JPH08304550A - Radar equipment - Google Patents

Abstract

PURPOSE: To obtain a radar equipment being improved in a distance of detection of a target and the accuracy of detection thereof under weather conditions such as rain or fog, with the safety for eyes maintained, regarding the radar equipment detecting the target by transmitting light. CONSTITUTION: This equipment has a light-transmitting means 1 for transmitting a laser light to a prescribed coverage, a lightreceiving means 2 for receiving the light in a prescribed visual field area and a target detecting means 3 for detecting a target reflecting the laser light on the basis of the light received by the light-receiving means 2. The area wherein the coverage and the visual field area overlap each other is limited to the area wherein a scattered light generated on the occasion when the laser light is scattered by raindrops or fog is at a prescribed allowable level or below, in this constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar apparatus for transmitting light to detect a target, and more particularly to a radar having an improved detection ability by reducing the amount of scattered light received by raindrops or fog. Regarding the device.

[0002]

2. Description of the Related Art In recent years, in automobiles and automatic guided vehicles, a radar device has been developed which emits a laser beam or other light in the traveling direction to detect a preceding vehicle, obstacles or other targets.
In such a radar device, since the laser light is greatly attenuated by the influence of rain, fog, and other atmospheric phenomena, it is difficult to exhibit normal detection capability.

Therefore, there is known a radar device which detects a raindrop or a fog and narrows the beam width of the laser light or increases the number of beams to compensate for the propagation loss of the laser light (Japanese Patent Laid-Open No. 5-196735). (Described in the official gazette). In addition, in a radar device that measures scattered light by a scatterer distributed in the distance and detects the distribution of the scatterer (not a strong reflector in the distance), laser light is continuously transmitted to improve measurement efficiency. It is known that a dead zone is provided at a short distance for the purpose of improvement (described in Japanese Patent Publication No. 64-2903).

[0004]

Generally, in a radar device for detecting a strong reflector at a distance, there is a problem that the laser light is scattered and the scattered light is received as a noise component under the weather such as rain and fog. there were.

Since a noise component due to such scattered light is superimposed on the received light output, weak reflected light from a long distance cannot be detected, and the distance at which the target can be detected is shortened under rain or fog weather. There was a problem. Further, since the noise component due to scattered light reduces the SN ratio of the received light output, there is a problem that the ranging accuracy and other detection accuracy are significantly reduced in rainy or foggy weather.

Further, as in the radar device disclosed in Japanese Patent Laid-Open No. 5-196735, in order to compensate for the propagation loss of laser light due to raindrops, the beam width of laser light can be narrowed,
When the number of beams is increased, there is a problem that the safety when the laser light enters the human eye is lowered. The present invention
In order to solve the above-mentioned problems, it is an object of the present invention to provide a radar device that improves the detection distance and detection accuracy of a target under weather conditions such as rain and fog while maintaining eye safety. .

[0007]

FIG. 1 is a principle block diagram corresponding to the first aspect. The invention according to claim 1 is
A light transmitting means 1 for transmitting the laser light to a predetermined coverage area, a light receiving means 2 for receiving the light in the predetermined visual field area, and a target reflecting the laser light based on the light received by the light receiving means 2. In the radar device including the target detecting means 3 for detecting
It is characterized in that the area where the covering area and the field of view intersect is limited to an area where the scattered light generated when the laser light is scattered by raindrops or fog is below a predetermined allowable level.

FIG. 2 is a principle block diagram corresponding to claims 2-5. The invention according to claim 2 is based on the light transmitting means 1 for transmitting the laser light to a predetermined coverage area, the light receiving means 2 for receiving the light in the predetermined visual field area, and the light received by the light receiving means 2. Of the amount of raindrops or fog detected by the environment detection unit 4 and the environment detection unit 4 for detecting the amount of raindrops or fog in the atmosphere. The geometrical efficiency changing means 5 for moving away the area where the coverage area and the visual field intersect with each other according to the increase is provided.

