JP2013133633A - Communication device, security system, unlocking method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a door from being unlocked by a fraudulent act.SOLUTION: Every time identification information required for unlocking a vehicle door is received, determination is made as to whether the central frequency of an FSK signal indicating the identification information matches a preset central frequency (step S303). Only when the determination is positive, an unlocking command is output to a door lock device, which makes it possible to accurately prevent a door from being unlocked by a fraudulent act, in order to prevent such a criminal act.

Description

  The present invention relates to a communication device, a security system, an unlocking method, and a program, and more particularly, a communication device that transmits identification information for unlocking a door, a security system including the communication device, and an unlocking of a door. The present invention relates to an unlocking method and a program.

  There has been proposed a system that locks and unlocks a door of a vehicle or a house by transmitting identification information individually assigned to the electronic key using wireless communication. In this system, for example, when a user holding an electronic key approaches a door, authentication of identification information is automatically performed. When the authentication is successful, the door is unlocked. When this type of system is used, it is possible to get on and off the vehicle and enter and exit the house without manually locking and unlocking the door.

  However, since convenience and safety are in a trade-off relationship, it is becoming common for vehicles and houses equipped with the above system to also be equipped with a security system (for example, Patent Document 1 and 2).

  When the communication time between the electronic key and the vehicle is longer than a preset reference time, the system described in Patent Document 1 determines that the driver is not present in the vicinity of the vehicle, and the door Will not be unlocked. According to this system, when a driver carrying an electronic key moves far away from the vehicle, communication between the vehicle and the electronic key is established using a repeater, and the door is opened without being noticed by the driver. Unauthorized actions such as unlocking can be prevented.

  The system described in Patent Document 2 changes the output from the transmission side when communication between the electronic key and the vehicle is performed. In this system, when the receiving side determines that there is no change in the output from the output side, the door is not unlocked. Thereby, the act of unlocking the door using the copied identification information can be prevented.

Japanese Patent No. 3909226 JP 2010-185186 A

  In the system disclosed in Patent Document 1, a circuit and a program for calculating the communication time are newly required. For this reason, the manufacturing cost of a system will increase. In addition, since it is difficult to detect a slight difference in communication time, it may be possible that erroneous determination occurs.

  In the system disclosed in Patent Document 2, a circuit and a program for controlling the output on the transmission side are newly required. For this reason, the manufacturing cost of a system will increase. Further, when affected by noise or the like, it is difficult to accurately detect a change in output.

  The present invention has been made under the circumstances described above, and it is an object of the present invention to accurately prevent door unlocking due to fraud while suppressing an increase in manufacturing cost of the apparatus.

In order to achieve the above object, a communication device according to the first aspect of the present invention provides:
A communication device for transmitting a code for unlocking a door to an unlocking unit for unlocking the door,
Storage means for storing in advance the center frequency of the output signal transmitted to the release unit, stored in the release unit;
Output signal generating means for frequency-modulating a carrier wave based on the code to generate the output signal having a center frequency equal to the center frequency stored in the storage means;
Transmitting means for transmitting the output signal;
Is provided.

A communication device according to a second aspect of the present invention is:
A communication device for transmitting a code for unlocking a door to an unlocking unit for unlocking the door,
Storage means for storing in advance a first center frequency of the output signal transmitted to the release unit and a second center frequency different from the first center frequency, stored in the release unit;
Frequency-modulating a carrier wave based on a first code to generate a first output signal having a center frequency equal to the first center frequency, and frequency-modulating the carrier wave based on a second code different from the first code Output signal generating means for generating a second output signal having a center frequency equal to the second center frequency;
Transmitting means for transmitting the first output signal and the second output signal;
Is provided.

The security system according to the third aspect of the present invention is:
A security system for receiving a code for unlocking a door and unlocking the door,
A communication device according to a first aspect of the present invention;
Storage means for storing a center frequency of an output signal transmitted from the communication device;
Receiving means for receiving the output signal transmitted from the communication device;
Center frequency detecting means for detecting a center frequency of the output signal;
Code detecting means for demodulating the output signal and detecting the code;
Frequency collating means for collating the center frequency of the output signal detected by the center frequency detecting means with the center frequency stored in the storage means;
Code collating means for collating the code detected by the code detecting means with the code stored in the storage means;
When the collation result of the center frequency collating means and the code collating means is affirmative, the unlocking means for unlocking the door;
Is provided.

A security system according to a fourth aspect of the present invention is:
A security system for receiving a code for unlocking a door and unlocking the door,
A communication device according to a second aspect of the present invention;
Storage means for storing the first center frequency and the second center frequency of the output signal transmitted from the communication device;
Receiving means for receiving the first output signal and the second output signal transmitted from the communication device;
Center frequency detecting means for detecting a center frequency of the first output signal and the second output signal;
Code detecting means for demodulating the first output signal to detect the first code and demodulating the second output signal to detect the second code;
The second output signal detected by the center frequency detecting means by comparing the center frequency of the first output signal detected by the center frequency detecting means with the first center frequency stored in the storage means. Center frequency matching means for matching the second center frequency stored in the storage means with the center frequency of
The first code detected by the code detection means is collated with the first code stored in the storage means, and the second code detected by the code detection means is stored in the storage means. Code verification means for verifying the second code;
When the collation result of the center frequency collating means and the code collating means is affirmative, the unlocking means for unlocking the door;
Is provided.

