JP3327156B2 - Radar equipment for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vehicle radar device.

[0002]

2. Description of the Related Art Conventionally, a distance measuring pulse signal of an electromagnetic wave, a light wave or a sound wave is transmitted, and a reflected pulse signal of a reflector of the transmitted distance measuring pulse signal is different from each other corresponding to a plurality of discrete distances. The integration is performed by a plurality of distance calculating integration means each including an analog switch and a resistor and a capacitor, and the integration is performed by a predetermined integration time at each sampling timing. The vehicle radar device for determining the distance to the reflector was as shown in FIG.

[0003] This conventional vehicular radar device includes an electromagnetic wave,
A pulse signal transmission unit 1 for transmitting a pulse signal for distance measurement of a light wave or a sound wave in a predetermined direction;
Pulse signal receiving unit 2 for receiving a signal from a direction in which a pulse signal transmitted from the object is reflected by a reflector and returned
A variable gain signal amplifying unit 3 for amplifying the received signal of the reflected pulse signal receiving unit 2;
And a distance calculating and integrating circuit 4 composed of a number of analog switches and an integrator composed of a resistor and a capacitor, and integrating the received signal of the reflected pulse signal receiving unit 2 for a certain period of time. A receiving level calculating and integrating circuit 5, an A / D converter 6 for performing A / D conversion of the integrated outputs of the integrating circuits 4 and 5, and a receiving level of the reflected pulse signal based on the output of the receiving level calculating and integrating circuit 5; A determination unit 7 for determining the suitability of the above and calculating the distance to the reflector (target) based on the output of the distance calculation integration circuit 4; a pulse signal transmission unit 1; a signal amplification unit 3; And a control unit 8 for controlling the A / D conversion unit 6
It is composed of Note that the determination unit 7 and the control unit 8 are realized by a microcomputer in an actual machine, and programs necessary for executing the functions required for these components by software processing are incorporated.

The distance calculating and integrating circuit 4 has a configuration shown in FIG. 10 and includes a first integrator (# 1) to an n-th integrator (#
n) (integral numbers set in advance) up to n). Each of the integrators # 1 to #n has an analog switch 4c turned ON by an integrating element of a resistor 4a and a capacitor 4b.
The received signal input during the predetermined time dt is integrated and output as a voltage signal. Here, the analog switches 4c of the integrators # 1 to #n are shifted by a predetermined time τ, that is, the time τ corresponding to a certain distance interval.
Each of the integrators # 1 to #n outputs an integrated voltage at that distance.

The distance measuring operation of the conventional vehicle radar device having such a configuration will be described with reference to FIG. As shown in FIG. 1A, the pulse signal transmission unit 1 sends the control unit 8
, A pulse signal having a predetermined time width t is transmitted every predetermined period Δf. An electromagnetic wave, a light wave or a sound wave is used for the pulse signal. When there is another vehicle, obstacle, or the like in front of this pulse signal, the pulse signal is reflected by the target, and the reflected pulse signal returns to the reflected pulse signal receiving unit 2 and is received. FIG. 2B shows the received pulse signal. The received pulse signal is transmitted to the pulse signal transmitting unit 1
, Travels through the space, reflects on the target ahead, returns, and reaches the reflected pulse signal receiving unit 2.
The reflected pulse signal is received by the reflected pulse signal receiving unit 2 with a delay of a time δ corresponding to (reciprocation distance to the target), and the peak position thereof is shifted by δ from the pulse signal transmission timing.

Therefore, as shown in FIG. 11 (3), the control unit 8 controls the analog switch # of the distance calculating and integrating circuit 4 at intervals (sampling timing) τ corresponding to, for example, a reciprocating time of 20 m in the radar apparatus every 10 m. 1 to #n are sequentially turned on for a predetermined time dt, and the integrators output integrated voltage outputs # 1 to #n. (4) and (5) show the integrated voltage output of the # 1 integrator and the integrated voltage output of the # 5 integrator, respectively.

