JP2010283582A - In-vehicle device remote control system and in-vehicle device remote control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-vehicle device remote control system capable of increasing the number of multiplexing, by improving the reply interval accuracy of the response signal of a portable device. <P>SOLUTION: The portable device includes: an amplitude limiting circuit 57a for limiting the amplitude of a received ASK signal, when an ASK modulated interrogation signal transmitted from the in-vehicle device is larger than a predetermined value; an automatic gain control amplifier 57b for amplifying a received signal to fixed amplitude; a detection circuit 57c for performing an envelope detection; and a waveform-shaping circuit 47d for outputting the detection signal of the detection circuit as a pulse signal corresponding to the interrogation signal and is provided with a delay multiplex communication system which starts to transmit a signal subjected to spread spectrum modulation of a direct spread system, after a predetermined delay interval different in each portable device with the specific pulse of the pulse signal as a reference time, and is a means for correcting the delay time, when an amplitude-limiting circuit 57a detects that amplitude is limited. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an in-vehicle device remote control system and an in-vehicle device remote control method for performing code verification by communication with a portable device and controlling vehicle use permission or non-permission based on the verification result.

Conventionally, in addition to a remote control function for locking / unlocking the door of a vehicle by operating an operation unit of a portable device, a return code signal is sent in response to a transmission request signal from the vehicle without operating the operation unit. There is a smart entry system that locks / unlocks a door by returning it and checking the code.
For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 5-106376) states: “When a call signal is received by a first receiving unit, a portable radio apparatus including a first transmitting unit that transmits a response signal; Second
When the response signal transmitted by receiving the call signal transmitted from the transmission means at a predetermined time interval is received by the second reception means, a signal for unlocking the vehicle door is output and the response A keyless entry system (that is, a smart entry system) comprising a vehicle radio apparatus having a control means for outputting a signal for locking a door of a vehicle after a predetermined time has elapsed if no signal is received. Has been.

Further, conventionally, a return code signal is returned in response to a transmission request signal from the vehicle side, and the code is collated to unlock the steering lock mechanism and release the engine start prohibition device, and no mechanical key is used. There is a smart start system that enables engine start operation.
For example, in Patent Document 2 (Japanese Patent Laid-Open No. 63-1765), “When a call signal is transmitted to a portable wireless device, a code code signal is received from the portable wireless device, and collated with an internal code, they match. In addition, an ignition device (that is, a smart start system) configured by means for permitting the unlocking operation of the steering lock mechanism, the switching operation of the engine switch, and the switching operation of the accessory switch is described.
A system combining both the smart entry system and the smart start system is referred to as a smart entry / start system.

In the smart entry / start system, as described above, responsiveness to human operations such as door locking / unlocking and key cylinder unlocking is an important performance.
In order to shorten the response time, it is a problem to shorten the communication time for code authentication.
For example, in Patent Document 3 (Japanese Patent Laid-Open No. 9-144411), “a search signal for searching for a portable transmitter is transmitted from a receiver provided in a vehicle, while a transmitter transmits the search signal. When the ID code signal set for each transmitter in response to reception is transmitted, and then the ID code signal received by the receiver provided in the vehicle matches that set for the vehicle, In the keyless entry device for unlocking the vehicle door, the transmitter has a transmission means for transmitting the ID code signal with a preset delay time after receiving the search signal transmitted from the vehicle. " It is described.
As described above, in the conventional keyless entry device disclosed in Patent Document 3, communication between a receiver provided in a vehicle and a plurality of portable transmitters is performed in a time slot manner, so that a transmitter (that is, If the number of portable devices) increases, the communication time increases.

On the other hand, Patent Document 4 (Japanese Patent Publication No. 2003-500957) discloses "a method for controlling remote access using a device equipped with a transmission / reception unit, which simultaneously activates all access code generators. All access code code generators that send and receive polling signals, then send their unique access code signals at substantially the same time, and the transmitting and receiving units are received simultaneously. A method of remote access control characterized in that a code signal separation is modulated onto the access code signal and further disclosed herein: "Communication between a vehicle unit and an access code generator to respond to" In the course, one common polling signal for the access code code generator And the access code generator answers in parallel in time, and the transmission signal is modulated by a feature that allows parallel processing in the vehicle unit. " Has been.
In other words, Patent Document 4 proposes a spread spectrum communication system capable of multiple access with a constant communication time regardless of the number of transmitters (portable devices).

However, in this proposed communication method, the type of PN (PSEUDO-NOISE code: pseudorandom code) corresponding to the number of portable devices (= number of production vehicles × number of portable devices per vehicle) is required.
Therefore, the code length is 225 bits (chip) in order to prepare about 100,000 kinds of balanced GOLD codes with sufficiently long PN code length, for example, low cross-correlation and balanced occurrence frequency of 1 and -1.
become.
Further, since the first receiving means on the vehicle side requires as many correlators as the number of portable devices, the circuit scale is large and the manufacturing cost is high.
On the other hand, as a method of shortening the PN code length and reducing the number of correlators, a method of using an independent PN code by adding a phase difference of one chip or more with the same PN code is well known, For example, there is a method of multiplexing as proposed in Patent Document 5 (Japanese Patent Laid-Open No. 6-244821).
However, as will be described later, in the smart entry / start system, the LF band radio wave (typically 125 kHz) is used for the communication between the first transmission unit of the in-vehicle device and the second reception unit of the portable device, and the second of the portable device. UHF radio waves (typically 315 MHz) are used for communication between the transmitting means and the first receiving means of the in-vehicle station.

In order to realize the phase difference of one chip or more as described above, it is necessary to manage the μs order. On the other hand, the reception time of the second receiving means that determines the transmission timing of the second transmitting means is the difference between the portable device and the transmission antenna. Depending on the distance from the LF band, it is impossible to manage the LF band frequency to be used below several waves (several tens of μs).
Therefore, it is difficult to reliably prevent a communication collision (communication interference) with another portable device, and the communication reliability is low with the proposal of Patent Document 5, and multiplexing using the phase difference cannot be performed. .
Increasing the PN code length to an extent that allows time management, for example, 200 μs or more, is not preferable in terms of the system because the communication speed decreases and the correlator scale increases.

Patent Document 6 (Japanese Patent Application Laid-Open No. 2008-92267) discloses a transmission unit of an in-vehicle device that transmits question signals for authentication and existence confirmation to a plurality of portable devices, and a portable device that receives the question signals. Receiving means, a transmitting means of a portable device that returns a response signal to the in-vehicle device upon receipt of the interrogation signal, a receiving means of the in-vehicle device that receives a response signal returned by the transmitting means of the portable device, and a return to the in-vehicle device When the response code of the response signal is collated, the in-vehicle device remote control system has an operation control means for controlling the operation state of the in-vehicle device, and the transmission means of the portable device converts the response signal into binary data The carrier signal is modulated using a digital signal obtained by modulation with a plurality of pseudo-random codes corresponding to the binary data, and a response signal is transmitted. The response signals received using a plurality of corresponding correlators are correlated, and the response signals are demodulated by the outputs of the plurality of correlators. Describes an “in-vehicle device remote control system” that transmits an interrogation signal to a portable device again when there is an output from the mobile phone.
The in-vehicle device remote control system described in Patent Document 6 describes that “the responsiveness can be improved by multiplex communication, the communication reliability is high, and it is suitable for preventing unauthorized use of the vehicle and preventing theft”. Has been.
However, in the in-vehicle device remote control system disclosed in Patent Document 6, the response interval accuracy of the response signal of each portable device is not so good, and it is difficult to increase the number of multiplexing.