According to a third aspect of the present invention, in the radar apparatus according to the second aspect, the geometrical efficiency changing means 5 receives the light receiving means in accordance with an increase in the amount of raindrops or fog detected by the environment detecting means 4. The light receiving angle of 2 is narrowed. According to a fourth aspect of the present invention, in the radar apparatus according to the second aspect, the geometrical efficiency changing means 5 operates as the light transmitting means 1 in accordance with an increase in the amount of raindrops or fog detected by the environment detecting means 4. It is characterized in that the arrangement interval with the light receiving means 2 is widened.

According to a fifth aspect of the present invention, in the radar apparatus according to the second aspect, the geometrical efficiency changing means 5 transmits light in accordance with an increase in the amount of raindrops or fog detected by the environment detecting means 4. It is characterized in that the angle formed by the emitting direction of the laser light in the means 1 and the light receiving direction of the light receiving means 2 is widened.

[0011]

In the radar device according to the first aspect, the laser light is transmitted from the light transmitting means 1 to the predetermined coverage area. This laser light
Scattered by scatterers such as raindrops and fog that are present within the prescribed coverage area.

The light-receiving means 2 has a region (hatched portion shown in FIG. 1) in the covered area in which the scattered light is equal to or lower than a predetermined allowable level.
Only the field of view is included. Therefore, in the light receiving means 2,
The reflected light generated by the laser light being reflected by the target and the scattered light below the allowable level are received. In this way, scattered light exceeding the allowable level is blocked, so weak reflected light from a distance is detected, and the distance of the detectable target is extended.

Further, since the scattered light exceeding the allowable level is blocked, the noise component of the received light output caused by the scattered light is reduced, and the distance measuring accuracy and other detection accuracy are improved. The predetermined allowable level is, for example, a value determined from design values such as the distance and reflectance of the detectable target, and is set to a level smaller than the reflected light from the detectable target.

In the radar device of the second aspect, the environment detecting means 4 detects the amount of raindrops or fog in the atmosphere. The geometric efficiency changing means 5 moves away the area where the coverage area of the light transmitting means 1 and the visual field area of the light receiving means 2 intersect with each other as the amount of raindrops or fog increases. In this way, the scattered light generated in the vicinity of the radar device is not received by the light receiving means 2 because the area where the coverage area and the field of view intersect is moved away.

In general, scattered light due to raindrops or fog has a wider radiation angle than that of reflected light due to a target, and therefore spreads and a large loss occurs. Therefore, the scattered light exceeding the allowable level when detecting the reflected light from the target is generated only in the vicinity of the light receiving means 2. Therefore, depending on the amount of raindrops or fog, by blocking scattered light generated in the vicinity of the radar device, the incident level of scattered light is significantly reduced,
Weak reflected light generated at a distance can be detected.

Further, in fine weather, the area where the coverage area and the visual field area intersect is brought close to each other, so that the range for detecting the target is expanded to the vicinity. In the radar apparatus according to claim 3, the geometrical efficiency changing means 5 narrows the light receiving angle of the light receiving means 2 as the amount of raindrops or fog increases, so that the coverage area of the light transmitting means 1 and the field of view of the light receiving means 2 are reduced. Move away from the area that intersects with the area.

Generally, as described in Japanese Patent Application Laid-Open No. 5-196735, by narrowing the beam width of the light transmitting means 1, it is possible to move away the area where the coverage area and the viewing area intersect. However, the beam width is often set narrowly in advance in order to reduce the spread loss of the laser light, and it is possible to effectively distance the area where the coverage area and the viewing area intersect, compared with the case where the light receiving angle is narrowed. Have difficulty.

Further, when the beam width is narrowed, the amount of light per radiating area increases, so that the amount of scattered light generated in the area where the coverage area and the field of view intersect also increases. Therefore, the effect of reducing scattered light is lower than in the case of narrowing the light receiving angle.
In the radar apparatus according to claim 4, the geometric efficiency changing means 5
However, by increasing the arrangement interval between the light transmitting means 1 and the light receiving means 2 as the amount of raindrops or fog increases, the area where the coverage area of the light transmitting means 1 and the visual field area of the light receiving means 2 intersect is moved away.