The unlocking method according to the fifth aspect of the present invention is:
An unlocking method for receiving a code for unlocking a door and unlocking the door,
Pre-store the center frequency of the output signal generated by frequency modulating the carrier wave based on the code;
Receiving the output signal;
Detecting a center frequency of the output signal;
Demodulating the output signal to detect the code;
Collating the detected center frequency of the output signal with the center frequency stored in advance;
Collating the detected code with the previously stored code;
When the verification result of the center frequency and the verification result of the code are positive, unlocking the door;
including.

A program according to the sixth aspect of the present invention is:
On the computer,
Storing a center frequency of an output signal generated by frequency modulating a carrier wave based on a code for unlocking the door;
Detecting a center frequency of the output signal;
Detecting the code by demodulating the output signal;
A procedure for collating the detected center frequency of the output signal with the center frequency stored in advance;
A procedure for collating the detected code with the pre-stored code;
A step of unlocking the door when the result of collating the center frequency and the result of collating the code are positive;
Is executed.

  According to the present invention, the door can be unlocked only when the center frequency of the output signal indicating the identification information matches a preset center frequency. For this reason, when the center frequency of the output signal is different from the preset center frequency, it is possible to accurately prevent the door from being unlocked due to fraud by preventing the door from being unlocked. . The output signal can be received using an existing device. For this reason, the unlocking of the door due to fraud can be prevented while suppressing an increase in the manufacturing cost of the device.

It is a figure showing roughly the security system concerning this embodiment. It is a block diagram of a portable communication terminal and an unlocking unit. It is a block diagram of a portable control apparatus. It is a figure which shows typically identification information and each signal corresponding to the said identification information. It is a figure which shows the power spectrum of a FSK signal. It is a figure which shows the power spectrum of a FSK signal. It is a figure which shows the vector calculated from a FSK signal. It is a figure which shows the vector calculated from a FSK signal. It is a block diagram of a vehicle control device. It is a figure which shows typically communication with a portable communication terminal and an unlocking unit. It is a flowchart which shows a series of processes performed by a vehicle control apparatus and a portable control apparatus. It is a figure which shows typically identification information and each signal corresponding to the said identification information. It is a figure which shows the power spectrum of a FSK signal. It is a figure which shows the power spectrum of a FSK signal. It is a figure which shows the vector calculated from a FSK signal. It is a flowchart which shows a series of processes performed by a vehicle control apparatus and a portable control apparatus. It is a figure which shows the modification of a code | cord | chord.

<< First Embodiment >>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a security system 10 according to the present embodiment. The security system 10 is a system that automatically unlocks the door of the vehicle 92 when the driver 91 carrying the mobile communication terminal 20 approaches the vehicle 92. As shown in FIG. 1, the security system 10 includes a mobile communication terminal 20 and an unlocking unit 30.

  FIG. 2 is a block diagram of the mobile communication terminal 20 and the unlocking unit 30. As illustrated in FIG. 2, the mobile communication terminal 20 includes a transmission device 21, a mobile control device 22, and a reception device 23.

  The receiving device 23 receives an output signal transmitted from the unlocking unit 30 mounted on the vehicle 92. Then, the information indicated in the output signal is detected by demodulating the output signal. The receiving device 23 transmits the detected information to the portable control device 22.

  In the present embodiment, the output signal output from the unlocking unit 30 indicates a command for requesting the mobile communication terminal 20 to transmit identification information (hereinafter referred to as an identification information transmission command). Therefore, when the output signal is received by the receiving device 23, an identification information transmission command is transmitted from the receiving device 23 to the unlocking unit 30.

  The portable control device 22 is a microcomputer that comprehensively controls the portable communication terminal 20. FIG. 3 is a block diagram of the portable control device 22. As shown in FIG. 3, the portable control device 22 includes a CPU (Central Processing Unit) 22a, a main storage unit 22b, an auxiliary storage unit 22c, an interface 22d, and a system bus 22e that connects the above-described units.

  The CPU 22a executes processing to be described later according to a program stored in the auxiliary storage unit 22c.

  The main storage unit 22b has a RAM (Random Access Memory) and the like. The main storage unit 22b is used as a work area for the CPU 22a.

  The auxiliary storage unit 22c has a nonvolatile memory such as a semiconductor memory. The auxiliary storage unit 22c stores a program executed by the CPU 22a. Further, identification information necessary for unlocking the door of the vehicle 92 and information indicating the center frequency fc of the output signal output from the mobile communication terminal 20 are stored.