JP-A-5-106376 JP-A 63-1765 JP-A-9-144411 Japanese translation of PCT publication No. 2003-500757 JP-A-6-244821 JP 2008-92267 A

As described above, in the conventional keyless entry device disclosed in Japanese Patent Application Laid-Open No. 9-144411, communication between a receiver provided on the vehicle and a plurality of portable transmitters is performed in a time slot manner. As the number of transmitters (portable devices) increases, the communication time increases.
In addition, in the conventional technique (remote access control method) disclosed in JP-T-2003-500957, a PN code type corresponding to the number of portable devices is required, and therefore the PN code length is sufficiently long. In addition, since the vehicle-side receiving means requires as many correlators as the number of portable devices, the circuit scale increases and the manufacturing cost increases.
In addition, in the “method of multiplexing using a spread spectrum communication system” disclosed in Japanese Patent Laid-Open No. 6-244821, it is difficult to reliably prevent communication collisions with other portable devices, and communication reliability Is low.
In addition, in the “in-vehicle device remote control system” disclosed in Japanese Patent Application Laid-Open No. 2008-92267, it is difficult to increase the number of multiplexing by greatly improving the response interval accuracy of the response signal of each portable device. It was.

  The present invention has been made to solve such problems, can improve the responsiveness by multiplex communication, has high communication reliability, is suitable for preventing unauthorized use of the vehicle and preventing theft, Furthermore, the purpose is to provide an “in-vehicle device remote control system” or “in-vehicle device remote control method” that can greatly improve the reply interval accuracy of the response signal of each portable device and can increase the number of multiplexing. To do.

An in-vehicle device remote control system according to the present invention includes an on-vehicle device transmitting means for transmitting an ASK (Amplitude Shift Keying) signal to a plurality of portable devices as authentication and presence / absence confirmation interrogation signals, and receiving the interrogation signal. Receiving means of the portable device, transmitting means of the portable device for returning a response signal subjected to spread spectrum modulation to the in-vehicle device when the receiving means of the portable device receives the interrogation signal, and transmitting means of the portable device Receiving means for receiving the response signal returned by the vehicle, and an operation control means for controlling the operating state of the on-vehicle device when code verification of the response code of the response signal returned to the on-vehicle apparatus is performed. The receiving unit of the portable device receives the interrogation signal transmitted as an ASK signal, and generates a pulse signal corresponding to the interrogation signal from the received ASK signal. A control system,
The receiving unit of the portable device includes: an amplitude limiting unit that limits the amplitude of the received ASK signal when the received ASK signal is greater than a predetermined value; and an automatic gain that amplifies the received signal that has passed through the amplitude limiting unit to a constant amplitude Control means, detection means for envelope detection of the reception signal amplified by the automatic gain control means, and waveform shaping means for outputting the detection signal output from the detection means as a pulse signal corresponding to the interrogation signal With
Transmission means of the portable device, delay multiplex communication means to start transmission after a predetermined delay time different in each portable device with a specific pulse of the pulse signal output from the waveform shaping means as a reference time;
An amplitude limit detecting unit that detects that the amplitude limiting unit limits the amplitude, and a delay time correcting unit that corrects the predetermined delay time when the amplitude limit detecting unit detects that the amplitude is limited. is there.

Further, the in-vehicle device remote control method according to the present invention includes an in-vehicle device transmission means for transmitting a question signal for authentication and existence confirmation to a plurality of portable devices by an ASK (Amplitude Shift Keying) signal, and the question signal. Receiving means of the portable device for receiving, transmitting means of the portable device for returning a response signal response signal subjected to spread spectrum modulation to the in-vehicle device when the receiving means of the portable device receives the interrogation signal, and the portable device An on-vehicle device receiving means for receiving the response signal sent back by the sending means, and an operation control for controlling the operating state of the on-vehicle equipment when code verification of the response code of the response signal sent back to the on-vehicle device is made An in-vehicle device that receives the interrogation signal transmitted as an ASK signal and generates a pulse signal corresponding to the interrogation signal from the received ASK signal Remote control method,
Regarding the reception of the portable device, an amplitude limiting step for limiting the amplitude of the received ASK signal when the received ASK signal is larger than a predetermined value, and an automatic gain for amplifying the received signal that has passed in the amplitude limiting step to a constant amplitude A control step; a detection step for detecting an envelope of the reception signal amplified in the automatic gain control step; and a waveform shaping step for outputting the detection signal output from the detection step as a pulse signal corresponding to the interrogation signal. A delay multiplex communication step of starting transmission after a predetermined delay time different in each portable device with a specific pulse of the pulse signal output in the waveform shaping step as a reference time, and the amplitude limiting step An amplitude limit detecting step for detecting that the amplitude is limited in the step, and the amplitude limit Those having a delay time correction step of correcting said predetermined delay time when it is detected that the amplitude limited in knowledge step.

According to the in-vehicle device remote control system or the in-vehicle device remote control method of the present invention, the transmission means of the portable device is different for each portable device using the specific pulse of the pulse signal corresponding to the interrogation signal transmitted by the ASK signal as a reference time. Delay multiplex communication means for starting transmission after a predetermined delay time, amplitude limit detecting means for detecting that the amplitude limiting means has limited the amplitude, and delay time correcting means for correcting the predetermined delay time when detecting that the amplitude is limited Since the response interval of the response signal (= predetermined delay time) of the portable device can be greatly improved, the number of multiplexing can be increased.
By increasing the number of multiplexes, the number of portable devices that can send back response signals almost simultaneously within 1 bit is increased, responsiveness can be improved, communication reliability is high, small size and low cost, and unauthorized use of vehicles It is possible to provide a vehicle-mounted device remote control system or a vehicle-mounted device remote control method suitable for prevention of the occurrence of damage and theft prevention.