[0007] Then, in the determination unit 7, the distance calculation integration circuit 4
11 output by the A / D converter 6
With respect to the # 1 to #n integrated outputs shown in (6), four points are searched from the one with the largest peak value (# 3, # 4,
5, # 6), these are connected by a straight line, the intersection of the two straight lines is defined as the peak P of the received signal, and the time position δ of this peak P is converted into a distance 2D to the target, and the result is output.

Since it is necessary to make the amplification gain of the received signal appropriate, the reception level calculating and integrating circuit 5 detects the level of the received signal, and based on the detected signal level, the judging section 7 instructs the control section 8 to judge whether the gain is appropriate or not. And the control unit 8 adjusts the amplification gain of the signal amplifier 3.

The receiving level calculating and integrating circuit 5 has the configuration shown in FIG. 12, and is composed of an analog switch 5a, a resistor 5b and a capacitor 5c which constitute an integrating element. As shown in FIG. 13, the reception level calculating and integrating circuit 5 uses a gate signal (3) for a predetermined time θ from the time when the pulse signal transmitting unit 1 transmits the pulse signal shown in FIG. The determination unit 7 integrates all the received signals (2) of the reflected pulse signal receiving unit 2 and determines the integrated voltage (4).
Output to Thereby, the reception level calculation integration circuit 5
If the reflected pulse signal receiving unit 2 actually receives the signal, it outputs an integrated voltage according to the magnitude of the received signal.

[0010] Therefore, based on the integrated output, the determination section 7 determines whether the received signal level is appropriate or not, and gives a control command to increase or decrease the gain to the control section 8. The control section 8 increases or decreases the gain of the signal amplification section 3. Control is performed so that the S / N of the received signal is always constant. This control method will be described with reference to FIG. The received signal level of the reflected pulse signal receiving section 2 and the integrated output of the signal level calculating and integrating circuit 5 have a relationship shown in FIG. 14, and the signal amplifying section 3 is controlled so that the integrated voltage output is always between V1 and V2. The gain is adjusted so that the level of the received signal output therefrom is between the threshold value 1 and the threshold value 2. It is necessary to adjust the signal level of the received signal of the reflected pulse signal receiving unit 2 and thereafter input the signal to the distance calculation and integration circuit 4. 4 so that an integral output can be obtained at a higher speed than the distance calculating / integrating circuit 4.

[0011]

However, such a conventional vehicle radar apparatus has the following problems. For example, in the case of a vehicle radar device using laser light as a pulse signal, as shown in FIG.
When 1 is calculating the distance irradiated on the vehicle body 9 of the vehicle ahead, the amplification gain of the received signal is controlled by the signal level from the vehicle body 9. However, when the optical signal 11 is emitted to the vicinity of the reflector 10 of the vehicle body 9,
Depending on the state of the vehicle, as shown in FIG.
1 may hit the reflector 10. In this case, since the reflection of the optical signal by the reflector 10 is larger than the reflection of other parts of the vehicle body 9, the reflected pulse signal received by the reflected pulse signal receiving unit 2 may increase rapidly in a short time. In such a case, in the related art, even if control for lowering the gain of the signal amplifier 3 is performed by detecting that the received signal level has become excessive as shown in FIG. Since the gate signal (3) applied to the switch 5a always has a constant period, the integration circuit 5
Will be input. That is, as shown in FIG. 16, the reflected pulse reception signal (2) becomes excessive with respect to the transmission pulse (1), and the integration output (4) of each of a large number of continuous integrators of the distance calculation integration circuit 4 sharply increases. Is charged to the upper limit of the voltage range of the received signal input. Further, since the integration time constant is large, there is also a problem that the integrated output still attempts to increase the potential even if the gain is controlled to be reduced.

In the conventional vehicle radar device, the conduction period of the analog switch of the distance calculation and integration circuit is fixed so as to coincide with the transmission period of the transmission pulse signal. It was not possible.

The present invention has been made in view of such a conventional problem, and each integration element of the distance calculating and integrating means according to the magnitude of the integrated voltage signal of the receiving level calculating and integrating means for monitoring the received signal level. The conduction cycle of the analog switch does not coincide with the transmission cycle of the transmission pulse signal.
Variably so that it conducts at a rate of once or more every three cycles, it can quickly follow a sudden change in the received signal level and accurately determine the distance to the target. It is an object of the present invention to provide a vehicular radar device that can be used.