  FIG. 4 is a diagram schematically showing identification information and signals corresponding to the identification information. As shown in FIG. 4, the identification information described above is composed of a plurality of (for example, four) codes C1 to C4. Each of the codes C1 to C4 is, for example, a 6-bit, 8-bit, or 16-bit code having binary values “0” and “1” as constituent elements. Note that the number of bits of the codes C1 to C4 can be arbitrarily determined.

  The center frequency fc is an intermediate frequency between the maximum frequency and the minimum frequency of the output signal generated by frequency-modulating the carrier wave based on the identification information. Usually, the center frequency fc is a value equivalent to the frequency of the carrier wave. The center frequency fc is stored in association with the codes C1 to C4, for example. Here, as shown in Table 1, the center frequency corresponding to the code C1 is fc1, the center frequency corresponding to the code C2 is fc2, the center frequency corresponding to the code C3 is fc1, and the center frequency corresponding to the code C4 is fc2. As will be described later, the value of the center frequency fc1 and the value of the center frequency fc2 are different.

  The interface 22d connects the transmission device 21 and the reception device 23 to the system bus 22e.

  In the mobile control device 22 configured as described above, when the identification information transmission / reception command is output from the reception device 23, the CPU 22a reads the corresponding identification information from the auxiliary storage unit 22c. Then, a code signal indicating the read identification information is generated and output. This code signal is a binary signal, a low level corresponds to a component of identification information whose value is “0”, and a high level corresponds to a component of identification information whose value is “1”. ing.

  Further, the CPU 22a reads the center frequency fcn from the auxiliary storage unit 22c. Then, a center frequency switching signal for defining the center frequency of the output signal is generated. The center frequency switching signal is a binary signal, and the low level corresponds to the center frequency fc1, and the high level corresponds to the center frequency fc2.

  When generating the code signal and the center frequency switching signal, the CPU 22a outputs these signals to the transmission device 21 via the interface 22d.

  The transmission device 21 generates an output signal by frequency-modulating the carrier wave based on the code signal and the center frequency switching signal output from the portable control device 22. An output signal from the transmission device 21 is an FSK (Frequency Shift Keying) signal generated by modulating a carrier wave based on identification information for unlocking the door. Hereinafter, this signal is referred to as an FSK signal.

  As shown in FIG. 4, the FSK signal is a signal having a center frequency of fc1 when the center frequency switching signal is at a low level. As shown in FIG. 5, this signal is a signal whose center frequency is fc1 and whose power spectrum appears at frequency f1- and frequency f1 +.

  The FSK signal is a signal having a center frequency of fc2 (> fc1) when the center frequency switching signal is at a high level. As shown in FIG. 6, this signal is a signal whose center frequency is fc2 and whose power spectrum appears at frequency f2- and frequency f2 +. As shown in FIGS. 5 and 6, the deviation width of the FSK signal is constant at D1.

  The transmitter 21 generates and outputs the FSK signal whose center frequency changes in synchronization with the change in the level of the center frequency switching signal as described above.

  Returning to FIG. 2, the unlocking unit 30 includes a receiving device 31, a vehicle control device 32, a transmitting device 33, and a door lock device 34.

  The receiving device 31 has an antenna (not shown) provided on the door handle of the vehicle 92. As can be seen from FIG. 1, the receiving device 31 is located when the driver 91 carrying the mobile communication terminal 20 is located in an area surrounded by a circle C having a radius of about 1 m around the antenna. The FSK signal transmitted from the mobile communication terminal 20 is received.

  When receiving the FSK signal, the receiving device 31 detects the center frequency of the FSK signal. Specifically, the receiving device 31 first calculates a vector whose magnitude corresponds to the amplitude and whose angle corresponds to the phase based on the received FSK signal. FIG. 7 shows complex coordinates and vectors A1 and A2 calculated from the FSK signal. FIG. 8 shows complex coordinates and vectors A3 and A4 calculated from the FSK signal. A set of vectors A1 and A2 are vectors obtained from an FSK signal having a center frequency of fc1. A set of vectors A3 and A4 are vectors obtained from an FSK signal having a center frequency of fc2. In this embodiment, since the code signal is a rectangular wave, two vectors are calculated for each center frequency.

The center frequency fcn of the FSK signal received by the receiving device 31 can be obtained by the following equation (1). n is 1 or 2. Note that n is 1 or 2. Further, f1 ₁ is the angle of the vector A1, f1 ₂ is the angle of the vector A2. Then, f2 ₁ is the angle of the vector A3, f2 ₂ are the angles of the vector A4. The vector angle refers to the angle with the real axis Re.

fcn = (fn ₁ + fn ₂ ) / 2 (1)

  Therefore, the receiving device 31 detects the center frequency of the FSK signal based on the angles of the vectors A1 and A2 or the angles of the vectors A3 and A4. Then, a center frequency detection signal indicating the detected center frequency is generated. As shown in FIG. 4, the value of the center frequency detection signal changes to a level corresponding to the center frequency of the FSK signal. Specifically, the value of the center frequency detection signal becomes a low level when the center frequency of the detected FSK signal is fc1. Further, it becomes a high level when the center frequency of the FSK signal is fc2. The receiving device 31 outputs the generated center frequency detection signal to the vehicle control device 32.