It is a block diagram which shows the whole structure of the vehicle equipment in the vehicle equipment remote control system by Embodiment 1. FIG. It is the figure which showed typically the arrangement | positioning state of the in-vehicle transmission antenna of a vehicle equipment, and a transmission antenna outside a vehicle, and a communication state with a portable device. It is a block diagram which shows the whole structure of the portable device in the vehicle equipment remote control system by Embodiment 1. It is a figure which shows the example of a structure of the response signal and remote control signal corresponding to the question signal for authentication and existence confirmation, and each question signal. It is a block diagram which shows the internal structure of the receiving part of the portable device shown in FIG. It is a figure of the waveform and timing for demonstrating operation | movement of the portable receiver part at the time of normal time (at the time of amplitude limitation non-operation). It is a figure of the waveform and timing for demonstrating operation | movement of the portable receiver part at the time of an input excessive (at the time of an amplitude limitation operation | movement). It is a principal part enlarged view of the envelope detection waveform output from the envelope detector of the receiving part of a portable device. 4 is a flowchart for explaining an operation when the ECU of the in-vehicle device in Embodiment 1 executes communication with the portable device. 3 is a flowchart for illustrating an operation performed by the ECU of the portable device in the first embodiment. 10 is a detailed flowchart of step 205 shown in FIG. 9. 3 is a block diagram illustrating a detailed configuration of a transmission unit of the portable device according to Embodiment 1. FIG. It is a timing chart for demonstrating operation | movement until a some portable machine receives a response signal after receiving a question signal. 6 is a graph showing an example of an error density function of delay time for explaining the probability of occurrence of interference in delay multiplexing communication of a plurality of portable devices in the first embodiment. 6 is a graph showing an example of the probability of occurrence of interference in delay multiplexing communication of a plurality of portable devices in the first embodiment. The relationship of Formula (8) is made into a graph. It is the graph which deleted (alpha) by the relationship of Formula (8). 11 is a detailed flowchart of Example 1 and Example 2 of Step 115 shown in FIG. 10. FIG. 11 is a detailed flowchart of Example 3 in Step 115 shown in FIG. 10. FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the drawings, the same reference numerals indicate the same or equivalent ones.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing the overall configuration of an in-vehicle device in the in-vehicle device remote control system according to the present embodiment.
As shown in the figure, the in-vehicle device 10 includes, for example, a first in-vehicle transmitting antenna 11a and a second in-vehicle transmitting antenna 11b as the in-vehicle transmitting antenna 11, and a first out-of-vehicle transmitting antenna 12a to a fourth outside as the out-of-vehicle transmitting antenna 12. The transmission antenna 12d has six transmission antennas.
FIG. 2 is a diagram schematically illustrating an arrangement state of each in-vehicle transmission antenna and an external transmission antenna in the in-vehicle device and a communication state with the portable device. 2A shows the case where the portable device 50 is outside the vehicle, and FIG. 2B shows the case where the portable device 50 is inside the vehicle.
As shown in FIGS. 2A and 2B, the first vehicle exterior transmission antenna 12a to the fourth vehicle exterior transmission antenna 12d are provided, for example, at the handle of a door of a vehicle (four-wheeled vehicle).
On the other hand, the first in-vehicle transmission antenna 11a is installed in the center console portion of the vehicle interior, and the second in-vehicle transmission antenna 11b is installed near the rear seat.

Further, as shown in FIG. 1, the first in-vehicle transmission antenna 11 a and the second in-vehicle transmission antenna 11 b are connected to the transmission unit 17 of the in-vehicle device 10, and the transmission unit 17 is connected to an ECU (electronic control unit) 20. Yes.
The ECU 20 supplies the transmission unit 17 with a signal designating one of the transmission code and the in-vehicle transmission antenna (that is, one of the first in-vehicle transmission antenna 11a and the second in-vehicle transmission antenna 11b). An interrogation signal (signal for authentication of portable device and presence / absence confirmation) of a frequency where the code is modulated, for example, 125 kHz, is transmitted to the designated portable device 50.
The question signal transmitted from the in-vehicle device 10 to the portable device 50 is an ASK (Amplitude Shift
The response signal returned from the portable device 50 to the in-vehicle device 10 is a signal subjected to spread spectrum modulation.
As shown in FIG. 1, the vehicle is provided with a receiving antenna 18, and a signal (for example, a signal having a frequency of 315 MHz) received from the portable device 50 received by the receiving antenna 18 is demodulated by the receiving unit 19. And supplied to the ECU 20.

The ECU 20 has a built-in memory 24. The memory 24 stores an ID code for a question signal and an immobilizer, which will be described later, and an encryption key for decrypting the immobilizer and the answer code. The immobilizer is a device for preventing an unauthorized start of the engine and preventing the vehicle from being stolen.
For example, the memory 24 stores a plurality of different encryption keys corresponding to a door lock question code, a transponder ID code, and the like.
The memory 24 is a nonvolatile memory such as an EEPROM, and its stored contents are retained even when the power is turned off.
The operation detection unit 21 detects various switch operations by the user, for example, an activation switch (a switch for inputting a signal for starting transmission of a question signal) installed in each outer door handle, The key knob switch for starting communication for unlocking by pressing the engine switch and the position of the engine switch (starting, ignition on, accessory on, off and lock) are detected, and the operation detection signal is sent The ECU 20 is supplied.
The door opening / closing detection unit 22 detects individual opening / closing of all doors and individual locking / unlocking states of all doors, and supplies the detection signal to the ECU 20.
The sensor group 23 includes various sensors that detect the vehicle speed, the shift position, and the engine operating state, and detection signals from these various sensors are supplied to the ECU 20.

Further, the ECU 20 is connected with a steering lock unit 32, an immobilizer unit 34, a door lock unit 36, a shift lock unit 38, and a notification unit 25.
The steering lock unit 32 releases the rotation lock mechanism from the lock position of the engine switch and simultaneously releases the mechanical lock mechanism for steering operation.
When the engine switch is returned to the lock position, both lock mechanisms are locked.
The immobilizer unit 34 is a mechanism that prohibits fuel supply to the engine 40 and ignition operation.
The door lock unit 36 is a mechanism for locking / unlocking all doors.
The shift lock unit 38 is a lock device that prohibits the shift from the parking range to the other range by the transmission gear shift mechanism, and issues an unlock / permitted signal from the ECU 20.
The notification unit 25 is a so-called answerback when the door is locked / unlocked, an answerback device for lighting a vehicle or sounding a horn, an alarm device that emits a buzzer for various alarms, and a status display Includes display device.
The ECU 20 is connected to an engine control unit 30, and the engine control unit 30 can control the start of the engine 40 using a cell motor and can also control the driving stop of the engine 40.