Since the scattered light from the vicinity is blocked in this way, the light receiving angle of the light receiving means 2 does not change, and the lateral range for detecting the target is not narrowed. In the radar apparatus according to claim 5, the geometrical efficiency changing means 5 increases the amount of raindrops or fog, and the emission direction of the light transmitting means 1 and the light receiving means 2 are increased.
By widening the angle formed by the light receiving direction of 1, the area where the coverage area of the light transmitting means 1 and the visual field area of the light receiving means 2 intersect is moved away.

Since the scattered light from the vicinity is blocked in this way, the light receiving angle of the light receiving means 2 does not change, and the lateral range for detecting the target is not narrowed.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a diagram showing a first embodiment corresponding to the first aspect. In the figure, the arithmetic and control unit 11 is connected to the time measuring unit 12, and the control output of the time measuring unit 12 is connected to the laser diode driving unit 13. The drive output of the laser diode drive unit 13 is the laser diode 1
4 and the time measuring unit 12, a light sending optical system 15 is arranged on the optical axis of the light emitting surface of the laser diode 14.

On the other hand, a light receiving optical system 16 is arranged at a position adjacent to the light transmitting optical system 15, and a diaphragm 17 is arranged at a position close to the image forming position in the light receiving optical system 16. The diameter of the diaphragm 17 is adjusted in advance so as to exclude, from the field of view, a region where scattered light due to raindrops or fog exceeds an allowable level within the coverage of the transmitted laser light. Further, the light receiving surface of the light receiving element 18 is arranged on the optical axis of the light receiving optical system 16, and the light receiving output of the light receiving element 18 is connected to the time measuring section 12 via the amplifier 19.

Regarding the correspondence relationship between the invention according to claim 1 and the first embodiment, the light sending means 1 corresponds to the laser diode driving section 13, the laser diode 14 and the light sending optical system 15, and receives light. The means 2 is a light receiving optical system 16 and a diaphragm 1.
7 and the light receiving element 18, and the target detecting means 3 corresponds to the time measuring unit 12 and the arithmetic and control unit 11. Less than,
The operation of the first embodiment will be described.

First, the laser diode drive section 13 excites the laser diode 14 to generate laser light. This laser light is sent to the outside via the light sending optical system 15. The laser light thus sent to the outside is scattered by raindrops, fog, etc. existing in the covered area. Of this scattered light, scattered light exceeding the allowable level is blocked by the diaphragm 17 and is not received by the light receiving element 18.

Therefore, the light receiving element 18 receives the scattered light below the allowable level generated in the area where the covering area and the visual field overlap, and the reflected light from the target object located in that area. The light thus received is photoelectrically converted by the light receiving element 18, and passed through the amplifier 19 to the time measuring unit 1.
Entered in 2.

The time measuring unit 12 measures the propagation delay from the transmission of the laser light to the reception of the reflected light, and outputs it to the arithmetic and control unit 11. The arithmetic and control unit 11 calculates the distance to the target based on this propagation delay.

As described above, in the radar apparatus according to the first embodiment, the scattered light exceeding the permissible level is blocked by the diaphragm 17, so weak reflected light from a distance is detected, and the distance of the detectable target is detected. Can be extended. Further, since the S / N ratio of the received light output is increased by blocking the scattered light exceeding the allowable level, the phase fluctuation of the received light output due to the noise component is reduced and the distance measurement accuracy can be improved.

Next, another embodiment will be described. FIG.
FIG. 8 is a diagram showing a second embodiment corresponding to claims 2 and 3. Regarding the structural feature of the second embodiment, a known raindrop sensor 21 that detects the amount of raindrops and a known fog sensor 22 that detects the amount of fog are connected to the arithmetic and control unit 11. Further, a diaphragm control unit 23 that drives the diaphragm 17 to open and close.
Is arranged, and the control output of the arithmetic and control unit 11 is connected to the control input of the aperture control unit 23.

The same components as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted. Regarding the correspondence relationship between the invention described in claims 2 and 3 and the second embodiment, the light transmitting means 1 corresponds to the laser diode driving section 13, the laser diode 14 and the light transmitting optical system 15, and the light receiving means. Reference numeral 2 corresponds to the light receiving optical system 16, diaphragm 17 and light receiving element 18, target object detecting means 3 corresponds to the time measuring unit 12 and the arithmetic and control unit 11, and environment detecting means 4 corresponds to the raindrop sensor 21 and the fog sensor 22. The geometrical efficiency changing means 5 corresponds to the arithmetic and control unit 11 and the diaphragm control unit 23.

