JP2010283429A - Onboard receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an onboard receiver having an antenna excellent in receiving characteristics and directivity characteristics. <P>SOLUTION: The onboard receiver receives a transmission signal including identification information of a vehicle and control information of the vehicle from a portable device existing around the vehicle and controls the vehicle on the basis of the control information if the identification information matches previously registered authentication information. The onboard receiver includes: slot antennas 1, 2 provided on at least two surfaces different from each other of side surfaces and front and rear surfaces of the vehicle and each receiving the transmission signal from the portable device; a signal processing means for down-converting the signal having the strongest signal strength from among the transmission signals received by the slot antennas 1, 2; a demodulator 6 for demodulating the signal from the signal processing means; and CPU 7 and an ECU 8 for comparing the identification information included in the signal from the demodulator 6 with the previously registered authentication information and controlling the vehicle on the basis of the control information included in the signal from the demodulator 6 if both the items of information matches each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention receives a transmission signal including vehicle identification information and control information from a portable device, and controls the vehicle based on control information when authentication information and identification information registered in advance match. Regarding the receiver.

2. Description of the Related Art In recent years, electronic control of vehicles has been advanced due to miniaturization and high performance of IC (Integrated Circuit) and chip parts.
Regarding locking and unlocking of vehicle keys, instead of using conventional mechanical keys for authentication confirmation, a transmission signal from a portable device storing vehicle identification information is received by an in-vehicle receiver, and the identification information and in-vehicle information are received. A keyless entry system that performs authentication confirmation using authentication information registered in advance in a receiver has become widespread. In the keyless entry system, an antenna mounted on a vehicle receives a transmission signal from a portable device existing around the vehicle, so an antenna having excellent reception characteristics and directivity is required.

  Conventionally, as an antenna device for improving reception characteristics and directivity, there are an antenna device using a plurality of whip antennas, an antenna device using a plurality of glass antennas, or an antenna device using both. These antenna devices complement each other's directivity, thereby reducing the directivity of the entire antenna device and improving reception characteristics (see, for example, Patent Document 1).

FIG. 5 is a perspective view showing a vehicle in which a conventional antenna device is incorporated.
In FIG. 5, antenna conductors 52 and 53 are independently provided on the windshield 51 of the vehicle 50, and a windshield antenna 54 is formed. A rear whip antenna 55 is provided behind the vehicle 50.

  In this antenna device, by selectively selecting a signal having a high gain among the signals extracted from the antenna conductors 52 and 53 of the windshield antenna 54 and the rear whip antenna 55, the directivity is low and the reception characteristic is reduced. A good space diversity antenna is constructed.

  In general, when a transmission signal from a portable device is received by an antenna provided inside the vehicle, a large power loss occurs when the signal passes through the vehicle body, and the reception characteristics deteriorate. Therefore, a space diversity antenna that receives a transmission signal from a portable device with the windshield antenna 54 and the rear whip antenna 55 provided outside the vehicle 50 is very effective.

JP-A-61-203702

However, the prior art has the following problems.
In the conventional antenna device, since the whip antenna is provided outside the vehicle, there is a problem that the antenna itself is damaged due to force majeure or abnormal noise such as wind noise is generated during traveling. Further, the glass antenna has a problem that the degree of freedom of the installation position is limited so as not to disturb the driver's field of view.

In order to solve the above problem, Japanese Patent Application No. 2009-101103 proposes that a slot antenna be formed on the side surface of the vehicle using a gap between the vehicle body and the door.
However, as shown in FIG. 6, when the slot antenna 61 is formed on the right side of the vehicle, the reception area 63 capable of receiving a transmission signal from the portable device 62 is biased to the right side of the vehicle. Further, as shown in FIG. 7, when the slot antenna 64 is formed on the left side of the vehicle, the reception area 65 that can receive the transmission signal from the portable device 62 is biased toward the left side of the vehicle.
That is, depending on the position where the slot antenna is formed, there is a problem that the reception area capable of receiving the transmission signal from the portable device is biased to the right or left side of the vehicle, and the directivity is deteriorated.

  The present invention has been made to solve the above-described problems. An antenna having excellent reception characteristics and directivity characteristics without any damage to the antenna, generation of abnormal noise, and freedom of installation position is provided. An object is to obtain an in-vehicle receiver having the above-described structure.