[0014]

According to a first aspect of the present invention, there is provided a radar apparatus for a vehicle, comprising: a pulse signal transmitting means for transmitting a pulse signal for distance measurement at a predetermined period; A reflected pulse signal receiving means for receiving a reflected pulse signal that is reflected back, and a plurality of different samplings corresponding to a plurality of discrete distances from the pulse signal sending means, respectively, for the received signal of the reflected pulse signal receiving means. A plurality of distance calculating integration means each including an analog switch and a resistance capacitor, each of which integrates by a predetermined integration time at each timing; and a distance to the target based on an integration output of each of the plurality of distance calculation integration means. Distance determining means for determining, a receiving level calculating integrating means for integrating a received signal of the reflected pulse signal receiving means for a predetermined integration time, and a receiving level calculating means Gain adjustment means for adjusting the gain of the reception signal level by looking at the integration output of the integration means; and conduction of the analog switches of each of the plurality of distance calculation integration means by looking at the integration output of the reception level calculation integration means. And a conduction cycle adjusting means for adjusting the cycle.

In the radar apparatus for a vehicle according to the first aspect of the present invention, the pulse signal transmitting means transmits a pulse signal for distance measurement at predetermined intervals, and the pulse signal for distance measurement is reflected on the target and returns. A signal from the incoming direction is received by reflected pulse signal receiving means, and a plurality of distance calculating integrating means including an analog switch and a resistor capacitor are used to convert the received signal of the reflected pulse signal receiving means into a plurality of signals from the pulse signal transmitting means. Integrate a predetermined time for each of a plurality of different sampling timings corresponding to each discrete distance,
The distance to the target is calculated by the distance determining means based on the integrated output of each of the plurality of distance calculating integrating means.

In parallel with this distance measuring operation, the received signal of the reflected pulse signal receiving means is integrated for a predetermined time by the receiving level calculating integrating means, and this integrated output is checked by the gain adjusting means to check the received signal level. By adjusting the gain and, at the same time, adjusting the conduction cycle of each analog switch of each of the plurality of distance calculation integration means while observing the integrated output by the conduction cycle adjusting means, even if the received signal level sharply increases, An accurate distance determination can be performed without saturating an integrated output.

According to a second aspect of the present invention, there is provided a radar apparatus for a vehicle for transmitting a pulse signal for distance measurement at predetermined intervals, and the pulse signal for distance measurement is reflected back to a target. A reflected pulse signal receiving means for receiving the reflected pulse signal, and a plurality of different samplings corresponding to a plurality of discrete distances from the pulse signal transmitting means, respectively. A plurality of distance calculating integration means, each of which includes an analog switch and a resistance capacitor, for integrating for a predetermined integration time at each timing, and a distance to the target based on an integrated output of each of the plurality of distance calculation integration means; Distance determination means for determining the peak value of the received signal of the reflected pulse signal receiving means; Gain adjustment means for adjusting the gain of the reception signal level by looking at the peak value of the reception signal detected by the means; and calculating the plurality of distances by looking at the peak value of the reception signal detected by the reception level peak detection means. And a conduction cycle adjusting means for adjusting a conduction cycle of the analog switch of each of the integrating means.

In the vehicle radar device according to the second aspect of the invention, the distance is determined in the same manner as the radar device according to the first aspect of the invention. The reception level peak detection means detects the peak value of the reception signal of the reflected pulse signal reception means, and the gain adjustment means adjusts the gain of the reception signal level by looking at the peak value of the reception signal. Means for adjusting the conduction cycle of each analog switch of each of the plurality of distance calculating integration means by looking at the peak value of the reception signal, without saturating the integration output even when the reception signal level sharply increases. , So that the distance can be accurately determined.

[0019]

As described above, according to the first aspect of the present invention,
The received signal of the reflected pulse signal receiving means is integrated for a predetermined time, the gain of the received signal level is adjusted by looking at the integrated output, and the analog of each of the plurality of distance calculating integrating means is seen by looking at the integrated output. Since the conduction period of the switch is also adjusted, the distance can be accurately determined without saturating the integrated output even when the received signal level rises sharply.