FIG. 3 is a block diagram showing the overall configuration of the portable device in the in-vehicle device remote control system according to the present embodiment.
The ECU 52 has a built-in memory 53, which stores the same ID code and encryption key that are stored in the memory 24 of the in-vehicle device if it is authorized.
As shown in the figure, the portable device 50 has a transmission antenna 56 and a reception antenna 58.
The transmission antenna 56 is connected to the transmission unit 55, the transmission unit 55 is connected to the ECU 52, the reception antenna 58 is connected to the reception unit 57, and the reception unit 57 is connected to the ECU 52.
An interrogation signal (for example, an interrogation signal having a frequency of 125 kHz) received from the in-vehicle device 10 received by the reception antenna 58 is demodulated by the reception unit 57 and supplied to the ECU 52.
Further, the ECU 52 reads an encryption key corresponding to the question signal from the memory 53, encrypts the question code in the question signal, creates a response signal, and supplies the created response signal to the transmission unit 55.
The response signal supplied to the transmission unit 55 is modulated by the transmission unit 55 and transmitted from the transmission antenna 56 to the in-vehicle device 10 as a signal having a frequency of 315 MHz, for example.
Further, as a keyless entry function, there are a LOCK key / UNLOCK key signal for performing remote operation of locking / unlocking the door, and these signals are input from the operation detection unit 51 to the ECU 52. .

FIG. 4 is a diagram illustrating a configuration example of an authentication signal and an existence confirmation question signal transmitted and received between the in-vehicle device 10 and the portable device 50, a response signal corresponding to each question signal, and a remote control signal.
FIG. 4A shows the structure of a presence / absence confirmation question signal. The presence / absence confirmation question signal includes a preamble (for example, a burst signal of about 2 ms) and a fixed ID code (for example, 20) Bit), an additional code (for example, 4 bits) including identification information of the portable device to respond to, and error control information, for example, a CRC (Cyclic Redundancy Check) type code (for example, 10 bits).
FIG. 4B shows the configuration of the presence / absence confirmation response signal, and the presence / absence confirmation response signal includes an identification code (for example, 10 bits) of the portable device, a fixed ID code, and a CRC code.
FIG. 4C shows a configuration of the authentication question signal. The authentication question signal includes a preamble, a fixed ID code, an identification code including identification information of a portable device to respond, and a plaintext randomly generated each time ( For example, it is composed of a question code which is 32 bits) and a CRC code.
FIG. 4D shows the configuration of the authentication response signal. The authentication response signal is obtained by encrypting the identification code of the portable device, the fixed ID code, the bit indicating the answer signal, and the received question code with the encryption key. It consists of an answer code that is a ciphertext and a CRC code.
FIG. 4E shows the configuration of the authentication response signal. The authentication response signal includes an identification code including information identifying the portable device and information indicating that it is a remote control signal, a fixed ID code, and a remote operation. It consists of a code, a rolling code and a CRC code.

FIG. 5 is a block diagram showing a detailed configuration of the receiving antenna 58 and the receiving unit 57 (see FIG. 3) of the portable device 50 in the present embodiment, and FIGS. 6, 7, and 8 are waveforms of respective units in FIG. It is an example.
In FIG. 5, a receiving antenna 58 is a coiled loop antenna, which generates a voltage proportional to the signal magnetic flux passing through the coil cross section, and is represented by an inductance L in terms of an electric circuit.
This voltage is multiplied by Q (Q = 2πfL / R, Q) in the LC resonance circuit of the capacitor C and the resistor R of the receiving unit 57.
f: signal frequency) and the reception voltage 571 is obtained.
As described above, the LF (low frequency) used has a magnetic field strength that is inversely proportional to the cube of the distance. For example, when the reception voltage is 5 mV at a distance of 1 m, the reception voltage is about 12 V at a distance of 0.075 m. At a distance of 0.05 m, the received voltage is 40V.
Therefore, when the portable device is operated with a 3V battery, in order to protect or guarantee the operation of the electronic circuit of the receiving unit 57, the voltage limiter 57a for limiting the received voltage 571 to the allowable maximum voltage or less (eg, 6V) is provided. I need it.

The reception voltage 571 is amplified to a voltage signal 572 having a constant amplitude by an amplifier 57b with automatic gain control (hereinafter referred to as AGC). Since the control output of the AGC corresponds to the received voltage (that is, corresponds to the received magnetic field strength), it is output to the ECU 52 as a received magnetic field strength signal (RSSI) 577.
The envelope detector 57c detects the voltage signal 572 to generate a detection signal 573. The detection signal 573 is a waveform shaping circuit (comparator with hysteresis) 57d, which is shaped into a pulse signal 574 corresponding to the transmission signal in FIG. 6 or FIG. Is done.

The activation detection circuit 57e detects the predetermined frequency after a predetermined frequency component has been demodulated for a predetermined time or more in a preamble portion of the received signal (shown in FIGS. 4A and 4C) for a predetermined time or longer. When the component falls below the predetermined value, the ECU 52 outputs the wake signal 575 to prepare for receiving the data portion of the subsequent received signal, and outputs the pulse signal 574 to the ECU 52 as the data 576. 57f is closed.
When the reception of the LF reception signal is completed, the ECU 52 outputs a reset signal 578 to return the activation circuit to the initial state (activation signal undetected state) for the next reception.

FIG. 6 is a waveform of each part when the reception voltage 571 is small and the voltage limiter 57 is not operating (normal time).
In FIG. 6, when the information bit is “0”, the “transmission signal” has a carrier wave amplitude 100% mark part (time width tm0x) and a carrier wave amplitude 0% space part (time width ts0x). In this case, a mark portion (time width tm1x) having a carrier amplitude of 100% and a space portion (time width ts1x) having a carrier amplitude of 0% are configured.
For example, tm0x = ts0x, tm1x = ts1x, and tm1x + ts1x = 2 (tm0x + ts0x).
In the example of FIG. 6, the carrier wave amplitude on the transmission side changes in a step shape like the transmission signal for the sake of simplicity.
By the LC resonance circuit, “rise” and “fall” of the “572 waveform” on the receiving side become exponential.
The “573 waveform” after the envelope detection is shaped into a pulse signal “574 waveform” by the threshold value (Vtha, Vthb) of the waveform shaping circuit (comparator with voltage hysteresis) 57d.
The time widths of the mark portion and the space portion corresponding to the “transmission signal” are tm0r and ts0r when the information bit is “0”, and tm1r and ts1r when the information bit is “1”. With reference to the transmission signal, for example, “rise” of the mark portion of the information bit “1” is delayed by ta1, and the fall is delayed by tb1.
On the receiving side, the time from the “rising” to the “rising” (or “falling” to “falling”) of the pulse signal 578 is measured to determine whether the information bit “1” or the information is longer or shorter than the threshold. In order to determine whether the bit is “0”, this delay time (ta1, tb1) basically has no effect.

FIG. 7 is a waveform example of each part when the reception voltage 571 is large and the voltage limiter 57 is activated (when the input is excessive).
In FIG. 7, in the 574 waveform of the “portion corresponding to the information bit“ 1 ”” in which the mark portion of the 572 waveform is expanded, t′a1 <ta1, t′b1> tb1, and as a result, t′m1r> tm1r , T's1r <ts1r.