  The in-vehicle receiver according to the present invention receives a transmission signal including vehicle identification information and vehicle control information from a portable device existing around the vehicle, and the authentication information registered in advance matches the identification information. A plurality of slot antennas that are provided on at least two different sides of the vehicle and the front and rear sides of the vehicle and receive transmission signals from the portable device, respectively. A signal processing means for down-converting and outputting a signal having the strongest signal strength among transmission signals received by each of the plurality of slot antennas, a demodulation means for demodulating the signal from the signal processing means, and a demodulation means The identification information included in the signal from the signal is compared with the authentication information registered in advance, and if both match, it is included in the signal from the demodulation means In which a control means for controlling the vehicle based on the control information.

According to the vehicle-mounted receiver according to the present invention, the plurality of slot antennas that respectively receive the transmission signals from the portable device are provided on at least two different surfaces of the vehicle and the front and rear surfaces.
Thereby, the reception area which can receive the transmission signal from a portable machine can be set to the area without a bias centering on a vehicle.
Therefore, it is possible to obtain an in-vehicle receiver having an antenna having excellent reception characteristics and directivity characteristics without causing damage to the antenna, generation of abnormal noise, and restriction on the degree of freedom of the installation position.

It is a block block diagram which shows the vehicle-mounted receiver which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the receiving area of the vehicle-mounted receiver which concerns on Embodiment 1 of this invention. It is explanatory drawing for demonstrating the process of CPU and ECU which concern on Embodiment 1 of this invention. It is a block block diagram which shows the vehicle-mounted receiver which concerns on Embodiment 2 of this invention. It is a perspective view which shows the vehicle incorporating the conventional antenna device. It is explanatory drawing which shows a receiving area when a slot antenna is formed in the right side surface of a vehicle. It is explanatory drawing which shows a receiving area when a slot antenna is formed in the left side surface of a vehicle.

Hereinafter, preferred embodiments of the in-vehicle receiver of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts will be described with the same reference numerals.
In the following embodiment, a case where two slot antennas are provided will be described as an example. However, the present invention is not limited to this, and three or more slot antennas may be provided.

Embodiment 1 FIG.
1 is a block diagram showing a vehicle-mounted receiver according to Embodiment 1 of the present invention.
In FIG. 1, this in-vehicle receiver includes two slot antennas 1 and 2, a comparator 3 (comparison means), a selector 4 (selection means), a frequency converter 5 (frequency conversion means), A demodulator 6 (demodulating means), a CPU (Central Processing Unit) 7 (control means), and an ECU (Electronic Control Unit) 8 (control means) are provided.
Here, the comparator 3, the selector 4 and the frequency converter 5 constitute a signal processing means.

Hereinafter, the function of this in-vehicle receiver will be described.
The slot antennas 1 and 2 are provided on at least two different surfaces of the vehicle side and front and rear surfaces (such as a passenger door and a trunk door). Each of the slot antennas 1 and 2 receives a transmission signal including vehicle identification information and vehicle control information from portable devices existing around the vehicle. Here, the vehicle identification information is, for example, authentication information registered in the vehicle-mounted receiver and the portable device in a one-to-one correspondence, and a transmission signal from the portable device is registered from the registered portable device. It is used to identify whether the signal is a signal. Further, the vehicle control information is information corresponding to unlocking and locking of a key as described in FIG.

FIG. 2 shows a reception area in which the slot antennas 1 and 2 of this in-vehicle receiver can receive a transmission signal from a portable device.
In FIG. 2, slot antennas 1 and 2 are provided on the right side and left side of the vehicle, respectively, and the reception area 21 by the slot antenna 1 and the reception area 22 by the slot antenna 2 have no bias around the vehicle (directivity). A reception area is set. In FIG. 2, the transmission signal from the portable device 23 is received by the slot antenna 1.

The comparator 3 compares the signal strengths of the transmission signals received by the slot antennas 1 and 2, and outputs a switching signal corresponding to the signal strength.
Specifically, first, the comparator 3 converts each received signal into an intensity signal, for example, by means for converting a radio signal into signal power intensity by diode detection or the like. Subsequently, the comparator 3 compares the intensity signals corresponding to the reception signals at the slot antennas 1 and 2 and outputs a switching signal.

  Here, for example, when the signal strength of the transmission signal received by the slot antenna 1 is stronger than the signal strength of the transmission signal received by the slot antenna 2, the comparator 3 outputs the switching signal at “H”. . Further, the comparator 3 outputs a switching signal “L” when the signal strength of the transmission signal received by the slot antenna 2 is stronger than the signal strength of the transmission signal received by the slot antenna 1.