According to the second aspect of the present invention, the peak value of the received signal of the reflected pulse signal receiving means is detected, and the gain of the received signal level is adjusted by looking at the peak value of the received signal. Since the conduction period of each analog switch of each of the plurality of distance calculating integration means is adjusted by looking at the peak value of the signal, accurate distance determination can be performed without saturating the integrated output even when the received signal level sharply increases. Can be performed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a circuit configuration of a vehicle radar device according to a first embodiment of the present invention. The vehicle radar device according to the first embodiment includes a pulse signal transmitting unit 1 that transmits a pulse signal for distance measurement of an electromagnetic wave, a light wave, or a sound wave in a predetermined direction, similarly to the conventional example illustrated in FIG. A reflected pulse signal receiving unit 2 for receiving a signal from a direction in which the pulse signal transmitted from the pulse signal transmitting unit 1 is reflected by the reflector and returned, and amplifies the received signal of the reflected pulse signal receiving unit 2 This is for integrating the signal amplifying section 3 with variable gain and the received signal of the reflected pulse signal receiving section 2 at different sampling timings. The distance calculating and integrating circuit 4 includes a large number of analog switches and resistance capacitors.
(This internal configuration is shown in FIG. 10), a reception level calculation integration circuit 5 for integrating the reception signal of the reflected pulse signal reception unit 2 for a certain period, and these integration circuits 4 and 5
An A / D converter 6 for performing A / D conversion of the integrated output of the above, and a reception level calculation / integration circuit 5 for judging whether or not the reception level of the reflected pulse signal is appropriate based on the output.
Is provided with a determination unit 7 for calculating the distance to the reflector (target) based on the output of.

As a feature of the vehicular radar device of the first embodiment, an integration cycle variable section 12 for variably adjusting the conduction cycle of each analog switch 4c of the distance calculation integration circuit 4 is provided. It has a function of controlling the pulse signal transmitting unit 1, the signal amplifying unit 3, the integrating circuits 4, 5 and the A / D converting unit 6, and instructing the integrating cycle variable unit 12 of the integration cycle.

Next, the operation of the vehicular radar device having the above configuration will be described. The pulse signal transmitting unit 1 transmits a pulse signal at a constant period Δf under the control of the control unit 80.
Then, a reflected pulse signal that is reflected by a vehicle, a sign, or another target ahead of the vehicle and returns is received by the reflected pulse signal receiving unit 2, and the received signal is amplified to an appropriate level by the signal amplifying unit 3 to calculate a distance. The signals are input to the integration circuit 4 and the reception level calculation integration circuit 5.

The distance calculating / integrating circuit 4 has the same configuration as that of the conventional example shown in FIG. 10, but a gate signal is given to each analog switch 4c at a predetermined conduction cycle by the integration cycle varying section 12, and each integrator # The integration operation is performed for each of 1 to #n only during the ON period of the gate signal to output integrated voltage signals # 1 to #n. As shown in FIG. 11, since only a noise signal is input as a reception signal to the integrator that gates on at a sampling timing that does not correspond to the distance to the target, the integrated output of the integrator is the noise component. It becomes an integral value, which is almost half the level of the lower limit and the upper limit of the input. In a sampling timing integrator in which a reflected pulse signal exists, the level of the reflected pulse signal is dominant over noise because the level of the reflected pulse signal is large, and the integration output of the integrator at the sampling timing of only the noise according to the input level. A higher integrated voltage is output. Thus, the determination unit 7 selects four points having a large integrated value, connects two adjacent points with a straight line, sets the intersection P as a peak point of the received signal, and determines the peak point between the transmission timing of the pulse signal and this peak point. The time δ is regarded as the time required for the radar signal to travel to and from the target, and the distance 2D to the target is determined.

