JP2013219479A - On-vehicle receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a receiving device mounted in a vehicle to have its antenna characteristic adjusted easily.SOLUTION: When an operation directive signal instructing a vehicle to perform a designated operation is received, the antenna characteristic is adjusted on the basis of the operation directive signal. In this way, the antenna characteristic can be adjusted in a routine operation in which the receiving device receives the operation directive signal. Therefore, even when the antenna characteristic changes as when the seat position or inclination is changed, an appropriate antenna characteristic can always be maintained. Furthermore, since the adjustment is made while the user of the vehicle is unaware of it, the adjustment can be achieved easily without imposing any burden on the user.

Description

  The present invention relates to a receiving device mounted on a vehicle, and more particularly to a receiving device that receives a signal (operation instruction signal) instructing a predetermined operation for the vehicle via an antenna.

  As represented by the so-called keyless entry system, a receiving device is mounted on a vehicle, and a user of the vehicle operates a portable device to transmit a signal wirelessly to the receiving device, so that it can be remotely performed from a remote place. A technique has been developed that can execute a predetermined operation such as unlocking and locking a door or opening and closing a window (Patent Document 1). In addition, a technique for monitoring tire air pressure by mounting a tire pressure detector and a transmitter on a wheel and wirelessly transmitting the detected air pressure to a receiving device on the vehicle body side has been developed (Patent Document 2). ). Thus, in order to receive a signal transmitted wirelessly with high sensitivity, it is necessary to adjust the antenna characteristics of the receiving apparatus with high accuracy in advance.

JP 2010-228538 A JP 2010-230281 A

  However, there is a problem that it is actually not easy to accurately adjust the antenna characteristics of the receiving device mounted on the vehicle. This is due to the following reason. First, the antenna characteristics of the receiving device vary depending on the type of vehicle on which the receiving device is mounted. Therefore, even when the same receiving device is mounted, adjustment of antenna characteristics is required if the vehicle type is different. In addition, even in the case of a vehicle of the same vehicle type, the antenna characteristics change only when the user of the vehicle changes the position and inclination of the seat or places a large load. Therefore, it is necessary to adjust the antenna characteristics on a daily basis for each individual vehicle. As described above, the antenna characteristics of a receiving device mounted on a vehicle change on a daily basis due to various factors. Therefore, in order to maintain a state where the antenna characteristics are accurately adjusted, the antenna characteristics must be adjusted again according to such fluctuations. There was a problem that a lot of labor was required.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a technique capable of easily adjusting the antenna characteristics of a receiving device mounted on a vehicle.

  In order to solve the above-described problem, when the in-vehicle receiving apparatus of the present invention receives an operation instruction signal instructing a vehicle to perform a predetermined operation, it adjusts antenna characteristics based on the received operation instruction signal.

  In this way, it is possible to adjust the antenna characteristics during the daily operation in which the receiving apparatus receives the operation instruction signal. For this reason, even if the antenna characteristics fluctuate due to, for example, the position or inclination of the seat being changed or a large load is placed on the sheet, appropriate antenna characteristics can always be maintained in accordance with such fluctuations. In addition, since such adjustment is performed without the knowledge of the vehicle user, the antenna characteristics can be easily adjusted without imposing any burden on the user.

  Moreover, in the vehicle-mounted receiving apparatus of the present invention described above, the following may be performed. First, when an operation instruction signal is received, it is determined whether or not the operation instruction signal is a signal from a registered transmitter (a transmitter registered in advance in association with a vehicle). As a result, when it is determined that the operation instruction signal is a signal from the registered transmitter, the antenna characteristics may be adjusted based on the operation instruction signal.

  In this way, the operation characteristic signal for another vehicle is not received and the antenna characteristics are not adjusted. For this reason, adjustment is performed based on an operation instruction signal from a transmitter that is not a registered transmitter, and the antenna characteristics do not shift.

  In the in-vehicle receiving device of the present invention, it may be determined as follows whether or not the operation instruction signal is a signal from a registered transmitter. That is, identification information that is information for identifying the transmitter is registered in advance. When the operation instruction signal is received, the identification information included in the operation instruction signal is extracted, and it is determined whether or not the identification information is registered. As a result, when the identification information is registered, it is determined that the operation instruction signal is from the registered transmitter.

  In this way, it is possible to easily determine whether or not the operation instruction signal is a signal from the registered transmitter based on the identification information included in the operation instruction signal.

  Moreover, in the vehicle-mounted receiving apparatus of the present invention described above, the antenna characteristics may be adjusted based on the operation instruction signal from the registered transmitter as follows. That is, the operation instruction signal is continuously transmitted from the transmitter a plurality of times. If it is determined that the operation instruction signal is a signal from the registered transmitter, the antenna characteristics may be adjusted based on the operation instruction signal received after the operation instruction signal.

  In this way, it is possible to reliably prevent the antenna characteristic from being adjusted based on the operation instruction signal from the transmitter that is not registered.

  Further, on the assumption that the operation instruction signal is continuously transmitted from the transmitter a plurality of times, if the operation instruction signal is determined to be a signal from the registered transmitter, the antenna reception adjustment according to the present invention is started. The apparatus may be as follows. That is, even during the adjustment of the antenna characteristics, even if it is determined that the continuously transmitted operation instruction signal is a signal from the registered transmitter, without starting a new adjustment based on the continuously received operation instruction signal, The adjustment may be continued as it is.

  In this way, even if an operation instruction signal is subsequently received from the registered transmitter during the adjustment of the antenna characteristics, the adjustment in progress is not wasted, so that the adjustment can be made quickly.

  In the vehicle-mounted receiving device of the present invention described above, the signal strength of the operation instruction signal may be detected, and the antenna characteristics may be adjusted based on the detected signal strength.