The selector 4 has a first switch 41 (first SW) and a second switch 42 (second SW), and is received by each of the slot antennas 1 and 2 based on the switching signal from the comparator 3. Of the transmission signals, the signal having the strongest signal strength is output.
Specifically, the first switch 41 and the second switch 42 are in an ON state and an OFF state, respectively, when the switching signal is “H”, and are respectively in an OFF state and an ON state, when the switching signal is “L”. It becomes.

  That is, when the signal strength of the transmission signal received by the slot antenna 1 is stronger than the signal strength of the transmission signal received by the slot antenna 2, the transmission signal received by the slot antenna 1 is output from the selector 4. The When the signal strength of the transmission signal received by the slot antenna 2 is stronger than the signal strength of the transmission signal received by the slot antenna 1, the transmission signal received by the slot antenna 2 is output from the selector 4. The

The frequency converter 5 down-converts and outputs the signal output from the selector 4 to, for example, an intermediate frequency band or a baseband frequency band.
The demodulator 6 demodulates the signal from the frequency converter 5 by a method according to a predetermined modulation method (amplitude modulation method, frequency modulation method, phase modulation method, etc.) in the portable device, and generates a demodulated data signal. Is output. When secondary modulation using spread spectrum modulation is performed after information modulation is performed on the portable device side, spectrum despreading (spread demodulation) may be performed before information demodulation.

  The CPU 7 and the ECU 8 compare the identification information included in the demodulated data signal from the demodulator 6 with the authentication information registered in advance, and if both match, they are included in the demodulated data signal from the demodulator 6. The vehicle is controlled based on the control information.

  Specifically, first, the CPU 7 compares the demodulated data signal from the demodulator 6 with a stored data sequence stored in advance. Subsequently, when there is a stored data series that matches the demodulated data signal, the CPU 7 outputs a vehicle control signal corresponding to the stored data series.

  Here, the CPU 7 outputs the vehicle control signal as “HH” when the demodulated data signal matches, for example, the first data series shown in FIG. 3. Further, when the demodulated data signal matches each of the second data series, the third data series, and the fourth data series, the CPU 7 outputs the vehicle control signals as “HL”, “LH”, and “LL”, respectively. To do. When encoding is performed before information modulation is performed on the portable device side, decoding may be performed before comparison determination.

  The ECU 8 controls the vehicle based on a vehicle control signal from the CPU 7. For example, as shown in FIG. 3, the ECU 8 unlocks the vehicle key when the vehicle control signal is “HH”. The ECU 8 locks the vehicle key when the vehicle control signal is “HL”. The ECU 8 opens the window glass of the vehicle when the vehicle control signal is “LH”. Further, the ECU 8 closes the window glass of the vehicle when the vehicle control signal is “LL”.

As described above, according to the first embodiment, the plurality of slot antennas that respectively receive the transmission signals from the portable device are provided on at least two different surfaces of the vehicle and the front and rear surfaces.
Thereby, the reception area which can receive the transmission signal from a portable machine can be set to the area without a bias centering on a vehicle.
Therefore, it is possible to obtain an in-vehicle receiver having an antenna having excellent reception characteristics and directivity characteristics without causing damage to the antenna, generation of abnormal noise, and restriction on the degree of freedom of the installation position.
Further, since the demodulation means has a spectrum despreading function, it can be applied to a keyless entry system that performs spread spectrum modulation in a portable device.

Embodiment 2. FIG.
In the first embodiment, the signal strength of the transmission signal received by each of the slot antennas 1 and 2 is compared before down-conversion by the frequency converter 5. However, the present invention is not limited to this, and the signal strength may be compared after down-converting the transmission signals received by each of the slot antennas 1 and 2.
Hereinafter, processing for comparing signal strengths after down-converting transmission signals received by the slot antennas 1 and 2 will be described.

FIG. 4 is a block diagram showing an in-vehicle receiver according to Embodiment 2 of the present invention.
In FIG. 4, this in-vehicle receiver includes two slot antennas 1 and 2, frequency converters 11 and 12 (frequency conversion means), a comparator 3 (comparison means), and a selector 4 (selection means). And a demodulator 6 (demodulating means), a CPU (Central Processing Unit) 7 (control means), and an ECU (Electronic Control Unit) 8 (control means).
Here, the frequency converters 11 and 12, the comparator 3 and the selector 4 constitute a signal processing means.