FIG. 5 is a flow chart showing the operation of the second embodiment. The operation of the second embodiment will be described below with reference to these figures. First, the arithmetic and control unit 11 fetches the amount of raindrops from the raindrop sensor 21 (step S1) and fetches the amount of fog from the fog sensor 22 (step S2). Also,
The arithmetic and control unit 11 controls the aperture 17 via the aperture controller 23.
Is fully opened (step S3).

In this state, when the amount of these raindrops or fog does not exceed the predetermined threshold value (step S3), the arithmetic and control unit 11 leaves the diaphragm 17 fully open,
The distance measurement operation after step S8 is performed. On the other hand, when the amount of raindrops or fog becomes equal to or less than the threshold value (step S3), the arithmetic and control unit 11 narrows the diaphragm 17 via the diaphragm controller 23 (step S4).

That is, the arithmetic and control unit 11 first preliminarily sends a laser beam from the laser diode 14 and receives the scattered light generated in the vicinity for a predetermined period of time, thereby receiving the light receiving element 18.
The output level of is observed to measure the "amount of light received from the vicinity" (step S5). The arithmetic and control unit 11 gradually narrows the diaphragm 17 until the amount of light received from this vicinity becomes equal to or less than a predetermined allowable value (steps S6 and S7).

In this way, by narrowing the diaphragm 17,
The light receiving angle of the light receiving element 18 is narrowed. Therefore, FIG.
As shown in, the area where the light-transmitting side coverage area and the light-receiving side visual field area intersect is moved away, and the amount of light received from the vicinity is appropriately reduced. In this state, the time measuring unit 12 measures the propagation delay from the transmission of the laser light to the reception of the reflected light (steps S8 and S9), and outputs it to the arithmetic and control unit 11. The arithmetic and control unit 11 calculates the distance to the target based on this propagation delay (step S10).

In general, the scattered light due to raindrops or fog has a larger radiation angle than the light reflected by the target, and therefore spreads greatly depending on the propagation distance. Therefore,
By stopping the stop 17 to block the light from the vicinity of the radar device, the incident level of scattered light can be significantly reduced. As described above, in the radar device according to the second embodiment, the area where the coverage area on the light-transmitting side and the visual field area on the light-receiving side intersect is moved away depending on the amount of raindrops or fog. The incident level of scattered light can be appropriately reduced.

Therefore, weak reflected light from a distance can be detected, and the detection distance of the target under the weather such as rain or fog can be extended. Further, by reducing the incident level of scattered light, the S / N ratio of the received light output becomes high, so that the distance measurement accuracy and other detection accuracy under the weather such as rain and fog can be improved.

Further, in fine weather, when the diaphragm 17 is opened, the area where the coverage area on the light transmitting side and the visual field area on the light receiving side intersect is approached, so the range for detecting the target is not narrowed, and the vicinity is close. Targets can be detected over a wide range from to distant place. Next, another embodiment will be described.
FIG. 7 is a diagram showing a third embodiment corresponding to claims 2 and 3.

The structure of the third embodiment is characterized in that a light receiving element position control unit 31 for driving the position of the light receiving element 18 back and forth is arranged, and the arithmetic control unit is used as a control input of the light receiving element position control unit 31. 11 control outputs are connected.
The same components as those shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted.

Further, regarding the correspondence relationship between the invention described in claims 2 and 3 and the third embodiment, the light transmitting means 1 corresponds to the laser diode driving section 13, the laser diode 14 and the light transmitting optical system 15. The light receiving means 2 corresponds to the light receiving optical system 16 and the light receiving element 18, the target detecting means 3 corresponds to the time measuring section 12 and the arithmetic and control unit 11, and the environment detecting means 4
Corresponds to the raindrop sensor 21 and the fog sensor 22, and the geometrical efficiency changing means 5 corresponds to the arithmetic and control unit 11 and the light receiving element position control section 31.