The reception level calculating and integrating circuit 5 has the configuration shown in FIG. 12, and performs the function of FIG. 13 similarly to the conventional example. That is, the time of the gate signal input to the switch 5a of the reception level calculation and integration circuit 5 is set to a predetermined time after the transmission of the pulse signal, for example, 10 distance calculation intervals (sampling timing) (distance conversion). At 1
The switch 5a is turned on during that time. As a result, the entire received signal is integrated regardless of where the reflected pulse signal exists during the distance interval of 10 distances, and the magnitude of the received signal level can be determined. FIG. 2 shows the relationship between the integrated output of the receiving level calculating and integrating circuit 5 and the received signal level. From the lower limit of the voltage of only the noise to the upper limit of the voltage at which the input is almost saturated, the output as shown in FIG. , And the received signal level can be estimated. Therefore, the level of the integrated output of the receiving level calculating and integrating circuit 5 is viewed by the determining unit 7, and the integrated voltage output is V1, and thus the received signal level is the threshold 1
A command to increase or decrease the gain of the signal amplifying unit 3 is given to the control unit 80 until the gain becomes constant, and the control unit 80 variably controls the gain of the signal amplifying unit 3.

Next, the operation of the integration cycle variable section 12 will be described. The integration cycle variable unit 12 variably adjusts the conduction period of the analog switch 4c of each integrator of the distance calculation integration circuit 4 in response to the integration cycle command calculated by the control unit 80 based on the integration output of the reception level calculation integration circuit 5. I do. The operation is as follows. Determined value V of integral output in FIG.
In the case where 1 is used as a reference, as shown in FIG.
Analog switch 4c of each integrator of distance calculation integration circuit 4
Is fixed to Δt0 (= Δf: pulse transmission cycle) which is a basic cycle. However, when the integration output of the reception level calculation integration circuit 5 exceeds V1, the integration cycle Δt corresponding to the integration output level Vx is increased according to the broken line characteristic A shown in FIG. 3, that is, the conduction cycle of each analog switch 4c. Are increased to 2Δf, 3Δf,.

Thus, the operation shown in FIG. 4 is realized. FIG. 4 shows a third integrator # 3 of the distance calculating / integrating circuit 4.
When the integrated output of the reception level calculation integration circuit 5 is equal to or less than V1, the control unit 80 gives a basic cycle command to the integration cycle variable unit 12, and the integration cycle variable unit 12 The conduction period of the analog switch 4c of each integrator of the integration circuit 4 is set to the basic period Δt0 (= Δf), and the gate of the analog switch 4c of each integrator is turned on at the same period (3) as the pulse signal transmission period (1). Perform control.
However, if the received signal level rises sharply and the integrated output of the reception level calculation integration circuit 5 rises, the control unit 8
0 changes the gate ON cycle (conduction cycle) Δt of the analog switch 4c of each integrator of the distance calculation integration circuit 4 corresponding to the integration output Vx based on the broken line characteristic A of FIG. , The conduction period Δt. Therefore, the integration cycle variable section 12 performs the gate ON control of the analog switch 4c of each integrator every conduction cycle (5) of the designated Δt, and performs control to suppress the integration output of each integrator of the distance calculation integration circuit 4. .

In this way, first, each integrator of the distance calculating and integrating circuit 4 is prevented from being saturated. After that, the control section 80 controls the receiving signal level so that the integrated output of the receiving level calculating and integrating circuit 5 becomes the initial level V1. Control is performed to reduce the gain of the signal amplifying unit 3 in order to suppress the above. When the integration output of the reception level calculation integration circuit 5 becomes the reference level V1, the control section 80 gives a command to return the gate ON cycle to the basic cycle Δt0 to the integration cycle variable section 12, and the integration cycle variable section 12 performs the distance calculation integration circuit. The gate of the analog switch 4c of each of the integrators 4 is controlled in the basic cycle. Therefore, the relationship between the integration cycle control and the gain control is as shown in FIG. 5, and during the period τ1 during which the integration output of the reception level calculation integration circuit 5 is V1, the integration cycle variable section 12 sets the distance calculation integration circuit 4 to the basic cycle. Integral gate control is performed at Δt0, and when the integrated output of the reception level calculation and integration circuit 5 becomes Vx during the period τ2, the integration gate cycle of the distance calculation and integration circuit 4 is changed to Δt, and the integration output of the reception level calculation and integration circuit 5 is changed to Δt. Period τ3 while maintaining Vx
However, the same integration gate period Δt is maintained. However, if the integrated output of the reception level calculating and integrating circuit 5 returns to V1 in the period τ4, control is performed to return to the basic period Δt0 in the next period τ5. Here, when the integration output of the reception level calculation integration circuit 5 becomes Vx again, the integration gate cycle of the distance calculation integration circuit 4 is changed to Δt again.