  Since the signal strength can be detected easily and accurately, it can be appropriately adjusted by adjusting the antenna characteristics based on the signal strength of the operation instruction signal.

  Further, in the in-vehicle receiver of the present invention that adjusts the antenna characteristic based on the signal strength of the operation signal on the assumption that the operation instruction signal is continuously transmitted from the transmitter a plurality of times, the adjustment of the antenna characteristic If the signal strength of the operation instruction signal becomes equal to or lower than a predetermined value, the adjustment may be terminated.

  By doing so, there is no possibility of adjusting the antenna characteristics under the condition that the signal intensity is small and therefore the S / N ratio is small. Therefore, the antenna characteristics can be adjusted appropriately.

  In the above-described in-vehicle receiver of the present invention, when the signal strength of the operation instruction signal is equal to or higher than a predetermined adjustable strength, the control value for adjusting the antenna characteristics is increased so that the signal strength is increased. It is good also as adjusting antenna characteristics by changing.

  Even if you intend to change the control value in the direction to increase the signal strength, but change the direction to decrease the signal strength, control is performed when the signal strength of the operation instruction signal is greater than or equal to the preset adjustable strength. By changing the value, it is possible to avoid a situation in which the signal cannot be received. Therefore, since the signal strength can be increased by changing the control value in the opposite direction, the antenna characteristics can be adjusted appropriately.

  In the in-vehicle receiver of the present invention that adjusts the antenna characteristics by changing the control value, the antenna characteristics may be adjusted by increasing or decreasing the control value by a predetermined adjustment amount.

  By doing so, the adjustment amount of the control value is fixed, so that the control for adjusting the antenna characteristics can be made simple.

  In the in-vehicle receiver of the present invention that adjusts the antenna characteristics by increasing or decreasing the control value by a predetermined adjustment amount, the adjustment amount may be set to the following value. That is, it may be set in a range not less than the adjustment amount (minimum adjustment amount) corresponding to the detection resolution of the signal intensity of the operation instruction signal and not more than twice the minimum adjustment amount.

  In this way, the control value can be changed little by little, so that it does not exceed the optimal control value. For this reason, it is always possible to set an optimal control value, and as a result, it is possible to adjust to an optimal antenna characteristic.

  Further, in the in-vehicle receiving apparatus of the present invention that adjusts the antenna characteristics by changing the control value so that the signal strength increases, the antenna characteristics may be adjusted as follows. First, the signal intensity (first signal intensity) at the current control value is detected. Next, the control value is changed, and the signal strength (second signal strength) at the changed control value is detected. Thereafter, the original control value (control value when the first signal strength is detected) is restored, and the signal strength (third signal strength) is detected again. Then, by determining a correction amount of the signal strength based on the deviation between the first signal strength and the third signal strength, and comparing the second signal strength and the third signal strength while considering the correction amount, It is determined whether the signal strength is increasing.

  In this way, even when the signal strength increases (or decreases) with time, it is possible to appropriately determine whether or not the signal strength is increased without being affected by the influence. As a result, the antenna characteristics can be adjusted appropriately.

  In the vehicle-mounted receiving device of the present invention described above, the antenna characteristics may be adjusted using an operation instruction signal that instructs the start or end of the operation of the movable device mounted on the vehicle.

  Since the operation instruction signal instructing the start or end of the operation of the movable device mounted on the vehicle is transmitted relatively frequently, if the antenna characteristic is adjusted using this operation instruction signal, the antenna characteristic is always appropriately adjusted. It becomes possible to adjust.

  Moreover, in the vehicle-mounted receiving apparatus of the present invention described above, the following may be performed. First, signal transmission means for transmitting a state display signal representing information related to the state of the vehicle using a frequency different from that of the operation instruction signal is mounted on the vehicle. Then, the operation instruction signal or the state display signal may be selectively received by switching the frequency.

  This makes it possible to receive a status display signal using a receiving device for receiving an operation instruction signal.

  Further, in the in-vehicle receiver of the present invention that selectively receives the operation instruction signal or the state display signal by switching the frequency, the adjustment of the antenna characteristic for receiving the state display signal is performed based on the operation instruction signal. You may make it perform.

  It is considered that the variation in antenna characteristics due to the seat position, the loaded luggage, etc. occurs in the same manner regardless of whether the received signal is an operation instruction signal or a status display signal. Therefore, if the antenna characteristic for the state display signal is also adjusted based on the adjustment result of the antenna characteristic for the operation instruction signal, it is not necessary to separately adjust the antenna characteristic for the state display signal.

It is explanatory drawing which shows the structure of the vehicle carrying the receiver of a present Example. It is explanatory drawing which shows the structure of the receiver of a present Example. It is explanatory drawing which shows a mode that the receiver of a present Example switches a receiving frequency. It is a time chart which shows a mode that the receiver of a present Example adjusts an antenna characteristic. It is a flowchart of the first half part of the antenna characteristic adjustment process which the receiver of a present Example performs. It is a flowchart of the intermediate part of the antenna characteristic adjustment process which the receiver of a present Example performs. It is a flowchart of the latter half part of the antenna characteristic adjustment process which the receiver of a present Example performs. It is a time chart which shows the content of reception sensitivity adjustment processing.