FIG. 8 is a diagram for explaining this change, and is an enlarged view of a main part of the 573 waveform.
In FIG. 8, the left is the “falling” portion and the right is the “rising” portion.
A thick line waveform is a waveform when the amplitude is not limited, and the maximum amplitude is controlled to a constant amplitude Vagc by the AGC.
A voltage V573 having a 573 waveform, where τ is a time constant, is ideally expressed by the following equation.
Falling part:
V573 = Vagc × exp (-t / τ) (1)
Where t is the time rising from P1 in FIG. 8:
V573 = Vagc {1-exp (-t / τ)} (2)
Where t is the time from R1 in FIG.
In the case of a large input signal that causes amplitude limitation, the amplitude limitation voltage Vlmt is controlled to Vagc by AGC, but it takes time corresponding to the delay time dtb before the reception voltage 571 becomes equal to or less than the amplitude limitation voltage.

The waveform of the thin line in FIG. 8 is a waveform larger than the amplitude limit voltage, and is a 573 waveform when the amplitude is not limited. In the range below the upper limit voltage Vagc, the voltage V573 of the 573 waveform is expressed by the following equation. .
Falling part:
V573 = Ves × exp (-t / τ) (3)
Where t is the time rising from P1 in FIG. 8:
V573 = Ves {1-exp (-t / τ)} (4)
Where t is the time from R1 in FIG.
From equation (3)
Vagc = Ves × exp (-dtd / τ) (5)
It becomes a relationship.
The time to the falling threshold Vthb is tb1 in normal time and t'b1 in amplitude limit. From Equation (1), Equation (3) and Equation (5),
dtb1 = t'b1-tb1 = τ × ln (α) (6)
Where α = Ves / Vagc

The time to the rising threshold Vtha is ta1 at all times, and t'a1 when the amplitude is limited. From Equation (2) and Equation (4),
dta1 = ta1-t'a1 = τ × ln {(1-β / α) / (1-β)} (7)
Where β = Vtha / Vagc
From the expressions (6) and (7), the change dtm1r of the mark portion length of the information bit “1” is
dtm1r = tm1r−t′m1r = dtb1 + dta1 = τ × ln {(α−β) / (1−β)} (8)
Since the threshold coefficient β is constant as a design value, it is basically a function of the input excess rate α (= Ves / Vagc).
In Expression (8), the change dtm1r of the time width is a value that can be measured. In the following description, the information bit “
Although only the mark portion length of “1” is described, the same applies to the space portion length of information bit “1”, the mark of information bit “0”, and the space portion.

Further, although the output waveform of the envelope detector is described as an exponential function, for example, the falling portion of the output waveform of the peak hold type envelope detector becomes linear depending on the conditions.
However, the fall delay time dtb1 when the amplitude is limited is caused by the point P (normal time) in FIG. 8 moving to the point Q (when the amplitude is limited), and the subsequent waveform depends on the shape. do not do.
In addition, the “rising part” of the output waveform of the peak hold type envelope detector has a stepped shape, but the change in the median value changes exponentially, so that the behavior is similar to that of the exponential function.
Therefore, even a peak hold type envelope detector can be expressed as a function of the input excess rate α as shown in equation (8), and therefore a function dta1 = f (dtm1r) described later exists.

By the way, FIG. 2 described above schematically shows the arrangement state of each in-vehicle transmission antenna and the in-vehicle transmission antenna and the communication state with the portable device 50 as described above. For example, there is a so-called challenge-response method (secret key encryption-based partner authentication method) as a method for confirming whether or not (party authentication method).
The challenge / response method (secret key encryption-based partner authentication method) will be described below.
In FIG. 2, from each transmission antenna (that is, the first in-vehicle transmitting antenna 11a, the second in-vehicle transmitting antenna 11b, the first in-vehicle transmitting antenna 12a to the fourth in-vehicle transmitting antenna 12d) of the vehicle-mounted device 10, a question with a frequency of 125 kHz. When the signal is transmitted and the portable device 50 receives this question signal, it returns a response signal having a frequency of 315 MHz modulated with a response code (cipher text) created from the encryption key and the question code (plain text) corresponding to the received question signal. To do.

A signal having a frequency of 315 MHz received by the receiving antenna 18 of the in-vehicle device 10 is demodulated by the receiving unit 19 and supplied to the ECU 20, and the ECU 20 receives the response signal.
The in-vehicle device 10 checks whether the portable device is a regular registration device by checking the transmitted question code (plain text) with the cipher text created with the corresponding encryption key and the received response code.
A transmission signal from each transmitting antenna (the first in-vehicle transmitting antenna 11a, the second in-vehicle transmitting antenna 11b, the first in-vehicle transmitting antenna 12a to the fourth in-vehicle transmitting antenna 12d) of the in-vehicle device 10 to the portable device 50 is a low frequency ( (Hereinafter abbreviated as LF).
The reason for using LF is to use a magnetic field component whose intensity is inversely proportional to the cube of the distance in the electromagnetic wave so that the position of the portable device 50 can be easily confirmed, and the normal communication distance is around 1 m. is there. On the other hand, the UHF band is used for communication from the portable device 50 to the receiving antenna 18 of the vehicle-mounted device, and the normal communication distance is a communication distance of 5 to 20 m.

The remote control signal for keyless entry for controlling the locking / unlocking of the vehicle door by pressing an operation button provided on the portable device 50 is, as shown in FIG. Instead, set a rolling code.
The rolling code is a value that is counted up each time the portable device transmits radio waves, and the in-vehicle device side stores the rolling code included in the predetermined code received from the portable device last time and received this time. When the rolling code included in the predetermined code is within a predetermined range from the value of the previous rolling code, it is determined that the current rolling code is correct, and the control corresponding to the control code for instructing locking / unlocking of the door is performed. .

FIG. 9 is a flowchart for explaining an operation when the ECU 20 of the in-vehicle device 10 according to the present embodiment communicates with the portable device 50.
FIG. 10 is a flowchart for explaining an operation executed by ECU 52 of portable device 50 in the present embodiment.
The detailed operation of the ECU 52 based on the flowchart of FIG. 10 will be described later.
In FIG. 9, step 200 is when each switch of the start SW (SW: switch), the key knob SW, and the ignition (IG) on position (hereinafter referred to as IG on) of the engine switch is turned on after the ECU 20 is started. And a start program that is executed when the driver's seat door changes from the closed state to the open state.
In step 201, it is confirmed which of the execution conditions is satisfied.

If the activation SW is on (step 202), authentication is performed from the outside antenna corresponding to the activation switch that is on in step 203 (for example, the first outside transmission antenna 12a if the outer handle activation SW of the right front door is on). An interrogation signal is transmitted.
In step 204, a response signal response to this question signal is confirmed.
If there is no reply, the process ends at step 299. If there is a reply, a communication error check for reply is performed in step 205.
FIG. 11 is a detailed flowchart of step 205 (communication error processing) shown in FIG.
As shown in FIG. 11, if there is a communication error in step 301, a question signal is retransmitted from the same outside antenna in step 302, and the process returns to step 204 in the flowchart of FIG.
If there is no communication error in step 205 in the flowchart of FIG.
The content of the response signal to this question signal is collated in 06, and if the reply is incorrect, the process ends in step 299.