  In addition, the receiving device 31 detects the identification information indicated by the FSK signal by demodulating the FSK signal. Then, a code detection signal indicating identification information is generated. This code detection signal is a signal equivalent to the code signal shown in FIG. When receiving the code detection signal indicating the identification information, the receiving device 31 outputs the code detection signal to the vehicle control device 32 in synchronization with the center frequency detection signal. As a result, both the center frequency detection signal and the code detection signal are output to the vehicle control device 32.

  FIG. 9 is a block diagram of the vehicle control device 32. As shown in FIG. 9, the vehicle control device 32 has a CPU 32a, a main storage unit 32b, an auxiliary storage unit 32c, an interface 32d, and a system bus 32e that connects the above-described units, like the portable control device 22. Yes.

  The CPU 32a executes processing to be described later according to a program stored in the auxiliary storage unit 32c.

  The main storage unit 32b has a RAM and the like. The main storage unit 22b is used as a work area for the CPU 22a.

  The auxiliary storage unit 32c includes a nonvolatile memory such as a ROM, a magnetic disk, and a semiconductor memory. The auxiliary storage unit 32c stores a program executed by the CPU 32a. Further, in the auxiliary storage unit 32 c, as in the auxiliary storage unit 22 c of the portable control device 22, identification information necessary for unlocking the door of the vehicle 92 and the center of the output signal output from the portable communication terminal 20. Information indicating the frequency fc is stored. This identification information consists of codes C1 to C4. Information indicating the center frequency fc is stored in a state associated with each code as shown in Table 1 above.

  The interface 32d connects the reception device 31, the transmission device 33, and the door lock device 34 to the system bus 32e.

  The vehicle control device 32 configured as described above instructs the transmission device 33 to transmit an output signal for prompting transmission of identification information.

  Further, when the vehicle control device 32 receives the center frequency detection signal and the code detection signal output from the receiving device 31, the vehicle control device 32 sequentially detects the codes C1 to C4 from the code detection signal. At the same time, the center frequency of the FSK signal when the codes C1 to C2 are detected is obtained from the center frequency detection signal indicating the center frequency of the FSK signal.

  Next, the vehicle control device 32 compares the center frequency detected from the received FSK signal with the center frequency fc1 stored in advance. When the absolute value of the difference between the detected center frequency value and fc1 is equal to or less than the threshold value, it is determined that the center frequency of the received FSK signal is fc1. Further, when the absolute value of the difference between the detected center frequency value and fc2 is equal to or less than the threshold value, it is determined that the center frequency of the received FSK signal is fc2. The center frequency when the code C1 is detected is fc1, the center frequency when the code C2 is detected is fc2, the center frequency when the code C3 is detected is fc1, and the code C4 is detected. When the center frequency of fc2 is fc2, the received identification information consisting of the codes C1 to C4 is collated with previously stored identification information.

  The vehicle control device 32 notifies the door lock device 34 of a door unlocking command when the received identification information including the codes C1 to C4 matches the previously stored identification information.

  When instructed by the vehicle control device 32 to transmit an output signal, the transmission device 33 outputs an output signal indicating an identification information transmission command. This output signal is received by the mobile communication terminal 20 only when the mobile communication terminal 20 is located in the area surrounded by the circle C, as can be seen with reference to FIG.

  The door lock device 34 unlocks the door of the vehicle 92 when a door unlock command is notified from the vehicle control device 32.

  FIG. 10 is a diagram schematically illustrating communication between the mobile communication terminal 20 and the unlocking unit 30. As shown in FIG. 10, in the security system 10 configured as described above, when the output signal CM indicating the identification information transmission command is output from the unlocking unit 30 and received by the mobile communication terminal 20, A code C1 constituting identification information is output from the communication terminal 20. Next, when the code C1 output from the mobile communication terminal 20 is received by the unlocking unit 30, an output signal ANS indicating that the command has been received is output from the unlocking unit 30. Next, when the output signal ANS is received by the mobile communication terminal 20, the code C <b> 2 is output from the mobile communication terminal 20. Thereafter, by repeating the above operation, the codes C3 and C4 are output from the mobile communication terminal 20 and received by the unlocking unit 30.

  Hereinafter, the unlocking operation of the security system 10 will be described with reference to FIG. FIG. 11 is a flowchart showing a series of processes executed by the vehicle control device 32 and the portable control device 22. For example, when the door of the vehicle 92 is locked, the vehicle control device 32 transmits an identification information transmission command (step S301). The identification information transmission command is transmitted by outputting an output signal CM indicating the command.