Hereinafter, examples will be described in order to clarify the contents of the present invention described above.
A. Configuration of this embodiment:
As illustrated in FIG. 1A, the receiving device 100 according to the present embodiment is mounted on the vehicle 1 together with the in-vehicle device control unit 10 and various actuators (movable devices). The in-vehicle device control unit 10 is configured by an electronic control unit (ECU) equipped with a CPU, ROM, RAM, and the like, and is connected to various actuators. For example, the door lock actuator 11 for unlocking or locking the door, the window actuator 12 for opening and closing the power window, the trunk lock actuator 13 for unlocking or locking the trunk 3, and the air conditioner are operated. The air conditioner actuator 14 and an alarm horn 15 that emits an alarm sound are connected. Further, an ignition switch 16 is connected to the in-vehicle device control unit 10 and an ignition signal indicating that the engine is operating is input. Furthermore, the four wheels of the vehicle 1 are also equipped with an air pressure sensor 17 that detects the tire air pressure and transmits the result wirelessly.

  The receiving device 100 receives a signal transmitted wirelessly from a portable device 20 described later, and outputs the content to the in-vehicle device control unit 10. In addition, an ignition signal is input from the ignition switch 16 to the receiving device 100. When the ignition signal is received, a signal from the air pressure sensor 17 is received and the air pressure of each tire is monitored. The portable device 20 of this embodiment corresponds to a “transmitter” in the present invention, and a signal transmitted from the portable device 20 corresponds to an “operation instruction signal” in the present invention. Further, the air pressure sensor 17 of this embodiment corresponds to a “signal transmission unit” in the present invention, and a signal transmitted from the air pressure sensor 17 corresponds to a “status display signal” in the present invention.

  FIG. 1B shows the configuration of the portable device 20 operated by the user of the vehicle 1. The portable device 20 includes a control unit 21 configured by a CPU and a RAM, a storage unit 23 configured by an EEPROM, a transmission unit 22 including an antenna, a switch unit 24, and the like. When the user of the vehicle 1 points the portable device 20 toward the vehicle 1 and operates the switch SW1 or the switch SW2 of the switch unit 24, a signal corresponding to the content is transmitted from the transmission unit 22 and received by the reception device 100. .

  FIG. 2 shows the internal structure of the receiving device 100. The receiving apparatus 100 includes a control unit 101 described later, an adjustment circuit 102 that adjusts the impedance (antenna characteristics) of the antenna under the control of the control unit 101, and a bandpass filter 103 that receives a signal from the adjustment circuit 102. An amplifier 104 that amplifies the filtered signal, a mixer 105 that mixes the amplified signal with the local oscillator output from the PLL circuit 108, a bandpass filter 106 that receives the intermediate frequency output of the mixer 105, An amplifier 107 that amplifies the filtered signal, a demodulator 110 that demodulates the amplified signal, a comparator 111 that binarizes the demodulated signal and outputs the digital signal to the control unit 101 are mounted. . Here, the PLL circuit 108 is a known oscillation circuit capable of generating an oscillating voltage waveform having a designated frequency. The signal before demodulation is also input to the received signal strength detector 109. The received signal strength detector 109 detects the received signal strength (hereinafter, RSSI) under the control of the control unit 101, and at the voltage level. Output.

  The control unit 101 includes a microcomputer including a CPU, ROM, RAM, a DA converter 101da that converts a digital signal into an analog signal, an AD converter 101ad that converts an analog signal into a digital signal, and a flash memory. The memory | storage part 101m comprised by these is provided. The control unit 101 adjusts the antenna characteristics by outputting an adjustment output from the DA converter 101 da toward the adjustment circuit 102. Further, when the control unit 101 receives the ignition signal from the ignition switch 16, the control unit 101 switches the impedance of the antenna according to the received frequency by operating the changeover switch 102 s built in the adjustment circuit 102, and the PLL circuit 108. Change the oscillation frequency. Further, the RSSI detected by the received signal strength detector 109 is received and converted into a digital signal by the AD converter 101ad, or the digital signal from the comparator 111 is received, and the result is output to the in-vehicle apparatus control unit 10. Or The control unit 101 of the present embodiment corresponds to “signal detection means”, “antenna characteristic adjustment means”, and “signal reception means” in the present invention.

  FIG. 3 shows an outline of a reception operation by the reception apparatus 100. While the ignition signal from the ignition switch 16 is OFF, the receiving apparatus 100 is in a state in which reception is possible intermittently at a predetermined interval for a certain period. Further, the reception frequency at this time is set to a frequency FRQ1 used for unlocking or locking the door or the trunk 3. The reason why the signal is intermittently received while the ignition signal is OFF is that the engine is not running while the ignition signal is OFF, so that consumption of a battery (not shown) mounted on the vehicle 1 is suppressed. It is to do. If a signal from the portable device 20 is detected when the signal is intermittently received, continuous reception is started until the signal is no longer detected. On the other hand, when the ignition signal is turned ON, the signal can be continuously received regardless of whether or not the signal is detected. Further, the reception frequency at this time is switched to the frequency FRQ2 for receiving the tire air pressure. Thereafter, when the ignition signal is turned off, the reception frequency is returned to the frequency FRQ1, and the intermittent reception is possible again.

  In order to smoothly perform such operations as unlocking / locking of the door and trunk 3 and opening / closing of the power window by performing such reception operation, the antenna characteristics are set so that the signal from the portable device 20 can be detected with high sensitivity. It needs to be coordinated. However, the antenna characteristics of the receiving apparatus 100 vary on a daily basis due to various factors such as the position and inclination of the seat of the vehicle 1 and the presence or absence of luggage. For this reason, even if the antenna characteristics are accurately adjusted at the time of shipment of the vehicle 1 from the factory, the antenna characteristics may be shifted due to such daily fluctuations. Of course, frequently forcing the user of the vehicle 1 to readjust the antenna characteristics is unrealistic because the burden on the user becomes too great. Therefore, in the receiving apparatus 100 according to the present embodiment, the antenna characteristics are adjusted during the daily operation of the user as described below, so that the antenna characteristics are always adjusted to appropriate antenna characteristics even for such daily fluctuations. be able to.

