portable terminal (child) 1b side.

  For example, in one example, the mobile terminal 1b includes the “distance calculation unit 5b”, the transceiver 1a does not include the “distance calculation unit 5a”, and the mobile terminal 1b side performs the distance calculation function so that the calculated distance is sequentially The predetermined function may be executed by the function execution unit 6a of the transmitter / receiver 1a by transmitting it to the transmitter / receiver 1a side. Similarly, necessary information may be appropriately exchanged between the transceiver 1a and the portable terminal 1b, and execution of a predetermined function may be performed by the portable terminal 1b including the “function execution unit 6b”.

  (Supplement 6) As in the above (Supplement 5), the role of transmission / reception of beacon signals in the range determination units 2a and 2b may be changed. That is, the beacon signal may be periodically transmitted on the mobile terminal 1b side and the reception of the beacon signal may be attempted on the transceiver 1a side.

  100 ... Distance measurement system, 1a ... Transmission / reception device, 1b ... Mobile terminal, 2a, 2b ... Range determination unit, 3a, 3b ... Authentication unit, 4a, 4b ... Ranging signal transmission / reception unit, 5a ... Distance calculation unit, 6a ... Function Execution part

Claims (11)

A distance measurement system that includes a portable terminal and a transceiver, measures a distance between the two, and executes a predetermined function based on the distance.
An authentication unit for performing wireless authentication between the two;
A ranging signal transmission / reception unit that continuously transmits and receives radio for measuring the distance between the two,
The portable terminal or the transceiver is
A distance calculation unit for calculating a distance between the two based on the transmission and reception time of the transmitted and received radio,
The transceiver is
A function execution unit for executing a predetermined function based on the calculated distance;
The distance measurement signal transmission / reception unit in both of them transmits and receives sound waves as radio for measuring the distance,
The distance measuring system, wherein the authentication unit in both uses a sound wave as a radio for performing the authentication. The mobile terminal or the transmitter / receiver further includes a setting unit configured to set a wireless transmission / reception interval to be transmitted / received by the ranging signal transmission / reception unit between the two based on the calculated distance. The described distance measuring system.   The setting unit is configured to set the radio transmission / reception interval transmitted and received by the distance measurement signal transmission / reception unit between the two as the absolute value of the difference between the calculated distance and the predetermined distance is smaller. The distance measuring system according to claim 2.   The said setting part provides a predetermined minimum transmission interval as the said lower limit, when setting the said radio | wireless transmission / reception space | interval narrowing so that the absolute value of the said difference is small, The predetermined | prescribed minimum transmission interval is provided. Distance measuring system.   5. The distance measuring system according to claim 3, wherein the function executing unit executes the predetermined function based on a magnitude determination between the calculated distance and the predetermined distance.   When the mobile terminal is determined to be stationary for a predetermined period, the wireless transmission / reception interval is set as a predetermined value longer than the case where the determination is not made. The distance measuring system according to any one of claims 1 to 5. Further, the both sides transmit beacon signals at a predetermined interval on one side and try to receive the beacon signals on the other side, so that the distance between the two is within a wireless communication range. Including a range determination unit that determines whether or not the wireless communication range is within the range,
The distance measuring system according to claim 1, wherein the authentication unit in the both performs the authentication, and the ranging signal transmitting / receiving unit in the both transmits and receives radio. If the distance measurement signal transmission / reception unit in both of them continues over a predetermined period of time when radio reception for measuring the distance between the two is not performed, the radio transmission / reception unit is interrupted,
8. The distance measuring system according to claim 7, wherein when the interruption is performed, the range determination unit in both of them tries to transmit and receive the beacon signal.   The distance measuring system according to claim 7 or 8, wherein the range determination unit determines an interval of transmission of the beacon signal based on position information of the transceiver and the portable terminal. The transceiver is installed in an automobile;
The distance measuring system according to claim 1, wherein the function execution unit performs control related to locking and unlocking keys of the automobile. It is a transceiver in a distance measuring system that includes a portable terminal and a transceiver, measures a distance between the two, and executes a predetermined function based on the distance,
An authentication unit for performing wireless authentication between the two;
A ranging signal transmission / reception unit that continuously transmits and receives radio for measuring the distance between the two,
The transceiver is
A distance calculation unit that calculates a distance between the two based on the transmission / reception time of the transmitted and received radio;
A function execution unit that executes a predetermined function based on the calculated distance,
The distance measurement signal transmission / reception unit in both of them transmits and receives sound waves as radio for measuring the distance,
The transmitter / receiver in the distance measuring system, wherein the authentication unit in both uses a sound wave as radio for performing the authentication.