  On the other hand, the portable control device 22 initializes the counter value n (step S201). As a result, the counter value n is initialized to 0. When receiving the identification information transmission command (step S202: Yes), the portable control device 22 increments the counter value n (step S203). Then, the code Cn is transmitted (step S204). Here, since the counter value n is 1, the code C1 is transmitted.

  When receiving the code Cn (step S302: Yes), the vehicle control device 32 determines whether or not the center frequency of the FSK signal indicating the code Cn matches the frequency stored in advance (step S303). As can be seen from FIG. 5, the code C1 is received as an FSK signal whose center frequency is originally fc1. Therefore, the vehicle control device 32 detects the center frequency of the received FSK signal. Then, the detected center frequency is compared with a center frequency fc1 stored in advance. When the absolute value of the difference between the detected center frequency and the previously stored center frequency fc1 is equal to or less than the threshold value, the vehicle control device 32 determines that the detected center frequency matches the stored center frequency fc1. (Step S303: Yes), the reception of the code Cn is notified via the transmission device 33 (Step S304). This notification of reception is performed by the transmission device 33 outputting the output signal ANS.

  When the portable control device 22 receives the output signal ANS output from the transmission device 33 (step S205: Yes), the portable control device 22 returns to step S202, and thereafter repeatedly executes the processing of steps S202 to S205. As a result, codes C2, C3, and C4 are sequentially output. On the other hand, when the portable control device cannot receive the output signal ANS (step S205: No), the portable control device returns to step S201 and repeatedly executes the processes of steps S201 to S205.

  In addition, when the vehicle control device 32 cannot receive the code Cn within a predetermined time after transmitting the identification information transmission command (step S302: No), or the detected center frequency and the center stored in advance. If it is determined that the frequency fc1 does not match (step S303: No), the process returns to step S301, and the processes of steps S301 to S303 are repeated. As a result, an identification information transmission command is periodically transmitted from the unlocking unit 30.

  If all the codes C1 to C4 constituting the identification information have not been received (step S305: No), the vehicle control device 32 returns to step S302 and repeatedly executes the processes of steps S302 to S305. Thereby, the codes C2, C3, and C4 are sequentially output from the portable control device 22 and received. Each time the code Cn is received, the center frequency detected from the FSK signal indicating the code Cn is compared with the center frequency stored in advance.

  On the other hand, when all the codes C1 to C4 constituting the identification information are received (step S305: Yes), the vehicle control device 32 collates the identification information consisting of the codes C1 to C4 with the identification information stored in advance. (Step S306). Then, when the received identification information including the codes C1 to C4 matches the previously stored identification information (step S306: Yes), the vehicle control device 32 instructs the door lock device 34 to unlock the door. Is notified (step S307). As a result, the door of the vehicle 92 is unlocked by the door lock device 34.

  Further, when the received identification information consisting of the codes C1 to C4 does not match the previously stored identification information (step S306: No), the vehicle control device 32 returns to step S301 and performs the processing after step S301. Repeatedly.

  As described above, in this embodiment, every time the identification information necessary for unlocking the vehicle door is received, the center frequency of the FSK signal indicating the identification information matches the center frequency stored in advance. It is determined whether or not to perform (step S303). Only when this determination is affirmative, an unlock command is output to the door lock device 34, and the door of the vehicle 92 is unlocked.

  For this reason, even if a repeater that relays the FSK signal is used due to criminal activity, if the center frequency of the FSK signal output from the repeater is different from the center frequency stored in advance, the door will be mistaken. It will not be unlocked. Thereby, the unlocking of the door due to fraud can be accurately prevented, and criminal acts can be prevented in advance.

  The center frequency can be detected using an existing receiving apparatus. For this reason, an increase in the manufacturing cost of the system can be suppressed.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described. In the security system 10 according to the first embodiment, the center frequency of the FSK signal is changed every time a code is transmitted. However, in the security system 10 according to the second embodiment, the FSK signal is transmitted every time a code is transmitted. Change the deviation width of.

  Hereinafter, the security system 10 according to the present embodiment will be described with reference to the drawings. In addition, about the structure same or equivalent to 1st Embodiment, while using an equivalent code | symbol, the description is abbreviate | omitted or simplified.

  In the present embodiment, information related to the shift amount corresponding to the code C is stored in the auxiliary storage unit 22 c of the portable control device 22. As shown in Table 2 below, the deviation amount D1 corresponds to the code C1, the deviation amount D2 corresponds to the code C2, the deviation amount D1 corresponds to the code C3, and the deviation amount corresponds to the code C4. The transfer amount D2 corresponds. As will be described later, the value of the shift amount D1 is different from the value of the shift amount D2.

  The CPU 22a reads the shift amount Dn from the auxiliary storage unit 22c. Then, as shown in FIG. 12, a deviation amount switching signal for defining the deviation width of the output signal is generated. This deviation amount switching signal is a binary signal, and the low level corresponds to the deviation amount D1, and the high level corresponds to the deviation amount D2.

  The CPU 22a outputs the generated center frequency switching signal to the transmission device 21 together with the code signal via the interface 22d.