B. Overview of antenna characteristics adjustment:
FIG. 4 shows an outline of an operation in which the receiving apparatus 100 according to the present embodiment adjusts the antenna characteristics during daily operations by the user. For example, it is assumed that a signal is transmitted from the portable device 20 to the receiving device 100 at a certain timing as shown in the uppermost stage in the figure. Further, as shown in the second row from the top in the figure, the receiving device 100 is in a state in which reception is intermittently possible until a signal from the portable device 20 is detected, but after the signal is detected, the receiving device 100 is continuously received. And receive the signal. Here, since the receiving apparatus 100 is intermittently in a receivable state, the signal from the portable device 20 may not be received from the head. Therefore, the portable device 20 continuously transmits a signal having the same content a plurality of times (four times in the illustrated example).

  The signal transmitted from the portable device 20 includes data indicating the head of the signal, data regarding the operation instructed to the vehicle 1 (such as unlocking or locking of the door or the trunk 3), unique to each portable device 20. The data indicating the identification information, data indicating the end of the signal, and the like are included. In this specification, a signal composed of a set of these data is called a “frame”. Here, the content of the operation instructed to the vehicle 1 is not limited to the unlocking or locking of the door or the trunk 3, but the operation of opening and closing the power window, the start or stop of the operation of the air conditioner, the rear part of the flip-up type The operation can be performed such as opening a door and generating or stopping an alarm sound for repelling a suspicious person.

  Further, the identification information of the portable device 20 is stored in advance in the storage unit 23 of the portable device 20 (see FIG. 1B). Here, the identification information is described as ID data composed of numbers, alphabets, and the like. However, if the portable device 20 can be identified, information other than the ID data is used as the identification information. You can also.

  As the data indicating the head of the signal or the data indicating the end of the signal, specific data determined for each can be used. Alternatively, as data indicating the end of the signal, data indicating the data length of the frame can be used. That is, data indicating the data length of the frame may be embedded in the frame, and when the data length from the head reaches the data length, it may be determined that the frame ends. Further, depending on the content of the operation to be instructed, the instruction may be performed by a plurality of frames without completing the instruction by one frame. For example, when the air conditioner is operated from the outside of the vehicle 1 using the portable device 20, the first frame is instructed to operate the air conditioner, and the second frame is instructed to operate such as cooling or heating. An instruction for temperature setting and air volume setting may be given in the third frame. In this case, since the receiving apparatus 100 cannot always receive the first frame from the beginning, the same frame may be transmitted again for the first frame.

  In the example illustrated in FIG. 4, the receiving apparatus 100 is in a receivable state in the middle of the first frame transmitted by the portable device 20, and signal reception is started as it is. However, since the first frame is received from the middle, the control unit 101 of the receiving apparatus 100 cannot decode the content of the transmitted signal, and starts decoding the signal from the second frame. As described above, the frame includes data indicating an operation content instruction and identification information of the portable device 20. When the control unit 101 of the receiving apparatus 100 reads the identification information from the frame, the control unit 101 determines whether the identification information is registered in the storage unit 101m. As a result, when the identification information is registered in the storage unit 101m, it is determined that the frame is a frame transmitted from the regular portable device 20 registered in the vehicle 1, and subsequent frames (example shown in the figure). Then, adjustment of antenna characteristics is started in the third and subsequent frames. Detailed operations for adjusting the antenna characteristics will be described later. Note that “FRAME CONFIRMATION” displayed in the drawing means that it is confirmed that the frame has been transmitted from the legitimate portable device 20, or a state in which this has been confirmed.

  In the example shown in FIG. 4, the antenna characteristics are adjusted in the third frame in response to frame determination for the second frame. In this example, the adjustment of the antenna characteristics during the reception of the third frame has been completed, and the adjustment of the antenna characteristics is started in the fourth frame after receiving the frame determination for the third frame. If the adjustment is not completed during reception of one frame, the adjustment of the antenna characteristics may be continued as it is even after the frame is determined for the frame. If the signal transmission from the portable device 20 is interrupted during the adjustment of the antenna characteristics, the adjustment of the antenna characteristics is ended. In the example shown in FIG. 4, the adjustment of the antenna characteristic is started upon receiving the frame determination of the fourth frame, but the adjustment is finished because there is no signal from the portable device 20.

  The regular portable device 20 in which the identification information is registered in the storage unit 101m of the control unit 101 corresponds to a “registered transmitter” in the present invention. The storage unit 101m in which the identification information is registered corresponds to the “identification information registration unit” in the present invention. The control unit 101 that determines whether or not the identification information is registered includes the “signal determination unit” in the present invention. Is equivalent to.

C. Antenna characteristics adjustment processing:
5 to 7 show detailed processing contents for the control unit 101 of the receiving apparatus 100 to adjust the antenna characteristics. This antenna characteristic adjustment process is executed by the control unit 101 in response to the frame determination described above.

  In the antenna characteristic adjustment process, first, the control value a stored in the storage unit 101m of the control unit 101 is read (S100). Here, the control value is data used to adjust the antenna characteristics. That is, as described above with reference to FIG. 2, the control unit 101 adjusts the antenna characteristics by outputting an adjustment output from the DA converter 101 da toward the adjustment circuit 102. The control value is data representing the value of the adjustment output output from the DA converter 101da.