As shown in the period τ7 to τ10, while the integration output of the reception level calculation integration circuit 5 is maintaining Vx, the integration gate cycle of the distance calculation integration circuit 4 is maintained at Δt, as shown in FIG. As described above, the distance calculation integration circuit 4 is controlled to perform the distance calculation integration once each time the pulse signal transmission operation is performed three times with a period three times as long as the basic period (= 3Δt0 = 3Δf). Prevent integrator saturation.

As described above, in the vehicular radar apparatus according to the first embodiment, when the received signal level of the reflected pulse signal receiving section 2 is high, each of the distance calculating / integrating circuits 4 is set in accordance with the received signal level. Increasing the integration gate control period of the integrator can prevent the integrator from saturating, and return the integration gate control to the basic period when the received signal level reaches an appropriate height by adjusting the gain. Therefore, the distance to the target can always be determined accurately.

Next, a second embodiment of the present invention will be described with reference to FIGS.
A description will be given based on FIG. In the vehicle radar device according to the first embodiment, the integration gate period of each integrator of the distance calculation integration circuit is variably adjusted according to the magnitude of the integration output of the reception level integration circuit. The vehicle radar apparatus according to the aspect is characterized in that a peak value of a received signal level is obtained, and the integration gate period of each integrator of the distance calculation integration circuit is variably adjusted according to the magnitude.

FIG. 6 shows a functional configuration of a vehicle radar device according to a second embodiment of the present invention. The vehicle radar device of this embodiment has the same pulse signal transmitting unit 1 as that of the first embodiment. , A reflected pulse signal receiving unit 2, a signal amplifying unit 3, a distance calculating and integrating circuit 4, an A / D converting unit 6, and a determining unit 7. As a feature of the vehicle radar device according to the second embodiment, a reception level peak detection unit 13 is provided instead of the reception level calculation and integration circuit 5 according to the first embodiment shown in FIG. The control section 81 adjusts the gain of the signal amplification section 3 and the integration cycle of the integration cycle variable section 12 based on the peak voltage detected by the reception level peak detection section 13.

The reception level peak detector 13 receives the signal of the reflected pulse signal receiver 2 through the signal amplifier 3 and detects the peak of the received signal. And outputs it to the control unit 81. Based on the polygonal line characteristic B shown in FIG. 7, the control unit 81 instructs the integration cycle variable unit 12 on the integration gate cycle of the fundamental frequency Δt0 if it is equal to or less than V1 with respect to the magnitude of the peak voltage value of the received signal. Peak voltage value Vx exceeding voltage V1
If so, the corresponding integration gate period Δt is indicated. The integration cycle variable section 12 controls the gate ON cycle of the analog switch 4c of each integrator of the distance calculation integration circuit 4 to be equal to the integration gate cycle Δt. To prevent each of the integrators from saturating. Then, the control unit 81 suppresses the level of the received signal by lowering the gain of the signal amplifying unit 3 and, when the peak voltage of the received signal becomes V1 or less, instructs the integration cycle variable unit 12 to return to the basic cycle Δt0.

As described above, in the vehicular radar apparatus according to the second embodiment, when the received signal peak of the reflected pulse signal receiving section 2 is high, each of the distance calculating and integrating circuits 4 according to the received signal peak voltage. Increasing the integration gate control period of the integrator can prevent the integrator from saturating, and return the integration gate control to the basic period when the received signal peak reaches an appropriate height by adjusting the gain. Therefore, the distance to the target can always be determined accurately.