If the answer to the reply is correct, it is checked in step 207 whether or not the door is unlocked. If the door is locked, the door unlocking output is instructed in step 213, and the process ends in step 299.
If the door is unlocked, it is checked in steps 208 and 209 whether the engine switch is in the locked position and all the doors are closed (condition 1).
If the condition 1 is established, a question signal for presence / absence confirmation is transmitted from all the antennas in step 209, and if it is confirmed in step 210 that the portable device is not in the vehicle (no reply), the door is locked in step 211. And the process ends at step 299.
If condition 1 is not satisfied in steps 208 and 209, or if there is a reply in step 210, an alarm output is instructed in step 212 to notify that the lock operation cannot be performed, and the process ends in step 299.

If the key knob SW is on (step 220), at step 221, an authentication question signal is transmitted from all the vehicle interior antennas.
In step 222, a response signal response to this question signal is confirmed. If there is no reply, the process ends at step 299. If there is a reply, a reply communication error check is performed in step 223, and if there is a communication error, the question signal is retransmitted and the process returns to step 222.
If there is no communication error in step 223, the contents of the response signal to this question signal are checked in step 224. If the reply answer is incorrect, the process ends in step 299.
If the answer to the reply is correct, the engine switch / unlock output is instructed in step 225, and the process ends in step 299.

If IG is on (step 230), an authentication question signal is transmitted from all in-vehicle antennas at step 231.
In step 232, the response of the response signal to the question signal is confirmed. If there is no reply, the process ends at step 299.
If there is a reply, a reply communication error check is performed in step 233, and if there is a communication error, the question signal is retransmitted and the process returns to step 232.
If there is no communication error in step 233, the content of the response signal to this question signal is checked in step 234, and if the reply is incorrect, the process ends in step 299.
If the answer to the reply is correct, engine start permission is output at step 236 and the process ends at step 299.
If the door changes from open to closed (step 250), it is checked in step 251 whether the engine switch is in the Lock position, and if it is in the Lock position, the process ends in Step 299.
If it is not at the Lock position, the presence / absence confirmation question signal is transmitted from all the antennas in Step 252. In step 253, a response signal response to the question signal is confirmed.
If there is a reply, the process ends at step 299. If there is no reply, an alarm output for notifying that the portable device has been taken out is instructed, and the process ends in step 299.

The communication error process of the above-mentioned step 205, step 223, and step 233 is a common process, and as described above, FIG. 11 is its detailed flow.
In FIG. 11, if there is a communication error in step 301, a question signal is retransmitted from the same outside antenna in step 302.
The communication error detection in step 301 is a method of detecting by checking with an error detection code (CRC code) included in the response information.

Next, the operation of the portable device 50 will be described based on the flowchart of FIG.
When the ECU 52 of the portable device 50 starts from the reset state due to battery replacement or the like, the process starts from START (step 100), the ECU 52 is initially set in step 101, and the process waits in step 102.
If there is a LOCK key input in step 103, WAKEUP (step 104) is performed and a LOCK signal which is a remote operation signal is transmitted (step 105). After the transmission is completed, the process returns to step 102.
If there is no LOCK key input in step 103, the process goes to step 106.
If there is an UNLOCK key input in step 106, WAKEUP (step 107) is performed and an UNLOCK signal which is a remote operation signal is transmitted (step 108). After the transmission is completed, the process returns to step 102.
If there is no UNLOCK key input in step 106, the process goes to step 109.

If there is signal reception (LF reception) from the vehicle-mounted device 10 in step 109, WAKE UP (step 110), reception processing in step 111, measurement of reception time Tr, and time width of mark portion or space After the reception is completed, the process goes to step 112, where it is confirmed whether the received signal is a presence / absence question signal.
If it is not a presence / absence question signal, in step 113, a response code is generated from the received question code, the authentication response signal is set in the transmission data, and the process goes to step 115.
If the presence / absence question signal is received in step 112, the presence / absence response signal is set in the transmission data in step 114, and the process goes to step 115.
If it is not necessary to reply from the received content in step 112 (for example, if it is a reply request to another designated portable device designated by the additional code), the process returns to step 102.
In step 115, a transmission time obtained by adding a predetermined time to the reception time is determined. In step 116, the transmission time is awaited. When the transmission time is reached, in step 117, the content of the transmission data is transmitted and transmitted. After completion, the process returns to step 102.

FIG. 12 is a block diagram showing a detailed configuration of the transmission unit 55 (see FIG. 3) of the portable device 50 in the present embodiment.
In FIG. 12, a section in which the binary (0 and 1) transmission data 520 of the response signal and remote control signal generated by the ECU 52 is “0” is a PN code generator 55a in the transmitter 55 by the primary modulator 55c. The spread code (PN0) 550 generated in step S1 is selected, and in the interval where the binary transmission data is “1”, the spread signal (PN1) 551 generated in the PN code generator 55b is selected, and the direct spread spectrum signal is used. A certain primary modulation signal 552 is generated.
Based on the primary modulation signal 552, a secondary modulation signal 553 obtained by phase-shift keying (PSK) or frequency shift keying modulation (FSK) of the carrier wave by the modulation unit 55d is generated, amplified by the amplification unit 55e, and transmitted from the antenna 56 as a radio wave. Send.

FIG. 13 is a timing chart for explaining the operation from when a plurality of portable devices (No. 1 and No. 2) receive an interrogation signal (LF) from the vehicle-mounted device to when a response signal (RF) is transmitted. The timing when a plurality of portable devices (No. 1 and No. 2) transmit response signals with a phase difference ΔT12 in response to the interrogation signal from the vehicle-mounted device is shown.
In the waveform of the LF transmission signal in FIG. 13, the leading portion tpri indicates the preamble portion of FIG. 4A or 4C, and the rest period for the ECU 52 to prepare for reception after receiving the wake signal 575. (Period of carrier wave amplitude 0) After the elapse of tpos, the fixed data portion of FIG. 4 (a) or FIG. 4 (c) continues.
The first rising edges (information bit “1”) of the portable device No. 1 pulse signal 574 and the portable device No. 2 pulse signal 574 are delayed by dta1 from the LF transmission signal as described above.
The portable device No. 1 starts transmitting the response signal at the time when the reception of the inquiry signal = LF reception signal is completed and the response signal is ready (after time Td from the rise of the first pulse signal).
On the other hand, portable device No. 2 starts transmitting a response signal at a time after Td + ΔTd from the rise of the first pulse signal. Similarly, when there are three or more portable devices, transmission is started with a phase difference of ΔTd.
In the actual machine, since dta1 varies due to manufacturing variations of the receiving unit 57, the phase difference is not ΔTd but ΔT12.