  The transmission device 21 of the mobile communication terminal generates a FSK signal by frequency-modulating the carrier wave based on the code signal and the center frequency switching signal output from the mobile control device 22. The FSK signal is a signal having a deviation width D1 when the deviation amount switching signal is at a low level. As shown in FIG. 13, this signal is a signal whose center frequency is fc and whose power spectrum appears at frequency f1− and frequency f1 +. Therefore, the absolute value of the difference between the center frequency fc and the frequency f1− and the absolute value of the difference between the center frequency fc and the frequency f1 + are equal to the deviation amount D1.

  The FSK signal is a signal having a deviation width D2 (> D1) when the deviation amount switching signal is at a high level. As shown in FIG. 14, this signal is a signal whose center frequency is fc and whose power spectrum appears at frequency f2- and frequency f2 +. The absolute value of the difference between the center frequency fc and the frequency f2- and the absolute value of the difference between the center frequency fc and the frequency f2 + are equal to the shift amount D2.

  The transmission device 21 generates and outputs an FSK signal whose deviation width changes in synchronization with the change in the level of the deviation amount switching signal as described above.

  When receiving the FSK signal, the receiving device 31 of the unlocking unit 30 detects the deviation width (deviation amount) of the FSK signal. Specifically, the receiving device 31 first calculates a vector whose magnitude corresponds to the amplitude and whose angle corresponds to the phase based on the received FSK signal. FIG. 15 shows complex coordinates and vectors A1 to A4 calculated from the FSK signal. A set of vectors A1 and A2 are vectors obtained from an FSK signal having a deviation amount D1. A set of vectors A3 and A4 are vectors obtained from an FSK signal having a deviation amount D2. In the present embodiment, since the code signal is a rectangular wave, two vectors are calculated for each deviation amount.

The deviation width Swn of the FSK signal received by the receiving device 31 can be obtained by the following equation (2). Note that n is 1 or 2. Further, f1 ₁ is the angle of the vector A1, f1 ₂ is the angle of the vector A2. Then, f2 ₁ is the angle of the vector A3, f2 ₂ are the angles of the vector A4.

Swn = (fn ₁ −fn ₂ ) / 2 (2)

  Therefore, the receiving device 31 detects the shift width of the FSK signal based on the angles of the vectors A1 and A2 or the angles of the vectors A3 and A4. Then, a deviation width detection signal (deviation amount detection signal) indicating the detected deviation width is generated. As shown in FIG. 12, the value of the deviation width detection signal changes to a level corresponding to the deviation width of the FSK signal. Specifically, the value of the deviation width detection signal becomes a low level when the deviation width of the detected FSK signal is D1. Further, it becomes high level when the deviation width of the detected FSK signal is D2. The receiving device 31 outputs the generated deviation width detection signal to the vehicle control device 32 together with a code detection signal equivalent to the code signal.

  When the vehicle control device 32 receives the deviation width detection signal and the code detection signal output from the receiving device 31, the vehicle control device 32 sequentially detects the codes C1 to C4 from the code detection signal. At the same time, the deviation width of the FSK signal when the codes C1 to C2 are detected is obtained from the deviation width detection signal indicating the deviation width of the FSK signal.

  Next, the vehicle control device 32 compares the deviation width of the received FSK signal with the deviation amount D1. When the absolute value of the difference between the deviation width of the FSK signal and the deviation amount D1 is equal to or smaller than the threshold value, it is determined that the deviation width of the FSK signal is equal to the deviation amount D1. Further, when the absolute value of the difference between the deviation width of the FSK signal and the deviation amount D2 is equal to or smaller than the threshold value, it is determined that the deviation width of the FSK signal is equal to the deviation amount D2. The deviation width when the code C1 is detected is equal to the deviation amount D1, the deviation width when the code C2 is detected is equal to the deviation amount D2, and the deviation width when the code C3 is detected is the deviation width. When the shift width when the code C4 is detected is equal to the shift amount D1, and the shift amount D2 is equal to the shift amount D2, the received identification information consisting of the codes C1 to C4 is compared with the previously stored identification information.

  The vehicle control device 32 notifies the door lock device 34 of a door unlocking command when the received identification information including the codes C1 to C4 matches the previously stored identification information.

  Next, the unlocking operation of the security system 10 will be described with reference to the flowchart shown in FIG. In this flowchart, processes other than the process in step S403 following step S302 are the same as the processes in the flowchart in FIG.

  For example, when the door of the vehicle 92 is locked, the vehicle control device 32 transmits an identification information transmission command (step S301). The identification information transmission command is transmitted by outputting an output signal CM indicating the command.

  On the other hand, the portable control device 22 initializes the counter value n (step S201). As a result, the counter value n is initialized to 0. When receiving the identification information transmission command (step S202: Yes), the portable control device 22 increments the counter value n (step S203). Then, the code Cn is transmitted (step S204). Here, the code C1 is transmitted.