  Subsequently, it is determined whether or not the control value a read from the storage unit 101m has reached an upper limit value that can be specified for the adjustment circuit 102 (S101). As a result, if the upper limit value has been reached (S101: yes), the control value a cannot be increased any further, so the adjustment direction flag is set to “0” in order to adjust the antenna characteristics in the decreasing direction ( S102). Here, the adjustment direction flag is a flag indicating whether the antenna characteristic is adjusted in the direction of increasing or decreasing the control value a, and is set in a RAM (not shown) in the control unit 101. When the adjustment direction flag is “1”, the adjustment is performed in the direction of increasing the control value “a”, and when the adjustment direction flag is “0”, the adjustment is performed in the direction of decreasing. On the other hand, if the control value a read from the storage unit 101m has not reached the upper limit value (S101: no), the adjustment direction flag is set to “1” in order to adjust the antenna characteristics in the direction of increasing the control value a. (S103).

  Then, the control value a read from the storage unit 101m is stored in a RAM (not shown) as a control value at the start of antenna characteristic adjustment (starting control value s) (S104), and then RSSI (reception with the control value a) is received. Signal strength) is measured (S105). That is, the adjustment output corresponding to the control value a is output from the DA converter 101da to the adjustment circuit 102, and the signal strength (RSSI) when the signal is received in that state is converted into the voltage level by the reception signal strength detector 109. Then, the value is measured by the AD converter 101ad.

  In this way, when the RSSI at the control value a is obtained, it is determined whether or not the RSSI is not less than the adjustable intensity (S106). The adjustable strength is a value that is predetermined as the minimum RSSI necessary for appropriately adjusting the antenna characteristics. Therefore, when the RSSI is less than the adjustable intensity (S106: no), as will be described later, the control value a at that time is stored in the storage unit 101m (S126 in FIG. 7), and the antenna characteristic adjustment processing is performed. finish. On the other hand, when the RSSI is not less than the adjustable intensity (S106 in FIG. 5: yes), the obtained RSSI is stored in the RAM of the control unit 101 as a reference value (S107).

  Subsequently, the control value a is changed by a predetermined adjustment amount da to set a comparison control value (S108). For example, when the adjustment direction flag is set to “1”, a value (a + da) obtained by adding the adjustment amount da to the control value a is set as the comparison control value. When the adjustment direction flag is set to “0”, a value (a−da) obtained by subtracting the adjustment amount da from the control value a is set as a comparison control value.

  Then, the RSSI at the comparison control value is measured (S109), and it is determined whether or not the obtained RSSI is equal to or greater than the adjustable intensity (S110 in FIG. 6). As a result, when the RSSI is less than the adjustable intensity (S110: no), it is considered that the antenna characteristics cannot be adjusted because the signal from the portable device 20 is interrupted. Therefore, the control value a at that time is stored in the storage unit 101m (S126 in FIG. 7), and the antenna characteristic adjustment process is terminated. On the other hand, when the RSSI is equal to or greater than the adjustable intensity (S110: yes), the RSSI (RSSI with the comparison control value) is stored in the RAM of the control unit 101 as the actually measured comparison value (S111). .

  The adjustable intensity is set to a value larger than the minimum RSSI with which the control unit 101 can read a signal. This is because when the adjustment output from the DA converter 101da is changed in order to measure the RSSI at the comparison control value, the RSSI is lowered and the signal from the portable device 20 cannot be received. This is to prevent the designated operation such as unlocking or locking from being disabled.

  Thereafter, the RSSI at the control value a is measured again (S112), and it is determined whether or not the obtained RSSI is equal to or greater than the adjustable intensity (S113). As a result, if the RSSI is less than the adjustable intensity (S113: no), the control value a is written in the storage unit 101m (S126 in FIG. 7), and the antenna characteristic adjustment process is terminated. On the other hand, if the RSSI is equal to or greater than the adjustable intensity (S113: yes), the RSSI (RSSI remeasured with the control value a) is stored as a remeasurement reference value in the RAM of the control unit 101 (S114).

  Here, two values of the reference value and the remeasurement reference value are measured as the RSSI at the control value a because the user of the vehicle 1 operates the portable device 20 while approaching (or moving away from) the vehicle 1. This is because the RSSI is different even if the control value a is the same. For example, when the portable device 20 is operated while approaching the vehicle 1, the remeasurement reference value is larger than the reference value. Conversely, when the portable device 20 is operated while moving away from the vehicle 1, the remeasurement is performed. The reference value is smaller than the reference value.

  Subsequently, a correction amount for correcting the actual comparison value is calculated using the reference value and the remeasurement reference value. That is, if the portable device 20 is operated while approaching the vehicle 1, the remeasurement reference value is a large value not only for the reference value but also for the actually measured comparison value. On the other hand, when operated while moving away from the vehicle 1, the remeasurement reference value should be a smaller value than the actual measurement comparison value. Therefore, a correction amount for correcting the actual comparison value is calculated based on the reference value and the remeasurement reference value.

  In calculating the correction amount, first, it is determined whether or not the control value a at that time coincides with the starting control value s (S115). As will be described later, since the control value a is updated as the antenna characteristic is adjusted, the control value a and the starting control value s coincide with each other because the adjustment has just started and the control value a is still updated. This is the case. Therefore, when the control value a and the starting control value s match (S115: yes), the value obtained by subtracting the reference value from the remeasurement reference value and dividing by 2 is corrected in the RAM of the control unit 101. The amount is stored (S116). On the other hand, when the control value a and the starting control value s do not match (S115: no), a value obtained by subtracting the reference value from the remeasurement reference value and dividing by 3 is used as the correction amount. Store (S117). The reason why the value to be divided is different depending on whether the control value a and the starting control value s match will be described later.