When the LC resonance circuit voltage (voltage of 571) without the voltage limiter 57 is Es, the input excess rate α = Ves / Vagc = Es / Vlmt.
When the resonant frequency of the LC resonant circuit is 125 kHz and Q = 30, the time constant τ is τ = Q / πf = 76.4 μs, and the input excess rate α generated at the distance between the LF transmitting antennas 11 and 12 and the receiving antenna 58 is In the case of 1 or more, for example, when α = 2 (in the example of FIG. 16 to be described later, 75 μs of time change) and the threshold coefficient β of the waveform shaping circuit 57d is 0.75, the delay time change amount dta1 is expressed by the following equation ( 7) is 70 μs (the time is earlier).

FIG. 14 is a graph showing an example of an error density function of delay time for explaining the probability of occurrence of interference in delay multiplex communication of a plurality of portable devices (portable device No. 1, portable device No. 2). The spread spectrum signal is shown when the error density function of the phase difference is transmitted in a normal distribution (average value μ = 4, standard deviation s = 1). The phase difference error is caused by variations in the Q of the LC resonance circuit, the threshold Vtha, and the AGC.
FIG. 15 is a graph showing an example of interference occurrence probability in delay multiplex communication of a plurality of portable devices. When the PN code length is 128 chips and the phase difference is 42 chips, the standard deviation s of the phase difference variation is changed. This is an example in which the probability that the phase difference is within ± 0.5 chips = interference occurrence probability Pc is calculated.
In this case, when the interference occurrence probability Pc is desired to be 1/1000 or less, the standard deviation should be 42/4 = 10.5 chips or less. When the standard deviation of the actual machine is 10.5 chips or more, it is necessary to make the phase difference larger than 42, and the number of multiplexing decreases from 128/42 = 3.
When the transmission speed is 4.8 kbps and the PN code length is 128 chips, one chip is 1.63 μs, the required standard deviation is 1.63 × 10.5 = 17.1 μs, and the (average) phase difference is 1.63 × 42 = 68.4 μs.

FIG. 16 is a graph showing the relationship of the above formula (8). When τ = 76.4 μs and β = 0.75, dtm1r and dta1 are calculated by formula (8) and formula (7) and plotted. It is.
FIG. 17 is a graph showing the relationship between dtm1r and dta1 with α deleted based on FIG.
Since the ECU 52 can measure tm1r and know the change amount dtm1r, it can also know dta1 from the relationship shown in FIG.
Assuming that the input excess rate α of the portable device No. 2 is 1.5, the change time dta1 is 53 μs (faster) from FIG. 16, and when the portable device No. 1 has the input excess rate α <1 (change time is 0), ( (Average) Phase difference is 68.4
−53.0 = 15.4μs. When this value is converted to the horizontal axis in FIG. 15 (divided by the standard deviation), 15.4
Since /17.1=0.9, the interference occurrence probability increases from 1/1000 to 1.5 / 100 from FIG.
Therefore, in order to keep the probability of occurrence of interference low, it is necessary to compensate for a delay time change (dta1 or the like) caused by amplitude limitation.

An embodiment of this compensation will be described below.
Example 1.
FIG. 18 is a detailed flowchart example of the transmission time determination process of step 115 in the flowchart of FIG. 10 showing the operation of the portable device 50.
In FIG. 18, first, at step 403, the transmission time Tx when there is no excessive input is calculated by the following equation.
Tx = Reception time Tr + Fixed interval Td + Fixed delay time ΔTd × Numeric value n for each portable device
Here, n is an integer of 0, 1, 2,..., And is designated for each portable device. Next, in step 404, whether or not amplitude is limited is determined by the mark part time width tm1r of the information bit “1”.
And whether or not the difference dtm1r between the predetermined reference time width tm1rn and the predetermined reference time width is equal to or greater than a predetermined value.
In step 405, the correction amount ΔTx = dta1 is obtained from the relationship dta1 = f (dtm1r) in FIG. 17 described above, the transmission time Tx is corrected to the expression Tx = Tx + ΔTx, and this transmission time determination step 115 is completed.
When the difference dtm1r is less than the predetermined value in step 404, the transmission time determination step 115 is finished while the transmission time is obtained in step 403.

Example 2
In the flowchart of FIG. 18 according to the first embodiment, only the method for determining whether or not the amplitude is limited in Step 404 is different, and the others are the same.
That is, if the output RSSI of the magnetic field strength detection means received in step 404 in FIG. 18 is equal to or greater than a predetermined value, it is determined that there is an amplitude limit, and the process branches to step 405. End 115.

Example 3 FIG.
FIG. 19 is a detailed flowchart example of the transmission time determination process in step 115 of the flowchart of FIG. 18 showing the operation of the portable device 50. Steps 401 and 402 are added to FIG. 18 of the first embodiment. Steps 403 to 405 are the same as those in the first embodiment, and thus description thereof is omitted.
In FIG. 19, in step 401, if the received RSSI of the magnetic field strength detection means is less than a predetermined value, that is, there is no amplitude limitation, the process goes to step 402, and if the RSSI is greater than or equal to the predetermined value, the process goes to step 403.
In step 402, an averaging operation is performed with a weight coefficient k (here, 0 <k <1) between the mark partial time width tm1r of the information bit “1” measured in step 111 of FIG. 10 and the reference time width tm1rn so far. The obtained result is set as a new reference time width tm1rn, and the process goes to the next step 403.
If the transmission antennas (11, 12) have a time delay element such as a resonance circuit, and the time delay is different for each transmission antenna, the reference time width tm1rn for each transmission antenna.
Is preferably set.

As described above, the in-vehicle device remote control system according to the present embodiment transmits an in-vehicle device that transmits a question signal for authentication and existence confirmation to a plurality of portable devices 50 using an ASK (Amplitude Shift Keying) signal. Means (transmitting unit 17), receiving unit of the portable device that receives the interrogation signal, and when the receiving unit (receiving unit 57) of the portable unit receives the interrogation signal, a response signal subjected to spread spectrum modulation is returned to the in-vehicle device. The transmission means (transmission section 55) of the portable device, the reception means (reception section 19) of the in-vehicle device that receives the response signal returned by the transmission means (transmission portion 55) of the portable device, and the returned information to the in-vehicle device An operation control means (ECU 20) for controlling the operation state of the in-vehicle device when the response code of the response signal is collated is provided, and the reception means (reception unit 57) of the portable device transmits the quality transmitted by the ASK signal. An in-vehicle device remote control system for receiving a question signal and generating a pulse signal corresponding to the question signal from the received ASK signal,
The reception unit (reception unit 57) of the portable device receives an amplitude limiter (voltage limiter 57a) for limiting the amplitude of the received ASK signal when the received ASK signal is larger than a predetermined value, and a received signal that has passed through the amplitude limiter. Automatic gain control means (57b) for amplifying to a constant amplitude, detection means (envelope detector 57c) for detecting the received signal amplified by the automatic gain control means (voltage limiter 57a), and the detection A waveform shaping means (comparator 57d) for outputting a detection signal output from the means (envelope detector 57c) as a pulse signal corresponding to the interrogation signal;
The transmission unit of the portable device includes a delay multiplex communication unit (step 115) that starts transmission after a predetermined delay time different from each portable device with a specific pulse of the pulse signal output from the waveform shaping unit as a reference time, and the amplitude limiting unit performs amplitude limitation An amplitude limit detecting means (step 404) for detecting the occurrence of the failure and a delay time correcting means (step 405) for correcting the predetermined delay time when the amplitude limiting means detects that the amplitude is limited.