Hereinafter, the function of this in-vehicle receiver will be described. Since functions other than the signal processing means (frequency converters 11 and 12, comparator 3 and selector 4) are the same as those in the first embodiment described above, description thereof will be omitted.
The frequency converters 11 and 12 down-convert the transmission signals received by the slot antennas 1 and 2 to, for example, an intermediate frequency band and a baseband frequency band, respectively, and output the signals.

The comparator 3 compares the signal strengths of the signals from the frequency converters 11 and 12 and outputs a switching signal corresponding to the signal strength.
Specifically, first, the comparator 3 converts each signal from the frequency converters 11 and 12 into an intensity signal by means for converting a radio signal into an intensity of signal power by, for example, diode detection. Subsequently, the comparator 3 compares the intensity signals corresponding to the signals from the frequency converters 11 and 12 and outputs a switching signal.

  Here, for example, when the signal strength of the signal from the frequency converter 11 is stronger than the signal strength of the signal from the frequency converter 12, the comparator 3 outputs the switching signal as “H”. Further, the comparator 3 outputs a switching signal “H” when the signal strength of the signal from the frequency converter 12 is stronger than the signal strength of the signal from the frequency converter 11.

The selector 4 includes a first switch 41 (first SW) and a second switch 42 (second SW), and signals from each of the frequency converters 11 and 12 based on a switching signal from the comparator 3. The signal with the strongest signal strength is output.
Specifically, the first switch 41 and the second switch 42 are in an ON state and an OFF state, respectively, when the switching signal is “H”, and are respectively in an OFF state and an ON state, when the switching signal is “L”. It becomes.

  That is, when the signal strength of the signal from the frequency converter 11 is stronger than the signal strength of the signal from the frequency converter 12, the signal received by the slot antenna 1 and down-converted by the frequency converter 11 is selected. Output from the device 4. When the signal strength of the signal from the frequency converter 12 is stronger than the signal strength of the signal from the frequency converter 11, the signal received by the slot antenna 2 and down-converted by the frequency converter 12 is selected. Output from the device 4.

As described above, according to the second embodiment, the signal strength is compared by the comparison unit after the transmission signals received by each of the plurality of slot antennas are down-converted by the frequency conversion unit.
Thereby, the signal strength can be compared with a signal from which the influence of noise superimposed on the signal in the UHF (Ultra High Frequency) band used as the transmission signal is removed.
Therefore, in addition to the same effects as those of the first embodiment, a better comparison result can be obtained by the comparison means.

  1, 2 slot antenna, 3 comparator (comparison means), 4 selector (selection means), 5 frequency converter (frequency conversion means), 6 demodulator (demodulation means), 7 CPU (control means), 8 ECU ( Control means), 11, 12 Frequency converter (frequency conversion means).

Claims (4)

When a transmission signal including the vehicle identification information and the vehicle control information is received from a portable device existing around the vehicle, and the authentication information registered in advance matches the identification information, the control information An in-vehicle receiver for controlling the vehicle based on:
A plurality of slot antennas provided on at least two different surfaces of the vehicle side and front and rear surfaces, respectively, for receiving the transmission signals from the portable device;
Signal processing means for down-converting and outputting a signal having the strongest signal strength among the transmission signals received by each of the plurality of slot antennas;
Demodulation means for demodulating the signal from the signal processing means;
The identification information included in the signal from the demodulating means is compared with the authentication information registered in advance, and when both match, based on the control information included in the signal from the demodulating means Control means for controlling the vehicle;
A vehicle-mounted receiver comprising: The signal processing means includes
Comparing means for comparing the signal strength of the transmission signal received by each of the plurality of slot antennas and outputting a switching signal according to the signal strength;
Selection means for selecting and outputting a signal having the strongest signal strength among the transmission signals received by each of the plurality of slot antennas based on the switching signal;
A frequency conversion means for down-converting and outputting the signal from the selection means;
The in-vehicle receiver according to claim 1, comprising: The signal processing means includes
Frequency conversion means for down-converting and outputting the transmission signals received by each of the plurality of slot antennas;
Comparing means for comparing the signal strength of the signal from the frequency converting means and outputting a switching signal according to the signal strength;
A selection unit that selects and outputs a signal having the strongest signal strength among the signals from the frequency conversion unit based on the switching signal;
The in-vehicle receiver according to claim 1, comprising:   The in-vehicle receiver according to any one of claims 1 to 3, wherein the demodulation means has a spectrum despreading function.

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