FIG. 8 is an explanatory diagram showing changes in the light receiving angle in the third embodiment. The operation of the third embodiment will be described below with reference to these drawings. First, the arithmetic and control unit 11
Receives the amount of raindrops from the raindrop sensor 21, and further takes in the amount of fog from the fog sensor 22.

The arithmetic and control unit 11 refers to the table in which the moving distance of the light receiving element 18 is set based on the amount of raindrops or fog. In this table, a moving distance that monotonically increases as the amount of raindrops or fog increases is preset. The arithmetic and control unit 11 uses the light-receiving element position control unit 31 to move the light-receiving element 18 by the reference movement distance.
Away from the principal point of the light receiving optical system 16.

Thus, the light receiving element 18 and the light receiving optical system 1
By increasing the distance from the principal point of 6, the light receiving angle of the light receiving element 18 is narrowed as shown in FIG. 8, and as described above in the second embodiment, the coverage area on the light transmitting side and the light receiving side are received. The area where the side visual fields intersect is moved away. Therefore, also in the third embodiment, the same effect as in the second embodiment can be obtained.

Next, another embodiment will be described. Figure 9
FIG. 8 is a diagram showing a fourth embodiment corresponding to claims 2 and 4. Regarding the structural feature of the fourth embodiment, the light receiving element 18 and the light receiving optical system 16 are fixedly provided in the light receiving block 41, and the arrangement interval control section 42 for driving the light receiving block 41 left and right is arranged. . The control output of the arithmetic and control unit 11 is connected to the control input of the arrangement interval control unit 42.

The same components as those shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted. Regarding the correspondence relationship between the invention according to claims 2 and 4 and the fourth embodiment, the light transmitting means 1 corresponds to the laser diode drive section 13, the laser diode 14 and the light transmitting optical system 15, and the light receiving means. 2 corresponds to the light receiving optical system 16 and the light receiving element 18, the target detecting means 3 corresponds to the time measuring section 12 and the arithmetic and control unit 11, and the environment detecting means 4
Corresponds to the raindrop sensor 21 and the fog sensor 22, and the geometrical efficiency changing means 5 corresponds to the arithmetic control unit 11 and the arrangement interval control unit 42.

FIG. 10 is an explanatory diagram showing changes in the detection area in the fourth embodiment. The operation of the fourth embodiment will be described below with reference to these figures. First, the arithmetic and control unit 11 takes in the amount of raindrops from the raindrop sensor 21, and further takes in the amount of fog from the fog sensor 22. The arithmetic and control unit 11 refers to a table in which the moving distance of the light receiving block 41 is set based on the amount of these raindrops or fog. In this table, a moving distance that monotonically increases as the amount of raindrops or fog increases is preset.

The arithmetic and control unit 11 includes an arrangement interval control unit 42.
The light-receiving block 41 is moved away from the light-transmitting optical system 15 by the reference movement distance. In this way, by widening the arrangement interval between the light-transmitting side and the light-receiving side, as shown in FIG. 10, the area where the light-transmitting-side covering area and the light-receiving-side visual field intersect is moved away. Therefore, also in the fourth embodiment, the same effect as in the second embodiment can be obtained.

Next, another embodiment will be described. FIG.
FIG. 1 is a diagram showing a fifth embodiment corresponding to claims 2 and 5. Regarding the structural features of the fifth embodiment,
A tilt control unit 51 for driving the light receiving optical system 16 to the left and right is arranged. The control output of the arithmetic and control unit 11 is connected to the control input of the tilt control unit 51.

The same components as those shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted. Regarding the correspondence relationship between the invention according to claims 2 and 5 and the fifth embodiment, the light transmitting means 1 corresponds to the laser diode driving section 13, the laser diode 14 and the light transmitting optical system 15, and the light receiving means. 2 corresponds to the light receiving optical system 16 and the light receiving element 18, the target detecting means 3 corresponds to the time measuring section 12 and the arithmetic and control unit 11, and the environment detecting means 4
Corresponds to the raindrop sensor 21 and the fog sensor 22, and the geometric efficiency changing means 5 corresponds to the arithmetic and control unit 11 and the tilt control unit 51.