  When receiving the code Cn (step S302: Yes), the vehicle control device 32 determines whether or not the deviation width of the FSK signal indicating the code Cn matches the deviation amount stored in advance (step S403). . As can be seen with reference to FIG. 13, the code C1 is received as an FSK signal with a deviation width of D1. Therefore, the vehicle control device 32 detects the deviation width of the received FSK signal. Then, the detected deviation width is compared with a deviation amount D1 stored in advance. When the absolute value of the difference between the deviation width and the deviation amount D1 is equal to or smaller than the threshold value, the vehicle control device 32 determines that the deviation width and the deviation amount D1 match (step S403: Yes). The reception of the code Cn is notified via the transmission device 33 (step S304). This notification of reception is performed by the transmission device 33 outputting the output signal ANS.

  When the portable control device 22 receives the output signal ANS output from the transmission device 33 (step S205: Yes), the portable control device 22 returns to step S202, and thereafter repeatedly executes the processing of steps S202 to S205. As a result, codes C2, C3, and C4 are sequentially output. On the other hand, when the portable control device cannot receive the output signal ANS (step S205: No), the portable control device returns to step S201 and repeatedly executes the processes of steps S201 to S205.

  Further, when the vehicle control device 32 cannot receive the code Cn within a predetermined time after transmitting the identification information transmission command (step S302: No), or the difference between the deviation width and the deviation amount D1. Is larger than the threshold value, and it is determined that the deviation width and the deviation amount D1 do not match (step S403: No), the process returns to step S301, and the processes of steps S301, S302, and S403 are repeatedly executed. As a result, an identification information transmission command is periodically transmitted from the unlocking unit 30.

  If all the codes C1 to C4 constituting the identification information have not been received (step S305: No), the vehicle control device 32 returns to step S302, and thereafter repeatedly executes the processes of steps S302 to S305 and S403. To do. Thereby, the codes C2, C3, and C4 are sequentially output from the portable control device 22 and received. Each time the code Cn is received, the deviation width detected from the FSK signal indicating the code Cn is compared with the deviation amount stored in advance.

  On the other hand, when all the codes C1 to C4 constituting the identification information are received (step S305: Yes), the vehicle control device 32 collates the identification information consisting of the codes C1 to C4 with the identification information stored in advance. (Step S306). Then, when the received identification information including the codes C1 to C4 matches the previously stored identification information (step S306: Yes), the vehicle control device 32 instructs the door lock device 34 to unlock the door. Is notified (step S307). As a result, the door of the vehicle 92 is unlocked by the door lock device 34.

  Further, when the received identification information consisting of the codes C1 to C4 does not match the previously stored identification information (step S306: No), the vehicle control device 32 returns to step S301 and performs the processing after step S301. Repeatedly.

  As described above, in this embodiment, every time the identification information necessary for unlocking the vehicle door is received, the deviation width of the FSK signal indicating the identification information is set to the preset deviation amount. Is determined (step S403). Only when this determination is affirmative, an unlock command is output to the door lock device 34, and the door of the vehicle 92 is unlocked.

  For this reason, even if a repeater that relays the FSK signal is used due to criminal activity, if the deviation width of the FSK signal output from the repeater is different from the preset deviation amount, the door It will not be unlocked accidentally. Thereby, the unlocking of the door due to fraud can be accurately prevented, and criminal acts can be prevented in advance.

  The deviation width can be detected using an existing receiving apparatus. For this reason, an increase in the manufacturing cost of the system can be suppressed.

  As mentioned above, although embodiment of this invention was described, this invention is not limited by the said embodiment. For example, in the above-described embodiment, the case where the identification information is composed of four codes C1 to C4 has been described. However, the identification information is not limited to this, and may include five or more codes. Further, the identification information may be composed of two or three codes.

  In the above embodiment, the case where the identification information is composed of a plurality of codes has been described. Not limited to this, the identification code may be a single code. Even in this case, even if the code is illegally read, if the deviation width of the FSK signal is not the original deviation width or if the center frequency is not the original frequency, the door is unlocked by mistake. It will not be done. Thereby, it becomes possible to prevent a criminal act beforehand.

  In the above embodiment, one code is transmitted as an FSK signal having the same deviation width or center frequency. Not limited to this, for example, as shown in FIG. 17, when the code is divided into partial codes indicating training, ID, identification information, etc., the deviation width of the FSK signal for each partial code, Alternatively, the code may be transmitted by changing the center frequency.

  In the above embodiment, the deviation width of the FSK signal is changed so that the deviation width of the FSK signal becomes two deviation amounts D1 and D2. Not limited to this, the deviation width of the FSK signal may be changed so that the deviation width of the FSK signal becomes three or more deviation amounts.

  In the above embodiment, the center frequency of the FSK signal is changed so that the center frequency of the FSK signal becomes two center frequencies fc1 and fc2. However, the center frequency of the FSK signal may be changed so that the center frequency of the FSK signal becomes three or more center frequencies.