  Subsequently, the actual comparison value is corrected by adding the obtained correction amounts, and the obtained value is stored as a correction comparison value in the RAM of the control unit 101 (S118). The correction comparison value obtained in this way is a value that can be compared with the remeasurement reference value because the influence of the change in the distance between the vehicle 1 and the portable device 20 is corrected. Accordingly, it is determined whether or not the corrected comparison value is larger than the remeasurement reference value by a certain value or more (S119 in FIG. 7). As a result, when the corrected comparison value is larger than the remeasurement reference value by a certain value or more (S119: yes), the comparison control value is set to the new control value a (S120), and the actual comparison value is set to the new reference value. A value is set (S121). Then, it is determined whether or not the new control value a has reached a limit value (upper limit value or lower limit value) that can be specified for the adjustment circuit 102 (S122). If it has not reached the limit value (S122: no), returning to S108 of FIG. 5, a new control value for comparison is set. That is, when the adjustment direction flag is “1”, a value obtained by adding the predetermined adjustment amount da to the newly set control value a, and when the adjustment direction flag is “0”, the newly set control value a. A value obtained by subtracting the predetermined adjustment amount da from is set as a new comparison control value. Then, after measuring the RSSI at the new comparison control value (S109), the following series of processing is performed.

  Here, as shown in S115 to S117 in FIG. 6, the reason why the value to be divided is different depending on whether or not the control value a and the starting control value s coincide with each other will be described.

  FIG. 8 illustrates a state where the control unit 101 of the receiving apparatus 100 adjusts the antenna characteristics. FIGS. 8A to 8C show changes in RSSI measured by the received signal strength detector 109 during adjustment of antenna characteristics. FIG. 8D shows a change in the control value set in the DA converter 101da as the antenna characteristic is adjusted. The illustrated example is the case where the adjustment direction flag is “1” (when the control value a is adjusted to increase). First, referring to FIG. 8A, the adjustment contents from the start of the adjustment of the antenna characteristics to the update of the control value a will be described.

  When the antenna characteristic adjustment process is started, the control value a is read from the storage unit 101m, and the control value a is stored as the starting control value s. Then, the RSSI (reference value) at the control value a is measured (see FIG. 5 S100 to S107). Then, after measuring the RSSI (actual comparison value) at the comparison control value larger than the control value a by the adjustment amount da, the RSSI (remeasurement reference value) at the control value a is measured again (S108 in FIG. 5). (See S144 in FIG. 6). Subsequently, by adding a correction amount to the actual measurement comparison value, correction is made to a value comparable to the remeasurement reference value. At this time, the correction amount is half the value obtained by subtracting the reference value from the remeasurement reference value. Become. This is because, as shown in FIG. 8A, the time from the measurement of the actual comparison value to the measurement of the remeasurement reference value is the time from the measurement of the reference value to the measurement of the remeasurement reference value. This is because only half of the time has passed. Therefore, in this case, half of the value obtained by subtracting the reference value from the remeasurement reference value is the correction amount, and the correction value obtained by adding this correction amount to the actual comparison value (correction comparison value) and the remeasurement reference value are obtained. Compare. As is clear from the above description, the remeasurement reference value may be corrected by subtracting the correction amount from the remeasurement reference value, and the corrected value may be compared with the actually measured comparison value.

  As a result, if the corrected comparison value is larger than the remeasurement reference value by a certain value or more, the comparison control value (here a + da) is considered to have a larger RSSI than the control value a. When receiving a signal from the portable device 20, it is desirable to use a control value for comparison. Therefore, the comparison control value (here a + da) is read as a new control value a, and the actually measured comparison value obtained for the comparison control value is read as a new reference value (S118 in FIG. 6 to S121 in FIG. 7). reference). Then, it is determined whether or not the new control value a has reached the limit value (here, the upper limit value). If not (S122: no), the same adjustment is started again.

  FIG. 8B shows a state in which the comparison control value is set for the new control value a and the new reference value, and the actual comparison value and the remeasurement reference value are measured. In addition, the thin broken line in FIG.8 (b) represents the change of RSSI in the last loop. Here, as shown in FIG. 8A, the adjustment of the antenna characteristics is started, and in the first loop, three RSSIs of a reference value, an actual comparison value, and a remeasurement reference value are measured. However, in the second and subsequent loops, the actual comparison value measured in the previous loop is used as a reference value, and therefore, as shown in FIG. 8B, two actual comparison values and a remeasurement reference value are used. What is necessary is just to measure RSSI. The correction amount for correcting the actual measurement comparison value is 1/3 of the value obtained by subtracting the reference value from the remeasurement reference value. This is because the reference value at this time is obtained by rereading the actual comparison value measured in the previous loop, and as shown in FIG. 8B, until the remeasurement reference value is measured after the actual comparison value is measured. This is because this time corresponds to 1/3 of the time from the measurement of the reference value to the measurement of the remeasurement reference value.

  When it is determined in S115 of FIG. 6 that the control value a and the starting control value s match (S116: yes), the value obtained by subtracting the reference value from the remeasurement reference value and dividing by 2 is used as the correction amount ( In S116, when it is determined that the control value a and the starting control value s do not match (S116: no), a value obtained by subtracting the reference value from the remeasurement reference value and dividing by 3 is used as the correction amount (S116). ) For the above reasons.

  Further, as is clear from the above description, the adjustment of the antenna characteristic is performed by adjusting the control value a to the correction comparison value when the correction comparison value is larger than a certain value compared to the correction comparison value and the remeasurement reference value. This is done by updating the value to the comparison control value obtained. Therefore, if the difference between the comparison control value and the control value a (corresponding to the adjustment amount da) is too small, the difference between the corrected comparison value and the remeasurement reference value does not appear and the antenna characteristics cannot be adjusted. However, if the difference between the control value for comparison and the control value a (corresponding to the adjustment amount da) is too large, there may be a case where the RSSI cannot be measured because it is far from the optimal control value. Therefore, the adjustment amount da is larger than the value (minimum adjustment amount) that causes the RSSI to fluctuate by an amount equivalent to the resolution that can be detected by the reception signal strength detector 109, and can be detected by the reception signal strength detector 109. It is set in a range smaller than a value (twice the minimum adjustment amount) that causes the RSSI to fluctuate by about twice the resolution.