FIG. 12 is an explanatory diagram showing changes in the detection area due to tilting in the fifth embodiment. The operation of the fifth embodiment will be described below with reference to these figures. First,
The arithmetic and control unit 11 takes in the amount of raindrops from the raindrop sensor 21, and further takes in the amount of fog from the fog sensor 22.

The arithmetic and control unit 11 refers to a table in which the moving distance of the light receiving optical system 16 is set based on the amount of raindrops or fog. In this table, a moving distance that monotonically increases as the amount of raindrops or fog increases is preset. The arithmetic and control unit 11 includes the tilt control unit 5
The light-receiving optical system 16 is moved away from the light-transmitting optical system 15 by the reference moving distance via 1. In this way, the light receiving optical system 1
By shifting 6 from the light receiving axis of the light receiving element 18, tilting is applied to the light receiving direction on the receiving side to widen the angle formed with the emitting direction.

In this way, the angle between the emission direction on the light-transmitting side and the light-receiving direction on the light-receiving side is widened, and as shown in FIG. Can be kept away. Therefore, also in the fifth embodiment, the same effect as that of the second embodiment can be obtained.

In the above embodiment, the radar device for measuring the distance to the target has been described, but the present invention is not limited to this, and a radar device for detecting the presence or absence of the target may be used. Further, in the above-described embodiment, the raindrop sensor 21 and the fog sensor 22 are used to measure the amounts of raindrops and fog, but the present invention is not limited to this configuration.
For example, a measuring unit that measures the propagation loss of reflected light and a calculating unit that calculates the amount of raindrops or fog based on the propagation loss may be provided.

Further, although the diaphragm 17 is used in the first and second embodiments, the invention is not limited to this configuration, and a shielding plate for shielding the visual field of the light receiving element 18 may be provided. Further, although the light receiving element 18 is moved back and forth in the third embodiment, the present invention is not limited to this, and the principal point position of the light receiving optical system 16 may be moved back and forth.

Further, in the fourth embodiment, the light receiving side is moved left and right, but the present invention is not limited to this, and the light transmitting side may be moved left and right. Further, in the fifth embodiment, the tilt on the light receiving side is changed, but the invention is not limited to this, and the tilt on the light transmitting side may be changed. Further, in the fifth embodiment, the tilt is changed to tilt the light receiving direction, but the present invention is not limited to this, and the light receiving element 18 and the light receiving optical system 16 are integrally rotated to receive light. The direction may be tilted, or the light sending direction may be tilted by integrally rotating the laser diode 14 and the light sending optical system 15.

[0055]

As described above, according to the first aspect of the invention, the area where the coverage area and the visual field area intersect is limited to the area where the scattered light is below the allowable level. It is possible to detect light and extend the distance of a detectable target. Further, since the scattered light exceeding the allowable level is blocked, the noise component included in the light receiving output of the light receiving means 2 is reduced, and the distance measuring accuracy and other detection accuracy can be improved.

Further, since the amount of laser light per radiated area is not increased, the safety to the eyes can be maintained. In the invention according to claim 2, since the area where the coverage area and the viewing area intersect is moved away according to the amount of raindrops or fog, only scattered light with a large spread loss is received,
The incident level of scattered light can be reduced.

Therefore, under the weather such as rain or fog, faint reflected light from a distance can be detected, and the detection distance of the target can be extended. Further, since the incident level of the scattered light is reduced in this way, the SN ratio of the received light output is increased, so that the ranging accuracy and other detection accuracy can be improved. Furthermore, in fine weather, since the area where the coverage area and the visual field area intersect is brought close to each other, the range for detecting the target is not narrowed, and the target can be detected over a wide range from near to far.

Further, since the amount of laser light per radiated area is not increased, sufficient safety for eyes can be obtained. In the invention according to claim 3, since the geometric efficiency changing means narrows the light receiving angle of the light receiving means as the amount of raindrops or fog increases, it is possible to effectively distance the area where the covered area and the visual field intersect. it can.