In the in-vehicle device remote control system according to the present embodiment, the response signal is a delay multiplex communication system in which the spectrum is directly spread with the same PN code, and a plurality of LF ASK-modulated interrogation signals are received from the in-vehicle device. When each portable device transmits a response signal with a phase delay of a PN code, it detects the amplitude limiting operation of the received LF signal and compensates for the received signal delay time due to the amplitude limiting operation, thereby reducing each phase delay. Since it can be performed more accurately, there is an advantage that the occurrence rate of communication errors due to interference between a plurality of portable devices can be reduced and a highly reliable communication device can be realized.
As the amplitude limit detection means for detecting that the amplitude is limited, it is configured by the software of the ECU or the RSSI function of the receiver is used. There is a cost reduction effect that it can be used as it is.
In addition, the accuracy of time from on-board device transmission to mobile device reception and transmission to on-vehicle device reception is improved, and the round-trip communication time management from question signal transmission to response signal reception on the on-vehicle device can be performed, so-called relay attack (for example, (See Japanese Patent No. 3909226).

  The present invention is suitable for preventing unauthorized use of the vehicle and preventing theft, and is useful for realizing an in-vehicle device remote control system capable of increasing the number of multiplexing.

DESCRIPTION OF SYMBOLS 10 In-vehicle device 11 In-vehicle transmission antenna 12 Out-of-vehicle transmission antenna 18 In-vehicle device receiving antenna 19 In-vehicle device receiving unit 20 In-vehicle device ECU
50 Portable machine 52 ECU of portable machine
DESCRIPTION OF SYMBOLS 56 Transmitting antenna of portable machine 57 Reception part of portable machine 57a Amplitude limiting means 57b Automatic gain control means 57c Detection means 57d Waveform shaping means 58 Reception antenna of portable machine 115 Step for explaining operation of delay multiplexing communication means 404 Amplitude limiting Step 405 for explaining the operation 4 of the detecting means 405 Step for explaining the operation of the delay time correcting means

Claims (6)

Transmitting means of an in-vehicle device that transmits question signals for authentication and existence confirmation to a plurality of portable devices by ASK (Amplitude Shift Keying) signals, receiving means of the portable device that receives the question signals, and the portable When the reception means of the machine receives the interrogation signal, the response means subjected to spread spectrum modulation is returned to the in-vehicle apparatus, and the in-vehicle apparatus receives the response signal returned by the transmission means of the portable apparatus. Receiving means of the machine, and an operation control means for controlling the operating state of the on-vehicle device when the code verification of the response code of the response signal returned to the on-vehicle machine is made, and the receiving means of the portable machine includes an ASK signal An in-vehicle device remote control system that receives the interrogation signal transmitted in a step and generates a pulse signal corresponding to the interrogation signal from the received ASK signal,
The receiving means of the portable device is:
Amplitude limiting means for limiting the amplitude of the received ASK signal when the received ASK signal is greater than a predetermined value;
Automatic gain control means for amplifying the received signal that has passed through the amplitude limiting means to a constant amplitude;
Detection means for detecting an envelope of the received signal amplified by the automatic gain control means;
A waveform shaping means for outputting a detection signal output from the detection means as a pulse signal corresponding to the interrogation signal;
The transmission means of the portable device is:
Delay multiplex communication means for starting transmission after a predetermined delay time different in each portable device with a specific pulse of the pulse signal output from the waveform shaping means as a reference time;
Amplitude limit detection means for detecting that the amplitude limit means is amplitude limited;
A vehicle-mounted device remote control system comprising delay time correcting means for correcting the predetermined delay time when the amplitude limit detecting means detects that the amplitude is limited.   2. The amplitude limit detection unit according to claim 1, wherein the amplitude limit detection unit detects the amplitude limit when a difference between a time width of a mark portion or a space portion of the pulse signal and a predetermined reference time is a predetermined value or more. In-vehicle equipment remote control system.   The in-vehicle device remote control system according to claim 1, wherein the correction delay time amount of the delay time correction means is a function of a time width change amount of a mark portion or a space portion of the pulse signal.   The receiving means of the portable device includes magnetic field strength detecting means for detecting the strength of the received magnetic field, and the delay time correcting means corrects the predetermined delay time when the output of the magnetic field strength detecting means is a predetermined value or more. The in-vehicle device remote control system according to claim 1.   The receiving means of the portable device includes magnetic field strength detecting means for detecting the strength of the received magnetic field, and the time width of the mark part or the space part of the pulse signal when the output of the magnetic field strength detecting means is a predetermined value or less is a reference time. When the difference between the stored reference time width and the time width of the mark portion or the space portion of the pulse signal is greater than or equal to a predetermined value, the delay time correcting means corrects the predetermined delay time. The in-vehicle device remote control system according to claim 1. Transmitting means of an in-vehicle device that transmits question signals for authentication and existence confirmation to a plurality of portable devices by ASK (Amplitude Shift Keying) signals, receiving means of the portable device that receives the question signals, and the portable When the reception unit of the machine receives the interrogation signal, the response signal response signal subjected to spread spectrum modulation is returned to the in-vehicle device, and the response signal returned by the transmission unit of the portable device is received. Receiving means of the in-vehicle device, and an operation control means for controlling the operating state of the in-vehicle device when code verification of the response code of the response signal returned to the in-vehicle device is performed, and the receiving means of the portable device includes: An in-vehicle device remote control method for receiving the interrogation signal transmitted by an ASK signal and generating a pulse signal corresponding to the interrogation signal from the received ASK signal,
Regarding the reception of the portable device, an amplitude limiting step for limiting the amplitude of the received ASK signal when the received ASK signal is larger than a predetermined value, and an automatic gain for amplifying the received signal that has passed in the amplitude limiting step to a constant amplitude A control step; a detection step for detecting an envelope of the reception signal amplified in the automatic gain control step; and a waveform shaping step for outputting the detection signal output from the detection step as a pulse signal corresponding to the interrogation signal. A delay multiplex communication step of starting transmission after a predetermined delay time different in each portable device with a specific pulse of the pulse signal output in the waveform shaping step as a reference time, and the amplitude limiting step An amplitude limit detecting step for detecting that the amplitude is limited in the step, and the amplitude limit Vehicle equipment remote control method being characterized in that a delay time correction step of correcting said predetermined delay time when it is detected that the amplitude limited in knowledge step.