  The reference value of this embodiment corresponds to “first signal strength” in the present invention, and the actually measured comparison value of this embodiment corresponds to “second signal strength” in the present invention. The value corresponds to “third signal strength” in the present invention. In addition, the control unit 101 of the present embodiment includes the “first signal intensity storage unit”, “second signal intensity storage unit”, “third signal intensity storage unit”, “correction amount determination unit”, “increase” in the present invention. This corresponds to “determination means”.

  As described above, when the control value a is updated by each adjustment amount da, the difference between the actually measured comparison value and the remeasurement reference value becomes small as illustrated in FIG. 8C. In some cases, the actual comparison value may be smaller than the remeasurement reference value. Therefore, it is determined whether or not the corrected comparison value is larger than the remeasurement reference value by a certain value or more (S119). If it is determined that the correction comparison value is not larger as a result (S119: no), the control value a is the starting control value. It is determined whether or not it matches s (S123).

  As illustrated in FIG. 8, if the control value a has been updated even once, the control value a and the start time control value s do not coincide with each other, so “no” is determined in S123. In this case, the control value a is considered to have been improved to a more preferable control value a. Therefore, after storing the control value a at that time in the storage unit 101m (S126), the antenna characteristics are adjusted. finish.

  On the other hand, when the control value a and the starting control value s match (S123: yes), the following two cases can be considered. First, since the adjustment direction of the control value a is incorrect, there may be a case where the reception state is deteriorated by changing the control value to the comparison control value. Alternatively, since the control value is already adjusted to the optimum control value a, there are cases where the reception state is not improved even if the control value is changed, or the reception state is deteriorated. Therefore, when the control value a and the starting control value s match (S123: yes), the setting of the adjustment direction flag is confirmed (S124). As described above, the adjustment of the antenna characteristics starts from the direction in which the control value a is increased as much as possible (setting of the adjustment direction flag is “1”). Therefore, when the adjustment direction flag is set to “1” ( S124: yes), the adjustment direction may be incorrect. Therefore, after changing the setting of the adjustment direction flag to “0” (S125), the process returns to S108 in FIG. 5 to set a new comparison control value. Then, this time, the above-described series of processes is started in the reverse adjustment direction.

  On the other hand, if it is determined in S124 that the setting of the adjustment direction flag is not “1” (“no”), it is considered that the optimal control value a has already been set. After storing a in the storage unit 101m (S126), the adjustment of the antenna characteristics is finished.

  As described above, the receiving apparatus 100 according to the present embodiment can adjust the antenna characteristics of the receiving apparatus 100 during daily operations performed by the user of the vehicle 1 using the portable device 20. For this reason, it is possible to always adjust to an appropriate characteristic even with respect to a routine change in antenna characteristic due to a change in the position and inclination of the seat or a large load being loaded. Further, the adjustment of the antenna characteristics is performed without the user's knowledge while the user operates the portable device 20 on a daily basis, so that no burden is imposed on the user. Furthermore, since the antenna characteristics are adjusted little by little with an adjustment amount da corresponding to the resolution of the received signal strength detector 109, the reception sensitivity is not lowered by the adjustment, and stable adjustment is realized. Is possible.

  In addition, in the receiving apparatus 100 according to the present embodiment, the signal from the portable device 20 is received at the frequency FRQ1, the signal from the air pressure sensor 17 is received at the frequency FRQ2, and the frequency to be received is switched by the adjustment circuit 102. The changeover switch 102s is used (see FIG. 2). Therefore, if the antenna characteristic is adjusted for the signal (frequency FRQ1) from the portable device 20, the adjustment of the antenna characteristic for the signal (frequency FRQ2) from the air pressure sensor 17 is also completed. For this reason, it becomes possible to adjust the antenna characteristics more easily.

D. Modified example:
There are several modifications to the present embodiment described above. Hereinafter, these modified examples will be briefly described.
D-1. First modification:
In the above-described embodiment, it has been described that the adjustment of the antenna characteristic is started when the frame is determined for the signal transmitted from the portable device 20. However, the adjustment of the antenna characteristics may be started in consideration of the content of the operation specified in the frame. For example, when the content of the operation designated by the frame is the unlocking of the door or trunk 3 or the start of the operation of the air conditioner, the adjustment of the antenna characteristics is started. When these operations are instructed, the operator of the portable device 20 often approaches the vehicle 1, so the RSSI gradually increases. Therefore, if the antenna characteristics are adjusted at such a time, even if the initial adjustment direction is incorrect, the antenna characteristics can be reliably adjusted.

D-2. Second modification:
In the above-described embodiment, when the receiving apparatus 100 receives the signal from the portable device 20 and can “confirm the frame” (the frame has been confirmed to have been transmitted from the regular portable device 20). In the case), the antenna characteristics are adjusted using the next frame. However, antenna characteristics adjustment is started without waiting for frame confirmation, and if the frame cannot be confirmed, the adjustment result is discarded, and if the frame is confirmed, the adjustment result is reflected (obtained control The value a may be stored in the storage unit 101m).

  In this way, it is possible to adjust the antenna characteristics from a timing earlier by one frame. Further, since the antenna characteristic can be adjusted only by receiving at least one frame that can be determined, the antenna characteristic can be adjusted more frequently. As a result, even when the antenna characteristic is changed due to the adjustment of the seat position of the vehicle 1, the antenna characteristic can be adjusted more quickly.