In the fourth aspect of the invention, the geometrical efficiency changing means widens the arrangement interval between the light transmitting means and the light receiving means in accordance with the increase in the amount of raindrops or fog, so that the coverage area and the visual field area intersect. You can move the area away. Since the scattered light from the vicinity is blocked in this manner, the light receiving angle of the light receiving means does not change, and a wide target detection range can be secured in the lateral direction under the weather such as rain or fog.

In the fifth aspect of the invention, the geometrical efficiency changing means widens the angle formed by the emitting direction of the light transmitting means and the light receiving direction of the light receiving means in accordance with the increase in the amount of raindrops or fog. The area where the coverage area and the visual field intersect can be effectively distanced. In this way, since the scattered light from the vicinity is blocked, the light receiving angle of the light receiving means does not change, and a wide range for detecting the target can be secured in the lateral direction under the weather such as rain or fog.

As described above, in the radar device to which the present invention is applied, it is possible to improve the detection distance and the detection accuracy of the target under the weather such as rain and fog while ensuring high safety for the eyes. Therefore, a safe and high-performance radar device can be realized.

[Brief description of drawings]

1 is a principle block diagram corresponding to claim 1. FIG.

FIG. 2 is a principle block diagram corresponding to claims 2 to 5.

FIG. 3 is a diagram showing a first embodiment corresponding to claim 1;

FIG. 4 is a diagram showing a second embodiment corresponding to claims 2 and 3;

FIG. 5 is a flowchart showing the operation of the second embodiment.

FIG. 6 is an explanatory diagram showing changes in the detection area in the second embodiment.

FIG. 7 is a diagram showing a third embodiment corresponding to claims 2 and 3.

FIG. 8 is an explanatory diagram showing changes in the light receiving angle in the third embodiment.

FIG. 9 is a diagram showing a fourth embodiment corresponding to claims 2 and 4.

FIG. 10 is an explanatory diagram showing changes in the detection area in the fourth embodiment.

FIG. 11 is a diagram showing a fifth embodiment corresponding to claims 2 and 5.

FIG. 12 is an explanatory diagram showing changes in the detection area due to tilting in the fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light transmitting means 2 Light receiving means 3 Target detecting means 4 Environment detecting means 5 Geometrical efficiency changing means 11 Arithmetic control device 12 Time measuring unit 13 Laser diode drive unit 14 Laser diode 15 Light transmitting optical system 16 Light receiving optical system 17 Aperture 18 Light receiving element 19 Amplifier 21 Raindrop sensor 22 Fog sensor 23 Aperture control section 31 Light receiving element position control section 41 Light receiving block 42 Arrangement interval control section 51 Tilt control section

Claims (5)

[Claims] 1. A light transmitting means for transmitting a laser beam to a predetermined coverage area, a light receiving means for receiving a light in a predetermined visual field area, and a laser beam based on the light received by the light receiving means. In a radar device provided with a target detection means for detecting a reflected target, a region where the coverage area and the field of view intersect, scattered light generated when the laser light is scattered by raindrops or fog is predetermined. A radar device characterized by being limited to an area below an allowable level. 2. A light transmitting means for transmitting a laser beam to a predetermined coverage area, a light receiving means for receiving a light in a predetermined visual field area, and a laser beam based on the light received by the light receiving means. Target detection means for detecting the reflected target, environment detection means for detecting the amount of raindrops or fog in the atmosphere, and the coverage area according to the increase in the amount of raindrops or fog detected by the environment detection means A radar device, comprising: geometric efficiency changing means for moving away a region where the visual fields intersect. 3. The radar device according to claim 2, wherein the geometric efficiency changing means narrows a light receiving angle of the light receiving means in accordance with an increase in the amount of raindrops or fog detected by the environment detecting means. A radar device characterized by. 4. The radar device according to claim 2, wherein the geometrical efficiency changing means includes the light transmitting means and the light receiving means in accordance with an increase in the amount of raindrops or fog detected by the environment detecting means. A radar device characterized by widening the arrangement interval of the. 5. The radar device according to claim 2, wherein the geometrical efficiency changing means emits laser light from the light transmitting means in accordance with an increase in the amount of raindrops or fog detected by the environment detecting means. A radar device, characterized in that an angle formed between a direction and a light receiving direction of light in the light receiving means is widened.