As shown in FIG. 8, a plurality of peaks P1, P1 appear in the received signal (2) because there are reflected pulse signals that are reflected and returned to a plurality of targets having different distances.
Since P2 may be included, the reception level peak detection unit 13 detects the peak P1 that first appears from the pulse signal transmission timing and outputs the peak voltage, so that especially the target located at the closest distance is detected. Can be determined, and the received signal gain can be controlled.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between an input signal level and an integrated output when gate control is not performed on each integrator of the distance calculation and integration circuit.

FIG. 3 is an operation characteristic diagram of the integration period variable section in the embodiment.

FIG. 4 is a timing chart showing an operation of the embodiment.

FIG. 5 is a timing chart of an integration cycle variable operation of the distance calculation integration circuit in the embodiment.

FIG. 6 is a circuit block diagram according to a second embodiment of the present invention.

FIG. 7 is an operation characteristic diagram of the integration period variable section in the embodiment.

FIG. 8 is a timing chart showing operation characteristics of a reception level peak detection unit according to the embodiment.

FIG. 9 is a circuit block diagram of a conventional example.

FIG. 10 is a circuit diagram showing an internal configuration of a distance calculation and integration circuit in the conventional example.

FIG. 11 is a timing chart showing the operation of the conventional example.

FIG. 12 is a circuit diagram showing an internal configuration of a reception level calculation and integration circuit in the conventional example.

FIG. 13 is a timing chart showing the operation characteristics of the reception level calculation and integration circuit.

FIG. 14 is a graph showing a control characteristic of a received signal gain of the conventional example.

FIG. 15 is an explanatory diagram showing a situation where a pulse signal is reflected on a reflector of a preceding vehicle.

FIG. 16 is a timing chart showing a saturation operation of the distance calculation and integration circuit in the conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pulse signal sending section 2 reflected pulse signal receiving section 3 signal amplifying section 4 distance calculating and integrating circuit 5 receiving level calculating and integrating circuit 6 A / D converter 7 determining section 12 integration cycle variable section 13 receiving level peak detecting section 80 control section 81 Control unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01S ⁷ /00-7/42 G01S 13/00-13/95

Claims (2)

(57) [Claims] 1. A pulse signal transmitting means for transmitting a distance measuring pulse signal at predetermined intervals, and a reflected pulse signal receiving means for receiving a reflected pulse signal from which the distance measuring pulse signal is reflected by a target and returns. An analog switch and a resistive capacitor for integrating a received signal of the reflected pulse signal receiving means by a predetermined integration time at each of a plurality of different sampling timings corresponding to a plurality of discrete distances from the pulse signal transmitting means. A plurality of distance calculating integrating means, a distance determining means for calculating a distance to the target based on an integrated output of each of the plurality of distance calculating integrating means, and a received signal of the reflected pulse signal receiving means. A receiving level calculating integration means for integrating for a predetermined integration time; and an integrated output of the receiving level calculating integration means, and Gain adjustment means for adjusting the conduction cycle of the analog switch of each of the plurality of distance calculation integration means while observing the integrated output of the reception level calculation integration means. Vehicle radar device. 2. A pulse signal transmitting means for transmitting a distance measuring pulse signal at predetermined intervals, and a reflected pulse signal receiving means for receiving a reflected pulse signal from which the distance measuring pulse signal is reflected by a target and returns. An analog switch and a resistive capacitor for integrating a received signal of the reflected pulse signal receiving means by a predetermined integration time at each of a plurality of different sampling timings corresponding to a plurality of discrete distances from the pulse signal transmitting means. A plurality of distance calculation integration means, a distance determination means for calculating a distance to the target based on an integrated output of each of the plurality of distance calculation integration means, and a reception signal of the reflected pulse signal reception means. Receiving level peak detecting means for detecting a peak value; and receiving the signal by looking at a peak value of the received signal detected by the receiving level peak detecting means. Gain adjustment means for adjusting the gain of the signal level; and conduction for adjusting the conduction cycle of the analog switch of each of the plurality of distance calculation integration means by looking at the peak value of the reception signal detected by the reception level peak detection means. A vehicle radar device comprising: a period adjusting unit.