  As the mobile communication terminal 20 according to the above-described embodiment, a smart key, a smart phone, a communication device that can use wi-fi, and the like are conceivable.

  The functions of the remote control device according to the above embodiment can be realized by dedicated hardware or by a normal computer system.

  In the above embodiment, the programs stored in the auxiliary storage unit of the mobile communication terminal 20 and the unlocking unit 30 are a flexible disk, a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disk), an MO (Magneto). A device that executes the above-described processing may be configured by storing and distributing in a computer-readable recording medium such as -Optical disk) and installing the program in the computer.

  Further, the program may be executed entirely or partially on the server device, and the above-described processing may be executed while transmitting / receiving information regarding the processing via the communication network.

  Various embodiments and modifications can be made to the present invention without departing from the broad spirit and scope of the present invention. Further, the above-described embodiment is for explaining the present invention, and does not limit the scope of the present invention.

  The communication device, the security system, the unlocking method, and the program according to the present invention are suitable for preventing the door from being unlocked due to fraud.

DESCRIPTION OF SYMBOLS 10 Security system 20 Portable communication terminal 21 Transmission apparatus 22 Portable control apparatus 22a CPU
22b Main storage unit 22c Auxiliary storage unit 22d Interface 22e System bus 23 Receiver 30 Unlocking unit 31 Receiver 32 Vehicle controller 32a CPU
32b Main storage unit 32c Auxiliary storage unit 32d Interface 32e System bus 33 Transmitter 34 Door lock device 91 Driver 92 Vehicle C Circle

Claims (6)

A communication device for transmitting a code for unlocking a door to an unlocking unit for unlocking the door,
Storage means for storing in advance the center frequency of the output signal transmitted to the release unit, stored in the release unit;
Output signal generating means for frequency-modulating a carrier wave based on the code to generate the output signal having a center frequency equal to the center frequency stored in the storage means;
Transmitting means for transmitting the output signal;
A communication device comprising: A communication device for transmitting a code for unlocking a door to an unlocking unit for unlocking the door,
Storage means for storing in advance a first center frequency of the output signal transmitted to the release unit and a second center frequency different from the first center frequency, stored in the release unit;
Frequency-modulating a carrier wave based on a first code to generate a first output signal having a center frequency equal to the first center frequency, and frequency-modulating the carrier wave based on a second code different from the first code Output signal generating means for generating a second output signal having a center frequency equal to the second center frequency;
Transmitting means for transmitting the first output signal and the second output signal;
A communication device comprising: A security system for receiving a code for unlocking a door and unlocking the door,
A communication device according to claim 1;
Storage means for storing a center frequency of an output signal transmitted from the communication device;
Receiving means for receiving the output signal transmitted from the communication device;
Center frequency detecting means for detecting a center frequency of the output signal;
Code detecting means for demodulating the output signal and detecting the code;
Frequency collating means for collating the center frequency of the output signal detected by the center frequency detecting means with the center frequency stored in the storage means;
Code collating means for collating the code detected by the code detecting means with the code stored in the storage means;
When the collation result of the center frequency collating means and the code collating means is affirmative, the unlocking means for unlocking the door;
Security system with A security system for receiving a code for unlocking a door and unlocking the door,
A communication device according to claim 2;
Storage means for storing the first center frequency and the second center frequency of the output signal transmitted from the communication device;
Receiving means for receiving the first output signal and the second output signal transmitted from the communication device;
Center frequency detecting means for detecting a center frequency of the first output signal and the second output signal;
Code detecting means for demodulating the first output signal to detect the first code and demodulating the second output signal to detect the second code;
The second output signal detected by the center frequency detecting means by comparing the center frequency of the first output signal detected by the center frequency detecting means with the first center frequency stored in the storage means. Center frequency matching means for matching the second center frequency stored in the storage means with the center frequency of
The first code detected by the code detection means is collated with the first code stored in the storage means, and the second code detected by the code detection means is stored in the storage means. Code verification means for verifying the second code;
When the collation result of the center frequency collating means and the code collating means is affirmative, the unlocking means for unlocking the door;
Security system with An unlocking method for receiving a code for unlocking a door and unlocking the door,
Pre-store the center frequency of the output signal generated by frequency modulating the carrier wave based on the code;
Receiving the output signal;
Detecting a center frequency of the output signal;
Demodulating the output signal to detect the code;
Collating the detected center frequency of the output signal with the center frequency stored in advance;
Collating the detected code with the previously stored code;
When the verification result of the center frequency and the verification result of the code are positive, unlocking the door;
Unlocking method. On the computer,
Storing a center frequency of an output signal generated by frequency modulating a carrier wave based on a code for unlocking the door;
Detecting a center frequency of the output signal;
Detecting the code by demodulating the output signal;
A procedure for collating the detected center frequency of the output signal with the center frequency stored in advance;
A procedure for collating the detected code with the pre-stored code;
A step of unlocking the door when the result of collating the center frequency and the result of collating the code are positive;
A program for running

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