D-3. Third modification:
In the above-described embodiments, the antenna characteristics are adjusted when the portable device 20 is operated and a signal is transmitted from the portable device 20 toward the receiving device 100. However, it suffices if a signal is transmitted from the portable device 20 toward the receiving device 100, and the signal does not have to be transmitted by operating the portable device 20. For example, when a user wearing the portable device 20 makes an intention to unlock the door by touching the door knob of the vehicle 1, the vehicle 1 inquires the portable device 20 for identification information wirelessly. When the identification information transmitted from the portable device 20 is the identification information registered in advance, the door is unlocked. For this reason, in the communication performed between the vehicle 1 and the portable device 20, the antenna characteristic may be adjusted by confirming that the identification information from the portable device 20 is the registered identification information. .

  Although the receiving apparatus 100 of the present embodiment or various modifications has been described above, the present invention is not limited to the above-described embodiment or modifications, and can be implemented in various modes without departing from the gist thereof. it can.

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 10 ... Vehicle-mounted apparatus control part, 16 ... Ignition switch,
17 ... Air pressure sensor, 20 ... Portable device, 100 ... Receiver,
DESCRIPTION OF SYMBOLS 101 ... Control part, 102 ... Adjustment circuit, 109 ... Received signal strength detector

Claims (14)

A vehicle-mounted receiving device that is mounted on a vehicle and receives an operation instruction signal transmitted from a portable device via an antenna,
Signal detection means for detecting the operation instruction signal corresponding to the operation of the user of the vehicle;
An in-vehicle receiving apparatus comprising: antenna characteristic adjusting means that adjusts an antenna characteristic that is a characteristic that the antenna receives the operation instruction signal when the detection means detects the operation instruction signal. The in-vehicle receiving device according to claim 1,
When the operation instruction signal is received, the operation instruction signal includes signal determination means for determining whether or not the operation instruction signal is a signal transmitted from a registered transmitter that is a transmitter registered in advance in association with the vehicle,
The on-vehicle receiving device is a means for adjusting the antenna characteristics when the antenna characteristics adjusting means is determined to be a signal from the registered transmitter. The in-vehicle receiving device according to claim 2,
Comprising identification information registration means for registering identification information which is information for identifying the transmitter;
When the signal determination unit receives the operation instruction signal, the signal determination unit extracts the identification information included in the operation instruction signal, and the operation is performed when the extracted identification information is registered in the identification information registration unit. A vehicle-mounted receiving device which is means for determining that an instruction signal is a signal from the registered transmitter. The in-vehicle receiving device according to claim 2 or 3,
The operation instruction signal is a signal that is continuously transmitted from the transmitter a plurality of times,
When the signal determining unit determines that the operation instruction signal is a signal from the registered transmitter, the antenna characteristic adjusting unit is configured to receive the antenna based on the operation instruction signal received following the operation instruction signal. A vehicle-mounted receiving device that adjusts the characteristics. The vehicle-mounted receiving device according to claim 4,
The antenna characteristic adjusting means may determine whether the operation instruction signal is a signal from the registered transmitter during the adjustment of the antenna characteristic, based on the new operation instruction signal received following the operation instruction signal. A vehicle-mounted receiving device, which is means for continuing the adjustment without starting a simple adjustment. The vehicle-mounted receiving device according to any one of claims 1 to 5,
The on-vehicle receiving device is a means for adjusting the antenna characteristic based on the signal strength of the operation instruction signal. The in-vehicle receiving device according to claim 6,
The on-vehicle receiving device is a means for ending the adjustment when the signal strength of the operation instruction signal becomes a predetermined value or less during the adjustment of the antenna characteristic. The vehicle-mounted receiving device according to claim 6 or 7,
The antenna characteristic adjusting means changes a control value for adjusting the antenna characteristic so that the signal intensity increases when the signal intensity of the operation instruction signal is equal to or higher than a predetermined adjustable intensity. A vehicle-mounted receiving device which is means for adjusting the antenna characteristics. The in-vehicle receiving device according to claim 8,
The on-vehicle receiving device is a means for adjusting the antenna characteristic by increasing or decreasing the control value by a predetermined adjustment amount. The vehicle-mounted receiving device according to claim 9,
The adjustment amount is a value set in a range that is not less than the minimum adjustment amount that is the adjustment amount corresponding to the detection resolution of the signal intensity of the operation instruction signal and that is not more than twice the minimum adjustment amount. Receiver device. The vehicle-mounted receiving device according to any one of claims 8 to 10,
The antenna characteristic adjusting means includes
First signal strength storage means for storing a first signal strength that is the signal strength detected at the current control value;
A second signal strength storage means for changing the control value from the current control value and storing a second signal strength that is the signal strength detected by the changed control value;
A third signal strength storage means for changing the control value to the control value obtained by detecting the first signal strength and storing a third signal strength which is the signal strength detected by the control value;
A correction amount determining means for determining a correction amount of the signal strength based on a deviation between the first signal strength and the third signal strength;
An in-vehicle receiving apparatus comprising: an increase determination unit that determines whether or not the signal intensity is increased by comparing the second signal intensity and the third signal intensity in consideration of the correction amount. The vehicle-mounted receiving device according to any one of claims 1 to 11,
The in-vehicle receiving device is a signal for instructing start or end of operation of a movable device mounted on the vehicle. The vehicle-mounted receiving device according to any one of claims 1 to 12,
The vehicle is equipped with a signal transmission means for transmitting a state display signal representing information on the state of the vehicle using a frequency different from that of the operation instruction signal.
A vehicle-mounted receiving device comprising: a signal receiving unit that selectively receives the operation instruction signal or the state display signal by switching the frequency. The in-vehicle receiving device according to claim 13,
The on-vehicle receiving apparatus is a means for adjusting the antenna characteristics for receiving the state display signal based on the operation instruction signal.

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